Solar cell and photovoltaic module
By setting solder pads and forks at both ends of the solar cell semi-finished product, problems such as broken grids and open welds were solved, welding performance and photoelectric conversion efficiency were improved, the risk of microcracks and cell breakage was reduced, and low-cost production was achieved.
Patent Information
- Application Number
- CN202510283550.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2025-11-11
AI Technical Summary
When welding 0BB solar cells, problems such as broken grids, open welds, and incomplete welds are prone to occur, which leads to a decrease in the welding performance of the cell module and poses a risk of microcracks and cell breakage.
A first solder pad and a second solder pad are set at both ends of the solar cell semi-finished product, and a fork is set at one end. After the solder strip is welded to the fork and the second solder pad, it is bent and extended to another solar cell. The second solder pad and the fork are used to increase the connection area and avoid or reduce the risk of microcracks and fragmentation caused by lamination and tension during welding.
This ensures the welding performance of the battery module, reduces the risk of microcracks and breakage of solar cells, and at the same time reduces the area of the metallized region, improves photoelectric conversion efficiency, and reduces production costs.
Smart Images
Figure CN120936110A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cell technology, and more particularly to a solar cell and photovoltaic module. Background Technology
[0002] With continuous technological innovation, the conversion efficiency of solar cells is increasing dramatically, and high efficiency and low cost are gradually becoming the trend in solar cell technology development. Among related technologies, 0BB (OBusbar, no main grid) technology has been proposed to reduce production costs. However, when welding 0BB cells, problems such as broken grids, open welds, and incomplete welds are prone to occur, affecting the welding performance of the cell module and easily causing microcracks and cell breakage. Summary of the Invention
[0003] This application discloses a solar cell and photovoltaic module that can ensure the welding performance of the cell module and reduce the risk of microcracks and breakage of the solar cell.
[0004] To achieve the above objectives, in a first aspect, embodiments of this application disclose a solar cell, which is applied to a photovoltaic module. The photovoltaic module includes a plurality of the solar cells, and the solar cell includes a solar cell semi-finished product and an electrode structure. The electrode structure includes:
[0005] Multiple sub-gates are arranged at intervals along a first direction, and each sub-gate extends along a second direction;
[0006] A pad assembly, comprising a first pad and a second pad spaced apart along the first direction, wherein the first pad and the second pad are respectively disposed at both ends of the solar cell semi-finished product; and,
[0007] A harpoon, which is located on the edge of one end of the solar cell semi-finished product and connected to the second pad;
[0008] The harpoon and the second pad are configured to be welded to a solder strip such that the solder strip bends and extends from the connection point with the harpoon and the second pad to be welded to another solar cell;
[0009] The first direction and the second direction intersect.
[0010] As an optional implementation, in an embodiment of the first aspect of this application, the first pad has a dimension L1 in the first direction, and the second pad has a dimension D1 in the first direction, where D1 > L1.
[0011] As an optional implementation, in an embodiment of the first aspect of this application, the dimension L1 of the first pad in the first direction is 0.3 mm to 1 mm, and the dimension L2 of the first pad in the second direction is 0.5 mm to 1.2 mm; and / or,
[0012] The second pad has a dimension D1 of 0.3mm to 1mm in the first direction and a dimension D2 of 0.5mm to 1.2mm in the second direction.
[0013] As an optional implementation, in an embodiment of the first aspect of this application, the edge of the end of the solar cell semi-finished product where the first pad is located is not provided with the harpoon; and / or,
[0014] The pad group consists of the first pad and the second pad.
[0015] As an optional implementation, in an embodiment of the first aspect of this application, the electrode structure further includes a main gate connection line, which extends along the first direction, and the two ends of the main gate connection line are respectively provided with the first pad and the second pad.
[0016] As an alternative implementation, in an embodiment of the first aspect of this application, the number of pad groups is greater than or equal to the number of main gate interconnects.
