A solder strip, a manufacturing method thereof and a photovoltaic module

Abstract

The application discloses a solder strip and a manufacturing method thereof and a photovoltaic module, and relates to the technical field of photovoltaic technology. The solder strip is used for connecting adjacent solar cell pieces. The solder strip comprises a substrate layer and a coating layer covering the outer surface of the substrate layer. In the thickness direction of the solder strip, the cross section of the substrate layer is a regular polygon, and the cross section of the solder strip is a circle with at least one positioning structure. The positioning structure is located on the side of the solder strip which is not connected with the solar cell pieces. The solder strip can improve the soldering effect and reduce the production cost.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and more specifically, to a solder strip and its manufacturing method, and a photovoltaic module. Background Technology

[0002] Photovoltaic modules mainly consist of solar cells, solder strips, cover plates, encapsulating films, frames, junction boxes, and other components.

[0003] Among them, while reducing costs, materials such as frames and encapsulants can significantly impact the reliability of photovoltaic modules. In order to reduce costs and increase efficiency of photovoltaic modules under the premise of rising prices of solar cells and auxiliary materials, efforts can be made to promote the development of the solder strips that are in direct contact with solar cells in photovoltaic modules. Summary of the Invention

[0004] In view of this, this application provides a welding strip and its manufacturing method, as well as a photovoltaic module, which can improve the welding effect while reducing production costs.

[0005] In a first aspect, this application provides a solder strip for connecting adjacent solar cells. The solder strip includes a substrate layer and a coating covering the outer surface of the substrate layer. Along the thickness direction of the solder strip, the cross-section of the substrate layer is a regular polygon, and the cross-section of the solder strip is a circle with at least one positioning structure located on the side of the solder strip that is not connected to the solar cell.

[0006] Optionally, where:

[0007] Along the radial direction of the weld strip, the spacing between the coating and the substrate layer at the positioning structure is smaller than at other locations.

[0008] Optionally, where:

[0009] Along the thickness direction of the solder strip, the cross-section of the substrate layer is a regular polygon with a rounded apex.

[0010] Optionally, where:

[0011] Along any radial direction of the weld strip, there is a first spacing d1 between the outer surface of the coating and the outer surface of the arc apex of the substrate layer, where 2μm≤d1≤5μm.

[0012] Optionally, where:

[0013] When the solder strip is connected to the light-facing side of the solar cell, the solder strip has a proximity to the solar cell.

[0014] On the backlight side and the light-facing side away from the solar cell, at least one positioning structure is located on the light-facing side.

[0015] Optionally, where:

[0016] In the cross-section along the thickness direction of the solder strip, the extension directions of the coating and the substrate layer at the positioning structure intersect; or,

[0017] In the cross-section along the thickness direction of the solder strip, the coating located at the positioning structure has at least two different extension directions.

[0018] Optionally, where:

[0019] In the cross-section along the thickness direction of the solder strip, the extension directions of the coating and the substrate layer at the positioning structure are parallel.

[0020] Secondly, this application also provides a method for manufacturing the solder strip described in the first aspect, comprising:

[0021] A prefabricated substrate layer is provided, wherein the cross-section of the prefabricated substrate layer is circular along the thickness direction;

[0022] The prefabricated substrate layer is calendered to obtain a substrate layer with a regular polygonal cross-section along the thickness direction;

[0023] A coating is applied to the outer surface of the substrate layer, and the coating covers the substrate layer;

[0024] At least one positioning structure is formed on the coating to obtain a solder strip;

[0025] 0 In this case, the coating and substrate layer at the positioning structure extend in the same direction; along the diameter of the weld strip

[0026] In this case, the distance between the coating and the substrate layer at the positioning structure is smaller than at other locations.

[0027] Optionally, where:

[0028] After calendering the precast substrate layer to obtain a substrate layer with a regular polygonal cross-section along the thickness direction,

[0029] The method for fabricating solder strips further includes, before the coating is applied to the outer surface of the substrate layer, the method of fabricating solder strips including:

[0030] The calendered substrate layer is then annealed.

[0031] Thirdly, this application also provides a photovoltaic module, which includes a plurality of solar cells, with adjacent solar cells connected by solder strips as described in the first aspect.

