A photovoltaic cell string and photovoltaic module

Abstract

This utility model discloses a photovoltaic cell string and a photovoltaic module, relating to the field of photovoltaic module technology. The photovoltaic cell string includes solar cells, solder ribbons, and busbars; multiple solar cells are arranged sequentially, with adjacent cells connected by solder ribbons; the busbars are disposed on the back of the solar cells, and along their length, include multiple welded portions and non-welded portions connecting adjacent welded portions; wherein the welded portions are electrically connected to the solder ribbons on the back of the solar cells, and the non-welded portions are arched relative to adjacent welded portions and disposed between at least a portion of two adjacent solder ribbons, with the welded portions electrically connected to the two adjacent solder ribbons. By placing the non-welded portions between adjacent solder ribbons, this photovoltaic cell string avoids the risk of arcing during photovoltaic module use.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic module technology, and in particular to a photovoltaic cell string and a photovoltaic module. Background Technology

[0002] The following problems exist when welding busbars to the back of the battery cell: During the welding process of the busbar to the solder strip, thermal stress will be generated due to the thermal expansion and contraction characteristics of the busbar. Therefore, during the cooling process after welding, the busbar will shrink, causing the busbar to pull the solder strip and pull the solder strip off from the main grid line, which in turn causes the EL (Electroluminescence) in this area to turn black.

[0003] To address the technical problem of the busbar pulling the solder strip during shrinkage, a solution was proposed to arch up a portion of the busbar to form a non-welded section. However, in this solution, the non-welded section is located above the solder strip and is spaced apart from it. This means that some solder strips on the solar cell are not welded to the busbar, leading to a risk of arcing during the subsequent use of the photovoltaic module. Utility Model Content

[0004] In view of this, the present invention provides a photovoltaic cell string and a photovoltaic module to solve the technical problem of arcing risk during the use of photovoltaic modules.

[0005] To solve the above-mentioned technical problems, this utility model provides a photovoltaic cell string, including cell cells, solder strips and busbars;

[0006] Multiple solar cells are arranged in sequence, and adjacent solar cells are connected by solder strips;

[0007] The busbar is disposed on the back of the battery cell. Along the length of the busbar, the busbar includes multiple welded portions and non-welded portions connecting two adjacent welded portions. The welded portions are electrically connected to the welding strips on the back of the battery cell, and the non-welded portions are arched relative to two adjacent welded portions and disposed between two adjacent welding strips.

[0008] Optionally, a non-welded portion may be provided between any two adjacent weld strips.

[0009] Optionally, the two welded parts connected to the non-welded parts are electrically connected to any two adjacent weld strips.

[0010] Optionally, the height of each non-welded portion is 0.2 to 0.8 mm along the direction perpendicular to the solar cell.

[0011] Alternatively, the non-welded portion may have one or more of the following shapes:

[0012] Arc, rectangle, trapezoid, triangle, wavy, sawtooth.

[0013] Optionally, the length of each weld is 3 to 4 mm along the length of the busbar.

[0014] Optionally, the busbar has a thickness of 0.05–0.12 mm and a width of 4–12 mm.

[0015] Optionally, the solder strip is a tin-lead solder strip with a diameter of 0.12–0.3 mm.

[0016] Optionally, the solar cells are either triple-cut or quadruple-cut solar cells.

[0017] This utility model also provides a photovoltaic module, including the photovoltaic cell string in any of the above embodiments.

[0018] The technical solution of this utility model has the following advantages or beneficial effects: Since the welded part is electrically connected to the welding strip on the back of the solar cell, and the non-welded part is located between two adjacent welding strips, there is no gap between the non-welded part and the welding strip, thereby avoiding the risk of arcing during the subsequent use of the photovoltaic module. Moreover, the busbar has a sufficient number of non-welded parts, which can fully release the thermal stress generated during the welding process between the busbar and the welding strip. This can effectively prevent the welding strip between the main grid lines from being pulled off due to the shrinkage of the busbar after welding, thereby effectively preventing EL blackening in this area and improving the process yield and reliability of the photovoltaic module. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a top view of a photovoltaic cell string according to an embodiment of the present utility model;

[0021] Figure 2a , Figure 2b , Figure 2c and Figure 2d This is a top view of a busbar being welded onto a photovoltaic cell string according to an embodiment of the present invention;

[0022] Figure 3 This is a top view of welding busbars onto multiple photovoltaic cell strings according to an embodiment of the present invention;

[0023] Figure 4a , Figure 4b , Figure 4c , Figure 4d , Figure 4e , Figure 4f and Figure 4g This is a schematic diagram of the welding of the busbar and the welding strip according to an embodiment of the present utility model.

