Photovoltaic ribbon, photovoltaic ribbon forming method, solar cell string and photovoltaic module

Abstract

This application relates to a photovoltaic (PV) welding ribbon, a method for forming the PV welding ribbon, a solar cell string, and a PV module. The PV welding ribbon includes: a first welding wire, one end of which has a first connecting segment, and the outer surface of the first welding wire has a first reflective surface and a first mounting surface; and a second welding wire, one end of which has a second connecting segment; wherein the first connecting segment and / or the second connecting segment are flattened, and the first connecting segment and the second connecting segment are stacked to form an overlapping segment. The PV welding ribbon can be connected to the front side of the preceding solar cell through the first mounting surface of the first welding wire, and to the back side of the adjacent following solar cell through the second welding wire. Thus, the PV welding ribbon adopts a segmented structural design, eliminating the need for flattening or twisting by 180°, reducing the manufacturing difficulty of the PV welding ribbon, increasing the bifaciality of the PV module, and also reducing the distance between adjacent components, thereby improving the efficiency of the PV module.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a photovoltaic ribbon, a photovoltaic ribbon forming method, a solar cell string, and a photovoltaic module. Background Technology

[0002] Photovoltaic modules are the most important part of a photovoltaic power generation system. Their function is to convert solar energy into electrical energy to power loads. The basic unit of a photovoltaic module is the solar cell, which is connected in series by solder ribbons. A single solar cell string cannot be used directly as a power source; several individual solar cell strings must be connected in parallel and tightly sealed to form a photovoltaic module.

[0003] With the rapid increase in market penetration of bifacial photovoltaic modules, the performance of their core component, the interconnecting ribbon, needs to match the demands of bifacial power generation. Currently, irregularly shaped ribbons are used to connect the front and back of adjacent cells, i.e., a composite form of front welding wire (enhanced light capture) + back welding wire (low-resistance interconnection).

[0004] Typically, an irregularly shaped solder ribbon is a complete triangular solder ribbon. When connecting the front and back of adjacent solar cells, the base of the triangular solder ribbon is placed on the front of the solar cell, and the top edge of the triangular solder ribbon is placed on the back of the adjacent solar cell. However, when the top edge of the triangular solder ribbon contacts the back of the solar cell, the solar cell may crack.

[0005] To address this, the triangular solder strip on the back of the solar cell can be flattened and then attached to the back of the cell. However, this operation increases the processing difficulty of the irregularly shaped solder strip and also increases the shading area of ​​the solder strip on the back of the solar cell, affecting the bifaciality of the photovoltaic module.

[0006] Alternatively, the triangular solder strip can be twisted 180° so that its base is positioned on the back of the solar cell. However, this method is technically challenging and cannot accurately ensure that the base of the triangular solder strip is aligned with the back of the solar cell. Furthermore, the 180° twist will result in a certain length that increases the spacing between adjacent solar cells, reducing the efficiency of the photovoltaic module. Summary of the Invention

[0007] Therefore, it is necessary to address the problems of high process difficulty and low efficiency in connecting the front and back of adjacent solar cells with a triangular solder strip of irregularly shaped solder strip. A photovoltaic solder strip, photovoltaic solder strip forming method, solar cell string and photovoltaic module are provided, which adopts a segmented structure design to reduce process difficulty and improve the efficiency of photovoltaic module.

[0008] A photovoltaic welding ribbon, comprising:

[0009] A first welding wire, one end of which has a first connecting section, and the outer surface of which has a first reflective surface and a first mounting surface; and

[0010] The second welding wire has a second connecting section at one end;

[0011] The first connecting segment and / or the second connecting segment are arranged in a flat shape, and the first connecting segment and the second connecting segment are stacked to form an overlapping segment. The photovoltaic welding strip can be connected to the front of the previous cell through the first mounting surface of the first welding wire, and connected to the back of the adjacent subsequent cell through the second welding wire.

[0012] In one embodiment of this application, the overlap dimension of the first connecting segment and the second connecting segment along the length direction is greater than or equal to 0.5 mm;

[0013] And / or, the dimension of the overlapping segment along the thickness direction is less than 0.15 mm;

[0014] And / or, the overlapping segment is separated from the front metal electrode of the preceding cell and / or the back metal electrode of the following cell.

[0015] In one embodiment of this application, the first welding wire further includes a first main body segment, and the first connecting segment is disposed at one end of the first main body segment, and the first main body segment can be connected to the front side of the previous battery cell;

[0016] The second welding wire also includes a second main body segment, and the second connecting segment is disposed at one end of the second main body segment. The second main body segment can be connected to the back of the next battery cell.

[0017] In one embodiment of this application, the dimension of the first main body segment along the thickness direction is greater than or equal to the dimension of the second main body segment along the thickness direction;

[0018] And / or, the thickness of the overlapping segment is less than the thickness of the first main segment and / or the second main segment.

[0019] In one embodiment of this application, the cross-sectional shape of the first main body segment is triangular;

[0020] The side length of the first main body segment ranges from 0.1mm to 0.35mm.

[0021] In one embodiment of this application, adjacent sides of the first main body segment are connected by a chamfered portion.

[0022] In one embodiment of this application, the first main body segment further includes a first connecting portion and a second connecting portion. The first connecting portion is disposed on the second connecting portion along the thickness direction. The cross-sectional shape of the first connecting portion is triangular, and the cross-sectional shape of the second connecting portion is rectangular. The second connecting portion is connected to the front side of the preceding battery cell.

[0023] In one embodiment of this application, the cross-sectional shape of the second main body segment is circular, and the diameter of the second main body segment ranges from 0.1 mm to 0.3 mm.

[0024] Alternatively, the cross-sectional shape of the second main body segment is triangular, and the side length of the second main body segment ranges from 0.1mm to 0.35mm.

[0025] In one embodiment of this application, when the cross-sectional shape of the second main body segment is triangular, the second welding wire further includes a second reflective surface and a second mounting surface. The second mounting surface is connected to the back of the subsequent battery cell, and the second reflective surface is used to reflect light on the back of the subsequent battery cell.

[0026] In one embodiment of this application, along the thickness direction, the first connecting segment is located on the upper surface of the second connecting segment, or the first connecting segment is located on the lower surface of the second connecting segment.

[0027] In one embodiment of this application, the first connecting segment and the second connecting segment are welded together.

[0028] In one embodiment of this application, the first connecting segment and the second connecting segment are welded together by laser welding, ultrasonic welding, infrared welding or electric arc welding.

[0029] In one embodiment of this application, the first welding wire includes a first copper substrate, a first welding coating, and a reflective coating. The first welding coating and the reflective coating cover the outer periphery of the first copper substrate. The first welding coating forms the first mounting surface for welding connection with the previous battery cell, and the reflective coating forms the first reflective surface.

[0030] The second welding wire includes a second copper substrate and a second welding coating. The second welding coating covers the outer periphery of the second copper substrate and is welded to the next battery cell.

[0031] In one embodiment of this application, the first welding coating includes a tin-lead alloy coating, a tin-lead-bismuth alloy coating, or a tin-silver alloy coating;

[0032] And / or, the reflective coating includes a silver coating or an aluminum coating;

[0033] And / or, the second welding coating includes a tin-lead alloy coating, a tin-lead-bismuth alloy coating, or a tin-silver alloy coating.

[0034] In one embodiment of this application, the first welding coating includes a tin-lead alloy coating or a tin-lead-bismuth alloy coating, the reflective coating includes an aluminum coating or a silver coating, and when the second welding coating includes a tin-lead alloy coating or a tin-lead-bismuth alloy coating, the overlapping section includes at least tin, lead, and copper elements, and also includes one of aluminum or silver elements.

[0035] In one embodiment of this application, the overlapping segment further includes a first fusion portion, wherein the first welding coating, the reflective coating, and the second welding coating are fused to form the first fusion portion;

[0036] And / or, the overlapping segment further includes a second fusion portion, wherein the first copper substrate and the second copper substrate are fused to form the second fusion portion.

[0037] A method for forming photovoltaic solder ribbon, used to form photovoltaic solder ribbon as described in any of the above technical features, the photovoltaic solder ribbon forming method comprising at least the following steps:

[0038] The first raw material is fed by a first feeding mechanism, and the first raw material is cut by a first wire drawing mechanism to form a first welding wire of a predetermined length. The first welding wire is then fed to the interconnection platform.

[0039] A second feeding mechanism is used to feed the second raw material, and a second wire drawing mechanism is used to cut the second raw material to form a second welding wire of a predetermined length, and then the second welding wire is fed to the interconnection platform;

[0040] The first welding wire and the second welding wire are connected to form the photovoltaic welding strip. The first welding wire can be connected to the front side of the previous cell, and the second welding wire can be connected to the back side of the next cell.

[0041] In one embodiment of this application, connecting the first welding wire and the second welding wire to form the photovoltaic welding ribbon includes at least the following steps:

[0042] One end of the first welding wire is flattened to form a first connecting segment, and one end of the second welding wire is flattened to form a second connecting segment. The first connecting segment and the second connecting segment are connected to form an overlapping segment.

[0043] Alternatively, one end of the first welding wire can be connected to one end of the second welding wire to form an overlapping section, and the overlapping section can be flattened.

[0044] Alternatively, one end of the first welding wire can be flattened to form a first connecting segment, one end of the second welding wire can be flattened to form a second connecting segment, the first connecting segment and the second connecting segment can be connected to form an overlapping segment, and the overlapping segment can be flattened.

[0045] In one embodiment of this application, the first welding wire includes a first copper substrate, a first welding coating, and a reflective coating. The first welding coating and the reflective coating cover the outer periphery of the first copper substrate. The first welding coating forms a first mounting surface, and the reflective coating forms a first reflective surface.

[0046] The second welding wire includes a second copper substrate and a second welding coating, the second welding coating covering the outer periphery of the second copper substrate.

[0047] In one embodiment of this application, connecting the first welding wire and the second welding wire to form the photovoltaic welding ribbon further includes at least the following steps:

[0048] The reflective coating, the first welding coating, and the second welding coating are melted using laser welding, ultrasonic welding, infrared welding, or electric arc welding.

[0049] The first copper substrate and the second copper substrate are welded together.

