Photovoltaic module and photovoltaic system

Abstract

The invention relates to the technical field of solar cells, and mainly provides a photovoltaic module and a photovoltaic system. The photovoltaic module comprises at least two groups of series battery modules, a first welding strip, a second welding strip and a bus bar, wherein each group of series battery modules comprises at least two series battery pieces; one battery piece in one group of series battery components is partially overlapped with one battery piece in the adjacent group of series battery components; the bus bar is arranged on the overlapped part of the two overlapped battery pieces; a through hole is formed in the bus bar and penetrates through the thickness direction of the bus bar; the first welding strip penetrates through the through hole and is electrically connected with the bus bar, part of the first welding strip is located above the bus bar, and part of the first welding strip is located below the bus bar; and the second welding strip is insulated from the bus bar through the insulating layer. According to the photovoltaic module in the technical scheme, the current transmission efficiency can be improved, the welding quality can be ensured, and the bonding firmness of the welding strip is improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a photovoltaic module and a photovoltaic system. Background Art

[0002] With the continuous development of photovoltaic technology, BC (Back Contact) solar cells have gradually shown their great application potential due to their unique back contact structure design. In the production of photovoltaic modules, in order to hide the busbars, after the battery strings are arranged, the battery strings are connected in series through the busbars on the back of the battery. Therefore, the interconnection method between the busbars and the welding ribbons will affect the current collection effect and the reliability of the battery.

[0003] At present, for online welding, the welding strip is below the bus bar, and there is an insulating strip above the non-lead-out welding strip, resulting in a height difference between the lead-out welding strip and the bus bar; during the welding process of the lead-out welding strip and the bus bar, due to the poor fit between the lead-out welding strip and the bus bar, welding is difficult and the reliability of the solder joint is at a certain risk; if the lead-out welding strip is above the bus bar, the solder joint is above the bus bar, and the overall structure of the bus bar is at the battery stack, the height of the welding strip will also increase, and the thermal expansion and contraction of the bus bar after welding will pull the adjacent solder joints (PAD points) and fixed glue points, affecting the firmness of the welding strip. For offline welding, the bus bar and the lead-out welding strip have been welded, and the prefabricated part needs to be fixed to the battery cell, that is, the welding strip is fixed to the battery cell through an adhesive component, and the glue point corresponding to the welding strip below the bus bar cannot be cured by light due to the obstruction of the bus bar. Therefore, during the subsequent lamination process, the welding strip below the bus bar will move, resulting in the risk of desoldering of the welding strip below the bus bar.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0005] The present application provides a photovoltaic module and a photovoltaic system to solve or alleviate the above-mentioned technical problems. The photovoltaic module in the technical solution of the present application can not only improve the current transmission efficiency, but also ensure the welding quality and increase the firmness of the welding strip bonding.

[0006] In a first aspect, an embodiment of the present application provides a photovoltaic assembly, including: At least two groups of battery assemblies connected in series, each group of battery assemblies connected in series includes at least two battery cells connected in series; a battery cell in one group of battery assemblies connected in series partially overlaps with a battery cell in an adjacent group of battery assemblies connected in series; the two overlapping battery cells each include a first electrode and a second electrode with opposite polarities; a first welding strip, the first welding strip being electrically connected to the first electrode; a second welding strip, the second welding strip being electrically connected to the second electrode; A bus bar, the bus bar is arranged on the overlapping part of the two overlapping battery cells; the bus bar is provided with a through hole, the through hole runs through the thickness direction of the bus bar; the first welding strip passes through the through hole and is electrically connected to the bus bar, part of the first welding strip is located above the bus bar, and part of the first welding strip is located below the bus bar; the second welding strip is insulated from the bus bar by an insulating layer; Wherein, an adhesive component with an insulating function is arranged below the portion of the first welding strip located at the through hole position, and is used to bond the first welding strip and the battery cell.

[0007] Optionally, there are N first welding strips, and there are N through holes, the first welding strips correspond to the through holes one by one, and each of the first welding strips passes through one of the through holes correspondingly; wherein N is an integer greater than or equal to 1.

[0008] Optionally, there are N first welding strips, and there are 2N through holes, the 2N through holes are arranged in pairs, and each of the first welding strips correspondingly passes through two of the through holes arranged in pairs; wherein N is an integer greater than or equal to 1.

[0009] Optionally, the first welding strips are in N groups, the through holes are in N numbers, and each group of the first welding strips corresponds to one through hole; each group of the first welding strips includes a first sub-welding strip and a second sub-welding strip that do not overlap each other; the first end of the first sub-welding strip is electrically connected to one of the two overlapping battery cells, and the first end of the second sub-welding strip is electrically connected to the other battery cell of the two overlapping battery cells; the second end of the first sub-welding strip and the second end of the second sub-welding strip pass through the same through hole and are electrically connected to the bus bar respectively; wherein N is an integer greater than or equal to 1.

