A connection structure for ends of photovoltaic cell strings

Abstract

The utility model provides a connection structure at the end of a photovoltaic cell string, including a cell and a bus bar, wherein the cell is densely covered with conductive wires, the conductive wires extend to the tail of the cell, and a bridge bar is used to overlap between the tail of the cell and the bus bar, wherein the bridge bar is in the shape of a long strip, and has welding parts on the long sides of the long strip bridge bar, and there is a connection part between the welding parts, the welding part on one side overlaps the bus bar and is welded to the bus bar, and the welding part on one side overlaps the tail of the cell and covers the tail of the conductive wire and is welded to the conductive wire. Through the connection structure of the utility model, the bridge bar is used to solve the process problem of stacked grid cell series and parallel connection, and the connection structure of the utility model can achieve effective welding with the stacked grid cell through a lower welding temperature, thereby ensuring the appearance and efficiency of the stacked grid cell.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, in particular to a connection structure for ends of a photovoltaic cell string. Background Art

[0002] With the continuous changes in the photovoltaic technology industry, traditional photovoltaic solar modules can no longer meet the diversified needs of the market, and new photovoltaic module technologies continue to emerge. At present, related technologies such as multi-main grid battery modules, 0BB battery modules, and stacked grid modules have been put into use. However, in the production process of all modules, the traditional photovoltaic module preparation method of connecting battery strings in parallel with busbars can no longer meet the needs of all types of photovoltaic modules, among which the stacked grid module technology is particularly difficult. In the stacked grid module, since the conductive wires on the stacked grid cell are thin and dense, if the traditional busbar welding is directly used, large-scale desoldering and conductive wire bending due to heat often occur, affecting the appearance and power generation efficiency of the stacked grid cell. Therefore, in order to solve the process problems of stacked grid battery strings in parallel, it is necessary to improve the connection structure of the photovoltaic cell string. Utility Model Content

[0003] The purpose of the utility model is to provide a connection structure at the end of a photovoltaic cell string to solve the problem of difficulty in parallel connection of stacked grid components. At the same time, the connection structure can also be used in other battery components such as multi-busbar, OBB, etc.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A connection structure at the end of a photovoltaic cell string includes a cell and a bus bar. The cell is densely covered with conductive wires, which extend to the tail of the cell. A bridge bar is used to overlap the tail of the cell and the bus bar. The bridge bar is in the shape of an elongated strip, and has welding portions on both long sides of the elongated bridge bar. There are connecting portions between the welding portions. The welding portion on one side overlaps the bus bar and is welded to the bus bar, and the welding portion on one side overlaps the tail of the cell and covers the tail of the conductive wire and is welded to the conductive wire.

[0006] Preferably, the bridge bar is composed of a base layer and a solder layer, wherein the solder layer contacts the bus bar and the conductive wire downwards respectively.

[0007] More preferably, the base layer has a thickness of 0.07-0.08 mm, and the overall thickness of the bridging strip does not exceed 0.1 mm.

[0008] Preferably, a hollow portion is provided on the connecting portion.

[0009] More preferably, the hollow shape of the hollow portion is a rectangular hole.

[0010] In another embodiment, the connecting portion is painted black.

[0011] Compared with the prior art, the beneficial effects of the utility model are:

[0012] Through the connection structure of the utility model, the bridge bar is used to solve the process problem of stacked grid cells in series and parallel. The connection structure of the utility model can achieve effective welding with the stacked grid cell sheet at a lower welding temperature, thereby ensuring the appearance and efficiency of the stacked grid cell sheet.

[0013] The bridge bar in the connection structure of the utility model can be simply and conveniently used in the all-black single-glass grid-stacking assembly without the need for additional process development, thereby reducing the overall cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the connection structure of the utility model;

[0015] Figure 2 It is a schematic diagram of the bridging bar in the connection structure of the utility model;

[0016] Figure 3 This is a schematic diagram of the bridge bars used in the all-black single-glass stacked grid module.

[0017] In the figure: 1. Battery cell; 2. Conductive wire; 3. Bus bar; 4. Bridging bar; 5. Welding part; 6. Hollow part; 7. Connecting part. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0019] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] The utility model discloses a bridge bar to realize the connection structure of the end of the stacked grid battery string, which functions to safely and reliably weld with the stacked grid battery cell and realize the connection between the stacked grid battery cell and the traditional bus bar, thereby reducing the difficulty of the stacked grid assembly manufacturing process and reducing the process development of the stacked grid assembly. At the same time, the bridge bar used in the connection structure of the utility model has a low manufacturing cost, and can be obtained by purchasing ultra-thin bus bars for secondary machining, or by purchasing ultra-thin copper bars for first machining and then secondary tinning to obtain the bridge bar, so the manufacturing steps and costs are relatively low. If the welding of the stacked grid battery cell and the conventional bus bar is directly developed without using a bridge bar, the research and development time may be too long, and a series of costs such as research and development will be higher.