[0050] In one embodiment of this application, connecting the first welding wire and the second welding wire to form the photovoltaic welding ribbon further includes at least the following steps:

[0051] The reflective coating, the first welding coating, and the second welding coating are fused together between the first copper substrate and the second copper substrate to form a first fused portion;

[0052] And / or, the first copper substrate and the second copper substrate are fused together to form a second fused portion.

[0053] A solar cell string includes a front cell, a rear cell, and a photovoltaic ribbon as described in any of the above technical features;

[0054] The preceding and following solar cells are arranged along the length of the photovoltaic ribbon. The first welding wire of the photovoltaic ribbon is connected to the front of the preceding solar cell, and the second welding wire is connected to the back of the following solar cell, so that the preceding and following solar cells are connected in series.

[0055] In one embodiment of this application, the overlapping section of the photovoltaic ribbon is located on the back side of the subsequent solar cell, and / or the overlapping section of the photovoltaic ribbon is located on the front side of the preceding solar cell;

[0056] When the overlapping segment is located on the front side of the preceding battery cell and the back side of the following battery cell, the length of the overlapping segment on the back side of the following battery cell is greater than the length of the overlapping segment on the front side of the preceding battery cell.

[0057] A photovoltaic module includes at least a cover plate, a back sheet, and a plurality of solar cell strings as described in any of the above technical features;

[0058] Multiple solar cell strings are connected in parallel and / or in series. The cover plate and the back plate are disposed on both sides of the multiple solar cell strings, and the cover plate, the multiple solar cell strings and the back plate are encapsulated to form the photovoltaic module.

[0059] By adopting the above technical solution, this application has at least the following technical effects:

[0060] The photovoltaic ribbon, photovoltaic ribbon forming method, solar cell string, and photovoltaic module of this application, wherein the photovoltaic ribbon has a first connecting segment at one end of a first welding wire and a second connecting segment at one end of a second welding wire, the first connecting segment and / or the second connecting segment being flat, and the first connecting segment of the first welding wire and the second connecting segment of the second welding wire being stacked and connected to form an overlapping segment, so that the photovoltaic ribbon is formed as a whole. The first mounting surface of the first welding wire is connected to the preceding solar cell and reflects light through the first reflective surface, and the second welding wire is connected to the following solar cell, so that the photovoltaic ribbon is connected to the preceding solar cell and the following solar cell.

[0061] This photovoltaic welding ribbon uses a separate first welding wire and a second welding wire. The first welding wire connects to the front of the preceding solar cell, and the second welding wire connects to the back of the preceding solar cell. The first and second welding wires are connected in series via overlapping sections, forming a series connection between the preceding and following solar cells. This segmented design eliminates the need for flattening or twisting the welding wire 180° to connect to the back of the following solar cell, reducing the manufacturing complexity. Furthermore, the second welding wire reflects sunlight from the back of the following solar cell, improving the bifaciality of the photovoltaic module. The overlapping connection between the first and second welding wires also reduces the distance between the preceding and following solar cells, improving the efficiency of the photovoltaic module. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of a photovoltaic solder strip according to an embodiment of this application.

[0063] Figure 2 for Figure 1 The diagram shown illustrates the application of photovoltaic ribbons to a solar cell string from one perspective.

[0064] Figure 3 for Figure 2 The diagram shows a solar cell string from another perspective.

[0065] Figure 4 for Figure 1 The front view showing the disconnected photovoltaic ribbon.

[0066] Figure 5 for Figure 4 The image shows a magnified view of the photovoltaic ribbon at point A.

[0067] Figure 6 for Figure 2 The front view of the solar cell string shown.

[0068] Figure 7 for Figure 6 The diagram shows a disconnected solar cell string.

[0069] Figure 8 for Figure 7 The diagram shows a partial view of the solar cell string at point B.

[0070] Figure 9 for Figure 4 The cross-sectional view of the photovoltaic ribbon shown is along the CC direction.

[0071] Figure 10 for Figure 9 The first deformation diagram of the first main body section cross section is shown.

[0072] Figure 11 for Figure 9 The second deformation diagram of the first main body section shown.

[0073] Figure 12 for Figure 9 The third deformation diagram of the first main body section shown.

[0074] Figure 13 for Figure 4 The cross-sectional view of the photovoltaic ribbon along the DD direction is shown.

[0075] Figure 14 This is a combined cross-sectional view of one embodiment of the first main body segment and the second main body segment.

[0076] Figure 15 This is a combined cross-sectional view of another embodiment of the first main body segment and the second main body segment.

[0077] Figure 16 for Figure 1 The diagram shown is a flowchart of the photovoltaic ribbon forming process.

[0078] Wherein: 10, solar cell string; 100, photovoltaic welding strip; 110, first welding wire; 111, first connecting section; 112, first main body section; 113, first transition section; 114, first reflective surface; 115, first mounting surface; 116, first connecting part; 117, second connecting part; 120, second welding wire; 121, second connecting section; 122, second main body section; 123, second transition section; 130, overlapping section; 200, previous solar cell; 300, next solar cell. Detailed Implementation

[0079] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. 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.

[0080] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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.

[0081] Furthermore, where the terms "first" and "second" appear, these terms are 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 with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0082] 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 based on the specific circumstances.

[0083] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact, or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0084] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0085] Understandably, currently, irregularly shaped solder ribbons are used to connect the front and back of adjacent solar cells, i.e., a composite configuration of front solder wire (enhanced light capture) + back solder wire (low-resistance interconnect). Typically, the irregularly shaped solder ribbon is a complete triangular ribbon. When connecting the front and back of adjacent solar cells, the base of the triangular ribbon is positioned on the front of the solar cell, and the top edge of the triangular ribbon is positioned on the back of the adjacent solar cell. However, when the top edge of the triangular ribbon contacts the back of the solar cell, the solar cell may crack.

[0086] To address this, the triangular solder strip on the back of the solar cell can be flattened and then attached to the back of the cell. However, this increases the manufacturing difficulty of the irregularly shaped solder strip and also increases the shading area of ​​the solder strip on the back of the cell, affecting the bifaciality of the photovoltaic module. Alternatively, the triangular solder strip can be twisted 180° so that its base is positioned on the back of the cell. However, this method is technically challenging, as it cannot accurately guarantee that the base of the triangular solder strip is aligned with the back of the cell. Furthermore, the 180° twist will leave a certain length, increasing the spacing between adjacent cells and reducing the efficiency of the photovoltaic module.

[0087] For this purpose, please refer to Figures 1 to 3 This application provides a photovoltaic solder ribbon 100. The photovoltaic solder ribbon 100 is applied to the solar cell string 10 of a photovoltaic module (not shown). Figure 1 This is a schematic diagram of a photovoltaic solder ribbon 100 according to an embodiment of this application. Figure 2 for Figure 1 The diagram shown illustrates the application of the photovoltaic ribbon 100 to the solar cell string 10 from one perspective. Figure 3 for Figure 2 A schematic diagram of the solar cell string 10 shown from another perspective.

[0088] To better illustrate the structure of the photovoltaic ribbon 100, the structure of the photovoltaic module and the solar cell string 10 is briefly described below. The photovoltaic module includes at least a cover plate (not shown), a back sheet (not shown), and multiple solar cell strings 10 as described in this application. These multiple solar cell strings 10 are connected in series and / or in parallel and are positioned between the cover plate and the back sheet, which protect the multiple solar cell strings 10. Furthermore, sunlight (rays) passes through the cover plate and enters the surface of the multiple solar cell strings 10, allowing the solar cell strings 10 to generate charge carriers using the photovoltaic principle to output current.

[0089] See Figures 1 to 3 In one embodiment, the solar cell string 10 includes multiple solar cells and multiple photovoltaic ribbons 100 as described in this application. The multiple solar cells are arranged sequentially along the length direction, and the multiple solar cells are welded together by the multiple photovoltaic ribbons 100. It is worth noting that the structure and principle of the photovoltaic ribbon 100 connecting two adjacent solar cells are substantially the same as the structure and principle of the photovoltaic ribbon 100 connecting other solar cells. This application only uses the connection of two solar cells by the photovoltaic ribbon 100 as an example for explanation.

[0090] like Figures 1 to 3As shown, the extension direction of the photovoltaic ribbon 100 is the length direction, which is also the arrangement direction of multiple solar cells. The length direction perpendicular to the solar cell is the width direction of the solar cell, and the thickness direction of the solar cell is the thickness direction, which is also the up-down direction and the top-bottom direction. The length direction, width direction and thickness direction are not shown in the figure.

[0091] Figure 2 and Figure 3 The diagram shows a photovoltaic ribbon 100 connecting two solar cells in a solar cell string 10. For ease of description, it is referred to as... Figure 2 and Figure 3 The cell on the left is the front cell 200, and the cell on the right is the back cell 300. The surface of the cell facing the sunlight is the front of the cell, and the surface of the cell away from the sunlight is the back of the cell.

[0092] The photovoltaic ribbon 100 can be connected to the front side of the preceding solar cell 200 and to the back side of the following solar cell 300, thereby connecting adjacent preceding solar cells 200 and following solar cells 300 in series. Furthermore, the connection method between the following solar cell 300 and the next solar cell is the same as the connection method between the preceding solar cell 200 and the following solar cell 300. This process is repeated to connect multiple solar cells in series to form a solar cell string 10.

[0093] The photovoltaic ribbon 100 is a conductive component. After the photovoltaic ribbon 100 connects the previous cell 200 and the next cell 300 in series, the photovoltaic ribbon 100 can connect the current of the previous cell 200 and the next cell 300 in series, and then conduct the current. This allows the current generated by the previous cell 200 and the next cell 300 under sunlight to be transmitted to the external circuit through the photovoltaic ribbon 100, thereby realizing the output of current.

[0094] The photovoltaic ribbon 100 of this application adopts a segmented structural design, which eliminates the need for flattening or twisting 180° to connect to the back of the subsequent solar cell 300, reducing the manufacturing difficulty of the photovoltaic ribbon 100. Furthermore, it can reflect sunlight from the back of the subsequent solar cell 300, improving the bifaciality of the photovoltaic module. Simultaneously, the first welding wire 110 and the second welding wire 120 are connected by an overlapping section 130, which reduces the distance between the preceding solar cell 200 and the subsequent solar cell 300, improving the efficiency of the photovoltaic module. The specific structure of the photovoltaic ribbon 100 in some embodiments is described below.