[0017] As an optional implementation, in an embodiment of the first aspect of this application, the number of main gate interconnects includes multiple lines, and when the number of pad groups is greater than the number of main gate interconnects, each pair of adjacent main gate interconnects is further provided with a pad group; and / or,
[0018] The number of main gate connection lines is 0 to 24.
[0019] As an optional implementation, in an embodiment of the first aspect of this application, the main gate connection line includes a plurality of first sub-gate lines, the plurality of first sub-gate lines are spaced apart along the first direction, two adjacent sub-gates form a gate line group, each gate line group is spaced apart along the first direction, and each first sub-gate line is connected between two adjacent gate line groups.
[0020] As an optional implementation, in an embodiment of the first aspect of this application, the electrode structure further includes a main gate connection line, each of the sub-gates includes a plurality of second sub-gate lines, the plurality of second sub-gate lines are spaced apart along the second direction to form a break between two adjacent second sub-gate lines, the break is located at the main gate connection line, and / or the break is spaced apart from the main gate connection line in the second direction;
[0021] The electrode structure also includes a connection structure located at the break point to connect two adjacent second sub-gate lines.
[0022] Secondly, this application also discloses a photovoltaic module, including the solar cell as described in the first aspect above.
[0023] Compared with the prior art, the beneficial effects of this application are:
[0024] This application discloses a solar cell and a photovoltaic module. The application involves setting a first solder pad and a second solder pad at both ends of a semi-finished solar cell, and setting a fork at the end of the semi-finished solar cell with the second solder pad. The fork, the second solder pad, and the solder strip are then welded together, with the solder strip bending and extending from the connection point with the fork and the second solder pad to weld to another solar cell. When welding at least two solar cells, the presence of the second solder pad and the fork at the end where the solar cell is welded to the solder strip and the solder strip bends and extends to the other solar cell avoids or reduces the risk of microcracks and breakage of the solar cell caused by lamination and tension applied to the solder strip during welding. This helps to ensure the welding performance of the module and the integrity of the solar cells. Furthermore, since the first and second pads are respectively set at both ends of the solar cell semi-finished product, and the harpoon is only set at one end, a smaller metallization area can be provided, which reduces the contact area between the electrode structure and the solar cell semi-finished product, reduces metal contact recombination, and reduces shading of sunlight, which is beneficial to improving photoelectric conversion efficiency. At the same time, it also reduces the consumption of paste, thereby helping to reduce the production cost of solar cells. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic diagram of the structure of the photovoltaic module disclosed in this application;
[0027] Figure 2 This is one of the structural schematic diagrams of the solar cell disclosed in this application;
[0028] Figure 3 for Figure 2 Enlarged view of point A in the middle;
[0029] Figure 4 for Figure 2 Enlarged view of point B in the middle;
[0030] Figure 5 for Figure 2 Enlarged view of point C in the middle;
[0031] Figure 6 This is the second schematic diagram of the structure of the solar cell disclosed in this application;
[0032] Figure 7 for Figure 6 Enlarged view of point D in the middle;
[0033] Figure 8 This is the third schematic diagram of the structure of the solar cell disclosed in this application;
[0034] Figure 9 for Figure 8 Enlarged diagram of point E in the middle.
[0035] Explanation of reference numerals in the attached figures:
[0036] 100. Solar cell; O. Chamfer; 101. First unit; 102. Second unit; 103. Dashed line; 100a. First end; 100b. Second end; 10. Semi-finished solar cell; 20. Electrode structure; 210. Grid line group; 21. Sub-grid; 211. Second sub-grid line; 212. Break; 22. Pad group; 221. First pad; 222. Second pad; 23. Harpoon; 24. Main grid connection line; 241. First sub-grid line; 25. Connection structure;
[0037] 200. Photovoltaic modules; 201. Solder strips;
[0038] X, first direction; Y, second direction;
[0039] L1, the dimension of the first pad in the first direction; L2, the dimension of the first pad in the second direction;
[0040] D1, the dimension of the second pad in the first direction; D2, the dimension of the second pad in the first direction. Detailed Implementation
[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0042] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.
[0043] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0044] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0045] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.
