Battery string and photovoltaic module

Abstract

The utility model relates to a battery string and a photovoltaic module. The battery string comprises at least two battery pieces and a plurality of welding strips used for connecting all the battery pieces in series. And at least three welding strips which are arranged at intervals along the first direction are arranged on the front surface and the back surface of the battery piece. The welding strips on the front face and the back face respectively comprise a first welding strip arranged on the edge portion of the battery piece in the first direction and a second welding strip arranged on the other portion of the battery piece, and the cross section area of the first welding strip in the extending direction is smaller than the cross section area of the second welding strip in the extending direction. The sectional area of the first welding strip is designed to be small, so that the defect of inter-piece hidden cracks at the edge positions of the battery pieces in the arrangement direction of the welding strips can be effectively improved; besides, the design of the cross-sectional area of the second welding strip is not limited, for example, the cross-sectional area of the second welding strip is designed to be larger, so that higher power of the photovoltaic module can be realized.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and particularly to a battery string and a photovoltaic module. Background Art

[0002] The manufacturing process of a photovoltaic module includes the production of battery wafers, the series connection of battery wafers to form a battery string, and then steps such as lamination, pressing, and framing. Among them, the process of forming a battery string generally includes printing glue on the battery wafers; pulling and drawing multiple solder tapes of the same diameter size onto the battery wafers, and the glue is cured to fix the solder tapes at the corresponding grid line positions; flattening (or not flattening) the spaced parts corresponding to adjacent battery wafers; and so on. Multiple battery wafers are connected to each other to form a battery string. After forming the battery string, it is encapsulated together through lamination and pressing to realize the series circuit of the photovoltaic module.

[0003] In related technologies, in order to improve the power of a photovoltaic module, the diameter size of the solder tape is usually increased. However, when the diameter size of the solder tape increases, when the battery string is laminated with other components, inter-sheet crack defects are likely to occur at the edge positions of the battery wafers along the arrangement direction of the solder tape. Summary of the Invention

[0004] Based on this, it is necessary to overcome the defects of related technologies and provide a battery string and a photovoltaic module, which can achieve a relatively high power while effectively improving the inter-sheet crack defects at the edge positions of the battery wafers along the arrangement direction of the solder tape.

[0005] A battery string, the battery string includes: at least two battery wafers and a plurality of solder tapes for connecting all the battery wafers in series; at least three of the solder tapes are arranged at intervals along a first direction on the front and back surfaces of the battery wafers; the solder tapes on the front and back surfaces both include first solder tapes arranged at the edge parts of the battery wafers along the first direction, and second solder tapes arranged at the remaining parts of the battery wafers, and the cross-sectional area of the first solder tape along its extension direction is smaller than the cross-sectional area of the second solder tape along its extension direction.

[0006] In one embodiment, the cross-sectional profile shape of the first solder tape along its extension direction is circular, and the cross-sectional profile shape of the second solder tape along its extension direction is circular; the diameter of the first solder tape is set as D1, and the diameter of the second solder tape is set as D2, and D1 < D2.

[0007] In one embodiment, the number of the first solder tapes at any one of the edge parts along the first direction on the front or back surface is from 0 to 3.

[0008] In one embodiment, the number of the first solder tapes at any one of the edge portions of the front or the back along the first direction is one or two.

[0009] In one embodiment, the diameter D1 of the first solder tape is set to be 0.2 mm to 0.25 mm; and / or, the diameter D2 of the second solder tape is set to be 0.25 mm to 0.3 mm.

[0010] In one embodiment, the solar cell is connected to the solder tape by welding, adhesive connection or fixed connection through a hot melt layer.

[0011] In one embodiment, for any two adjacent solar cells, a part of the solder tape for serially connecting the two solar cells is connected to the back of one solar cell, and the other part is connected to the front of the other solar cell.

[0012] In one embodiment, the battery string further includes two bus bars, and the two bus bars are respectively arranged at opposite ends of the battery string along the arrangement direction of the solar cells. One of the bus bars is connected to the solder tape on the solar cell at one end of the battery string, and the other bus bar is connected to the solder tape on the solar cell at the other end of the battery string.

[0013] A photovoltaic module, the photovoltaic module includes the battery string described above.

[0014] In one embodiment, the photovoltaic module further includes an encapsulant layer, a cover plate and a back plate; the battery strings are at least two and are connected in parallel with each other to form an array, and the encapsulant layers are two and are respectively arranged on both sides of the array; the cover plate is connected to one side of the encapsulant layer facing away from the array, and the back plate is connected to the other side of the encapsulant layer facing away from the array.