[0095] See Figures 1 to 8In one embodiment, the photovoltaic welding ribbon 100 includes a first welding wire 110 and a second welding wire 120. One end of the first welding wire 110 has a first connecting section 111, and the outer surface of the first welding wire 110 has a first reflective surface 114 and a first mounting surface 115. One end of the second welding wire 120 has a second connecting section 121. The first connecting section 111 and / or the second connecting section 121 are flat and stacked to form an overlapping section 130. The photovoltaic welding ribbon 100 can be connected to the front side of the preceding solar cell 200 through the first mounting surface 115 of the first welding wire 110, and connected to the back side of the adjacent following solar cell 300 through the second welding wire 120. Figure 4 for Figure 1 The disconnected front view of the photovoltaic ribbon 100 is shown. Figure 5 for Figure 4 The image shown is a partial enlarged view of the photovoltaic ribbon 100 at point A. Figure 6 for Figure 2 The front view of the solar cell string 10 shown is shown. Figure 7 for Figure 6 The diagram shown illustrates the disconnection of the solar cell string 10. Figure 8 for Figure 7 A partial schematic diagram of the solar cell string 10 at point B.

[0096] The first welding wire 110 and the second welding wire 120 extend along the length direction. The first welding wire 110 is positioned on the front side of the preceding battery cell 200 and is used to collect the current from the preceding battery cell 200. The second welding wire 120 is positioned on the back side of the following battery cell 300 and is also used to collect the current from the following battery cell 300. Furthermore, the first welding wire 110 and the second welding wire 120 are connected to connect the preceding battery cell 200 and the following battery cell 300 in series, thereby achieving the collected output of the battery.

[0097] Furthermore, the end of the first welding wire 110 facing the next solar cell 300 has a first connecting segment 111, and the end of the second welding wire 120 facing the previous solar cell 200 has a second connecting segment 121. When the first welding wire 110 and the second welding wire 120 are connected, the first connecting segment 111 and the second connecting segment 121 are stacked along the thickness direction to form an overlapping segment 130. In this way, the first welding wire 110 and the second welding wire 120 are connected to form an integral photovoltaic welding ribbon 100.

[0098] See Figures 4 to 8Both the first connecting segment 111 and the second connecting segment 121 are flat. The flat first connecting segment 111 and the flat second connecting segment 121 are stacked and connected to form the photovoltaic ribbon 100. This reduces the dimension of the overlapping segment 130 along the thickness direction, thereby reducing the dimension of the solar cell string 10 in the thickness direction and reducing the overall thickness of the photovoltaic module. At the same time, by arranging the flat overlapping segment 130 on the front of the preceding cell 200 and / or the following cell 300, the gap between the preceding cell 200 and the following cell 300 can also be reduced, allowing more cells to be arranged in a limited space and improving the efficiency of the photovoltaic module.

[0099] Of course, in other embodiments of this application, the first connecting segment 111 or the second connecting segment 121 may be arranged in a flat shape, and the principle is essentially the same as that of both the first connecting segment 111 and the second connecting segment 121 being arranged in a flat shape. When describing the structure of the photovoltaic ribbon 100 below, only the example of both the first connecting segment 111 and the second connecting segment 121 being arranged in a flat shape will be used for explanation.

[0100] When the first welding wire 110 is manufactured, a wire with a uniform cross-section (the cross-section here refers to the surface cut along the thickness direction, which will not be elaborated further) is used. The wire is cut to a specified length, which matches the length of the first welding wire 110. One end of the wire is flattened to form a flat first connecting segment 111, while the rest of the wire retains its original shape, which is the first main body segment 112 described later. The second welding wire 120 is manufactured in the same manner.

[0101] Understandably, since the first connecting segment 111 and the second connecting segment 121 have a flat structure, during the forming process of the first welding wire 110 and the second welding wire 120, the first connecting segment 111 and the second connecting segment 121 can be flattened first and then connected together to form the overlapping segment 130. Alternatively, the first connecting segment 111 and the second connecting segment 121 can be connected together first, and then the first connecting segment 111 and the second connecting segment 121 can be flattened to form the overlapping segment 130. Of course, the first connecting segment 111 and the second connecting segment 121 can also be flattened first and then connected together, and then the connected first connecting segment 111 and the second connecting segment 121 can be flattened to form the overlapping segment 130.

[0102] exist Figure 7 and Figure 8 In the process, the upper surface of the first battery cell 200 is the front side of the first battery cell 200, the first welding wire 110 is located above the first battery cell 200 and connected to the front side of the first battery cell 200, the lower surface of the second battery cell 300 is the back side of the second battery cell 300, and the second welding wire 120 is located below the second battery cell 300 and connected to the back side of the second battery cell 300.

[0103] Furthermore, the outer surface of the first welding wire 110 has a first reflective surface 114 and a first mounting surface 115 (hereinafter referred to as the first reflective surface 114). Figure 9 The first welding wire 110 has a first mounting surface 115 on the surface facing the preceding battery cell 200. The first mounting surface 115 is used to connect the first welding wire 110 to the preceding battery cell 200. The surface of the first welding wire 110 facing away from the preceding battery cell 200 has a first reflective surface 114, which is used to reflect sunlight. The first welding wire 110 is connected to the front side of the preceding battery cell 200 through the first mounting surface 115, and the first reflective surface 114 faces away from the front side of the preceding battery cell 200.

[0104] When sunlight shines on the first reflective surface 114 of the first welding wire 110, the first reflective surface 114 can reflect the sunlight to the back of the cover plate, and then the cover plate can reflect the sunlight to the front of the preceding solar cell 200. In this way, the sunlight reflected by the first welding wire 110 can be reflected to the front of the preceding solar cell 200, thereby improving the utilization rate of sunlight and thus increasing the power of the photovoltaic module.

[0105] Meanwhile, after the second welding wire 120 is connected to the back of the next cell 300, the second welding wire 120 can also reflect a portion of sunlight to the back sheet, and then reflect it to the back of the next cell 300 through the back sheet. In this way, the next cell 300 can also utilize the sunlight reflected by the second welding wire 120 to further improve the utilization rate of sunlight, thereby improving the bifaciality of the photovoltaic module.

[0106] When forming the solar cell string 10, the first welding wire 110 and the second welding wire 120 are connected through an overlapping section 130. Simultaneously, the first welding wire 110 is connected to the front side of the preceding solar cell 200, and the second welding wire 120 is connected to the back side of the following solar cell 300, thus connecting the preceding solar cell 200 and the following solar cell 300 in series. In this way, the photovoltaic welding ribbon 100 has a split (segmented) structure, consisting of the first welding wire 110 and the second welding wire 120, with the first welding wire 110 connected to the front side of the preceding solar cell 200 and the second welding wire 120 connected to the back side of the following solar cell 300.

[0107] In this way, the photovoltaic welding ribbon 100 does not need to be flattened or twisted 180° to connect to the back of the next cell 300, reducing the process difficulty of the photovoltaic welding ribbon 100. In addition, the second welding wire 120 can reflect sunlight from the back of the next cell 300, improving the bifaciality of the photovoltaic module. At the same time, the first welding wire 110 and the second welding wire 120 are connected by the overlapping section 130, which can reduce the distance between the previous cell 200 and the next cell 300, improving the efficiency of the photovoltaic module.

[0108] There are two optional implementation methods for connecting the photovoltaic welding ribbon 100 to the preceding solar cell 200 and the following solar cell 300:

[0109] One implementation involves connecting the first welding wire 110 to the front of the preceding battery cell 200 and the second welding wire 120 to the back of the following battery cell 300, and then directly connecting the first welding wire 110 and the second welding wire 120. However, in the actual process, the welding temperature between the first welding wire 110 and the second welding wire 120 is higher than the temperature at which the first welding wire 110 is connected to the preceding battery cell 200, and also higher than the temperature at which the second welding wire 120 is connected to the following battery cell 300. This can lead to incomplete soldering between the first welding wire 110 and the preceding battery cell 200, and between the second welding wire 120 and the following battery cell 300, which can also increase the risk of hot spots.

[0110] Another implementation method is as follows: When the photovoltaic ribbon 100 is connected in series with the preceding cell 200 and the following cell 300, the first welding wire 110 and the second welding wire 120 are first connected together to form a complete photovoltaic ribbon 100. Then, the photovoltaic ribbon 100 is connected to the preceding cell 200 and the following cell 300. In this way, when the first welding wire 110 is connected to the preceding cell 200 and the second welding wire 120 is connected to the following cell 300, it will not be affected by the connection temperature of the first welding wire 110 and the second welding wire 120, thereby avoiding the risk of cold solder joints and hot spots.

[0111] It is worth noting that both of the above implementation methods can achieve the connection between the segmented first welding wire 110 and the second welding wire 120, and between the previous solar cell 200 and the next solar cell 300. The focus of this application is the segmented design of the photovoltaic welding ribbon 100, which facilitates the connection between the second welding wire 120 and the back of the next solar cell 300, reduces the manufacturing difficulty of the photovoltaic welding ribbon 100, and reduces the shading area of ​​the second welding wire 120 on the back of the next solar cell 300.

[0112] Because the photovoltaic ribbon 100 is formed as a whole before being connected to the preceding cell 200 and the following cell 300, the problem of incomplete soldering can be avoided. Therefore, its specific connection method is also described here. When the photovoltaic ribbon 100 is connected in series with the preceding cell 200 and the following cell 300, the first connecting segment 111 of the first welding wire 110 and the second connecting segment 121 of the second welding wire 120 are first stacked to connect the first welding wire 110 and the second welding wire 120 to form a whole photovoltaic ribbon 100. Then, the first welding wire 110 is connected to the front side of the preceding cell 200, and the second welding wire 120 is connected to the back side of the following cell 300. In this way, the photovoltaic ribbon 100 is connected to the preceding cell 200 and the following cell 300. At the same time, the problem of incomplete soldering of the photovoltaic ribbon 100 to the preceding cell 200 and the following cell 300 will not occur, and the risk of hot spots can also be avoided, ensuring the product quality of the solar cell string 10.

[0113] Moreover, when forming the solar cell string 10, after positioning the previous cell 200 and the next cell 300, the first welding wire 110 can be connected to the front side of the previous cell 200 and the second welding wire 120 can be connected to the back side of the next cell 300. There is no need to correct the relative position of the first welding wire 110 and the second welding wire 120 before welding, which simplifies the forming process of the solar cell string 10 and improves the forming efficiency of the solar cell string 10.