[0010] Optionally, the first welding strips are in N groups, the through holes are in 2N number, and every two of the through holes form a pair; each group of the first welding strips includes a first sub-welding strip and a second sub-welding strip that do not overlap each other; the first end of the first sub-welding strip is electrically connected to one of the two overlapping battery cells, and the first end of the second sub-welding strip is electrically connected to the other of the two overlapping battery cells; the second end of the first sub-welding strip passes through one of the pair of through holes and is electrically connected to the bus bar, and the second end of the second sub-welding strip passes through the other through hole in the pair of through holes and is electrically connected to the bus bar; wherein N is an integer greater than or equal to 1.

[0011] Optionally, the first sub-welding strip and / or the second sub-welding strip is a bent welding strip; The bending type welding strip comprises a first area, a second area, and a connection area connecting the first area and the second area; the bending type welding strip is electrically connected to the corresponding first electrode through the first area, and the bending type welding strip is electrically connected to the bus bar through the second area, and the connection area is located in the through hole area; one of the first area and the second area is located above the bus bar, and the other is located below the bus bar; The angle formed by the first area, the connecting area and the second area is 0-90 degrees.

[0012] Optionally, an angle formed by the first area, the connecting area and the second area is 90 degrees.

[0013] Optionally, an angle formed by the first region, the connecting region and the second region is 0 degree.

[0014] Optionally, an angle formed by the first area, the connecting area and the second area is 45 degrees.

[0015] Optionally, a distance between the first sub-welding strip and the second sub-welding strip is 0-2 mm.

[0016] Optionally, the length of the second region is 1 / 2-3 / 4 of the width of the bus bar.

[0017] Optionally, a welding length of the first welding strip with the bus bar is 1 / 2-3 / 4 of a width of the bus bar.

[0018] Optionally, the diameter of the through hole is 0.2-4 mm.

[0019] In a second aspect, an embodiment of the present application provides a photovoltaic system, comprising any of the photovoltaic components described above.

[0020] The above technical solution adopted in the embodiment of the present application may have the following advantages: In the photovoltaic module of the embodiment of the present application, a through hole is provided on the bus bar, and the first welding strip passes through the through hole of the bus bar and is connected to the bus bar, which can not only reduce the distance between the first welding strip and the battery cell, improve the fit between the first welding strip and the bus bar, and reduce the pulling of the first welding strip on nearby PAD points and solder paste points, thereby ensuring the first welding quality; but also reduce the contact resistance, which helps to improve the current transmission efficiency of the photovoltaic module, and thus improve the performance of the photovoltaic module; in addition, the adhesive component with insulating function at the through hole can overflow to the bus bar surface through the through hole position, thereby increasing the firmness of the bonding of the first welding strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0022] Figure 1 is a schematic structural diagram of a photovoltaic assembly according to an embodiment of the present application; Figure 2-Figure 9 It is a schematic diagram of the structure of the first welding strip and the bus bar of an embodiment of the present application.

[0023] Description of reference numerals: 10. Series connected battery components; 11. Battery cells; 20. bus bar; 21. through hole; 30. first welding strip; 31. first sub-welding strip; 32. second sub-welding strip; 33. first area; 34. second area; 35. connection area; 40. Second welding strip; 50. Insulation layer; L1, the distance between the first sub-welding strip and the second sub-welding strip; L2, the length of the second area; W1, the width of the busbar; D1, first direction; D2, second direction; α, the angle formed by the first area, the connecting area and the second area. DETAILED DESCRIPTION

[0024] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. Wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0025] like Figures 1 to 9 As shown, an embodiment of the present application provides a photovoltaic assembly, including: At least two groups of battery assemblies 10 connected in series, each group of battery assemblies 10 in series includes at least two battery cells 11 connected in series; a battery cell 11 in one group of battery assemblies 10 in series partially overlaps with a battery cell 11 in an adjacent group of battery assemblies 10 in series; the two overlapping battery cells 11 each include a first electrode and a second electrode with opposite polarities; A first welding strip 30, the first welding strip 30 is electrically connected to the first electrode; A second welding strip 40, the second welding strip 40 is electrically connected to the second electrode; The bus bar 20 is arranged on the overlapping part of the two overlapping battery cells 11; the bus bar 20 is provided with a through hole 21, and the through hole 21 runs through the thickness direction of the bus bar 20; the first welding strip 30 passes through the through hole 21 and is electrically connected to the bus bar 20, part of the first welding strip 30 is located above the bus bar 20, and part of the first welding strip 30 is located below the bus bar 20; the second welding strip 40 is insulated from the bus bar 20 by the insulating layer 50; An adhesive component with an insulating function is disposed below a portion of the first welding ribbon 30 located at the position of the through hole 21 , and is used to bond the first welding ribbon 30 and the battery cell 11 .

[0026] In the photovoltaic module of the embodiment of the present application, a through hole is provided on the bus bar, and the first welding strip passes through the through hole of the bus bar and is connected to the bus bar, which can not only reduce the distance between the first welding strip and the battery cell, improve the fit between the first welding strip and the bus bar, and reduce the pulling of the first welding strip on nearby PAD points and solder paste points, thereby ensuring the first welding quality; but also reduce the contact resistance, which helps to improve the current transmission efficiency of the photovoltaic module, and thus improve the performance of the photovoltaic module; in addition, the adhesive component with insulating function at the through hole can overflow to the bus bar surface through the through hole position, thereby increasing the firmness of the bonding of the first welding strip.