[0032] Compared with the prior art, the solder strip and its manufacturing method, as well as the photovoltaic module provided in this application, achieve at least the following beneficial effects:

[0033] In the solder strip provided in this application embodiment, the cross-section of the substrate layer in the thickness direction of the solder strip is a regular polygon. This not only significantly increases the area ratio of the substrate layer, thereby reducing the series resistance of the photovoltaic module and improving the power of the photovoltaic module, but also reduces the proportion of the coating, reducing the cost of the coating, and thus reducing the production cost, which is conducive to cost reduction and efficiency improvement of photovoltaic modules. At the same time, the solder strip provided in this application embodiment can be smoothly welded to the solar cell through the straight edge of the substrate layer with a regular polygon cross-section in the thickness direction, increasing the contact area between the substrate layer and the solar cell, thereby reducing the contact resistance of the solar cell and the series resistance of the photovoltaic module, and further improving the power of the photovoltaic module. On the other hand, compared with conventional circular cross-section solder strips, the solder strip provided in this application embodiment has more coating under the substrate layer at the contact position with the solar cell, which significantly improves the welding effect of the solder strip, while having the same solder strip size. At the same time, the cross-section of the solder strip in the thickness direction also has at least one positioning structure, and the positioning structure is not located on the side where the solder strip is connected to the solar cell, so that the solder strip has a clear positioning identification area, which facilitates the positioning of the straight edge of the substrate layer during welding, ensuring that the solder strip contacts the solar cell through the straight edge of the substrate layer, further improving the welding effect, ensuring the welding quality, and contributing to further cost reduction and efficiency improvement of photovoltaic modules.

[0034] Of course, any product implementing this application does not necessarily need to achieve all of the technical effects described above at the same time.

[0035] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0037] Figure 1 The figure shown is a schematic diagram of the cross-section of the solder strip in the thickness direction provided in an embodiment of this application;

[0038] Figure 2 The diagram shown is a schematic representation of a connection between the solder strip and the light-facing surface of a solar cell in the thickness direction, according to an embodiment of this application.

[0039] Figure 3 The diagram shown is a schematic diagram of a connection between the solder strip and the back surface of the solar cell in the thickness direction according to an embodiment of this application.

[0040] Figure 4 The diagram shown is a structural schematic of the photovoltaic module provided in the embodiment of this application. Detailed Implementation

[0041] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0042] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0043] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0044] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0046] Photovoltaic modules mainly consist of solar cells, solder strips, cover plates, encapsulating films, frames, junction boxes, and other components.

[0047] With the soaring prices of solar cells and auxiliary materials in photovoltaic modules, and the weak bargaining power of module manufacturers leading to a continuous decline in production profits, all module manufacturers have increased their investment in cost reduction and efficiency improvement projects. However, since materials such as frames and encapsulants can significantly impact the reliability of photovoltaic modules while reducing costs, it is difficult to promote them to a large extent. Meanwhile, there is still considerable room for cost reduction and efficiency improvement of photovoltaic modules in the solder ribbons that are in direct contact with solar cells.

[0048] The current design of circular solder strips on regular polygonal copper substrates does not take into account the solder strip positioning problem. There are cases where the top corner area of ​​the copper substrate is directly facing the gate line, which can easily lead to poor welding effect, high contact resistance and microcracks. Moreover, the proportion of tin-lead layer is only significantly reduced when the number of sides of regular polygonal copper substrates is ten, twelve or more. The proportion of octagonal copper substrates will actually decrease significantly, which will lead to problems such as poor welding quality.

[0049] To address the aforementioned technical problems, this application proposes a welding strip and its manufacturing method, as well as a photovoltaic module, which can improve welding performance while reducing costs.

[0050] The following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0051] Figure 1 The figure shown is a schematic diagram of the cross-section of the solder strip in the thickness direction provided in an embodiment of this application; Figure 2 The diagram shown is a schematic representation of a connection between the solder strip and the light-facing surface of a solar cell in the thickness direction, according to an embodiment of this application. Figure 3 The diagram shown is a schematic diagram of a connection between the solder strip and the back surface of the solar cell in the thickness direction, according to an embodiment of this application.

[0052] like Figures 1-3 As shown, this application embodiment provides a solder ribbon 1 for connecting adjacent solar cells 2. The solder ribbon 1 includes a substrate layer 11 and a coating 12 covering the outer surface of the substrate layer 11. Along the thickness direction of the solder ribbon 1, the cross-section of the substrate layer 11 is a regular polygon, and the cross-section of the solder ribbon 1 is a circle with at least one positioning structure 13. The positioning structure 13 is located on the side of the solder ribbon 1 that is not connected to the solar cell 2.

