Bus bar and photovoltaic module

Abstract

The utility model discloses a bus bar and a photovoltaic assembly, the bus bar can be connected with a battery piece through a welding strip, at least part of the bus bar is bent along the width direction, and the thickness T of the bus bar at any position is smaller than the height H of the bus bar. According to the bus bar and the photovoltaic assembly, the bending structure is arranged on the bus bar, so that the sectional area of the bus bar along the width direction is increased, the resistivity of the bus bar is reduced, and the conductivity of the bus bar is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of photovoltaic components, and in particular relates to a bus bar and a photovoltaic component. Background Art

[0002] Within a photovoltaic module, the DC power generated by the cells must be connected and transmitted to the photovoltaic system via busbars. Busbars are a crucial component of the photovoltaic module cells, serving as the conductive strips that connect the electricity generated by the photovoltaic cells. They are also called cell connectors. Copper is the most widely used material for busbars, as it is affordable and offers relatively stable performance. Aluminum, while used in inexpensive photovoltaic modules, has a relatively weak power transmission capability, making it suitable only for low-power photovoltaic modules.

[0003] Copper-clad aluminum (CCA) combines the advantages of copper, such as excellent conductivity, high strength, and strong weldability, with the advantages of aluminum, such as low density and easy processing. Furthermore, it features uniform copper layer density, high compactness, and high stretchability, offering significant advantages over pure copper conductors. Furthermore, CCA itself offers advantages such as light weight, ease of transportation and network construction, reduced labor intensity, soft wire quality, ease of processing, reduced copper resource consumption, and low cost. Therefore, CCA busbars can be made from this material; however, the resistivity of CCA is greater than that of copper, and the spacing between components in many existing photovoltaic modules is already at its maximum, leaving insufficient space for larger busbars. Therefore, when CCA busbars are made from this material, their resistivity remains high.

[0004] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Utility Model Content

[0005] The purpose of the present utility model is to provide a busbar and a photovoltaic assembly, which can increase the cross-sectional area of ​​the busbar along the width direction, thereby reducing the resistivity of the busbar.

[0006] In order to achieve the above-mentioned purpose, a technical solution provided by a specific embodiment of the present invention is as follows: a busbar, which can be connected to the battery cell through a welding strip, the busbar is at least partially bent along the width direction, and the thickness T of the busbar at any position is less than the height H of the busbar.

[0007] In one or more embodiments of the present invention, the bus bar includes a main body portion and a first extension portion bent and extended from the main body portion away from the welding ribbon, and the main body portion is used to be connected to the welding ribbon.

[0008] In one or more embodiments of the present invention, a bending angle between the first extension portion and the main body portion is 90° to 180°.

[0009] In one or more embodiments of the present invention, the bus bar further includes a second extension portion that bends and extends from the first extension portion toward the main body portion.

[0010] In one or more embodiments of the present invention, the width of the bus bar in the second direction is equal to the width of the main body in the second direction.

[0011] In one or more embodiments of the present invention, the main body is in the shape of a strip or a sheet.

[0012] In one or more embodiments of the present invention, the busbar includes a main body portion, the main body portion is used to be connected to the welding strip, and the main body portion is at least partially bent.

[0013] In one or more embodiments of the present invention, the main body has a connection surface for connecting to a welding strip, and the area of ​​the connection surface is larger than the projection area of ​​the connection surface in the height direction.

[0014] In one or more embodiments of the present invention, the cross-section of the main body in the width direction is any one of an arc-shaped surface, a V-shaped surface, and a wave-shaped surface.

[0015] In one or more embodiments of the present invention, the busbar includes an aluminum core layer, a copper coating layer coated on the outside of the aluminum core, and a solder layer coated on the outside of the copper layer.

[0016] A specific embodiment of the present invention also provides a photovoltaic module, including a cover plate, a back plate, and a battery string encapsulated between the cover plate and the back plate, the battery string including a plurality of battery cells, the photovoltaic module also including a bus bar and a welding strip, the bus bar being connected to the battery cells via the welding strip, and the bus bar being the above-mentioned bus bar.