[0027] In some embodiments, the first electrode and the second electrode with opposite polarities included in the battery cell are both located on the back side of the battery cell, that is, the battery cell may be a back contact battery.

[0028] In some embodiments, each group of series-connected battery assemblies includes at least one group of battery strings, and each battery string includes at least two battery cells connected in series; the battery cells in the battery strings in one group of series-connected battery assemblies partially overlap with the battery cells in the battery strings in another adjacent group of series-connected battery assemblies, wherein the bus bar is located on the overlapping portion of the two overlapping battery cells.

[0029] It should be noted that the multiple welding strips connected to a bus bar are welding strips of the same polarity (first welding strip), and the welding strips of opposite polarity (second welding strip) are separated from the bus bar by an insulating layer to prevent short circuit. In the embodiment of the present application, the first electrode, the first welding strip, and the first grid line are electrically connected with the same polarity as the bus bar of the present application, while the second electrode, the second welding strip, and the second grid line have opposite polarity to the bus bar of the present application.

[0030] In the embodiment of the present application, the bus bar disposed on the overlapping portion of the two overlapping cells is a middle bus bar. In some embodiments, the photovoltaic module may also include an edge bus bar, which is located at the edge area of ​​the back of the outermost cell; the edge bus bar may be provided with a through hole or may not be provided with a through hole.

[0031] like Figure 1-2 As shown, in some embodiments, there are N first welding strips 30 and N through holes 21, the first welding strips 30 correspond to the through holes 21 one by one, and each first welding strip 30 passes through a through hole 21 accordingly; wherein N is an integer greater than or equal to 1.

[0032] like Figure 3 As shown, in some embodiments, there are N first welding strips 30 and 2N through holes 21, the 2N through holes 21 are arranged in pairs, and each first welding strip 30 correspondingly passes through two through holes 21 arranged in pairs; wherein N is an integer greater than or equal to 1.

[0033] In some embodiments, a plurality of through holes may be provided on the bus bar, and the plurality of through holes are evenly spaced and arranged along the length direction of the bus bar, so that the positions of the through holes correspond to the positions of the welding strips to be electrically connected.

[0034] In some embodiments, the number of through holes in a bus bar can be the same as the number of first welding strips, and a first welding strip passes through a corresponding through hole. In other embodiments, the number of through holes in a bus bar can be twice the number of first welding strips, that is, there are N first welding strips and 2N through holes, and the 2N through holes are arranged in two rows, and every two through holes form a pair, and a first welding strip passes through the two through holes corresponding to it in sequence, thereby further improving the welding quality and reducing the contact resistance; in addition, the two through holes correspond to the bonding components at the edge of the two battery cells respectively, and the bonding components can be exposed through the through holes, which is conducive to the curing of the bonding components and improves the firmness of the bonding of the welding strips.

[0035] like Figure 5 and Figure 7-9 As shown, in some embodiments, there are N groups of first welding strips 30, and there are N through holes 21, and each group of first welding strips 30 corresponds to one through hole 21; each group of first welding strips 30 includes a first sub-welding strip 31 and a second sub-welding strip 32 that do not overlap each other; the first end of the first sub-welding strip 31 is electrically connected to one of the two overlapping battery cells 11, and the first end of the second sub-welding strip 32 is electrically connected to the other battery cell 11 of the two overlapping battery cells 11; the second end of the first sub-welding strip 31 and the second end of the second sub-welding strip 32 pass through the same through hole 21 and are electrically connected to the bus bar 20 respectively; wherein N is an integer greater than or equal to 1.

[0036] like Figure 4 and Figure 6As shown, in some embodiments, the first welding strips 30 are N groups, the through holes 21 are 2N, and every two through holes 21 form a pair; each group of first welding strips 30 includes a first sub-welding strip 31 and a second sub-welding strip 32 that do not overlap each other; the first end of the first sub-welding strip 31 is electrically connected to one of the two overlapping battery cells 11, and the first end of the second sub-welding strip 32 is electrically connected to the other battery cell 11 of the two overlapping battery cells 11; the second end of the first sub-welding strip 31 passes through one of the through holes 21 in the pair of through holes 21 and is electrically connected to the bus bar 20, and the second end of the second sub-welding strip 32 passes through the other through hole 21 in the pair of through holes 21 and is electrically connected to the bus bar 20; wherein N is an integer greater than or equal to 1.

[0037] In the present application, the first welding strip passing through one or a pair of through holes can be a complete welding strip or an interrupted welding strip (i.e., a first sub-welding strip and a second sub-welding strip). When the first welding strip is a complete welding strip, a long string process is adopted, and the perforated first welding strip needs to be welded to the bus bar first (offline welding), and then the first welding strip and the bus bar are placed on the battery cell; when the first welding strip is two interrupted welding strips (i.e., a first sub-welding strip and a second sub-welding strip, and the first sub-welding strip and the second sub-welding strip constitute a group of first welding strips), a short string process is adopted for splicing, and the battery cells can be spliced ​​first, and then the bus bar is placed, and finally the first welding strip is used for unified welding (online welding). The feasibility of the short string process is higher.