[0053] Based on this, such as Figures 1-3 As shown, in the solder ribbon 1 provided in the embodiment of this application, the solder ribbon 1 is composed of a substrate layer 11 and a coating 12 covering the outer surface of the substrate layer 11. When the solder ribbon 1 and the solar cell 2 are connected, the substrate layer 11 plays the role of transporting charge carriers, and the coating 12 covering the substrate layer 11 plays the role of welding and fixing. In the thickness direction of the solder strip 1, the cross-section of the substrate layer 11 is a regular polygon. Compared with conventional solder strips with a circular cross-section, the substrate layer 11 with a regular polygon cross-section has a larger cross-sectional area and fewer coatings 12 that can be applied to the outer surface, which not only significantly increases the area ratio of the substrate layer 11, thereby reducing the series resistance of the photovoltaic module and increasing the power of the photovoltaic module, but also reduces the proportion of the coating 12, reducing the cost of the coating 12, and thus reducing the production cost, which is conducive to cost reduction and efficiency improvement of photovoltaic modules. At the same time, compared with conventional solder strips with a circular cross-section of the same size, the solder strip 1 provided in this embodiment can be smoothly welded to the solar cell 2 through the straight edge of the substrate layer 11 with a regular polygon cross-section in the thickness direction, increasing the contact area between the substrate layer 11 and the solar cell 2, thereby reducing the contact resistance of the solar cell 2 and the series resistance of the photovoltaic module, and further improving the power of the photovoltaic module.

[0054] On the other hand, in the solder strip 1 provided in the embodiments of this application, the cross section of the solder strip 1 is a circle with at least one positioning structure 13 along the thickness direction of the solder strip 1, and the positioning structure 13 is located on the side of the solder strip 1 that is not connected to the solar cell 2. Compared to conventional circular cross-section solder strips, the solder strip 1 provided in this embodiment has more coating 12 under the substrate layer 11 at the contact position with the solar cell 2, while maintaining the same solder strip size. This results in more coating 12 being squeezed out to the periphery of the contact position during solder strip welding, significantly improving the welding effect of the solder strip 1. Simultaneously, the solder strip 1 also has at least one positioning structure 13 in its thickness direction cross-section. This positioning structure 13 is not located on the side where the solder strip 1 connects to the solar cell 2, giving the solder strip 1 a clear positioning identification area. This facilitates positioning the straight edge of the substrate layer 11 during welding, ensuring that the solder strip 1 contacts the solar cell 2 through the straight edge of the substrate layer 11. This avoids the apex of the substrate layer 11 being opposite the solar cell 2 during welding, further improving the welding effect, ensuring welding quality, and contributing to further cost reduction and efficiency improvement of photovoltaic modules.

[0055] It should be noted that the conventional circular cross-section solder strip with the same solder strip size as the one provided in the embodiments of this application refers to a conventional circular cross-section solder strip in which the substrate layer and the coating wrapped around the substrate layer are concentric circles in the thickness direction, and the coating radius is the same as the coating radius in the embodiments of this application, and the substrate layer radius is the same as the inscribed circle radius of the substrate layer provided in the embodiments of this application.

[0056] In some examples, the cross-section of the substrate layer along the thickness direction of the solder strip can be an equilateral triangle, square, pentagon, hexagon, heptagon, octagon, etc., without specifying a particular number of sides. It is important to note that, assuming the overall dimensions of the solder strip remain unchanged, as the number of sides of the substrate layer cross-section increases, the cross-section gradually approaches a circle, and the straight edges of the substrate layer become shorter. This results in a gradually decreasing contact area between the substrate layer and the solar cell during welding. Conversely, if the number of sides of the substrate layer cross-section is too small, the amount of coating used increases, reducing the proportion of the substrate layer, which contradicts the goal of cost reduction and efficiency improvement. Therefore, the number of sides of the substrate layer cross-section should be selected based on actual needs.

[0057] It is important to note that the number of sides of the cross-sectional pattern of the substrate layer in the thickness direction is also related to the connection method between the solder strip and the solar cell. For example, when adjacent solar cells are connected by solder strips with surfaces facing the same direction, only one side of the solder strip contacts the solar cell. In this case, the number of sides of the cross-sectional pattern of the substrate layer along the thickness direction of the solder strip can be an integer greater than 3. If adjacent solar cells are connected end-to-end by solder strips, both opposite sides of the solder strip need to contact the solar cell. In this case, the number of sides of the cross-sectional pattern of the substrate layer along the thickness direction of the solder strip can be an even number greater than 3 to ensure that the solder strip contacts the solar cell through the straight edge of the substrate layer, improving the welding effect and the power of the photovoltaic module.