[0024] The attached figures are labeled as follows:

[0025] 10-Photovoltaic cell string; 11-Solar cell; 12-Welding strip; 13-Busbar; 131-Welded part; 132-Non-welded part. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0027] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "circumferential", "radial", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model 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 utility model.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] The following problems exist when welding busbars to the back of solar cells: During the welding process, thermal stress is generated due to the thermal expansion and contraction characteristics of the busbar. Therefore, during the cooling process after welding, the busbar shrinks, causing it to pull the solder strip, pulling it detach from the main grid line, resulting in blackening of the EL in that area. To solve the technical problem of the busbar pulling the solder strip during shrinkage, patent CN221427754U (Chinese Utility Model Patent) proposes a solar cell string and solar cell module. However, the non-welded portion of the busbar is located above the solder strip and is spaced apart from it, resulting in some solder strips on the solar cell not being fully welded to the busbar (i.e., the busbar and solder strip are not fully welded), leading to the risk of arcing during the subsequent use of the photovoltaic module. Moreover, because the non-welded portion is spaced apart from at least one solder strip, the number of non-welded portions formed on the busbar is limited, and the thermal stress generated during welding can be released from the non-welded portion is also limited, making it impossible to effectively prevent the solder strip from being pulled apart due to shrinkage after welding. Therefore, this utility model embodiment proposes to avoid the risk of arcing during the use of photovoltaic modules by fully welding the busbar and the welding strip.

[0030] The specific structure of the photovoltaic cell string and photovoltaic module provided in the embodiments of this utility model will be described in detail below.

[0031] like Figure 1 , Figures 2a-2d As shown, the photovoltaic cell string 10 includes cell 11, solder ribbons 12, and busbars 13. Multiple cell 11 are arranged sequentially, and adjacent cell 11 are connected by solder ribbons 12. Further, the busbars 13 are disposed on the back side of the cell 11. Along the length of the busbars 13, the busbars 13 include multiple welded portions 131 and non-welded portions 132 connecting adjacent welded portions 131. The welded portions 131 are electrically connected to the solder ribbons 12 on the back side of the cell 11, and the non-welded portions 132 are arched relative to adjacent welded portions 131 and disposed between at least a portion of two adjacent solder ribbons 12. Because the welded portions 131 are electrically connected to the solder ribbons 12 on the back side of the cell 11, and the non-welded portions 132 are disposed between at least a portion of two adjacent solder ribbons 12, there is no gap between the non-welded portions 132 and the solder ribbons 12, thereby avoiding the risk of arcing during the subsequent use of the photovoltaic module.

[0032] It should be noted that multiple solar cells 11 are arranged sequentially, and are connected in series to form a photovoltaic cell string via solder ribbons 12. For example... Figure 1As shown, the photovoltaic cell string 10 includes a plurality of sequentially arranged cell sheets 11. For each cell sheet 11, the front side of the cell sheet 11 is welded to the back side of a cell sheet 11 on one side via a welding ribbon 12, and the back side of the cell sheet 11 is welded to the front side of a cell sheet 11 on the other side via a welding ribbon 12, thereby forming a photovoltaic cell string 10. It is understood that at least a portion of the welded portion 131 is planar, allowing this portion to contact and weld with the welding ribbon 12, thereby ensuring the reliability of the weld between the busbar 13 and the welding ribbon 12. The non-welded portion 132 is arched relative to two adjacent welded portions 131, and is disposed between at least a portion of two adjacent welding ribbons 12, and is not welded to the welding ribbon 12. In embodiments of this invention, the welded portion 131 is welded to each welding ribbon 12 on the back side of the cell sheet 11, referred to as full welding, which effectively avoids the risk of arcing caused by intermittent welding.

[0033] When the thermal stress of the busbar 13 is not high, the tensile force on the weld strip 12 caused by the shrinkage of the busbar 13 after welding is not large. Therefore, non-welded portions 132 can be provided only between some adjacent weld strips 12, such as... Figure 2a and Figure 2b As shown, the thermal stress generated during the welding process between the busbar 13 and the weld strip 12 is released through the non-welded portion 132. Figure 2a As shown, two welding strips 12 are provided between two adjacent non-welded parts 132, and each welded part 131 is welded to both welding strips 12. Figure 2b As shown, three welding strips 12 are provided between two adjacent non-welded parts 132, and each welding part 131 is welded to the three welding strips 12. That is, each welding strip 12 on the battery cell 11 is welded to the busbar 13.