[0038] If the first sub-weld ribbon and the second sub-weld ribbon pass through a through hole, the first sub-weld ribbon and the second sub-weld ribbon may be stacked. The stacking height may cause the risk of hidden cracks in the cell during the lamination process. The stacking of the ribbons may also cause interference, affecting the electrical performance of the photovoltaic module. In order to avoid the phenomenon of ribbon stacking of the first sub-weld ribbon and the second sub-weld ribbon passing through the same through hole, the first sub-weld ribbon and the second sub-weld ribbon should be staggered, that is, the first sub-weld ribbon and the second sub-weld ribbon do not overlap each other. When the first sub-weld ribbon and the second sub-weld ribbon pass through a through hole respectively (that is, the first ribbon passes through a pair of through holes), sometimes the stacking of the first sub-weld ribbon and the extended part of the second sub-weld ribbon may also be stacked. In order to avoid the phenomenon of stacking of the first sub-weld ribbon and the second sub-weld ribbon, the extended part of the first sub-weld ribbon and the extended part of the second sub-weld ribbon are also not overlapped.

[0039] like Figure 6-9 As shown, in some embodiments, the first sub-welding strip 31 and / or the second sub-welding strip 32 are bent-type welding strips; The bending type welding strip includes a first area 33, a second area 34, and a connection area 35 connecting the first area 33 and the second area 34; the bending type welding strip is electrically connected to the corresponding first electrode through the first area 33, and the bending type welding strip is electrically connected to the bus bar 20 through the second area 34, and the connection area 35 is located in the through hole 21 area; one of the first area 33 and the second area 34 is located above the bus bar 20, and the other is located below the bus bar 20; The angle α formed by the first area 33, the connecting area 35 and the second area 34 is 0-90 degrees.

[0040] In the embodiment of the present application, the angle formed by the first area, the connecting area and the second area is analyzed in the two-dimensional space of the busbar surface. When calculating the angle, the thickness of the busbar can be regarded as 0, that is, the angle caused by the thickness of the busbar can be ignored.

[0041] like Figure 4-9 As mentioned above, in some embodiments, the first sub-welding strip and the second sub-welding strip may be respectively and independently a straight strip or a bent strip.

[0042] like Figure 4-5 As shown, the straight strip refers to a strip that is not bent. For example, the first sub-strip or the second sub-strip enters the through hole along the first direction D1. After passing through the through hole, the first sub-strip or the second sub-strip still extends along the first direction D1.

[0043] like Figure 6-9 As shown, the bending type welding strip is formed by a straight strip welding strip, and the connection area 35 is bent to form a bending area. When preparing a photovoltaic module or a prefabricated part, the straight strip welding strip is passed through the through hole 21. After passing through the through hole 21, the straight strip welding strip is bent instead of passing directly through the through hole 21, so that a bending type welding strip can be formed. For example, the first sub-welding strip 31 enters the through hole 21 along the first direction, and after passing through the through hole 21, the first sub-welding strip 31 is bent so that the second area 34 of the first sub-welding strip 31 no longer extends along the first direction, but deviates from the first direction to extend, that is, the angle formed by the first area 33, the connection area 35 and the second area 34 of the first sub-welding strip 31 is greater than or equal to 0 degrees and less than 180 degrees. The first sub-welding strip or the second sub-welding strip that has been bent, especially the angle formed by the first area 33, the connection area 35 and the second area 34 is 0-90 degrees, can make the first sub-welding strip or the second sub-welding strip better fixed to the bus bar 20, and can also improve the firmness of subsequent welding.

[0044] like Figure 4-5As shown, in some embodiments, the first sub-welding strip 31 and the second sub-welding strip 32 can both be straight strips. The first sub-welding strip 31 enters the through hole 21 along the first direction D1, and after passing through the through hole 21, the second area 34 of the first sub-welding strip 31 still extends along the first direction D1; the second sub-welding strip 32 enters the through hole 21 along the second direction D2, and after passing through the through hole 21, the second area 34 of the second sub-welding strip 32 still extends along the second direction D2, and the first direction D1 and the second direction D2 are opposite.

[0045] like Figure 6-9 As shown, in some embodiments, the first sub-welding strip 31 and the second sub-welding strip 32 can both be bent-type welding strips. The first sub-welding strip 31 enters the through hole 21 along the first direction D1. When passing through the through hole 21, the first sub-welding strip 31 is bent, and the second area 34 of the first sub-welding strip 31 no longer extends along the first direction D1. The angle formed by the first area 33, the connecting area 35, and the second area 34 of the first sub-welding strip 31 is greater than or equal to 0 degrees and less than 180 degrees; the second sub-welding strip 32 enters the through hole 21 along the second direction D2. When passing through the through hole 21, the second sub-welding strip 32 is bent, and the second area 34 of the second sub-welding strip 32 no longer extends along the second direction D2. The angle formed by the first area 33, the connecting area 35, and the second area 34 of the second sub-welding strip 32 is greater than or equal to 0 degrees and less than 180 degrees. It should be noted that when the first sub-welding ribbon 31 and the second sub-welding ribbon 32 are bent, they should be moved away from each other, otherwise the first sub-welding ribbon 31 and the second sub-welding ribbon 32 will be stacked, affecting the electrical performance of the photovoltaic module.