[0046] Due to their cleanliness, safety, convenience, and high efficiency, solar cells have become a globally recognized and key industry for development. With continuous technological innovation, the conversion efficiency of solar cells is increasing dramatically, and high efficiency at low cost is gradually becoming the trend in solar cell technology development.
[0047] To reduce production costs, the industry has proposed 0BB (Zero Busbar). However, due to limitations in current battery module manufacturing processes, problems such as broken grids, open welds, and cold welds are prone to occur when soldering 0BB solar cells. Based on this, the inventors attempted to retain the pads at both ends for connection with the solder strip. This reduces the likelihood of broken grids, open welds, and cold welds while also reducing wet weight, thus lowering production costs.
[0048] However, the inventors discovered through further research that, during the welding of solar cells, the welding strip at one end is usually bent from the front of the current solar cell to the back of another solar cell. This method easily causes the two adjacent solar cells to be subjected to lamination forces during the welding and transfer process. Furthermore, due to the expansion difference between the welding strip and the solar cell, these two adjacent ends are subjected to large tensile forces, which can easily cause microcracks in the solar cells. In severe cases, the solar cells may even break apart.
[0049] To address this issue, this application provides a solar cell with a first and a second solder pad at both ends of a semi-finished solar cell. A fork is positioned at the end of the semi-finished solar cell with the second solder pad. The fork, the second solder pad, and the solder strip are welded together, with the solder strip bending and extending from the connection point with the fork and the second solder pad to weld to another solar cell. When welding at least two solar cells, the second solder pad and the fork at the end where the solar cell is welded to the solder strip and the solder strip bends and extends to the other solar cell increase the connection area between the solar cell and the solder strip. This reduces or avoids the risk of microcracks and breakage of the solar cell caused by lamination and the tension of the solder strip during welding, thus helping to ensure the welding performance of the solar module and the integrity of the solar cells.
[0050] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.
[0051] This application discloses a photovoltaic module 200. Please refer to... Figure 1 , Figure 1 A schematic diagram of the structure of a photovoltaic module 200 according to an embodiment of this application is shown. The photovoltaic module 200 may include a plurality of solar cells 100, which are connected in parallel or in series.
[0052] Understandably, two adjacent solar cells 100 are connected by solder ribbons 201. For example, a solar cell 100 has a front and a back side arranged opposite to each other. Solder ribbons 201 are soldered to the front side of the first solar cell 100 and extend from one end to the other. The solder ribbons 201 extending to the other end continue to extend beyond the end of the first solar cell 100, then bend and continue to extend to the back side of the second solar cell 100 for welding. At this time, the front side of the second solar cell 100 can continue to be connected with solder ribbons 201 and bend to extend to the back side of the third solar cell 100, and so on, connecting multiple solar cells 100 together by solder ribbons 201.
[0053] Of course, the photovoltaic module 200 may also include a frame, photovoltaic glass, encapsulation materials, etc., which together constitute the photovoltaic module 200. It is suitable for various outdoor environments, such as rooftops and building surfaces, and is widely used in solar photovoltaic systems.
[0054] The specific structure of the solar cell 100 of this application will be described in detail below with reference to the accompanying drawings.
[0055] In this embodiment of the application, the solar cell 100 includes a solar cell semi-finished product 10 and an electrode structure 20. The electrode structure 20 can be disposed on the front side, the back side, or both sides of the solar cell semi-finished product 10.
[0056] See Figures 2 to 5 ,in, Figure 2 This is a schematic diagram of the structure of the solar cell 100 according to an embodiment of this application. Figure 3 yes Figure 2 Enlarged diagram of point A in the middle. Figure 4 yes Figure 2 Enlarged diagram at point B in the middle, Figure 5 yes Figure 2 Enlarged diagram of point C in the middle.
[0057] It is worth noting that, combined Figure 2 The solar cell 100 has chamfered corners (O) at its edges. Typically, the solar cell 100 is square, and all four corners of this square solar cell 100 have chamfered corners (O). These chamfered corners (O) improve silicon utilization during the manufacturing process of the solar cell 100, prevent high-stress points at the apex of the solar cell 100, and prevent over-etching during the etching process, which could lead to leakage. Optionally, the chamfered corners (O) can be square, and the side length of the chamfered corners (O) of the solar cell 100 is generally not less than 0.5 mm.