[0114] See Figure 1 , Figure 4 and Figure 5 In one embodiment, the first welding wire 110 further includes a first main body segment 112, and a first connecting segment 111 is disposed at one end of the first main body segment 112. The first main body segment 112 can be connected to the front side of the preceding battery cell 200. The first main body segment 112 is disposed at the end of the first connecting segment 111 opposite to the second welding wire 120, and the first main body segment 112 is the main component for collecting current in the first welding wire 110. When the first welding wire 110 is connected to the front side of the preceding battery cell 200, the first welding wire 110 is connected to the front side of the preceding battery cell 200 through the first main body segment 112.

[0115] See Figure 1 , Figure 4 and Figure 5In one embodiment, the second welding wire 120 further includes a second main body segment 122, and a second connecting segment 121 is disposed at one end of the second main body segment 122. The second main body segment 122 can be connected to the back side of the subsequent battery cell 300. The second main body segment 122 is disposed at the end of the second connecting segment 121 opposite to the first welding wire 110, and the second main body segment 122 is the main component for collecting current in the second welding wire 120. When the second welding wire 120 is connected to the back side of the subsequent battery cell 300, the second welding wire 120 is connected to the back side of the subsequent battery cell 300 through the second main body segment 122.

[0116] See Figure 5 and Figure 8 In one embodiment, the first welding wire 110 further includes a first transition section 113, which transitionally connects the first main body section 112 and the first connecting section 111. One end of the first transition section 113 is connected to the first connecting section 111, and the other end is connected to the first main body section 112. It is understood that after the first connecting section 111 is flattened, the end connecting the first main body section 112 and the first connecting section 111 will deform; this deformed area is the first transition section 113.

[0117] See Figure 5 and Figure 8 In one embodiment, the second welding wire 120 further includes a second transition section 123, which transitionally connects the second main body section 122 and the second connecting section 121. One end of the second transition section 123 is connected to the second connecting section 121, and the other end is connected to the second main body section 122. It is understood that after the second connecting section 121 is flattened, the end connecting the second main body section 122 and the second connecting section 121 will deform; this deformed area is the second transition section 123.

[0118] See Figures 4 to 8 In one embodiment, the overlap dimension of the first connecting segment 111 and the second connecting segment 121 along the length direction is greater than or equal to 0.5 mm. That is, the dimension of the overlapping segment 130 along the length direction is greater than or equal to 0.5 mm. This ensures the connection length of the first connecting segment 111 and the second connecting segment 121, thereby improving the reliability of the connection between the first welding wire 110 and the second welding wire 120. At the same time, it also ensures the tensile strength between the first welding wire 110 and the second welding wire 120 and guarantees the conductivity of the photovoltaic welding ribbon 100.

[0119] See Figures 4 to 8In one embodiment, the overlapping segment 130 has a thickness dimension of less than 0.15 mm, and its thickness is less than that of the first main body segment 112 and / or the second main body segment 122. Thus, the thickness of the overlapping segment 130 is similar to that of the first main body segment 112 and the second main body segment 122. This prevents the overlapping segment 130 from protruding beyond the first main body segment 112 and the second main body segment 122, avoiding excessive space occupation and preventing the overlapping segment 130 from lifting the subsequent solar cell 300. This, in turn, prevents cell cracking during photovoltaic module lamination, ensuring the product quality of the photovoltaic module.

[0120] See Figures 4 to 8 In one embodiment, the dimension of the first main body segment 112 along the thickness direction is greater than or equal to the dimension of the second main body segment 122 along the thickness direction. This ensures that the dimension of the first welding wire 110 protruding from the front of the preceding solar cell 200 is approximately equal to the dimension of the second welding wire 120 protruding from the back of the following solar cell 300. This makes the overall thickness of the preceding solar cell 200 with the first main body segment 112 approximately equal to the main body thickness of the following solar cell 300 with the second main body segment 122, thus preventing unevenness in the solar cell string 10.

[0121] See Figures 4 to 8 In one embodiment, the overlapping segment 130 is separated from the front metal electrode of the preceding battery cell 200 and / or the back metal electrode of the following battery cell 300. In this embodiment, the overlapping segment 130 is located on the back of the following battery cell 300, and there is no conductive connection between the overlapping segment 130 and the following battery cell 300. That is, the overlapping segment 130 can contact the back of the following battery cell 300, but is not welded to the back metal electrode.

[0122] See Figure 4 and Figure 9 In one embodiment of this application, the cross-section of the first main body segment 112 (here, the cross-section refers to the surface cut along the thickness direction, which will not be described again below) is triangular in shape. Figure 9 for Figure 4 The diagram shows a cross-sectional view of the photovoltaic welding ribbon 100 along the CC direction. The first main body segment 112, with a triangular cross-section, reduces the light-shielding area of ​​the first welding wire 110 on the front side of the preceding solar cell 200 after being connected to the front side of the preceding solar cell 200, thereby increasing the light-receiving area of ​​the preceding solar cell 200. Simultaneously, the first main body segment 112, with its triangular cross-section, has two first reflective surfaces 114, ensuring reflectivity and improving the utilization rate of sunlight.

[0123] See Figure 9In one embodiment, the side length of the first main body segment 112 ranges from 0.1mm to 0.35mm. That is, the cross-section of the first main body segment 112 is triangular, with the side length of the triangle within the range of 0.1mm to 0.35mm. This reduces resistance, lowers current transmission loss, reduces the shading area, and improves the utilization rate of sunlight. Simultaneously, it ensures the mechanical strength of the first welding wire 110 and improves the reliability of the connection with the preceding solar cell 200.

[0124] See Figure 9 and Figure 10 In one embodiment, adjacent sides of the first main body segment 112 are connected by a chamfered portion. Figure 10 for Figure 9 The first deformation diagram of the first main body segment 112 cross section is shown. That is to say, the three sides of the triangle are connected by a chamfered transition, reducing the difficulty of manufacturing.

[0125] In one embodiment, the radius of the chamfer is greater than or equal to 5 μm. This ensures the area of ​​the first reflective surface 114 and the first mounting surface 115, while also facilitating the forming and processing of the first welding wire 110.

[0126] See Figure 11 and Figure 12 In another embodiment of this application, the first main body segment 112 further includes a first connecting portion 116 and a second connecting portion 117. The first connecting portion 116 is disposed on the second connecting portion 117 along the thickness direction. The cross-sectional shape of the first connecting portion 116 is triangular, and the cross-sectional shape of the second connecting portion 117 is rectangular. The second connecting portion 117 is connected to the front side of the previous battery cell 200. Figure 11 for Figure 9 The second deformation diagram of the first main body segment 112 cross section is shown. Figure 12 for Figure 9 The third deformation diagram of the first main body segment 112 cross section is shown.

[0127] In other words, the first connecting portion 116 is positioned above the second connecting portion 117, and the first main body segment 112 has a combination of triangular and rectangular shapes. Thus, the first main body segment 112 is connected to the front of the preceding solar cell 200 via the rectangular second connecting portion 117, and sunlight is reflected by the first reflective surface 114 on the second connecting portion 117, improving the utilization rate of sunlight. Figure 11 In the middle, the edges of the first main body segment 112 are all sharp angles. Figure 12 In the middle, the edges of the first main body segment 112 are connected by a chamfer transition.

[0128] See Figure 4 and Figure 13 In one embodiment of this application, the cross-sectional shape of the second main body segment 122 is circular. Figure 13 for Figure 4 The diagram shows a cross-sectional view of the photovoltaic welding ribbon 100 along the DD direction. The circularly shaped second main body segment 122, after being connected to the back of the subsequent solar cell 300, reduces the shading area of ​​the second welding wire 120 on the back of the subsequent solar cell 300. After sunlight is reflected from the ground or other surfaces through the cover plate to the back of the subsequent solar cell 300, the circular second main body segment 122 reduces its space occupation on the back of the subsequent solar cell 300, thereby improving the bifaciality of the photovoltaic module.

[0129] See Figure 13 In one embodiment, the diameter of the second main body segment 122 ranges from 0.1 mm to 0.3 mm. Having the diameter of the second main body segment 122 within this range reduces resistance, lowers current transmission loss, reduces the shading area, and improves the utilization rate of sunlight. Simultaneously, it ensures the mechanical strength of the second welding wire 120 and improves the reliability of its connection with the subsequent battery cell 300.

[0130] In another embodiment of this application, the cross-sectional shape of the second main body segment 122 is triangular. The side length of the second main body segment 122 ranges from 0.1mm to 0.35mm. That is to say, a wire with a triangular cross-section can be used as the second main body segment 122, which is actually the same as the first main body segment 112, and will not be described again here.

[0131] Understandably, after the first welding wire 110 and the second welding wire 120 are connected to form the photovoltaic welding strip 100, there is partial overlap between the first welding wire 110 and the second welding wire 120 in the side view of the photovoltaic welding strip 100. To facilitate the explanation of the combination of the cross-sectional shapes of the first main body segment 112 and the second main body segment 122, the first main body segment 112 and the second main body segment 122 are arranged offset along the thickness direction, and the cross-sections of the first main body segment 112 and the second main body segment 122 are combined together.

[0132] In one embodiment of this application, the first main body segment 112 has a triangular cross-sectional shape, and the second main body segment 122 has a circular cross-sectional shape, such as... Figure 14 As shown, Figure 14 This is a combined cross-sectional view of one embodiment of the first main body segment 112 and the second main body segment 122. The first main body segment 112, which has a triangular cross-section, is connected to the front side of the preceding battery cell 200, and the second main body segment 122, which has a circular cross-section, can be connected to the back side of the following battery cell 300.

[0133] Understandably, by using a triangular-section first welding wire 110 to connect the front side of the preceding solar cell 200 and a circular-section second welding wire 120 to connect the back side of the following solar cell 300, the first welding wire 110 can reflect sunlight, improving the utilization rate of sunlight, while the second welding wire 120 can reduce the shading area on the back side of the following solar cell 300, thereby increasing the bifaciality of the photovoltaic module and thus increasing the power of the photovoltaic module. Moreover, the first welding wire 110 and the second welding wire 120 are easy to manufacture, convenient to form and process, and easy to connect to the preceding solar cell 200 and the following solar cell 300, reducing the risk of hot spots and reducing the production cost of photovoltaic modules.