[0046] In some embodiments, the first sub-welding strip may be a straight strip, and the second sub-welding strip may be a bent strip. The first sub-welding strip enters the through hole along the first direction, and after passing through the through hole, the second area of ​​the first sub-welding strip still extends along the first direction; the second sub-welding strip enters the through hole along the second direction, and when passing through the through hole, the second sub-welding strip is bent, and the second area of ​​the second sub-welding strip no longer extends along the second direction, and the angle formed by the first area, the connecting area, and the second area of ​​the second sub-welding strip is greater than or equal to 0 degrees and less than 180 degrees. It should be noted that when the second sub-welding strip is bent, it should be moved away from the first sub-welding strip, otherwise it will cause the first sub-welding strip and the second sub-welding strip to stack, affecting the electrical performance of the photovoltaic module.

[0047] like Figure 6-7 As shown, in some embodiments, the angle α formed by the first region 33, the connecting region 35 and the second region 34 is 90 degrees.

[0048] Since the welding strip generally enters the through hole along the width direction of the bus bar, when the interrupted welding strip (i.e., the first sub-welding strip and the second sub-welding strip) passes through the through hole, it will still extend along the width direction of the bus bar or close to the width direction of the bus bar. The front end of the welding strip may exceed the range of the bus bar, which will cause hard contact damage between the welding strip and the battery cell and electrical short circuit between the battery cells. When the angle formed by the first area 33, the connection area 35 and the second area 34 is 90 degrees, the bent welding strip is an L-shaped welding strip, and the first area of ​​the welding strip enters the through hole along the width direction of the bus bar, and is bent 90 degrees after passing through the through hole. The direction in which the connection area of ​​the welding strip points to the second area is parallel to the length direction of the bus bar, so that the second area of ​​the welding strip is not only on the bus bar, but also the front end of the welding strip does not exceed the range of the bus bar, avoiding hard contact damage between the welding strip and the battery cell and electrical short circuit between the battery cells.

[0049] like Figure 8 As shown, in some embodiments, the angle α formed by the first region 33, the connecting region 35 and the second region 34 is 0 degree.

[0050] When the angle formed by the first area 33, the connection area 35 and the second area 34 is 0 degrees, the bent welding strip is a folded-back welding strip. A folded-back welding strip means that the first area of ​​the welding strip enters the through hole along the width direction of the bus bar, and the welding strip is folded back after passing through the through hole, so that the direction of the connection area pointing to the second area is the same as the direction of the connection area pointing to the first area, and the orthographic projection of the second area on the photovoltaic cell completely falls within the orthographic projection of the first area on the photovoltaic cell, and one of the first area and the second area is above the bus bar, and the other is above the bus bar, and the bus bar is clamped between the bent areas. The 0-degree bending area gives the welding strip a good fixing function, so that the bus bar and the welding strip are more firmly connected, and even if the bus bar and the welding strip are not welded together, the bus bar and the welding strip can still be firmly connected.

[0051] like Fig. 9 As shown, in some embodiments, the angle α formed by the first region 33, the connecting region 35 and the second region 34 is 45 degrees.

[0052] When the angle formed by the first area 33, the connecting area 35 and the second area 34 of the welding strip is 45 degrees, the welding strip can extend at an oblique angle after passing through the through hole, which helps to achieve a more reasonable layout in a limited space, making the distribution of the welding strip on the bus bar more uniform, and helping to improve the current collection and transmission efficiency; in addition, the 45-degree bending area gives the welding strip a certain fixing function, so that the connection between the bus bar and the welding strip is more firm.

[0053] In some embodiments, the angle α formed by the first region 33, the connecting region 35 and the second region 34 may also be 15 degrees, 30 degrees, 60 degrees, 75 degrees or any other degree, which is not specifically limited here.

[0054] like Figure 7-9 As shown, in some embodiments, the distance L1 between the first sub-welding strip 31 and the second sub-welding strip 32 is 0-2 mm.

[0055] If the first sub-weld strip and the second sub-weld strip are stacked, there will be a risk of hidden cracks caused by the collision between the battery cells; if the spacing between the first sub-weld strip and the second sub-weld strip is too large, the through hole will be too large, affecting the welding area between the bus bar and the first weld strip; controlling the spacing between the first sub-weld strip and the second sub-weld strip to 0-2mm can effectively control the distance between the battery strings, avoid the risk of hidden cracks caused by the collision between the battery cells, and will not affect the welding of the bus bar and the first weld strip. Specifically, the spacing between the first sub-weld strip and the second sub-weld strip is 0.1mm, 0.3mm, 0.5mm, 1mm, 1.2mm, 1.5mm, 1.8mm or 2mm.