[0058] In some examples, such as Figure 2 and Figure 3 As shown, the solder strip 1 provided in this application embodiment can be applied to a solar cell 2 with a main grid, and connected to the solar cell 2 through the main grid 21, or it can be applied to a solar cell without a main grid, and connected to the solar cell through a fine grid. This application embodiment does not limit this.

[0059] For example, the substrate layer can be a copper substrate, and the coating can be a tin coating, a tin-lead coating, a tin-silver coating, a tin-lead-silver coating, a tin-silver-copper coating, etc. This is just an example and is not a specific limitation.

[0060] In some examples, such as Figures 1-3 As shown, along the radial direction of the solder strip 1, the spacing between the coating 12 and the substrate layer 11 at the positioning structure 13 is smaller than at other locations.

[0061] Based on this, such as Figures 1-3 As shown, the radial spacing between the coating 12 at the positioning structure 13 and the substrate layer 11 in the solder strip 1 can be set to be smaller than that at other locations. That is, the coating 12 at the positioning structure 13 is thinned, making the positioning structure 13 significantly different from other locations on the solder strip 1. This results in the solder strip 1 having a clear positioning identification area, ensuring accurate positioning of the straight edge of the substrate layer 11 during welding. This ensures that the contact point between the solder strip 1 and the solar cell 2 is the straight edge of the substrate layer 11, avoiding poor welding effect and high contact resistance caused by the apex of the substrate layer 11 being opposite the solar cell 2. This further improves the welding effect and welding quality, reduces contact resistance, and is beneficial for further cost reduction and efficiency improvement of photovoltaic modules.

[0062] In some examples, such as Figures 1-3As shown, in order to better locate the straight edge of the substrate layer 11, the coating 12 wrapped on one of the straight edges of the substrate layer 11 can be thinned to form a positioning structure 13. In the cross section in the thickness direction of the solder strip 1, the projection length of the coating 12 at the positioning structure 13 on the substrate layer 11 is set to be the same as the length of the substrate layer 11. This allows the straight edge of the substrate layer 11 to be located directly according to the positioning structure 13, thereby improving the positioning accuracy of the positioning structure 13.

[0063] In some examples, the solder strip provided in the embodiments of this application may have one positioning structure, or two, three, four, etc. This is only an example and does not limit the specific number of positioning structures.

[0064] It is important to note that the specific number of positioning structures needs to be limited based on the number of sides of the cross-section of the substrate layer in the thickness direction, and they cannot be placed at the contact point between the solder strip and the solar cell, to avoid the thin coating at the positioning structure negatively impacting the welding quality and effect. For example, when the cross-section of the substrate layer in the thickness direction is an equilateral triangle, at least one and at most two positioning structures should be set; when the cross-section of the substrate layer in the thickness direction is a regular square, at least one and at most three positioning structures should be set; when the cross-section of the substrate layer in the thickness direction is a regular pentagon, at least one and at most four positioning structures should be set; when the cross-section of the substrate layer in the thickness direction is a regular hexagon, at least one and at most five positioning structures should be set, and so on. These are just examples and are not specific limitations.

[0065] For example, such as Figures 1-3 As shown, the substrate layer 11 in the solder strip 1 provided in this embodiment can be a regular hexagon in the thickness direction. The solder strip 1 is provided with two positioning structures 13. This is only an example and is not specifically limited.

[0066] As one possible implementation, such as Figures 1-3 As shown, along the thickness direction of the solder strip 1, the cross-section of the substrate layer 11 is a regular polygon with a rounded apex.