[0134] In another embodiment of this application, the cross-sectional shape of the first main body segment 112 is triangular, and the cross-sectional shape of the second main body segment 122 is also triangular, and the second main body segment 122 is inverted relative to the first main body segment 112, as shown below. Figure 15 As shown, Figure 15 This is a combined cross-sectional view of another embodiment of the first main body segment 112 and the second main body segment 122. In this way, the second main body segment 122 is inverted and connected to the back side of the subsequent solar cell 300, avoiding contact between the triangular corners and the back side of the subsequent solar cell 300, thus preventing cracking of the subsequent solar cell 300 during photovoltaic module lamination. Simultaneously, because the first welding wire 110 and the second welding wire 120 are segmented structures, the second welding wire 120 does not need to be formed by twisting 180°, facilitating the connection between the second welding wire 120 and the subsequent solar cell 300.

[0135] Of course, in other embodiments of this application, the cross-sectional shape of the first main body segment 112 may be other, as long as the first main body segment 112 has a small light-shielding area on the front side of the preceding battery cell 200 and can reflect sunlight. The cross-sectional shape of the second main body segment 122 may also be other, as long as the second main body segment 122 has a small light-shielding area on the back side of the following battery cell 300.

[0136] See Figure 15 In one embodiment, when the cross-sectional shape of the second main body segment 122 is triangular, the second welding wire 120 further includes a second reflective surface and a second mounting surface. The second mounting surface is connected to the back side of the subsequent solar cell 300, and the second reflective surface is used to reflect light on the back side of the subsequent solar cell 300. Thus, the second main body segment 122 is mounted to the back side of the subsequent solar cell 300 via the second mounting surface, and the sunlight on the back side of the subsequent solar cell 300 is reflected by the second reflective surface, thereby improving the utilization rate of sunlight by the photovoltaic module and thus increasing the power of the photovoltaic module.

[0137] See Figure 5 and Figure 8 In one embodiment, along the thickness direction, the first connecting segment 111 is located on the upper surface of the second connecting segment 121. That is, in Figure 5 and Figure 8 In the indicated direction, the first connecting segment 111 is located above the second connecting segment 121. This facilitates the connection between the first welding wire 110 and the second welding wire 120, and also facilitates connection to the preceding battery cell 200 and the following battery cell 300. When the overlapping segment 130 is located on the back side of the following battery cell 300, the first connecting segment 111 is located between the second connecting segment 121 and the back side of the following battery cell 300.

[0138] Of course, in other embodiments of this application, the first connecting segment 111 may also be located on the lower surface of the second connecting segment 121 along the thickness direction. That is, the first connecting segment 111 is located below the second connecting segment 121. When the overlapping segment 130 is located on the back side of the subsequent battery cell 300, the second connecting segment 121 is located between the first connecting segment 111 and the back side of the subsequent battery cell 300.

[0139] See Figures 1 to 8 In one embodiment, the first connecting segment 111 and the second connecting segment 121 are welded together. That is, the first connecting segment 111 and the second connecting segment 121 are connected by welding, thereby connecting the first welding wire 110 and the second welding wire 120 to form a complete photovoltaic welding ribbon 100. This ensures the reliability of the connection between the first welding wire 110 and the second welding wire 120, while also guaranteeing the electrical conductivity and heat resistance of the first welding wire 110 and the second welding wire 120.

[0140] Understandably, the welding method for the first connecting segment 111 and the second connecting segment 121 is not restricted in principle, as long as the conductive connection between the first connecting segment 111 and the second connecting segment 121 can be achieved and the reliability of the connection can be guaranteed. Optionally, the first connecting segment 111 and the second connecting segment 121 can be welded together by laser welding, ultrasonic welding, infrared welding, or arc welding, so that the first welding wire 110 and the second welding wire 120 are connected to form a photovoltaic welding ribbon 100. This can ensure the reliability of the connection between the first welding wire 110 and the second welding wire 120, and at the same time, it can also guarantee the conductivity and heat resistance of the first welding wire 110 and the second welding wire 120.

[0141] In one embodiment, the first welding wire 110 includes a first copper substrate, a first welding coating, and a reflective coating. The first welding coating and the reflective coating cover the outer periphery of the first copper substrate. The first welding coating forms a first mounting surface 115 for welding to the preceding battery cell 200, and the reflective coating forms a first reflective surface 114. The second welding wire 120 includes a second copper substrate and a second welding coating. The second welding coating covers the outer periphery of the second copper substrate and is welded to the following battery cell 300.

[0142] The first copper substrate serves as the conductive substrate in the first welding wire 110, ensuring the conductivity of the first welding wire 110. A first welding coating and a reflective coating coat the surface of the first copper substrate, forming a first mounting surface 115 and a first reflective surface 114. When the first main body segment 112 is welded to the front side of the preceding battery cell 200, the first welding coating acts as a welding flux, facilitating the welding connection between the first main body segment 112 and the front side of the preceding battery cell 200. Furthermore, the reflective coating reflects sunlight, improving the utilization rate of sunlight.

[0143] The second copper substrate is the conductive substrate in the second welding wire 120, ensuring the conductivity of the second welding wire 120. A second welding coating covers the surface of the second copper substrate. When the second main body segment 122 is welded to the front side of the preceding battery cell 200, the second welding coating acts as an flux, facilitating the welding connection between the second main body segment 122 and the back side of the following battery cell 300.

[0144] In one embodiment, a first welding coating covers the outer wall of the first copper substrate, and a reflective coating is disposed on a portion of the outer wall of the first welding coating. Thus, a first reflective surface 114 is formed by the reflective coating, and the surface of the first welding coating exposed above the reflective coating forms a first mounting surface 115. In this way, only the first welding coating is disposed at the first mounting surface 115, without the reflective coating. When the first main body segment 112 is welded to the front side of the preceding battery cell 200, the reflective coating is not between the first main body segment 112 and the preceding battery cell 200, thereby not affecting the welding effect between the first main body segment 112 and the preceding battery cell 200, ensuring the reliability of the connection between the first main body segment 112 and the preceding battery cell 200. Simultaneously, the reflective coating can also reflect sunlight.

[0145] Alternatively, the first welding coating and the reflective coating can be respectively disposed on the outer wall of the first copper substrate, and the first welding coating and the reflective coating can be disposed separately. That is to say, the reflective coating is not disposed on the outer wall of the first welding coating. In this way, the reliability of the connection between the first main body segment 112 and the previous battery cell 200 can be ensured while ensuring the reflective effect.

[0146] Understandably, the material of the first welding coating is not limited in principle, as long as it can act as a flux to facilitate the welding connection between the first main body segment 112 and the front side of the preceding battery cell 200. In one embodiment, the first welding coating includes a tin-lead alloy coating, a tin-lead-bismuth alloy coating, or a tin-silver alloy coating, etc. Thus, the first welding coating does not contain elements of a reflective coating, that is, it does not contain silver or aluminum. Of course, the tin-lead alloy coating may also include other trace elements, such as antimony, etc.

[0147] Understandably, the material of the reflective coating is not limited in principle, as long as the reflective coating can reflect sunlight. In one embodiment, the reflective coating includes a silver coating or an aluminum coating, etc.

[0148] Understandably, the material of the second welding coating is not limited in principle, as long as the second welding coating can act as a flux to facilitate welding between the second main body segment 122 and the back of the subsequent battery cell 300. In one embodiment, the second welding coating includes a tin-lead alloy coating, a tin-lead-bismuth alloy coating, or a tin-silver alloy coating, etc. Of course, the tin-lead alloy coating may also include other trace elements, such as antimony, etc.

[0149] In this way, when the second main body segment 122 is connected to the back of the subsequent battery cell 300, the second welding coating facilitates the welding connection between the second main body segment 122 and the subsequent battery cell 300, ensuring a good connection effect. Simultaneously, the surface of the second main body segment 122 facing away from the subsequent battery cell 300 can also reflect a certain amount of sunlight, thereby improving the utilization rate of sunlight. Alternatively, a reflective coating can be applied to the surface of the second main body segment 122 facing away from the subsequent battery cell 300 to further enhance the reflection effect of sunlight.

[0150] The purpose of reflective coating is to increase reflectivity and improve the utilization rate of sunlight by the solar cell. In traditional methods, a single solder ribbon is used to connect one solar cell to the next, with reflective coatings on both sides. During ribbon preparation, a tin layer must first be formed on the surface of the copper core, and then the reflective layer is deposited on top of that tin layer. When the solder ribbon is flattened, on the front side of the first solar cell, the lower surface of the ribbon will have a reflective side facing away from the front side, allowing for a reliable connection. However, on the back side of the second solar cell, the upper surface of the ribbon will have a reflective side facing away from the back side. When the ribbon is connected to the back side of the second solar cell, the reflective side will be in contact with the back side, affecting soldering performance.

[0151] Therefore, the photovoltaic welding ribbon 100 of this application adopts a segmented design structure, with the first welding wire 110 and the second welding wire 120 being set independently. In this way, the independent first welding wire 110 and second welding wire 120 can be set according to actual needs, so that the first welding wire 110 and the second welding wire 120 can exhibit different optical and electrical properties to adapt to the front side of the preceding solar cell 200 and the back side of the following solar cell 300, respectively. At the same time, it can also solve the welding problems existing in traditional processes and ensure the welding effect of the second welding wire 120 to the back side of the following solar cell 300.

[0152] Thus, during the manufacturing of the first welding wire 110, a reflective coating can be applied to a portion of the outer wall of the first copper substrate to form the first mounting surface 115 and the first reflective surface 114. Furthermore, the first welding coating and the reflective coating can be applied to different locations on the outer wall of the first copper substrate. This ensures that the elements present in the reflective coating are not present in the first welding coating, thus avoiding any impact on the welding effect between the first main body segment 112 and the preceding battery cell 200.

[0153] For the first welding wire 110, the back side of the first welding wire 110 has a first welding coating, and the front side of the first welding wire 110 has a reflective coating. The back side of the first welding wire 110 is aligned with the front side of the preceding battery cell 200, and the front side of the first welding wire 110 is away from the front side of the preceding battery cell 200. In this way, the functions of different positions of the first welding wire 110 are differentiated, so that the first welding wire 110 is welded to the front side of the preceding battery cell 200 through the first welding coating, and reflects sunlight through the reflective coating.