[0056] like Figure 6-9 As shown, in some embodiments, the length L2 of the second region is 1 / 2-3 / 4 of the width W1 of the bus bar.

[0057] The second area is used to connect with the bus bar, and the length of the second area should not be too short, otherwise the welding quality will be affected due to the small welding area; the length of the second area should not be too long, otherwise the second area will exceed the range of the bus bar, resulting in hard contact damage between the first welding strip and the battery cell and electrical short circuit between the battery cells, and also causing waste of resources. Specifically, the length of the second area is less than 1 / 2, 5 / 8 or 3 / 4 of the width of the bus bar.

[0058] like Figure 2-9 As shown, in some embodiments, the welding length of the first welding strip with the bus bar is 1 / 2-3 / 4 of the width of the bus bar.

[0059] The welding area between the first welding strip and the bus bar should not be too small, otherwise the welding quality will be affected due to the small welding area; the welding area between the first welding strip and the bus bar should not be too large, otherwise it will also cause waste of resources; the welding length between the first welding strip and the bus bar can be controlled to 1 / 2-3 / 4 of the width of the bus bar. Specifically, the welding length between the first welding strip and the bus bar is 1 / 2, 5 / 8 or 3 / 4 of the width of the bus bar.

[0060] In some embodiments, the diameter of the through-holes is 0.2-4 mm.

[0061] In some embodiments, the through hole is a circular through hole. The through hole can be processed by laser, wire cutting or stamping to ensure that the edge of the hole is smooth and burr-free, thereby improving the reliability of the electrical connection. The edge line of the circular through hole is smoother and has no sharp edges and corners, which helps to reduce the stress concentration of the solder ribbon when passing through the through hole, and avoids the fracture of the solder ribbon or damage to the battery cell caused by stress concentration. The diameter of the through hole can be 0.2-4mm; specifically, the diameter of the through hole can be 0.2mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm or 4mm.

[0062] In some embodiments, when the first welding strip is N strips (or N groups) and the through holes are N, the through holes are arranged in one row and are evenly spaced, and the diameter of the through holes is 0.2-4 mm. When the diameter of the through holes is within this range, not only the effective welding area can be guaranteed, but also the alignment accuracy of the through holes and the first welding strip can be guaranteed.

[0063] In some embodiments, when the first welding strip is N strips (or N groups) and the through holes are 2N, the number of through holes is twice the number of the first welding strips, the through holes are in two rows, and the through holes in each row are evenly spaced, and the diameter of the through holes is 0.2-2 mm. When there are two rows of through holes, the diameter of the through holes should not be too large, otherwise the effective area of ​​the bus bar will be small, the contact area between the first welding strip and the bus bar will be reduced, and the corresponding contact performance will be affected.

[0064] In some embodiments, the adhesive component with an insulating function is used to bond the first welding strip and the photovoltaic cell; specifically, the adhesive component with an insulating function includes one or both of a photocurable adhesive and a photothermal integrated adhesive, which can be cured by light.

[0065] In some embodiments, the photovoltaic module further includes a back sheet, a rear adhesive film, a front adhesive film and a cover sheet.

[0066] A rear film and a back sheet are sequentially arranged on one side of the photovoltaic cell, and a bus bar is arranged between the rear film and the photovoltaic cell. A front film and a cover sheet are sequentially arranged on the other side of the photovoltaic cell. The cover sheet is used to protect the cell from physical damage, allow sunlight to penetrate, and improve the photoelectric conversion efficiency of the module. The cover sheet can be made of high-transmittance glass or plastic material (such as polymethyl methacrylate). The front film and the back film are used to encapsulate the photovoltaic cell, provide physical protection for the photovoltaic cell, and prevent moisture and gas penetration. The front film also needs to provide good optical transparency. The materials of the front film and the back film can respectively and independently include ethylene-vinyl acetate copolymer (EVA) or polyolefin elastomer (POE). The back sheet is used to protect the back of the photovoltaic module from moisture, oxygen and ultraviolet erosion, and provide mechanical strength and durability for the photovoltaic module. The material of the back sheet can include polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF) or polyester (PET).

[0067] The following specific embodiments further describe the present application in detail, but should not be construed as limiting the present application. Without departing from the spirit and substance of the present application, modifications or replacements made to the structure of the present application are within the scope of the present application.