[0067] Based on this, such as Figures 1-3As shown in the embodiment of this application, in the solder strip 1, the apex angle of the substrate layer 11 in the thickness direction cross-section can be adjusted to a rounded apex angle. Compared with a right-angled apex angle that fixes the proportion of the substrate layer, this embodiment of the application can adjust the proportion of the substrate layer 11 and the coating 12 by adjusting the curvature of the rounded apex angle, thereby optimizing the welding quality and effect of the solder strip 1 and controlling production costs. As the curvature of the rounded apex angle increases, the cross-sectional shape of the substrate layer 11 in the thickness direction approaches a circle, the volume proportion of the substrate layer 11 increases, and the length of the straight edge of the substrate layer 11 in the cross-section is correspondingly shortened, thus reducing the amount of coating 12 wrapped around the straight edge. Therefore, in actual production, the proportion of the substrate layer 11 and the coating 12 can be adjusted by adjusting the curvature of the rounded apex angle, achieving cost reduction and efficiency improvement of photovoltaic modules while ensuring welding quality and effect. The specific curvature and range of the rounded apex angle can be determined in actual production and will not be listed here.

[0068] In some examples, such as Figures 1-3 As shown, along any radial direction of the weld strip 1, there is a first distance d1 between the outer surface of the coating 12 and the outer surface of the arc-shaped apex of the substrate layer 11, where 2μm≤d1≤5μm. Based on this, a thinner coating 12 can be left outside the arc-shaped apex of the substrate layer 11, preventing exposure of the substrate layer 11, ensuring welding quality, reducing the amount of coating 12 used, and lowering production costs. If the first distance d1 between the outer surface of the coating 12 and the outer surface of the arc-shaped apex of the substrate layer 11 is less than 2μm along any radial direction of the weld strip 1, the coating 12 left outside the arc-shaped apex is too thin, which may lead to exposure of the substrate layer 11 and adversely affect welding quality. If the first distance d1 between the outer surface of the coating 12 and the outer surface of the arc-shaped apex of the substrate layer 11 is greater than 5μm along any radial direction of the weld strip 1, the coating 12 left outside the arc-shaped apex is too thick, increasing the cost of the coating 12 and consequently increasing production costs.

[0069] For example, along any radial direction of the solder strip, the first spacing d1 between the outer surface of the coating and the outer surface of the arc corner of the substrate layer can be 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, etc., which are only examples and are not specifically limited.

[0070] As one possible implementation, such as Figures 1-3 As shown, when the solder ribbon 1 is connected to the light-facing side of the solar cell 2, the solder ribbon 1 has a back-light side close to the solar cell 2 and a light-facing side away from the solar cell 2, and at least one positioning structure 13 is located on the light-facing side.

[0071] Based on this, such as Figures 1-3As shown, since the cross-sectional shape of the substrate layer 11 in the thickness direction is a regular polygon, and the positioning structure 13 is formed by thinning the coating 12 at the straight edge of the substrate layer 11, when the solder ribbon 1 is connected to the light-facing surface of the solar cell 2, if at least one positioning structure 13 is located on the side of the solder ribbon 1 away from the solar cell 2, that is, the light-facing side of the solder ribbon 1, the positioning structure 13 can reflect the light incident on the solder ribbon 1 into the photovoltaic module at a certain angle, thereby improving the utilization rate of light and thus improving the module efficiency of the photovoltaic module.

[0072] In some examples, on a cross-section along the thickness direction of the solder strip, the extension directions of the coating and the substrate layer at the positioning structure intersect; or,

[0073] In the cross-section along the thickness direction of the solder strip, the coating located at the positioning structure has at least two different extension directions.

[0074] Based on this, to achieve light reflection by the positioning structure, the extension directions of the coating and substrate layer at the positioning structure in the thickness direction section can be set to intersect. That is, in the thickness direction section, the coating at the positioning structure extends at an angle relative to the substrate layer. Placing this positioning structure on the light-facing side of the solder ribbon and rotating it so that the extension direction of the positioning structure intersects with the extension direction of the solar cell in the thickness direction section achieves a similar effect to the triangular solder ribbon, improving light utilization and further enhancing the efficiency of the photovoltaic module. Alternatively, the extension direction of the coating at the positioning structure in the thickness direction section can be set to at least two different directions. In this case, the different extension directions of the coating can be used to create a light-trapping effect in the resulting positioning structure, further improving light utilization and enhancing the efficiency of the photovoltaic module.

[0075] For example, when the coating at the positioning structure has at least two different extension directions in the cross section of the thickness direction of the solder strip, the pattern of the coating at the positioning structure in the cross section of the thickness direction can be a concave surface with an opening away from the substrate layer, a textured surface composed of multiple small triangles, a textured surface composed of multiple small concave surfaces with openings away from the substrate layer, etc. This is just an example and is not specifically limited.