[0022] An embodiment of a battery string end connection structure using a bridge bar is shown in Figure 1 This embodiment takes the stacked grid assembly as an example. The original cell uses the stacked grid technology to tightly weld more than 100 conductive wires 2 with the current collection layer on the original cell to form a stacked grid cell 1, and then the multiple stacked grid cell 1 are welded together in series through the inter-sheet bus bar 3 to form a stacked grid cell string. Since the conductive wires 2 on the stacked grid cell 1 are thin and dense, if the traditional bus bar 3 is directly used for welding, large-scale desoldering and conductive wire bending due to heat and other undesirable phenomena often occur, affecting the appearance and power generation efficiency of the stacked grid cell. Therefore, the utility model cleverly connects the stacked grid cell and the traditional bus bar together through the bridge bar 4 shown in the figure. The bridge bar 4 shown has a welding portion 5 and a connecting portion 7, and the welding portion 5 contacts the conductive wire 2 and the bus bar 3 respectively and is welded together. The use of bridge bars can achieve a more flexible connection method. First, the use of bridge bars provides a buffer for the connection between the fine conductive wires on the battery cell and the bus bar, which improves the welding quality and avoids the undesirable phenomena of large-area desoldering and conductive wire bending due to heat when the fine conductive wires on the battery cell are directly welded to the bus bar. Second, the use of bridge bars can reduce the welding temperature. The reason is that since the bridge bar is a buffer connection, the solder ratio of the solder layer on the bridge bar can be adjusted. Traditional bus bar welding requires 200-300℃. By adjusting the solder ratio on the bridge bar, the welding temperature can be reduced to 130-140℃ and still achieve a good connection of the battery string.

[0023] Figure 2 An embodiment of a bridge bar is shown, in which the middle of the bridge bar is hollowed out by professional equipment to form a hollow portion 6. The existence of the hollow portion 6 can reduce the amount of material used, reduce the weight of the overall assembly, and facilitate welding. During welding, the welding quality can be observed and a space for the possible excess tin to overflow during welding is left, thereby improving the welding quality. Although in this embodiment, the shape of the hollow portion is formed into a rectangular hole, after understanding the above technical principles, technical personnel in the industry can understand that other shapes of hollow holes can also be used, such as regular shapes such as circular, elliptical, diamond, heart-shaped, polygonal, or even other irregular shapes.

[0024] The bridge strip is preferably made of a thin and narrow material and is divided into a base layer and a solder layer, with an overall thickness of ≤0.1 mm and a base layer thickness of 0.07-0.08 mm. In an embodiment of the present invention, when a hollow portion is provided and the hollow hole is a rectangular hole, the rectangular hole is 8 mm long, 4 mm wide, and the hole spacing is 2 mm.

[0025] Although the above embodiment is the application of the bridge bar in the battery string composed of stacked grid cells, the technicians in the industry can easily think that this connection structure can also be used in most other different components. In various battery strings using bridge bars, in addition to the role of ensuring the welding quality when used for stacked grid cells as in the above embodiment, the bridge bar can also be used as a buffer part of a battery string. If the length of the initial battery string is inconsistent, the bridge bar can be used to adjust the string length of the entire battery string to achieve the advantages of ensuring the appearance of the component.

[0026] For black single-glass stacked grid modules, the entire middle of the bridge strip can be coated with black material, and then the hollowing process can be selected; or the hollowing process can be selected on the bridge strip first, and then the remaining part can be coated with black material, such as Figure 3 As shown, a black traditional bus bar is finally matched. Through this method, the black grid stacking assembly is more beautiful, the process is simpler and more convenient, the difficulty of making the black grid stacking assembly is greatly reduced, and the comprehensive cost of the black grid stacking assembly is reduced.

[0027] When using the connection structure of the utility model, one side of the bridge bar is placed on the tail of the grid cell, and the grid string machine is used for welding, and the other side is welded to the traditional bus bar to form a bridge structure. This structure cleverly uses the new bridge bar to connect the grid cell with the traditional bus bar, and then the grid assembly is manufactured through the traditional assembly manufacturing process. Its advantage is that due to the thin thickness of the bridge bar, the welding part can reach a narrowness of about 4mm, and good welding with the grid cell can be achieved under relatively low temperature conditions, which can ensure the appearance and power generation efficiency of the grid cell, avoid the adverse phenomena caused by the direct welding of the grid cell with the traditional bus bar, and reduce the process difficulty of the grid assembly manufacturing; in addition, the use of this shape of bridge bar can appropriately reduce the amount of copper and tin, and reduce the overall comprehensive cost.

[0028] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

[0029] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model is described in detail with reference to the embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified and replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A connection structure at the end of a photovoltaic cell string, comprising a cell and a bus bar, wherein the cell is densely covered with conductive wires, and the conductive wires extend to the tail of the cell, characterized in that: A bridge bar is used to overlap the tail of the battery cell and the bus bar, wherein the bridge bar is in the shape of a long strip, and has welding parts on the long sides of both sides of the long strip bridge bar, and there are connecting parts between the welding parts. The welding part on one side overlaps the bus bar and is welded to the bus bar, and the welding part on one side overlaps the tail of the battery cell and covers the tail of the conductive wire and is welded to the conductive wire.

2. The connection structure of the photovoltaic cell string end according to claim 1, characterized in that: The bridge bar is composed of a base layer and a solder layer, wherein the solder layer contacts the bus bar and the conductive wire downwards respectively.

3. The connection structure of the photovoltaic cell string end according to claim 2, characterized in that: The thickness of the base layer is 0.07-0.08 mm, and the overall thickness of the bridge strip does not exceed 0.1 mm.

4. The connection structure of the photovoltaic cell string end according to claim 1, characterized in that: A hollow portion is provided on the connecting portion.

5. The connection structure of the photovoltaic cell string end according to claim 4, characterized in that: The hollow shape of the hollow part is a rectangular hole.

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