[0015] For the above-mentioned battery string and photovoltaic module, since in the arrangement direction of the solder tape on the solar cell, the cross-sectional area of the first solder tape arranged at the edge portion of the solar cell is smaller than the cross-sectional area of the second solder tape arranged at the remaining portion of the solar cell, that is, the cross-sectional areas of the solder tapes on the front and back of the solar cell are not of the same specification size as in the related art, but different specifications of solder tapes are used for series connection at the edge portion and the inner portion of the solar cell. In addition, the cross-sectional area of the first solder tape is designed to be smaller, so as to effectively improve the inter-sheet crack defect at the edge position of the solar cell along the arrangement direction of the solder tape; in addition, the design of the cross-sectional area of the second solder tape is not restricted. For example, the cross-sectional area of the second solder tape is designed to be larger, so as to achieve a higher power of the photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1Structural diagram of a battery string according to an embodiment of the present application.

[0017] Figure 2 is Figure 1 Structural diagram of a single cell in the shown structure and its connection with solder ribbons.

[0018] Figure 3 is Figure 1 Cross-sectional structural diagram at A - A.

[0019] 10. Battery string; 11. Cell; 12. Solder ribbon; 121. First solder ribbon; 122. Second solder ribbon; 13. Bus bar. Detailed implementation manners

[0020] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0021] It should be noted that in the lamination step, specifically, for example, the cover plate, the upper encapsulation film layer, the connected component string, the lower encapsulation film layer, and the backplane are assembled together to form a laminated component. In the lamination step, the laminated component is encapsulated by processes such as hot pressing to fix and protect the cells.

[0022] As described in the background art, in the related art, when the diameter size of the solder ribbon increases, in the lamination stage of laminating the battery string with other components to obtain a photovoltaic module, inter - cell micro - crack defects are likely to occur at the edge positions of the cells along the arrangement direction of the solder ribbon. Through research by the inventor, it is found that the reason for this problem is that: the solder ribbons used in the battery string have the same diameter size specification, and it is impossible to achieve both power improvement and reduction of process - induced micro - crack defects. When the diameter of the solder ribbon used is relatively large, the power of the photovoltaic module is relatively high, but inter - cell micro - crack defects at the cell edges will occur; when the diameter of the solder ribbon used is relatively small, there are no process - induced micro - crack defects, but the power of the photovoltaic module decreases.

[0023] For the above reasons, the present application provides a battery string and a photovoltaic module. By reducing the diameter of the solder ribbon in the local area, that is, at the edge positions of the cells along the arrangement direction of the solder ribbon, while not reducing the diameter of the solder ribbons in other areas of the cells, it is possible to achieve a relatively high power while effectively improving the inter - cell micro - crack defects at the edge positions of the cells along the arrangement direction of the solder ribbon.

[0024] Refer to Figures 1 to 3 , Figure 1The structural diagram of a battery string according to an embodiment of the present application is shown. Figure 2 shows Figure 1 The structural diagram of a single cell in the shown structure and the connection with the solder ribbon. Figure 3 shows Figure 1 The sectional structural diagram at A-A. A battery string 10 provided by an embodiment of the present application includes at least two cells 11 and a plurality of solder ribbons 12 for connecting all the cells 11 in series. At least three solder ribbons 12 are arranged at intervals along the first direction X on both the front and back surfaces of the cell 11. Among them, the front surface refers to the side of the cell 11 that receives light, and the back surface refers to the side of the cell that faces away from the light during operation. The number of solder ribbons 12 on the front and back surfaces is independently set according to actual needs, and all include but are not limited to 5 to 30, specifically for example 5, 10, 15, 20, 30, etc. Of course, it can also be set to more than 30 according to requirements. Among them, the solder ribbons 12 on the front and back surfaces both include a first solder ribbon 121 arranged at the edge part of the cell 11 along the first direction X, and a second solder ribbon 122 arranged at the remaining parts of the cell 11. The cross-sectional area of the first solder ribbon 121 along its extending direction Y is smaller than the cross-sectional area of the second solder ribbon 122 along its extending direction Y. Among them, the extending direction Y of the solder ribbon is also the second direction Y, and the second direction intersects the first direction X.