[0076] In some examples, such as Figures 1-3 As shown, in the cross-section along the thickness direction of the solder strip 1, the coating 12 and the substrate layer 11 located at the positioning structure 13 extend in parallel directions.

[0077] Based on this, such as Figures 1-3As shown, to achieve light reflection by the positioning structure 13, the coating 12 at the positioning structure 13 can be directly positioned so that its extension direction in the thickness direction section is parallel to the extension direction of the substrate layer 11. This positioning structure 13 is placed on the light-facing side of the solder ribbon 1 and rotated until its extension direction intersects with the extension direction of the solar cell 2 in the thickness direction section. This achieves a similar effect to the triangular solder ribbon in improving light utilization, further enhancing the efficiency of the photovoltaic module. Simultaneously, the parallel design of the coating 12 at the positioning structure 13 with the substrate layer 11 minimizes the amount of coating 12 used, thereby reducing production costs and facilitating further cost reduction and efficiency improvement in photovoltaic modules. Furthermore, the parallel design of the coating 12 at the positioning structure 13 with the substrate layer 11 is easier to form during production, reducing processing difficulty.

[0078] Based on the same inventive concept, this application also provides a method for manufacturing solder strips as described in the above embodiments, comprising:

[0079] A prefabricated substrate layer is provided, wherein the cross-section of the prefabricated substrate layer is circular along the thickness direction;

[0080] The prefabricated substrate layer is calendered to obtain a substrate layer with a regular polygonal cross-section along the thickness direction;

[0081] A coating is applied to the outer surface of the substrate layer, and the coating covers the substrate layer;

[0082] At least one positioning structure is formed on the coating to obtain a solder strip;

[0083] In this case, the coating and the substrate layer at the positioning structure extend in the same direction; along the radial direction of the weld strip, the distance between the coating and the substrate layer at the positioning structure is smaller than at other locations.

[0084] Compared with the prior art, the beneficial effects of the method for manufacturing solder strips are the same as those of the solder strips described in the above embodiments, and will not be repeated here.

[0085] In some examples, the prefabricated substrate layer can be formed by a wire drawing process; when forming the substrate layer, the shape of the calendering die can be changed so that the cross-section of the pressed substrate layer in the thickness direction is a regular polygon.

[0086] In some examples, when the coating and substrate layer are parallel at the location of the positioning structure on the cross section in the thickness direction of the weld strip, the positioning structure can be formed by blowing a plane parallel to the straight edge of the substrate layer on the coating after the coating is applied by changing the shape of the air knife.

[0087] In some examples, after calendering a precast substrate layer to obtain a substrate layer with a regular polygonal cross-section along the thickness direction, the method of fabricating the solder strip further includes coating the outer surface of the substrate layer with a coating before the coating covers the substrate layer:

[0088] The calendered substrate layer is then annealed.

[0089] Therefore, annealing the calendered substrate layer can remove residual stress, improve its plasticity and toughness, make its composition more uniform, and extend its service life. Specific annealing temperatures and times can be adjusted in actual production; examples are not provided here.

[0090] Figure 4 The diagram shown is a structural schematic of the photovoltaic module provided in the embodiment of this application.

[0091] Based on the same inventive concept, such as Figure 4 As shown, this application also provides a photovoltaic module, which includes a plurality of solar cells 2, and adjacent solar cells 2 are connected by solder strips 1 as described in the above embodiments.

[0092] Compared with the prior art, the beneficial effects of photovoltaic modules are the same as those of the solder strips described in the above embodiments, and will not be repeated here.

[0093] like Figure 4 As shown, the photovoltaic module includes a cell string, which is formed by connecting multiple solar cells 2; an encapsulation layer 40, which covers the surface of the cell string; and a cover plate 30, which covers the surface of the encapsulation layer 40 away from the cell string. The solar cells 2 are electrically connected in a whole or in multiple segments to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel.

[0094] Specifically, in some embodiments, such as Figure 4 As shown, multiple battery strings can be electrically connected via the solder ribbon 1 provided in the above embodiment. The encapsulation layer 40 covers the front and back of the solar cell 2. Specifically, the encapsulation layer 40 can be an organic encapsulation film such as ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene copolymer elastomer (POE) film, polyvinyl butyral resin (PVB) film, or polyethylene terephthalate (PET) film. In some embodiments, the cover plate 30 can be a glass cover plate, a plastic cover plate, or other light-transmitting cover plate 30. Specifically, the surface of the cover plate 30 facing the encapsulation layer 40 can be an uneven surface, thereby increasing the utilization rate of incident light.