[0034] When the thermal stress of the busbar 13 is high, the tensile force on the weld strip 12 caused by the shrinkage of the busbar 13 after welding is also large. Therefore, non-welded portions 132 can be provided between any two adjacent weld strips 12, such as... Figure 2c As shown, the non-welded portion 132 fully releases the thermal stress generated during the welding process between the busbar 13 and the welding strip 12. In this embodiment, a welding strip 12 is provided between two adjacent non-welded portions 132, and each welding portion 131 is welded to a welding strip 12.

[0035] It should be noted that the number of welding strips 12 provided between two adjacent non-welded parts 132 is not limited in this embodiment of the invention. Only one welding strip 12 can be provided, or multiple welding strips 12 can be provided, such as two, three, four, or five, etc. The number of welding strips 12 is mainly determined by the magnitude of the thermal stress generated between the busbar 13 and the welding strips 12 during the welding process. Generally speaking, the greater the thermal stress generated between the busbar 13 and the welding strips 12 during the welding process, the fewer welding strips 12 are provided between two adjacent non-welded parts 132; conversely, the smaller the thermal stress generated between the busbar 13 and the welding strips 12 during the welding process, the more welding strips 12 are provided between two adjacent non-welded parts 132.

[0036] It is understood that, in the embodiments of this utility model, the magnitude of the thermal stress generated during the welding process of the busbar 13 and the welding strip 12 is relative to the welding of the busbar 13 with each welding strip 12 on the same battery cell 11.

[0037] In some embodiments of this utility model, such as Figure 2c As shown, non-welded portions 132 are provided between any two adjacent solder strips 12. Therefore, the busbar 13 has a sufficient number of non-welded portions 132, which can effectively release the thermal stress generated during the welding process between the busbar 13 and the solder strips 12. Compared to the prior art technique of arching up a portion of the busbar to form non-welded portions, the photovoltaic cell string provided in this embodiment can have more non-welded portions 132 on the busbar 13. This more effectively prevents the solder strips 12 from being pulled off the main grid lines due to the contraction of the busbar 13 after welding, thus more effectively preventing EL blackening in this area and improving process yield and the reliability of the photovoltaic module.

[0038] Optionally, such as Figure 2c As shown, the two welded portions 131 connected to the non-welded portion 132 are electrically connected to any two adjacent solder strips 12. Therefore, the photovoltaic cell string 10 can, on the one hand, fully release the thermal stress generated by the busbar 13 during the welding process, ensuring that the solder strips 12 will not be pulled off by the busbar 13 during the cooling process after welding; on the other hand, the welded portions 131 of the busbar 13 are welded to each solder strip 12 on the cell 11, which can avoid the risk of arcing when the photovoltaic module is working under the condition of incomplete welding, thereby improving the reliability of the photovoltaic module.

[0039] Considering the significant tensile force exerted on the weld strips 12 at the edge of the battery cell 11 during the cooling process of the busbar 13, which could cause the battery cell 11 to warp, the number of non-welded portions 132 at the edge of the battery cell 11 can be appropriately increased. In other embodiments of this utility model, such as Figure 2dAs shown, for the solder strips 12 located in the middle of the battery cell 11, non-welded portions 132 are provided only between some of the adjacent two solder strips 12. That is, two or more solder strips 12 are provided between two adjacent non-welded portions 132, and each welding portion 131 is welded to two or more solder strips 12. For the solder strips 12 located at the edge of the battery cell 11, non-welded portions 132 are provided between any two adjacent solder strips 12. That is, only one solder strip 12 is provided between two adjacent non-welded portions 132, and each welding portion 131 is welded to one solder strip 12.

[0040] Furthermore, multiple photovoltaic cell strings 10 can be connected in parallel or in series via busbars 13. For example... Figure 3 As shown, two photovoltaic cell strings 10 are connected in parallel or in series via a busbar 13, which extends from the back of one photovoltaic cell string 10 to the back of another. Each photovoltaic cell string 10 includes a cell 11, a solder strip 12, and a busbar 13. Multiple cells 11 are arranged sequentially, and adjacent cells 11 are connected by solder strips 12. Further, the busbar 13 is disposed on the back of the cell 11. Along the length of the busbar 13, the busbar 13 includes multiple welded portions 131 and non-welded portions 132 connecting two adjacent welded portions 131. The welded portions 131 are electrically connected to the solder strips 12 on the back of the cell 11, and the non-welded portions 132 are arched relative to two adjacent welded portions 131 and disposed between at least a portion of two adjacent solder strips 12. By performing stacking, lamination, and framing steps on the photovoltaic cell strings 10 arranged above, a photovoltaic module is obtained.