[0068] Example 1 like Figure 1 and Figure 2 As shown, the structure of the photovoltaic module of Example 1 includes: At least two groups of battery assemblies 10 connected in series, each group of battery assemblies 10 in series includes at least two battery cells 11 connected in series; a battery cell 11 in one group of battery assemblies 10 in series partially overlaps with a battery cell 11 in an adjacent group of battery assemblies 10 in series; the two overlapping battery cells 11 each include a first electrode and a second electrode with opposite polarities; A first welding strip 30, the first welding strip 30 is electrically connected to the first electrode; A second welding strip 40, the second welding strip 40 is electrically connected to the second electrode; The bus bar 20 is arranged on the overlapping part of the two overlapping battery cells 11 (that is, the bus bar is located at the edge of the back of the battery cell), and a through hole 21 is arranged on the bus bar 20, and the through hole 21 runs through the thickness direction of the bus bar 20; the first welding strip 30 passes through the through hole 21 and is electrically connected to the bus bar 20, part of the first welding strip 30 is located above the bus bar 20, and part of the first welding strip 30 is located below the bus bar 20; the second welding strip 40 is insulated from the bus bar 20 by the insulating layer 50; wherein, an adhesive component with an insulating function is arranged below the part of the first welding strip located at the through hole position, which is used to bond the first welding strip and the battery cell; There are N first welding strips 30 , and there are N through holes 21 . One first welding strip passes through one through hole. The first welding strip is a straight strip. N is an integer greater than or equal to 1.

[0069] Example 2 like Figure 5 As shown, the structure of the photovoltaic module of Example 2 is different from that of the photovoltaic module of Example 1 in that there are N groups of first welding strips 30, there are N through holes 21, and each group of first welding strips 30 corresponds to one through hole 21; Each group of first welding strips 30 includes a first sub-welding strip 31 and a second sub-welding strip 32 which do not overlap each other; the first sub-welding strip 31 and the second sub-welding strip 32 are both straight strips; the first end of the first sub-welding strip 31 is electrically connected to one of the two overlapping battery cells 11, and the first end of the second sub-welding strip 32 is electrically connected to the other of the two overlapping battery cells 11; the second end of the first sub-welding strip 31 and the second end of the second sub-welding strip 32 pass through the same through hole 21 and are electrically connected to the bus bar 20 respectively; Wherein, N is an integer greater than or equal to 1.

[0070] Example 3 like Figure 7 As shown, the structure of the photovoltaic module of Example 3 is different from that of the photovoltaic module of Example 2 in that the first sub-welding strip 31 and the second sub-welding strip 32 are both bent-type welding strips; The bent solder strip includes a first region 33, a second region 34, and a connection region 35 connecting the first region 33 and the second region 34; the bent solder strip is electrically connected to the corresponding first electrode through the first region 33, and the bent solder strip is electrically connected to the bus bar 20 through the second region 34, and the connection region 35 is located in the through hole 21 region; the second region 34 is located above the bus bar 20, and the first region 33 is located below the bus bar 20; In the first sub-welding strip 31 and the second sub-welding strip 32 , the angle α formed by the first region 33 , the connecting region 35 , and the second region 34 is 90 degrees.

[0071] Example 4 like Figure 8 As shown, the structure of the photovoltaic module of Example 4 is different from that of the photovoltaic module of Example 3 in that, in the first sub-welding strip 31 and the second sub-welding strip 32, the angle α formed by the first region 33, the connecting region 35 and the second region 34 is 0 degree.

[0072] Example 5 like Fig. 9 As shown, the structure of the photovoltaic module of Example 5 is different from that of the photovoltaic module of Example 3 in that, in the first sub-welding strip 31 and the second sub-welding strip 32, the angle α formed by the first area 33, the connecting area 35 and the second area 34 is 45 degrees.

[0073] The photovoltaic modules of Examples 1 to 5 of the present application also include: a rear adhesive film and a back plate located on one side of the photovoltaic cell and stacked in a direction away from the photovoltaic cell, a front adhesive film and a cover plate located on the other side of the photovoltaic cell and stacked in a direction away from the photovoltaic cell, and wherein a bus bar is arranged between the rear adhesive film and the photovoltaic cell.

[0074] In order to more clearly illustrate the technical effects of the embodiments of the present application, the present application also provides a comparative example 1.

[0075] Comparative Example 1 The structure of the photovoltaic module of comparative example 1 is similar to that of the photovoltaic module of embodiment 1, except that the bus bar does not have a through hole, the welding strip is located under the bus bar and electrically connected to the bus bar, and the bus bar is located at the center of the back side of the cell.

[0076] The photovoltaic modules of Examples 1 to 5 of the present application and Comparative Example 1 and the performance of the corresponding solar cell modules were tested below to obtain the short-circuit current density Jsc, open-circuit voltage Voc, fill factor FF, and photoelectric conversion efficiency PCE of the corresponding solar cell modules. The test results are shown in Table 1.

[0077] Table 1

[0078] It can be seen from the data in Table 1 that, compared with the photovoltaic module of Comparative Example 1, the short-circuit current density, open-circuit voltage, fill factor and photoelectric conversion efficiency of the photovoltaic modules of Examples 1 to 5 of the present application are significantly improved.

[0079] To summarize, in the photovoltaic module of the embodiment of the present application, a through hole is provided on the bus bar, and the first welding strip passes through the through hole of the bus bar and is connected to the bus bar, which can not only reduce the distance between the first welding strip and the battery cell, improve the fit between the first welding strip and the bus bar, and reduce the pulling of the first welding strip on nearby PAD points and solder paste points, thereby ensuring the first welding quality; but also reduce the contact resistance, which helps to improve the current transmission efficiency of the photovoltaic module, and thus improve the performance of the photovoltaic module; in addition, the adhesive component with insulating function at the through hole can overflow to the bus bar surface through the through hole position, thereby increasing the firmness of the bonding of the first welding strip.