[0095] In summary, the solder strip, its manufacturing method, and photovoltaic module provided in this application achieve at least the following beneficial effects:

[0096] In the solder strip provided in this application embodiment, the cross-section of the substrate layer in the thickness direction of the solder strip is a regular polygon. This not only significantly increases the area ratio of the substrate layer, thereby reducing the series resistance of the photovoltaic module and improving the power of the photovoltaic module, but also reduces the proportion of the coating, reducing the cost of the coating, and thus reducing the production cost, which is conducive to cost reduction and efficiency improvement of photovoltaic modules. At the same time, the solder strip provided in this application embodiment can be smoothly welded to the solar cell through the straight edge of the substrate layer with a regular polygon cross-section in the thickness direction, increasing the contact area between the substrate layer and the solar cell, thereby reducing the contact resistance of the solar cell and the series resistance of the photovoltaic module, and further improving the power of the photovoltaic module. On the other hand, compared with conventional circular cross-section solder strips, the solder strip provided in this application embodiment has more coating under the substrate layer at the contact position with the solar cell, which significantly improves the welding effect of the solder strip, while having the same solder strip size. At the same time, the cross-section of the solder strip in the thickness direction also has at least one positioning structure, and the positioning structure is not located on the side where the solder strip is connected to the solar cell, so that the solder strip has a clear positioning identification area, which facilitates the positioning of the straight edge of the substrate layer during welding, ensuring that the solder strip contacts the solar cell through the straight edge of the substrate layer, further improving the welding effect, ensuring the welding quality, and contributing to further cost reduction and efficiency improvement of photovoltaic modules.

[0097] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A welding strip, characterized in that, For connecting adjacent solar cells, the solder strip includes a substrate layer and a coating covering the outer surface of the substrate layer; along the thickness direction of the solder strip, the cross-section of the substrate layer is a regular polygon, and the cross-section of the solder strip is a circle with at least one positioning structure located on the side of the solder strip not connected to the solar cell; Along the radial direction of the solder strip, the spacing between the coating and the substrate layer at the positioning structure is smaller than at other locations.

2. The welding strip according to claim 1, characterized in that, Along the thickness direction of the solder strip, the cross-section of the substrate layer is a regular polygon with a rounded apex.

3. The welding strip according to claim 2, characterized in that, Along any radial direction of the weld strip, there is a first distance d1 between the outer surface of the coating and the outer surface of the arc apex of the substrate layer, where 2μm≤d1≤5μm.

4. The welding strip according to claim 1, characterized in that, When the solder strip is connected to the light-facing side of the solar cell, the solder strip has a back-light side close to the solar cell and a light-facing side away from the solar cell, and at least one of the positioning structures is located on the light-facing side.

5. The welding strip according to claim 1, characterized in that, In a cross-section along the thickness direction of the solder strip, the extension directions of the coating and the substrate layer located at the positioning structure intersect. or, On a cross-section along the thickness direction of the solder strip, the coating located at the positioning structure has at least two different extension directions.

6. The welding strip according to claim 1, characterized in that, In a cross-section along the thickness direction of the solder strip, the coating and the substrate layer located at the positioning structure extend in parallel directions.

7. A method for manufacturing solder strips according to any one of claims 1 to 6, characterized in that, include: A prefabricated substrate layer is provided, wherein the cross-section of the prefabricated substrate layer is circular along the thickness direction; The prefabricated substrate layer is rolled to obtain a substrate layer with a regular polygonal cross-section along the thickness direction; A coating is applied to the outer surface of the substrate layer, the coating covering the substrate layer; At least one positioning structure is formed on the coating to obtain the solder strip; Wherein, the coating and the substrate layer located at the positioning structure extend in the same direction; along the radial direction of the solder strip, the distance between the coating and the substrate layer located at the positioning structure is smaller than at other locations.

8. The method for manufacturing solder strips according to claim 7, characterized in that, After calendering the pre-formed substrate layer to obtain a substrate layer with a regular polygonal cross-section along the thickness direction, and before coating the outer surface of the substrate layer with a coating that covers the substrate layer, the method for manufacturing the solder strip further includes: The calendered substrate layer is then annealed.

9. A photovoltaic module, characterized in that, The photovoltaic module includes a plurality of solar cells, and adjacent solar cells are connected by a solder strip as described in any one of claims 1 to 6.

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