[0154] Meanwhile, the outer surface of the second welding wire 120 has a second welding coating. The coatings on the first welding wire 110 and the second welding wire 120 are different, so that the first welding wire 110 and the second welding wire 120 exhibit different optical and electrical properties on the front side of the first solar cell 200 and the back side of the second solar cell 300, in order to meet the usage requirements of different installation positions and improve the bifaciality of the photovoltaic module.

[0155] Understandably, conventional solder ribbons can only be coated with a single tin layer, making it impossible to differentiate the optical and electrical functions of the front and back sides. Therefore, this application uses separate first solder wire 110 and second solder wire 120 to form a complete photovoltaic solder ribbon 100. In this way, the elements of the coating on the first solder wire 110 and second solder wire 120 can be set as needed to present differentiated optical and electrical properties, thereby improving the bifaciality of the photovoltaic module.

[0156] For example, when the first welding coating includes a tin-lead alloy coating or a tin-lead-bismuth alloy coating, the reflective coating includes an aluminum coating or a silver coating, and the second welding coating includes a tin-lead alloy coating or a tin-lead-bismuth alloy coating, the overlapping section 130 includes tin, lead, and copper elements, and also includes one of aluminum or silver elements.

[0157] In this way, the first welding coating is welded to the front side of the preceding battery cell 200 through the tin and lead elements in the tin-lead alloy coating, facilitating the welding connection between the first main body segment 112 and the preceding battery cell 200. Simultaneously, the reflective coating reflects sunlight through silver or aluminum elements, ensuring a good reflective effect. The second welding coating is connected to the back side of the following battery cell 300 through the tin and lead elements, facilitating the connection between the second main body segment 122 and the back side of the following battery cell 300.

[0158] In one embodiment, the overlapping segment 130 further includes a first fusion portion, formed by fusing a first welding coating, a reflective coating, and a second welding coating. It is understood that when the first connecting segment 111 and the second connecting segment 121 are welded together, the high temperature during welding can melt the first welding coating and the reflective coating on the outer surface of the first connecting segment 111, and simultaneously melt the second welding coating on the outer surface of the second connecting segment 121.

[0159] In this way, the first welding coating, the reflective coating, and the second welding coating can be fused together to form the first fused section. The tin and lead elements in the first fused section are fused together, and they are also fused together with either aluminum or silver elements.

[0160] In one embodiment, the overlapping segment 130 further includes a second fusion portion, formed by fusing the first copper substrate and the second copper substrate. When the first connecting segment 111 and the second connecting segment 121 are welded together, the high temperature during welding not only melts the first welding coating, the reflective coating and the second welding coating, but also melts the first copper substrate inside the first connecting segment 111 and the second copper substrate inside the second connecting segment 121.

[0161] In this way, the first copper substrate and the second copper substrate can be fused together to form a second fused portion. This enables a conductive connection between the first welding wire 110 and the second welding wire 120. In the second fused portion, tin, lead, and copper elements are fused together, and it is also fused together with either aluminum or silver.

[0162] The photovoltaic welding ribbon 100 of this application adopts a first connecting segment 111 and a second connecting segment 121 stacked together to form an overlapping segment 130. The photovoltaic welding ribbon 100 is connected to the front side of the preceding cell 200 through the first mounting surface 115 of the first welding wire 110, and connected to the back side of the following cell 300 through the second welding wire 120, so as to connect the preceding cell 200 and the following cell 300 in series. In this way, the photovoltaic welding ribbon 100 does not need to be flattened or twisted 180° to be connected to the back side of the following cell 300, reducing the manufacturing difficulty of the photovoltaic welding ribbon 100. In addition, the second welding wire 120 can reflect sunlight on the back side of the following cell 300, improving the bifaciality of the photovoltaic module. At the same time, the first welding wire 110 and the second welding wire 120 are connected through the overlapping segment, which can reduce the distance between the preceding cell 200 and the following cell 300, improving the efficiency of the photovoltaic module.

[0163] When using photovoltaic ribbon 100 to connect the preceding cell 200 and the following cell 300, the first mounting surface 115 of the first welding wire 110 in the photovoltaic ribbon 100 can be directly connected to the front side of the preceding cell 200, and the second welding wire 120 in the photovoltaic ribbon 100 can be connected to the back side of the following cell 300. In this way, by first forming a single photovoltaic ribbon 100 from the first welding wire 110 and the second welding wire 120, and then connecting the photovoltaic ribbon 100 to the preceding cell 200 and the following cell 300, the problem of incomplete connections between the photovoltaic ribbon 100 and the preceding cell 200 and the following cell 300 can be avoided, as well as the risk of hot spots, ensuring the product quality of the solar cell string 10. At the same time, it also ensures the connection accuracy of the first welding wire 110 and the second welding wire 120, making the connection method of the first welding wire 110 and the second welding wire 120 controllable and improving the reliability of the photovoltaic module.

[0164] See Figures 1 to 4 , Figure 7 , Figure 8 and Figure 16 , Figure 16 for Figure 1 The diagram shows the forming process of the photovoltaic solder ribbon 100. This application also provides a photovoltaic solder ribbon forming method for forming the photovoltaic solder ribbon 100 as described in any of the above embodiments. The photovoltaic solder ribbon forming method includes at least the following steps:

[0165] S1, the first material is fed by the first feeding mechanism, the first material is cut by the first wire drawing mechanism to form a first welding wire 110 of a predetermined length, and the first welding wire 110 is fed to the interconnection platform;

[0166] S2, the second material is fed by the second feeding mechanism, the second material is cut by the second wire drawing mechanism to form the second welding wire 120 of a predetermined length, and the second welding wire 120 is fed to the interconnection platform;

[0167] S3, the first welding wire 110 and the second welding wire 120 are connected to form a photovoltaic welding ribbon 100. The first welding wire 110 can be connected to the front side of the previous cell 200, and the second welding wire 120 can be connected to the back side of the next cell 300.

[0168] In the forming process of the photovoltaic welding ribbon 100 of this application, the first welding wire 110 and the second welding wire 120 are respectively made from corresponding raw materials. It is understood that because the first welding wire 110 and the second welding wire 120 are positioned differently, and consequently the coatings on the outer surfaces of the first welding wire 110 and the second welding wire 120 are different, different raw materials are used to make the first welding wire 110 and the second welding wire 120 respectively, so that the first welding wire 110 and the second welding wire 120 have differentiated optical and electrical functions.

[0169] Therefore, this application uses a first raw material to prepare a first welding wire 110 and a second raw material to prepare a second welding wire 120. During forming, a first feeding mechanism conveys the first raw material, and a first wire drawing mechanism cuts the first raw material to a fixed length to form a first welding wire 110 of a predetermined length. Subsequently, the first wire drawing mechanism conveys the first welding wire 110 to the interconnect platform.

[0170] A second feeding mechanism conveys a second raw material, which is then cut to a fixed length by a second wire drawing mechanism to form a second welding wire 120 of a predetermined length. Subsequently, the second wire drawing mechanism conveys the second welding wire 120 to the interconnect platform. After the first welding wire 110 and the second welding wire 120 are conveyed to the interconnect platform, one end of the first welding wire 110 is connected to the second welding wire 120 to form a complete photovoltaic welding ribbon 100.

[0171] Understandably, the process of the first feeding mechanism conveying the first raw material and the process of the second feeding mechanism conveying the second raw material can operate simultaneously or sequentially. Similarly, the first wire drawing mechanism and the second wire drawing mechanism can operate simultaneously or sequentially. Furthermore, the first raw material is the wire used to make the first welding wire 110, and the second raw material is the wire used to make the second welding wire 120. The first and second raw materials can be wound together. It is worth noting that the first feeding mechanism, the first wire drawing mechanism, the second feeding mechanism, the second wire drawing mechanism, and the interconnecting platform can adopt current welding wire feeding and connection structures, which will not be elaborated upon here.

[0172] When forming the solar cell string 10, the first welding wire 110 and the second welding wire 120 are connected through an overlapping section 130. Simultaneously, the first welding wire 110 is connected to the front side of the preceding solar cell 200, and the second welding wire 120 is connected to the back side of the following solar cell 300, thus connecting the preceding solar cell 200 and the following solar cell 300 in series. In this way, the photovoltaic welding ribbon 100 has a split structure, consisting of the first welding wire 110 and the second welding wire 1120, with the first welding wire 110 connected to the front side of the preceding solar cell 200 and the second welding wire 120 connected to the back side of the following solar cell 300.

[0173] In this way, the photovoltaic welding ribbon 100 does not need to be flattened or twisted 180° to connect to the back of the next cell 300, reducing the process difficulty of the photovoltaic welding ribbon 100. In addition, the second welding wire 120 can reflect sunlight from the back of the next cell 300, improving the bifaciality of the photovoltaic module. At the same time, the first welding wire 110 and the second welding wire 120 are connected by an overlapping section, which can reduce the distance between the previous cell 200 and the next cell 300, improving the efficiency of the photovoltaic module.

[0174] Furthermore, after the first welding wire 110 and the second welding wire 120 are connected to form an integral photovoltaic welding ribbon 100, it is then connected to the preceding solar cell 200 and the following solar cell 300. In this way, when the photovoltaic welding ribbon 100 is connected as a whole to the preceding solar cell 200 and the following solar cell 300, it will not be affected by the connection temperature of the first welding wire 110 and the second welding wire 120, thereby avoiding the risk of cold solder joints and hot spots.

[0175] In one embodiment, connecting the first welding wire 110 and the second welding wire 120 to form a photovoltaic welding ribbon 100 includes at least the following steps:

[0176] One end of the first welding wire 110 is flattened to form a first connecting segment 111, and one end of the second welding wire 120 is flattened to form a second connecting segment 121. The first connecting segment 111 and the second connecting segment 121 are then connected to form an overlapping segment 130. In other words, the end of the first welding wire 110 facing the second welding wire 120 is the first connecting segment 111, and the end of the second welding wire 120 facing the first welding wire 110 is the second connecting segment 121. After flattening the first connecting segment 111 and the second connecting segment 121 respectively, they are then stacked and connected to form the overlapping segment 130.

[0177] Alternatively, one end of the first welding wire 110 can be connected to one end of the second welding wire 120 to form an overlapping section 130, and the overlapping section 130 can be flattened. In other words, after one end of the first welding wire 110 is connected to one end of the second welding wire 120, an overlapping section 130 is formed, and the overlapping section 130 is flattened as a whole.