[0017] Compared with the prior art, the busbar and photovoltaic module of the present invention increase the cross-sectional area of ​​the busbar along the width direction by providing a bending structure on the busbar, thereby reducing the resistivity of the busbar and improving the conductive performance of the busbar. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A partial structural side view of a photovoltaic module in an example of the present utility model;

[0020] Figure 2 This is a partial structural perspective diagram of a photovoltaic module in an example of the present utility model;

[0021] Figure 3 This is a schematic diagram of the internal structure of a bus bar in an example of the present utility model;

[0022] Figure 4 This is a schematic diagram of the structure of a bus bar in an example of the present utility model;

[0023] Figure 5 This is a schematic diagram of the connection between the battery cell, welding ribbon and bus bar in Example 1 of the present utility model;

[0024] Figure 6 This is a schematic diagram of the connection between the battery cell, welding ribbon and bus bar in Example 2 of the present utility model;

[0025] Figure 7 This is a schematic diagram of the connection between the battery cell, welding ribbon and bus bar in Example 3 of the present utility model.

[0026] Description of main reference numerals:

[0027] 1. Busbar; 11. Aluminum core layer; 12. Copper coating; 13. Solder layer; 14. Main body; 15. First extension; 16. Second extension; 17. Connection surface; 2. Back plate; 3. Battery cell; 4. Solder ribbon; 5. Cover plate. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0029] As mentioned in the background, conventional busbars typically use a copper-clad aluminum structure, which balances conductivity and cost. However, when the busbar is small, the copper-clad aluminum structure's conductivity is not ideal. Busbars can be considered strips or sheets, and are connected to solder strips.

[0030] To solve the above problems, Figure 1 and 2As shown, the present invention discloses a photovoltaic module, comprising a cover plate 5, a back plate 2, a cell string encapsulated between the cover plate 5 and the back plate 2, a bus bar 1, and a welding ribbon 4. The cell string comprises a plurality of cells 3, and the bus bar 1 is connected to at least one cell 4 in the cell string via the welding ribbon 3. The bus bar 1 is at least partially bent along its width, and the thickness T of the bus bar 1 at any position is less than the height H of the bus bar 1.

[0031] It should be noted that in a photovoltaic module, the packaging position of the battery string, busbar 1 and welding ribbon 4 between the cover plate 5 and the back plate 2 and the area of ​​the packaging area occupied (the area of ​​the packaging area can be understood as the area of ​​the projection of the battery string, busbar 1 and welding ribbon 4 on the cover plate and back plate 2) are fixed, that is, the width and length of the battery string, busbar 1 and welding ribbon 4 are fixed. Figure 2 As shown, the distance between the busbar 1 and the edge of the back plate 2 is fixed (in order to meet the standard creepage distance S).

[0032] The photovoltaic module further includes an encapsulation film (not shown in the figure) disposed between the cover plate 5 and the back plate 2 and used for encapsulation.

[0033] In this utility model, Figure 2 The z direction in FIG. 1 can be considered as the height direction of the busbar 1 , the y direction can be considered as the length direction of the busbar 1 (can also be considered as the extension direction of the busbar 1 ), and the x direction can be considered as the width direction of the busbar 1 .

[0034] The present invention employs a bent busbar 1, while maintaining a constant xy-plane projected area (i.e., the length and width of the busbar 1 of the present invention remain unchanged relative to the busbar 1 of the prior art). This increases the cross-sectional area of ​​the busbar 1 perpendicular to the current transmission direction (the current transmission direction can be considered the y-direction) (this cross-sectional area can be referred to as the current-carrying cross-sectional area), thereby reducing the resistivity of the busbar 1 (taking a copper-clad aluminum structure as an example) and improving the electrical conductivity of the busbar 1. The cross-section of the busbar 1 along the width direction can be considered to be the cross-section of the busbar 1 perpendicular to the current transmission direction.

[0035] It is understandable that, Figure 3 and 4 In the specific example shown, busbar 1 is configured with equal thicknesses, i.e., T = T1 = T2 = T3. The thicknesses T, T1, T2, and T3 of busbar 1 are all less than the height H of busbar 1. Compared to the prior art, the busbar 1 of the present invention modifies the height H of busbar 1 through the bends (also referred to as bend structures or folded structures) on busbar 1, thereby increasing the cross-sectional area of ​​busbar 1 perpendicular to the direction of current transmission. In other examples, the thicknesses of T, T1, T2, and T3 can be different, as long as they are all less than the height H.

[0036] The soldering ribbon 4 can be connected to the busbar 1 and the cell 3, respectively, by welding. The cover plate 5 and back plate 2 can be made of PBT (polybutylene terephthalate) or glass. The cell 3 and soldering ribbon 4 are similar to those commonly found in commercial photovoltaic modules.