[0041] In some embodiments of this utility model, such as Figure 4aAs shown, along the direction perpendicular to the solar cell 11, the height (H) of each non-welded portion 132 is 0.2–0.8 mm. This ensures that the non-welded portion 132 can fully release the thermal stress generated during the welding process between the busbar 13 and the solder strip 12, thereby effectively preventing the solder strip 12 from being pulled off between the main grid lines due to the shrinkage of the busbar 13 after welding. If the height of the non-welded portion 132 is too small, the thermal stress generated during the welding process between the busbar 13 and the solder strip 12 cannot be fully released; if the height of the non-welded portion 132 is too large, the material used for the busbar 13 will be significantly increased, leading to a significant increase in the production cost of the photovoltaic cell string. Preferably, the height of the non-welded portion 132 is 0.22 mm–0.7 mm. Preferably, the height of the non-welded portion 132 is 0.28 mm–0.6 mm. Preferably, the height of the non-welded portion 132 is 0.3 mm–0.5 mm. For example, preferably, the height of the non-welded part 132 can be 0.25mm, 0.32mm, 0.4mm, 0.45mm, 0.56mm or 0.65mm, etc., and the present invention does not limit this.

[0042] Optionally, the non-welded portion 132 can be one or more of the following shapes: arc, rectangle, trapezoid, triangle, wave, sawtooth. These shapes of non-welded portions 132 can fully release the thermal stress generated between the busbar 13 and the welding strip 12 during the welding process, thereby effectively preventing the welding strip 12 between the main grid lines from being pulled off due to the shrinkage of the busbar 13 after welding.

[0043] like Figure 4a As shown, the non-welded portion 132 is arc-shaped. This arc shape effectively releases the thermal stress generated during the welding process between the busbar 13 and the solder strip 12, thereby preventing the solder strip 12 from being pulled off the main grid lines due to the contraction of the busbar 13 after welding. Figure 4b As shown, the non-welded portion 132 is rectangular in shape. This rectangular non-welded portion 132 can fully release the thermal stress generated during the welding process between the busbar 13 and the solder strip 12, thereby effectively preventing the solder strip 12 from being pulled off the main grid lines due to the shrinkage of the busbar 13 after welding. Figure 4c As shown, the non-welded portion 132 is trapezoidal in shape. This trapezoidal shape effectively releases the thermal stress generated during the welding process between the busbar 13 and the solder strip 12, thereby preventing the solder strip 12 from being pulled off the main grid lines due to the shrinkage of the busbar 13 after welding. Figure 4dAs shown, the non-welded portion 132 is triangular in shape. This triangular non-welded portion 132 can effectively release the thermal stress generated during the welding process between the busbar 13 and the solder strip 12, thereby effectively preventing the solder strip 12 from being pulled off the main grid lines due to the shrinkage of the busbar 13 after welding. Figure 4e As shown, the non-welded portion 132 has a wavy shape. This wavy shape effectively releases the thermal stress generated during the welding process between the busbar 13 and the solder strip 12, thereby preventing the solder strip 12 from being pulled off the main grid lines due to the shrinkage of the busbar 13 after welding. Figure 4f As shown, the non-welded part 132 is serrated. The serrated non-welded part 132 can fully release the thermal stress generated by the busbar 13 and the solder strip 12 during the welding process, thereby effectively preventing the solder strip 12 between the main grid lines from being pulled off due to the shrinkage of the busbar 13 after the busbar 13 and the solder strip 12 are welded.

[0044] It should be noted that the shapes of the non-welded portions 132 on the busbar 13 can be the same or different, and this embodiment of the present invention does not impose any limitations on this. Figures 4a-4f As shown, the non-welded portions 132 on the busbar 13 all have the same shape to facilitate the machining of the busbar 13. Figure 4g As shown, the shape of the non-welded portion 132 on the busbar 13 varies, mainly depending on the magnitude of the thermal stress generated during the welding process between the busbar 13 and the weld strip 12. Generally, if the thermal stress generated during the welding process between the busbar 13 and the weld strip 12 is large, the shape of the non-welded portion 132 can be arc-shaped; if the thermal stress generated during the welding process between the busbar 13 and the weld strip 12 is small, the shape of the non-welded portion 132 can be trapezoidal or rectangular.

[0045] It should also be noted that the length of the welded portion 131 is minimized to reduce the heat-exposed area of ​​the busbar 13 and the thermal stress generated between the busbar 13 and the weld strip 12 during welding, thereby reducing the shrinkage and deformation of the busbar 13 during cooling. This not only further prevents the busbar 13 from pulling on the weld strip 12 during cooling, but also reduces the height of the non-welded portion 132, thus saving material on the busbar 13.