[0080] The embodiment of the present application can provide a photovoltaic system, including the photovoltaic components in the above embodiment. The advantages of the above photovoltaic components are also possessed by the photovoltaic system, which will not be repeated here. The above photovoltaic system has a wide range of applications, not only limited to photovoltaic power stations, such as ground power stations, rooftop power stations and water power stations, but also includes various equipment and devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars and solar buildings. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be used in all fields where solar energy is required for power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid and then connected to the mains network to realize solar power supply.

[0081] It should be noted that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0082] It should be noted that the terms "first", "second", "front", "back", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0083] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0084] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0085] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A photovoltaic module, characterized in that: include: At least two groups of battery assemblies connected in series, each group of battery assemblies connected in series includes at least two battery cells connected in series; a battery cell in one group of battery assemblies connected in series partially overlaps with a battery cell in an adjacent group of battery assemblies connected in series; the two overlapping battery cells each include a first electrode and a second electrode with opposite polarities; a first welding strip, the first welding strip being electrically connected to the first electrode; a second welding strip, the second welding strip being electrically connected to the second electrode; A bus bar, the bus bar is arranged on the overlapping part of the two overlapping battery cells; the bus bar is provided with a through hole, the through hole runs through the thickness direction of the bus bar; the first welding strip passes through the through hole and is electrically connected to the bus bar, part of the first welding strip is located above the bus bar, and part of the first welding strip is located below the bus bar; the second welding strip is insulated from the bus bar by an insulating layer; Wherein, an adhesive component with an insulating function is arranged below the portion of the first welding strip located at the through hole position, and is used to bond the first welding strip and the battery cell.

2. The photovoltaic module according to claim 1, characterized in that: There are N first welding strips, and there are N through holes. The first welding strips correspond to the through holes one by one, and each first welding strip passes through one through hole correspondingly; wherein N is an integer greater than or equal to 1; or There are N first welding strips, and there are 2N through holes, which are arranged in pairs, and each first welding strip correspondingly passes through two of the through holes arranged in pairs; wherein N is an integer greater than or equal to 1.

3. The photovoltaic module according to claim 1, characterized in that: The first welding strips are N groups, the through holes are N, and each group of the first welding strips corresponds to one through hole; each group of the first welding strips includes a first sub-welding strip and a second sub-welding strip that do not overlap each other; the first end of the first sub-welding strip is electrically connected to one of the two overlapping battery cells, and the first end of the second sub-welding strip is electrically connected to the other of the two overlapping battery cells; the second end of the first sub-welding strip and the second end of the second sub-welding strip pass through the same through hole and are electrically connected to the bus bar respectively; wherein N is an integer greater than or equal to 1; or The first welding strips are in N groups, the through holes are in 2N numbers, and every two through holes form a pair; each group of the first welding strips includes a first sub-welding strip and a second sub-welding strip that do not overlap each other; the first end of the first sub-welding strip is electrically connected to one of the two overlapping battery cells, and the first end of the second sub-welding strip is electrically connected to the other of the two overlapping battery cells; the second end of the first sub-welding strip passes through one of the pair of through holes and is electrically connected to the bus bar, and the second end of the second sub-welding strip passes through the other of the pair of through holes and is electrically connected to the bus bar; wherein N is an integer greater than or equal to 1.

4. The photovoltaic module according to claim 3, characterized in that: The first sub-welding strip and / or the second sub-welding strip is a bent welding strip; The bending type welding strip comprises a first area, a second area, and a connection area connecting the first area and the second area; the bending type welding strip is electrically connected to the corresponding first electrode through the first area, and the bending type welding strip is electrically connected to the bus bar through the second area, and the connection area is located in the through hole area; one of the first area and the second area is located above the bus bar, and the other is located below the bus bar; The angle formed by the first area, the connecting area and the second area is 0-90 degrees.

5. The photovoltaic module according to claim 4, characterized in that: An angle formed by the first area, the connecting area and the second area is 90 degrees.

6. The photovoltaic module according to claim 4, characterized in that: An angle formed by the first region, the connecting region and the second region is 0 degree.

7. The photovoltaic module according to claim 4, characterized in that: An angle formed by the first area, the connecting area and the second area is 45 degrees.

8. The photovoltaic module according to any one of claims 3 to 7, characterized in that: The distance between the first sub-welding strip and the second sub-welding strip is 0-2 mm.

9. The photovoltaic module according to any one of claims 4 to 7, characterized in that: The length of the second region is 1 / 2-3 / 4 of the width of the bus bar.

10. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The welding length of the first welding strip and the bus bar is 1 / 2-3 / 4 of the width of the bus bar.

11. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The diameter of the through hole is 0.2-4 mm.

12. A photovoltaic system, characterized in that: Comprising the photovoltaic module according to any one of claims 1 to 11.

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