[0025] For the above-mentioned battery string 10, since in the arrangement direction of the solder ribbon on the cell 11, the cross-sectional area of the first solder ribbon 121 arranged at the edge part of the cell 11 is smaller than the cross-sectional area of the second solder ribbon 122 arranged at the remaining parts of the cell 11, that is, the cross-sectional areas of the respective solder ribbons 12 on the front and back surfaces of the cell 11 are not of the same specification size as in the related art, but different specifications of solder ribbons 12 are used for series connection at the edge part and the inner part of the cell 11. In addition, the cross-sectional area of the first solder ribbon 121 is designed to be smaller, so as to effectively improve the inter-sheet crack defect at the edge position of the cell 11 along the arrangement direction of the solder ribbon 12; in addition, the design of the cross-sectional area of the second solder ribbon 122 is not restricted. For example, the cross-sectional area of the second solder ribbon 122 is designed to be larger, so as to achieve a higher power of the photovoltaic module.

[0026] It should be noted that the cross-sectional profile shapes of the first solder ribbon 121 and the second solder ribbon 122 along their extending directions are independently adjusted and set according to actual needs, and each includes but is not limited to regular shapes such as circles, ellipses, polygons and other irregular shapes. Generally speaking, the solder ribbon 12 is drawn by traction, for example, it is an integrally formed metal wire, so the cross-sectional profile shape of the solder ribbon 12 is set as a circle.

[0027] For ease of understanding, in some embodiments, specifically, the cross-sectional profile shapes of the first solder tape 121 and the second solder tape 122 along their extension directions are taken as circular for illustration, but it is not limited thereto.

[0028] In one embodiment, the cross-sectional profile shape of the first solder tape 121 along its extension direction is circular, and the cross-sectional profile shape of the second solder tape 122 along its extension direction is circular; the diameter of the first solder tape 121 is set as D1, and the diameter of the second solder tape 122 is set as D2, where D1 < D2. In this way, the diameter D1 of the first solder tape 121 is smaller, and the diameter D2 of the second solder tape 122 is larger, enabling the cross-sectional area of the first solder tape 121 along its extension direction to be smaller than that of the second solder tape 122 along its extension direction.

[0029] In one embodiment, the number of the first solder tapes 121 at any edge part along the first direction X on the front or back surface is from 0 to 3.

[0030] Specifically, the number of the first solder tapes 121 at any edge part along the first direction X on the front or back surface includes but is not limited to 1, 2, or 3. In this way, the number of the first solder tapes 121 arranged at the edge parts on the front or back surface is not excessive to cause power reduction, that is, the number is more appropriate, enabling the photovoltaic module to have a higher power while effectively improving the inter-sheet crack defect at the edge position of the cell 11 along the arrangement direction of the solder tapes 12.

[0031] It should be noted that in some embodiments, it is not necessary to arrange the first solder tapes at both edge parts along the first direction on the front or back surface. For example, the number of the first solder tapes 121 at one of the edge parts on the front or back surface is 0 (i.e., no first solder tape 121 is arranged), and the number of the first solder tapes 121 at the other edge part is at least one. In this embodiment, the number of the first solder tapes 121 arranged at the edge part provided with the first solder tape 121 can be 1, 2, or 3.

[0032] In some embodiments, the number of the first solder tapes 121 at the two edge parts on the front or back surface can be the same or different, which is not limited herein, and can be specifically adjusted and set flexibly according to actual requirements.

[0033] In some embodiments, when the cross-sectional profile shape of the solder ribbon 12 along its extending direction is circular, the diameter of the solder ribbon 12 is usually set to be from 0.2 mm to 0.3 mm, specifically, for example, 0.2 mm, 0.22 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.28 mm or 0.3 mm. Of course, the diameter of the solder ribbon 12 can also be set to any value less than 0.2 mm and greater than 0.3 mm. As a specific example, the diameters D1 of the first solder ribbon 121 and D2 of the second solder ribbon 122 are both set to be from 0.2 mm to 0.3 mm, for example.

[0034] In one embodiment, the diameter D1 of the first solder ribbon 121 is set to be from 0.2 mm to 0.25 mm. In addition, the diameter D2 of the second solder ribbon 122 is set to be from 0.25 mm to 0.3 mm.

[0035] It should be noted that the diameters D1 of all the first solder ribbons 121 on the front and back surfaces can either be consistent or deviate due to, for example, processing technology errors or assembly, as long as they meet their preset diameter ranges. Similarly, the diameters D2 of all the second solder ribbons 122 on the front and back surfaces can either be consistent or deviate due to, for example, processing technology errors or assembly, as long as they meet their preset diameter ranges.