[0046] In some embodiments of this utility model, such as Figure 4aAs shown, along the length of the busbar 13, the length (L) of each welded portion 131 is 3-4 mm. This reduces the heat-receiving area of ​​the busbar 13, thereby reducing the thermal stress generated between the busbar 13 and the welding strip 12 during welding, and thus reducing the shrinkage deformation of the busbar 13 during cooling. If the length of the welded portion 131 is too small, the welding reliability between the welded portion 131 and the welding strip 12 cannot be guaranteed. Preferably, the length of the welded portion 131 is 3-4 mm. Preferably, the length of the welded portion 131 is 3-4 mm. Preferably, the length of the welded portion 131 is 3-4 mm. For example, preferably, the length of the welded portion 131 can be 0.25 mm, 0.32 mm, 0.4 mm, 0.45 mm, 0.56 mm, or 0.65 mm, etc., and this embodiment of the present invention does not limit this.

[0047] It should be noted that the length of the welding section 131 is the length of the welding area reserved for the busbar 13, not the length of the busbar 13 and the welding strip 12.

[0048] Optionally, the busbar 13 has a thickness of 0.05–0.12 mm and a width of 4–12 mm to ensure reliable welding between the busbar 13 and the solder strip 12. Optionally, the solder strip 12 is a tin-lead solder strip with a diameter of 0.12–0.3 mm to ensure a reliable welding effect after the solder strip 12 is tinned. Optionally, the solar cell 11 is a triple-cut or quadruple-cut solar cell.

[0049] This utility model embodiment also provides a photovoltaic module, which includes at least two photovoltaic cell strings 10 as described in any of the above embodiments. The at least two photovoltaic cell strings 10 can be connected in parallel or in series via busbars 13, which extend from the back of one photovoltaic cell string 10 to the back of another. The photovoltaic module is obtained by performing steps such as stacking, laminating, and framing the arranged photovoltaic cell strings 10.

[0050] Since the welded part 131 is electrically connected to the solder strip 12 on the back of the cell 11, and the non-welded part 132 is disposed between two adjacent solder strips 12, there will be no gap between the non-welded part 132 and the solder strip 12, thereby avoiding the risk of arcing during the subsequent use of photovoltaic modules.

[0051] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A photovoltaic cell string, characterized in that, Includes battery cells (11), solder strips (12), and busbars (13); Multiple solar cells (11) are arranged in sequence, and adjacent solar cells (11) are connected by the solder strip (12); The busbar (13) is disposed on the back side of the battery cell (11). Along the length direction of the busbar (13), the busbar (13) includes a plurality of welded portions (131) and non-welded portions (132) connecting two adjacent welded portions (131); wherein, the welded portions (131) are electrically connected to the solder strips (12) on the back side of the battery cell (11), and the non-welded portions (132) are arched relative to two adjacent welded portions (131) and disposed between at least a portion of two adjacent solder strips (12).

2. The photovoltaic cell string according to claim 1, characterized in that, The non-welded portion (132) is provided between any two adjacent weld strips (12).

3. The photovoltaic cell string according to claim 2, characterized in that, The two welded parts (131) connected to the non-welded part (132) are electrically connected to any two adjacent weld strips (12).

4. The photovoltaic cell string according to any one of claims 1-3, characterized in that, Along the direction perpendicular to the battery cell (11), the height of each of the non-welded portions (132) is 0.2 to 0.8 mm.

5. The photovoltaic cell string according to claim 4, characterized in that, The non-welded portion (132) has one or more of the following shapes: Arc, rectangle, trapezoid, triangle, wavy, sawtooth.

6. The photovoltaic cell string according to any one of claims 1-3, characterized in that, Along the length of the busbar (13), the length of each welded portion (131) is 3 to 4 mm.

7. The photovoltaic cell string according to any one of claims 1-3, characterized in that, The thickness of the busbar (13) is 0.05-0.12 mm and the width is 4-12 mm.

8. The photovoltaic cell string according to any one of claims 1-3, characterized in that, The solder strip (12) is a tin-lead solder strip, and the diameter of the solder strip (12) is 0.12 to 0.3 mm.

9. The photovoltaic cell string according to any one of claims 1-3, characterized in that, The battery cell (11) is a triple-cut battery cell or a quadruple-cut battery cell.

10. A photovoltaic module, characterized in that, It includes at least two photovoltaic cell strings as described in any one of claims 1-9.

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