[0037] In a specific example, the battery cell 3 may include multiple battery cells, each of which is connected to a welding ribbon 4. Therefore, multiple welding ribbons 4 may be connected to one battery cell 3, and the multiple welding ribbons 4 may all be connected to the same bus bar 1.

[0038] like Figure 3 As shown in the figure, in a specific example, the busbar 1 includes an aluminum core layer 11, a copper coating 12 covering the aluminum core, and a solder layer 13 covering the copper layer. This is equivalent to adding a solder layer 13 to the existing copper-clad aluminum busbar 1 to facilitate soldering to the solder ribbon 4. The solder layer 13 can be made of commercially available solder, such as conventional tin-containing solder.

[0039] The photovoltaic module of the present invention will be further described below with reference to specific embodiments.

[0040] Example 1

[0041] like Figure 5 As shown, in the photovoltaic assembly of the present invention, the busbar 1 includes a main body 14 and a first extension portion 15 bent and extended from the main body 14 away from the welding ribbon 4 . The main body 14 is used to connect with the welding ribbon 4 .

[0042] It should be noted that in this embodiment, the main body 14 is in the shape of a strip or sheet, that is, the main body 14 is non-bent. The main body 14 has a connection surface 17, which is connected to the welding ribbon 4, and the welding ribbon 4 is connected to the battery cell 3, thereby connecting the main body 14 to the battery cell 3. The first extension 15 is bent toward the side of the main body 14 away from the connection surface 17. While the bent busbar 1 maintains a constant projected area in the xy plane, the cross-sectional area of ​​the busbar 1 perpendicular to the current transmission direction is increased, thereby reducing the resistivity of the busbar 1 and improving the conductivity of the busbar 1.

[0043] Preferably, the bending angle between the first extension portion 15 and the main body portion 14 is 90° to 180°. In this embodiment, the bending angle between the first extension portion 15 and the main body portion 14 is 90°. In other embodiments, the bending angle between the first extension portion 15 and the main body portion 14 can be greater than or less than 90°.

[0044] Furthermore, the width of the busbar 1 is equal to the width of the main portion 14. That is, the main portion 14 of the busbar 1 in this embodiment corresponds to the entire busbar 1 in the prior art, and the first extension 15 corresponds to the additional portion. The cross-sectional area of ​​the first extension 15 perpendicular to the direction of current transmission represents the additional cross-sectional area of ​​the busbar 1 in this embodiment compared to the busbar 1 in the prior art. Furthermore, this arrangement ensures that the connection area between the connecting surface 17 and the soldering ribbon 4 in this embodiment remains consistent with the connection area between the entire busbar 1 and the soldering ribbon 4 in the prior art.

[0045] Of course, in other implementations (not shown in the figures), the width of the busbar 1 may be smaller than the width of the main body 14 , that is, the width of the busbar 1 is the sum of the width of the main body 14 and the width of the first extension portion 15 .

[0046] In this embodiment, along the y direction, a first extension portion 15 is bent and extended on both sides of the main body 14, that is, two first extension portions 15 are bent and extended on the main body 14, which further increases the cross-sectional area of ​​the busbar 1 perpendicular to the current transmission direction.

[0047] In other embodiments (not shown in the figures), the main body 14 may be bent and extended to form only one first extension portion 15 , which can also increase the cross-sectional area of ​​the busbar 1 perpendicular to the current transmission direction.

[0048] Example 2

[0049] like Figure 6 As shown, the structure of the photovoltaic assembly in this embodiment is substantially the same as that of the photovoltaic assembly in Example 1, except that the busbar 1 in this embodiment further includes a second extension portion 16 that bends and extends from the first extension portion 15 toward the main portion 14. The second extension portion 16 serves to further increase the cross-sectional area of ​​the busbar 1 perpendicular to the direction of current transmission.

[0050] In this embodiment, the width of the busbar 1 is equal to the width of the main body 14 in the second direction. This setting is also to ensure that the connection area between the connecting surface 17 and the welding strip 4 in this embodiment is consistent with the connection area between the entire busbar 1 and the welding strip 4 in the prior art.

[0051] In this embodiment, the bending angle between the second extension portion 16 and the first extension portion 15 is 90°. In other embodiments, the bending angle between the second extension portion 16 and the first extension portion 15 may be greater than or less than 90°.