[0036] In one embodiment, the solar cell 11 is connected to the solder ribbon 12 by welding, adhesive bonding or fixed through a hot melt layer.

[0037] In the process of preparing the photovoltaic module, there are many ways to connect and fix the solder ribbon 12 on the solar cell 11, which can be specifically selected according to actual needs. As an example, welding surfaces are provided on the front and back surfaces of the solar cell 11, and the solder ribbon 12 is connected and fixed to the welding surfaces by welding. As an example, glue is provided on the front and back surfaces of the solar cell 11, and the solder ribbon 12 is adhesively fixed to the front and back surfaces of the solar cell 11 through conductive glue. As an example, a hot melt layer is provided on the solder ribbon 12, and the hot melt layer is arranged circumferentially around the solder ribbon 12. In the embodiment where the solar cell 11 and the solder ribbon 12 are connected and fixed through the hot melt layer, the solder ribbon 12 can be arranged on the front and back surfaces of the solar cell 11, and then the solder ribbon 12 is heated so that the temperature of the solder ribbon 12 is higher than the melting point temperature of the hot melt layer. The hot melt layer on the solder ribbon 12 can be melted, so that the hot melt layer is arranged circumferentially around the solder ribbon 12. By reducing the temperature, the melted hot melt layer can be solidified again, and the solder ribbon 12 can be attached to the solar cell 11. Repeating the above steps to connect two adjacent solar cells 11 can realize the series connection of multiple solar cells 11.

[0038] In order to ensure that the solder ribbon 12 can play the role of connecting the solar cells 11 in series, the solder ribbon 12 needs to be made of a conductor material, and the lower the resistivity of the solder ribbon 12, the higher the power generation efficiency of the photovoltaic module.

[0039] In one embodiment, a part of the solder ribbon 12 for serially connecting two cell wafers 11 is connected to the back surface of one cell wafer 11, and the other part is connected to the front surface of the other cell wafer 11. Thus, at least two cell wafers 11 are serially connected through the solder ribbon 12 to form a cell string 10.

[0040] In some embodiments, there is at least one connection electrode on both the front surface and the back surface. The connection electrode can be a main grid. There are also fine grids on both the front surface and the back surface that are electrically connected to the main grid. For example, there can be two main grids on the front surface and the back surface, and fine grids are distributed on both sides of each main grid, and the fine grids intersect the main grid perpendicularly and are electrically connected.

[0041] In one embodiment, the cell string 10 further includes two bus bars 13. The bus bars 13 are arranged at opposite ends of the cell string 10 along the arrangement direction of the cell wafers 11. One bus bar 13 is connected to the solder ribbon 12 on the cell wafer 11 at one end of the cell string 10, and the other bus bar 13 is connected to the solder ribbon 12 on the cell wafer 11 at the other end of the cell string 10. Thus, the bus bars 13 arranged at the ends of the cell string 10 are the positive and negative electrodes of the cell string 10, and can conduct the current generated by the cell string 10.

[0042] In one embodiment, the cell wafer 11 includes, but is not limited to, a whole cell wafer 11 or a sliced cell wafer 11.

[0043] Please refer to Figures 1 to 3 , in one embodiment, the present application provides a photovoltaic module, and the photovoltaic module includes the cell string 10 of any of the above embodiments.

[0044] For the above photovoltaic module, since in the arrangement direction of the solder ribbon on the cell wafer 11, the cross-sectional area of the first solder ribbon 121 arranged at the edge part of the cell wafer 11 is smaller than the cross-sectional area of the second solder ribbon 122 arranged at the remaining part of the cell wafer 11, that is, the cross-sectional areas of the solder ribbons 12 on the front and back surfaces of the cell wafer 11 are not of the same specification size as in the related art, but different specifications of solder ribbons 12 are used for series connection at the edge part and the inner part of the cell wafer 11. In addition, the cross-sectional area of the first solder ribbon 121 is designed to be smaller, so as to effectively improve the inter-sheet crack defect at the edge position along the arrangement direction of the solder ribbon 12 on the cell wafer 11; in addition, the design of the cross-sectional area of the second solder ribbon 122 is not restricted. For example, the cross-sectional area of the second solder ribbon 122 is designed to be larger, so as to achieve a higher power of the photovoltaic module.