[0178] Alternatively, one end of the first welding wire 110 is flattened to form a first connecting segment 111, and one end of the second welding wire 120 is flattened to form a second connecting segment 121. The first connecting segment 111 and the second connecting segment 121 are connected to form an overlapping segment 130, and the overlapping segment 130 is flattened. In other words, the end of the first welding wire 110 facing the second welding wire 120 is the first connecting segment 111, and the end of the second welding wire 120 facing the first welding wire 110 is the second connecting segment 121. After flattening the first connecting segment 111 and the second connecting segment 121 respectively, they are then stacked and connected to form the overlapping segment 130. The overlapping segment 130 is then flattened again.

[0179] In one embodiment, the first welding wire 110 includes a first copper substrate, a first welding coating, and a reflective coating. The first welding coating and the reflective coating cover the outer periphery of the first copper substrate. The first welding coating forms a first mounting surface 115, and the reflective coating forms a first reflective surface 114. The second welding wire 120 includes a second copper substrate and a second welding coating. The second welding coating covers the outer periphery of the second copper substrate.

[0180] The first copper substrate serves as the conductive substrate in the first welding wire 110, ensuring the conductivity of the first welding wire 110. A first welding coating and a reflective coating coat the surface of the first copper substrate, forming a first mounting surface 115 and a first reflective surface 114. When the first main body segment 112 is welded to the front side of the preceding battery cell 200, the first welding coating acts as a welding flux, facilitating the welding connection between the first main body segment 112 and the front side of the preceding battery cell 200. Furthermore, the reflective coating reflects sunlight, improving the utilization rate of sunlight.

[0181] The second copper substrate is the conductive substrate in the second welding wire 120, ensuring the conductivity of the second welding wire 120. A second welding coating covers the surface of the second copper substrate. When the second main body segment 122 is welded to the front side of the preceding battery cell 200, the second welding coating acts as an flux, facilitating the welding connection between the second main body segment 122 and the back side of the following battery cell 300.

[0182] In one embodiment, connecting the first welding wire 110 and the second welding wire 120 to form the photovoltaic welding ribbon 100 further includes at least the following steps:

[0183] The reflective coating, the first welding coating, and the second welding coating are melted using laser welding, ultrasonic welding, infrared welding, or electric arc welding.

[0184] The first copper substrate and the second copper substrate are welded together.

[0185] One end of the first welding wire 110 has a first connecting segment 111, and one end of the second welding wire 120 has a second connecting segment 121. When the first welding wire 110 and the second welding wire 120 are connected, the first connecting segment 111 and the second connecting segment 121 are stacked and welded together so that the first welding wire 110 and the second welding wire 120 are welded together to form an integral structure, thereby making the first welding wire 110 and the second welding wire 120 electrically connected and ensuring the reliability of the connection between the first welding wire 110 and the second welding wire 120.

[0186] Understandably, the welding method for the first connecting segment 111 and the second connecting segment 121 is not restricted in principle, as long as the conductive connection between the first connecting segment 111 and the second connecting segment 121 can be achieved and the reliability of the connection can be guaranteed. Optionally, the first connecting segment 111 and the second connecting segment 121 can be welded together by laser welding, ultrasonic welding, infrared welding, or arc welding, so that the first welding wire 110 and the second welding wire 120 are connected to form a photovoltaic welding ribbon 100. This can ensure the reliability of the connection between the first welding wire 110 and the second welding wire 120, and at the same time, it can also guarantee the conductivity and heat resistance of the first welding wire 110 and the second welding wire 120.

[0187] When the first connecting segment 111 and the second connecting segment 121 are welded together using laser welding, ultrasonic welding, infrared welding or electric arc welding, the high temperature during welding enables the first copper substrate to be welded together with the second copper substrate, thereby achieving a conductive connection between the first welding wire 110 and the second welding wire 120 and ensuring the conductivity of the first welding wire 110 and the second welding wire 120.

[0188] In one embodiment, connecting the first welding wire 110 and the second welding wire 120 to form the photovoltaic welding ribbon 100 further includes at least the following steps:

[0189] A reflective coating, a first welding coating, and a second welding coating are fused together between a first copper substrate and a second copper substrate to form a first fused portion. Understandably, during the welding connection of the first connecting segment 111 and the second connecting segment 121, the high temperature during welding melts the first welding coating and the reflective coating on the outer surface of the first connecting segment 111, and simultaneously melts the second welding coating on the outer surface of the second connecting segment 121. In this way, the first welding coating, the reflective coating, and the second welding coating can fuse together to form the first fused portion. The tin and lead elements in the first fused portion are fused together, and also fused together with either aluminum or silver.

[0190] And / or, the first copper substrate and the second copper substrate are fused together to form a second fused portion. When the first connecting segment 111 and the second connecting segment 121 are welded together, the high temperature during welding not only melts the first welding coating, the reflective coating, and the second welding coating, but also melts the first copper substrate inside the first connecting segment 111 and the second copper substrate inside the second connecting segment 121. In this way, the first copper substrate and the second copper substrate can be fused together to form the second fused portion. Thus, a conductive connection can be achieved between the first welding wire 110 and the second welding wire 120. In the second fused portion, tin, lead, and copper elements are fused together, and it is also fused together with either aluminum or silver.

[0191] See Figures 1 to 8 This application also provides a solar cell string 10, including a front cell 200, a rear cell 300, and a photovoltaic ribbon 100 as described in any of the above embodiments. The front cell 200 and the rear cell 300 are arranged along the length direction of the photovoltaic ribbon 100. A first welding wire 110 of the photovoltaic ribbon 100 is connected to the front side of the front cell 200, and a second welding wire 120 is connected to the back side of the rear cell 300, so that the front cell 200 and the rear cell 300 are connected in series.

[0192] When forming the solar cell string 10 using the photovoltaic welding ribbon 100 in the above embodiment, because the first welding wire 110 and the second welding wire 120 are segmented, they can be connected to the preceding cell 200 and the following cell 300 respectively to form a complete solar cell string 10. In this way, the photovoltaic welding ribbon 100 does not need to be flattened or twisted 180° to connect to the back of the following cell 300, reducing the manufacturing difficulty of the photovoltaic welding ribbon 100. Furthermore, the second welding wire 120 can reflect sunlight from the back of the following cell 300, improving the bifaciality of the photovoltaic module. Simultaneously, the overlapping connection between the first welding wire 110 and the second welding wire 120 reduces the distance between the preceding cell 200 and the following cell 300, improving the efficiency of the photovoltaic module.

[0193] In one embodiment, multiple photovoltaic ribbons 100 are arranged at intervals along the width direction of the preceding solar cell 200 and connect the front side of the preceding solar cell 200 to the back side of the following solar cell 300. This allows the multiple photovoltaic ribbons 100 to evenly distribute the current, reducing the current carrying capacity of a single photovoltaic ribbon 100, lowering resistance loss and heat generation. Simultaneously, it increases the contact area, reduces the contact resistance of the current transmission path, and improves the overall efficiency of the photovoltaic module.

[0194] In one embodiment, the front side of the preceding battery cell 200 has a front metal electrode along its length, and the first mounting surface 115 of the first main body segment 112 is correspondingly connected to the front metal electrode. The back side of the following battery cell 300 has a back metal electrode along its length, and the second main body segment 122 is connected to the back metal electrode. Thus, the first welding wire 110 can collect the current from the preceding battery cell 200, and the second welding wire 120 can collect the current from the following battery cell 300.

[0195] See Figures 2 to 8 In one embodiment of this application, the overlapping section 130 of the photovoltaic ribbon 100 is located on the back side of the subsequent solar cell 300. That is, the overlapping section 130 is completely located on the back side of the subsequent solar cell 300 and is not located on the front side of the preceding solar cell 200. In this way, the overlapping section 130 will not block the front side of the preceding solar cell 200, thereby avoiding affecting the light-receiving area of ​​the preceding solar cell 200, improving the power of the photovoltaic module, reducing the spacing between the preceding solar cell 200 and the subsequent solar cell 300, and also ensuring the appearance of the front side of the solar cell string 10.

[0196] In another embodiment of this application, the overlapping section 130 of the photovoltaic ribbon 100 is located on the front side of the preceding solar cell 200. That is, the overlapping section 130 is completely located on the front side of the preceding solar cell 200 and is not located on the back side of the following solar cell 300. In this way, the overlapping section 130 will not block the back side of the following solar cell 300, and at the same time, the overlapping section 130 can also reflect a certain amount of sunlight on the front side of the preceding solar cell 200.

[0197] In another embodiment of this application, the overlapping section 130 of the photovoltaic ribbon 100 may also be partially located on the front side of the preceding solar cell 200 and partially located on the back side of the following solar cell 300. That is, a portion of the overlapping section 130 is on the front side of the preceding solar cell 200, and the remaining portion is on the back side of the following solar cell 300.

[0198] In one embodiment, when the overlapping segment 130 is located on the front side of the preceding battery cell 200 and the back side of the following battery cell 300, the length of the overlapping segment 130 on the back side of the following battery cell 300 is greater than the length of the overlapping segment 130 on the front side of the preceding battery cell 200. That is, the length of the overlapping segment 130 on the back side of the following battery cell 300 is greater than its length on the front side of the preceding battery cell 200. This reduces the obstruction of the front side of the preceding battery cell 200 by the overlapping segment 130.

[0199] This application discloses a photovoltaic module, which includes at least a cover plate, a back sheet, and a plurality of solar cell strings 10 as described in any of the above embodiments. The plurality of solar cell strings 10 are connected in parallel and / or in series. The cover plate and the back sheet are disposed on both sides of the plurality of solar cell strings 10, and the cover plate, the plurality of solar cell strings 10, and the back sheet are encapsulated to form a photovoltaic module.

[0200] Multiple solar cell strings 10 are connected in series and / or parallel. Subsequent processes such as layout, lamination, and frame assembly are used to encapsulate the cover plate, multiple solar cell strings 10, and backsheet to form a photovoltaic module. By using the solar cell strings 10 of the above embodiment, the photovoltaic module of this application reduces the processing difficulty of the photovoltaic solder ribbon 100, increases the bifaciality of the photovoltaic module, and also reduces the distance between the preceding cell 200 and the following cell 300, thereby improving the efficiency of the photovoltaic module.