[0052] In other embodiments (not shown), the width of the busbar 1 may be smaller than the width of the main body 14 , that is, the width of the busbar 1 is the sum of the width of the main body 14 , the width of the first extension portion 15 , and the width of the second extension portion 16 .

[0053] In other embodiments, the second extension portion 16 may be further bent to form a third extension portion, the third extension portion may be further bent to form a fourth extension portion, and so on.

[0054] Example 3

[0055] like Figure 7 As shown, the structure of the photovoltaic assembly in this embodiment is substantially the same as that in Example 1, except that the bus bar 1 in this embodiment includes a main body 14, which is used to connect with the welding strip 4, and the main body 14 is at least partially bent.

[0056] In this embodiment, at least a portion of the main body 14 is bent. Compared to Embodiments 1 and 2 (in which the main body 14 is not bent), the main body 14 can increase the cross-sectional area of ​​the busbar 1 perpendicular to the direction of current transmission. The main body 14 of the busbar 1 in this embodiment is equivalent to the entire busbar 1 in the prior art.

[0057] like Figure 7 As shown, in this embodiment, the main body 14 is a bent structure as a whole.

[0058] Furthermore, the main body 14 has a connection surface 17 for connecting to the soldering ribbon 4. The area of ​​the connection surface 17 is larger than its projection in the height direction. Compared to the prior art, this arrangement effectively increases the connection area between the connection surface 17 and the soldering ribbon 4, thereby improving the overcurrent capability. The projection in the height direction of the connection surface 17 can be considered to be the projection of the connection surface 17 onto the upper surface of the cover plate 5 or back plate 2 facing the main body 14.

[0059] Furthermore, the cross section of the main body 14 in the width direction is any one of an arc-shaped surface, a V-shaped surface, and a wave-shaped surface. In this embodiment, the cross section of the main body 14 in the width direction is an arc-shaped surface.

[0060] In this embodiment, the busbar 1 may further include a first extension portion 15 and a second extension portion 16 (not shown in the figure) as in Embodiment 2, thereby further increasing the current-carrying cross-sectional area of ​​the busbar 1 .

[0061] Example 4

[0062] The structure of the photovoltaic assembly in this embodiment is roughly the same as that of the photovoltaic assembly in Example 3. The difference is that the main body 14 in Example 3 is a whole bending structure, while a main body 14 in this embodiment includes multiple bending structures connected in sequence as shown in Example 3. The multiple bending structures connected in sequence can have the same structure or different structures.

[0063] It can be understood that the multiple bending structures in this embodiment are all the same, and in other embodiments, the multiple bending structures may not be completely the same.

[0064] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0065] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A busbar that can be connected to a battery cell via a welding ribbon, characterized in that: At least a portion of the busbar is bent along the width direction, and a thickness T of the busbar at any position is smaller than a height H of the busbar.

2. The bus bar according to claim 1, wherein: The bus bar includes a main body portion and a first extension portion bent and extended from the main body portion away from the welding ribbon, and the main body portion is used for connecting with the welding ribbon.

3. The bus bar according to claim 2, wherein: The bending angle between the first extension portion and the main body portion is 90° to 180°.

4. The bus bar according to claim 2, wherein: The bus bar further includes a second extension portion that bends and extends from the first extension portion toward the main body portion.

5. The bus bar according to claim 2, wherein: The width of the bus bar is equal to the width of the main body.

6. The bus bar according to claim 1, wherein: The busbar includes a main body portion, which is used to be connected to the welding strip, and at least a portion of the main body portion is bent.

7. The bus bar according to claim 6, wherein: The main body has a connection surface for connecting with a welding strip, and the area of ​​the connection surface is larger than the projection area of ​​the connection surface in the height direction.

8. The bus bar according to claim 6, wherein: The cross section of the main body in the width direction is any one of an arc-shaped surface, a V-shaped surface, and a wave-shaped surface.

9. The bus bar according to claim 1, wherein: The busbar includes an aluminum core layer, a copper coating layer covering the aluminum core, and a solder layer covering the copper layer.

10. A photovoltaic module, characterized in that: The photovoltaic module comprises a cover plate, a back plate, and a battery string encapsulated between the cover plate and the back plate, wherein the battery string comprises a plurality of battery cells. The photovoltaic module further comprises a bus bar and a welding ribbon, wherein the bus bar is connected to the battery cells via the welding ribbon, and the bus bar is the bus bar as described in any one of claims 1 to 9.

Images