[0045] In one embodiment, there are at least two cell strings 10 that are connected in parallel to form an array, and by utilizing the current output by the array, the conversion of solar energy into electrical energy can be completed.

[0046] In one embodiment, the photovoltaic module further includes an encapsulant layer, a cover plate, and a backsheet. There are at least two cell strings 10 which are connected in parallel to form an array. The encapsulant layer has two layers which are respectively disposed on two sides of the array. The cover plate is connected to one side of the encapsulant layer facing away from the array, and the backsheet is connected to the other side of the encapsulant layer facing away from the array. In this way, through the arrangement of the encapsulant layer, the cover plate, and the backsheet, the array formed by a plurality of juxtaposed cell strings 10 can be protected, preventing moisture from invading the array, and at the same time, the oxidation rate of the cells 11 can be retarded, reducing the probability of the cells 11 being corroded by external factors.

[0047] In the description of the present application, it should be understood that if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0048] In addition, if there are terms such as "first" and "second", these terms are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, if there is a term "plurality", the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0049] In the present application, unless otherwise clearly specified and limited, if there are terms such as "mounted", "connected", "coupled", "fixed", etc., these terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0050] In this application, unless otherwise clearly defined and limited, when a first feature is described as being "on" or "under" a second feature or similar descriptions, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower horizontal height than the second feature.

[0051] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If so, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0052] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0053] The above-described embodiments only represent several implementation manners of this application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of the patent of this application shall be subject to the appended claims.

Claims

1. A battery string (10), characterized in that: The battery string (10) comprises: at least two battery cells (11) and a plurality of welding strips (12) for connecting all the battery cells (11) in series; at least three welding strips (12) are arranged at intervals along a first direction on the front and back sides of the battery cells (11); the welding strips (12) on the front and back sides each comprise a first welding strip (121) arranged at an edge of the battery cell (11) along the first direction, and a second welding strip (122) arranged at the remaining portion of the battery cell (11); the cross-sectional area of ​​the first welding strip (121) along its extension direction is smaller than the cross-sectional area of ​​the second welding strip (122) along its extension direction.

2. The battery string (10) according to claim 1, characterized in that: The cross-sectional profile of the first welding strip (121) along its extension direction is circular, and the cross-sectional profile of the second welding strip (122) along its extension direction is circular; the diameter of the first welding strip (121) is set to D1, and the diameter of the second welding strip (122) is set to D2, D1 <D2。 3. The battery string (10) according to claim 2, characterized in that: The number of the first welding strips (121) at any one of the edge portions of the front surface or the back surface along the first direction is 0 to 3.

4. The battery string (10) according to claim 3, characterized in that: The number of the first welding strips (121) at any one of the edge portions of the front surface or the back surface along the first direction is 1 or 2.

5. The battery string (10) according to claim 2, characterized in that: The diameter D1 of the first welding strip (121) is set to 0.2 mm to 0.25 mm; and / or the diameter D2 of the second welding strip (122) is set to 0.25 mm to 0.3 mm.

6. The battery string (10) according to claim 1, characterized in that: The battery cell (11) and the welding strip (12) are connected by welding, adhesive bonding or fixed by a hot-melt layer.

7. The battery string (10) according to claim 1, characterized in that: A portion of the welding strip (12) used for connecting two adjacent battery cells (11) in series is connected to the back surface of one battery cell (11), and another portion is connected to the front surface of another battery cell (11).

8. The battery string (10) according to claim 1, characterized in that: The battery string (10) further comprises two bus bars (13), the two bus bars (13) being respectively arranged at opposite ends of the battery string (10) along the arrangement direction of the battery cells (11), one of the bus bars (13) being connected to a welding strip (12) on a battery cell (11) at one end of the battery string (10), and the other bus bar (13) being connected to a welding strip (12) on a battery cell (11) at the other end of the battery string (10).

9. A photovoltaic module, characterized in that: The photovoltaic assembly comprises a battery string (10) as claimed in any one of claims 1 to 8.

10. The photovoltaic module according to claim 9, characterized in that: The photovoltaic module further comprises an adhesive film layer, a cover plate and a back plate; the battery strings (10) are at least two and are connected in parallel to form an array, the adhesive film layers are two and are respectively arranged on two sides of the array; the cover plate is connected to a side of one of the adhesive film layers facing away from the array, and the back plate is connected to a side of the other adhesive film layer facing away from the array.

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