[0201] 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.

[0202] 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 patent application. 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.

Claims

1. A photovoltaic welding strip, characterized in that, include: A first welding wire (110), one end of which has a first connecting section (111), and the outer surface of the first welding wire (110) has a first reflective surface (114) and a first mounting surface (115); and The second welding wire (120) has a second connecting section (121) at one end. Wherein, the first connecting segment (111) and / or the second connecting segment (121) are arranged in a flat shape, the first connecting segment (111) and the second connecting segment (121) are stacked to form an overlapping segment (130), the first welding wire (110) and the second welding wire (120) are directly connected to form the photovoltaic welding strip (100), the photovoltaic welding strip (100) can be connected to the front of the previous battery cell (200) through the first mounting surface (115) of the first welding wire (110), and connected to the back of the adjacent subsequent battery cell (300) through the second welding wire (120), the overlapping segment (130) is located on the front of the previous battery cell (200) and / or the back of the subsequent battery cell (300); The first welding wire (110) has a triangular cross-sectional shape, and the second welding wire (120) has a circular cross-sectional shape, or the first welding wire (110) has a triangular cross-sectional shape, the second welding wire (120) has a triangular cross-sectional shape, and they are arranged inverted relative to the first welding wire (110).

2. The photovoltaic welding strip according to claim 1, characterized in that, The overlap dimension of the first connecting segment (111) and the second connecting segment (121) along the length direction is greater than or equal to 0.5 mm; And / or, the dimension of the overlapping segment (130) along the thickness direction is less than 0.15 mm; And / or, the overlapping segment (130) is separated from the front metal electrode of the preceding cell (200) and / or the back metal electrode of the following cell (300).

3. The photovoltaic welding strip according to claim 1, characterized in that, The first welding wire (110) also includes a first main body segment (112), and the first connecting segment (111) is disposed at one end of the first main body segment (112). The first main body segment (112) can be connected to the front side of the previous battery cell (200). The second welding wire (120) also includes a second main body segment (122), and the second connecting segment (121) is disposed at one end of the second main body segment (122). The second main body segment (122) can be connected to the back side of the next battery cell (300).

4. The photovoltaic welding strip according to claim 3, characterized in that, The dimension of the first main body segment (112) along the thickness direction is greater than or equal to the dimension of the second main body segment (122) along the thickness direction; And / or, the thickness of the overlapping segment (130) is less than the thickness of the first main segment (112) and / or the second main segment (122).

5. The photovoltaic welding strip according to claim 3, characterized in that, The side length of the first main body segment (112) ranges from 0.1mm to 0.35mm.

6. The photovoltaic welding strip according to claim 5, characterized in that, The adjacent sides of the first main body segment (112) are connected by a chamfered section.

7. The photovoltaic welding strip according to claim 3, characterized in that, The first main body segment (112) further includes a first connecting part (116) and a second connecting part (117). The first connecting part (116) is disposed on the second connecting part (117) along the thickness direction. The cross-sectional shape of the first connecting part (116) is triangular, and the cross-sectional shape of the second connecting part (117) is rectangular. The second connecting part (117) is connected to the front side of the previous battery cell (200).

8. The photovoltaic welding strip according to claim 3, characterized in that, The diameter of the second main body segment (122) ranges from 0.1 mm to 0.3 mm; Alternatively, the cross-sectional shape of the second main body segment (122) is triangular, and the side length of the second main body segment (122) ranges from 0.1mm to 0.35mm.

9. The photovoltaic welding strip according to claim 3, characterized in that, When the cross-sectional shape of the second main body segment (122) is triangular, the second welding wire (120) also includes a second reflective surface and a second mounting surface. The second mounting surface is connected to the back of the rear battery cell (300), and the second reflective surface is used to reflect light on the back of the rear battery cell (300).

10. The photovoltaic welding strip according to any one of claims 1 to 9, characterized in that, Along the thickness direction, the first connecting segment (111) is located on the upper surface of the second connecting segment (121), or the first connecting segment (111) is located on the lower surface of the second connecting segment (121).

11. The photovoltaic welding strip according to any one of claims 1 to 9, characterized in that, The first connecting segment (111) is welded to the second connecting segment (121).

12. The photovoltaic welding strip according to claim 11, characterized in that, The first connecting segment (111) and the second connecting segment (121) are connected by laser welding, ultrasonic welding, infrared welding or electric arc welding.

13. The photovoltaic welding strip according to any one of claims 1 to 9, characterized in that, The first welding wire (110) includes a first copper substrate, a first welding coating and a reflective coating. The first welding coating and the reflective coating cover the outer periphery of the first copper substrate. The first welding coating forms the first mounting surface (115) for welding connection with the previous battery cell (200). The reflective coating forms the first reflective surface (114). The second welding wire (120) includes a second copper substrate and a second welding coating. The second welding coating covers the outer periphery of the second copper substrate and is welded to the next battery cell (300).

14. The photovoltaic welding strip according to claim 13, characterized in that, The first welding coating includes a tin-lead alloy coating, a tin-lead-bismuth alloy coating, or a tin-silver alloy coating; And / or, the reflective coating includes a silver coating or an aluminum coating; And / or, the second welding coating includes a tin-lead alloy coating, a tin-lead-bismuth alloy coating, or a tin-silver alloy coating.

15. The photovoltaic welding strip according to claim 14, characterized in that, The first welding coating includes a tin-lead alloy coating or a tin-lead-bismuth alloy coating, the reflective coating includes an aluminum coating or a silver coating, and when the second welding coating includes a tin-lead alloy coating or a tin-lead-bismuth alloy coating, the overlapping section (130) includes at least tin, lead and copper, and also includes either aluminum or silver.

16. The photovoltaic welding strip according to claim 13, characterized in that, The overlapping section (130) further includes a first fusion portion, wherein the first welding coating, the reflective coating, and the second welding coating are fused to form the first fusion portion; And / or, the overlapping segment (130) further includes a second fusion portion, wherein the first copper substrate and the second copper substrate are fused to form the second fusion portion.

17. A method for forming photovoltaic ribbon, characterized in that, For forming a photovoltaic ribbon (100) as described in any one of claims 1 to 16, the photovoltaic ribbon forming method includes at least the following steps: The first raw material is fed by a first feeding mechanism, and the first raw material is cut by a first wire drawing mechanism to form a first welding wire (110) of a predetermined length. The first welding wire (110) is then fed to the interconnection platform. The second raw material is fed by a second feeding mechanism, and the second raw material is cut by a second wire drawing mechanism to form a second welding wire (120) of a predetermined length. The second welding wire (120) is then fed to the interconnection platform. The first welding wire (110) and the second welding wire (120) are connected to form the photovoltaic welding strip (100). The first welding wire (110) can be connected to the front side of the previous cell (200), and the second welding wire (120) can be connected to the back side of the next cell (300).

18. The photovoltaic ribbon forming method according to claim 17, characterized in that, Connecting the first welding wire (110) and the second welding wire (120) to form the photovoltaic welding strip (100) includes at least the following steps: One end of the first welding wire (110) is flattened to form a first connecting segment (111), and one end of the second welding wire (120) is flattened to form a second connecting segment (121). The first connecting segment (111) and the second connecting segment (121) are connected to form an overlapping segment (130). Alternatively, one end of the first welding wire (110) can be connected to one end of the second welding wire (120) to form an overlapping section (130), and the overlapping section (130) can be flattened. Alternatively, one end of the first welding wire (110) is flattened to form a first connecting segment (111), one end of the second welding wire (120) is flattened to form a second connecting segment (121), the first connecting segment (111) and the second connecting segment (121) are connected to form an overlapping segment (130), and the overlapping segment (130) is flattened.

19. The photovoltaic ribbon forming method according to claim 17 or 18, characterized in that, The first welding wire (110) includes a first copper substrate, a first welding coating and a reflective coating. The first welding coating and the reflective coating cover the outer periphery of the first copper substrate. The first welding coating forms a first mounting surface (115) and the reflective coating forms a first reflective surface (114). The second welding wire (120) includes a second copper substrate and a second welding coating, the second welding coating covering the outer periphery of the second copper substrate.

20. The photovoltaic ribbon forming method according to claim 19, characterized in that, Connecting the first welding wire (110) and the second welding wire (120) to form the photovoltaic welding strip (100) further includes at least the following steps: The reflective coating, the first welding coating, and the second welding coating are melted using laser welding, ultrasonic welding, infrared welding, or electric arc welding. The first copper substrate and the second copper substrate are welded together.

21. The photovoltaic ribbon forming method according to claim 20, characterized in that, Connecting the first welding wire (110) and the second welding wire (120) to form the photovoltaic welding strip (100) further includes at least the following steps: The reflective coating, the first welding coating, and the second welding coating are fused together between the first copper substrate and the second copper substrate to form a first fused portion; And / or, the first copper substrate and the second copper substrate are fused together to form a second fused portion.

22. A solar cell string, characterized in that, It includes a front cell (200), a rear cell (300), and a photovoltaic ribbon (100) as described in any one of claims 1 to 16. The preceding solar cell (200) and the following solar cell (300) are arranged along the length of the photovoltaic ribbon (100). The first welding wire (110) of the photovoltaic ribbon (100) is connected to the front side of the preceding solar cell (200), and the second welding wire (120) is connected to the back side of the following solar cell (300), so that the preceding solar cell (200) and the following solar cell (300) are connected in series.

23. The solar cell string according to claim 22, characterized in that, The overlapping section (130) of the photovoltaic ribbon (100) is located on the back side of the subsequent cell (300), and / or the overlapping section (130) of the photovoltaic ribbon (100) is located on the front side of the preceding cell (200). When the overlapping segment (130) is located on the front side of the preceding battery cell (200) and the back side of the following battery cell (300), the length of the overlapping segment (130) on the back side of the following battery cell (300) is greater than the length of the overlapping segment (130) on the front side of the preceding battery cell (200).

24. A photovoltaic module, characterized in that, It includes at least a cover plate, a back plate, and a plurality of solar cell strings (10) as described in claim 22 or 23; Multiple solar cell strings (10) are connected in parallel and / or in series. The cover plate and the back plate are disposed on both sides of the multiple solar cell strings (10) and encapsulate the cover plate, the multiple solar cell strings (10) and the back plate to form the photovoltaic module.

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