[0058] In some possible implementations, see [reference] Figure 2 The electrode structure 20 includes multiple sub-gates 21, which are spaced apart along a first direction X, and each sub-gate 21 extends along a second direction Y.
[0059] Understandably, the sub-grid 21 typically uses a burn-through paste, which can be a conductive paste with high corrosion resistance (e.g., silver paste). This allows the silicon nitride on the surface of the solar cell semi-finished product 10 to burn through, enabling the conductive metal powder to come into contact with the silicon material and form a conductive metal-silicon alloy, thus achieving good ohmic contact and enabling the collection of current inside the solar cell 100.
[0060] In this embodiment, the first direction X and the second direction Y intersect. For example, the first direction X can be longitudinal, the second direction Y can be transverse, and multiple sub-gates 21 can be arranged at intervals along the longitudinal direction, and the multiple sub-gates 21 are parallel or substantially parallel, with each sub-gate 21 extending transversely.
[0061] Combination Figures 2 to 5 In some possible embodiments, the electrode structure 20 includes a pad group 22, which may include a first pad 221 and a second pad 222 spaced apart along a first direction X. The first pad 221 and the second pad 222 are respectively located at both ends of the solar cell semi-finished product 10. Both the first pad 221 and the second pad 222 can be used to solder with the solder strip 201 to conduct current.
[0062] In other words, through the good ohmic contact between the sub-gate 21 and the substrate of the solar cell semi-finished product 10, the multiple sub-gates 21 can effectively collect charge carriers and thus form current; since the solder pads are soldered with solder ribbons 201, the current can be discharged through the solder pads.
[0063] In the embodiments of this application, the shapes of the first pad 221 and the second pad 222 can be rectangular, elliptical, rhomboid, or hexagonal, etc. The first pad 221 and the second pad 222 can be pads of the same shape, or they can be pads of different shapes; no limitation is imposed here.
[0064] To simplify the manufacturing process and ensure sufficient contact welding area between the first pad 221 and the solder strip 201 within the same size, preferably, both the first pad 221 and the second pad 222 can be rectangular pads.
[0065] Combination Figure 1 and Figure 5 In some possible embodiments, the electrode structure 20 may further include a harpoon 23, which is disposed at one end of the edge of the solar cell semi-finished product 10 and connected to the second pad 222. The harpoon 23 and the second pad 222 are configured to be welded to the solder ribbon 201 such that the solder ribbon 201 bends and extends from the connection with the harpoon 23 and the second pad 222 to be welded to another solar cell 100.
[0066] This application provides a first solder pad 221 and a second solder pad 222 at both ends of a solar cell semi-finished product 10, and a fork 23 at the end of the solar cell semi-finished product 10 with the second solder pad 222. The fork 23 and the second solder pad 222 are welded to the solder ribbon 201, so that the solder ribbon 201 bends and extends from the connection point with the fork 23 and the second solder pad 222 to be welded to another solar cell 100. When welding at least two solar cells 100, since the second solder pad 222 and the fork 23 are provided at the end of the solar cell 100 where it is welded to the solder ribbon 201 and the solder ribbon 201 bends and extends to the other solar cell 100, the risk of microcracks and breakage of the solar cell 100 caused by lamination and tension applied to the solder ribbon 201 during welding can be avoided or reduced. This helps to ensure the welding performance of the battery module and the integrity of the solar cell 100.
[0067] Furthermore, since the first pad 221 and the second pad 222 are provided at both ends of the solar cell semi-finished product 10, and the harpoon 23 is provided only at one end, a smaller metallization area can be provided, which reduces the contact area between the electrode structure 20 and the solar cell semi-finished product 10, reduces metal contact recombination, and reduces the shading of sunlight, which is beneficial to improving photoelectric conversion efficiency. At the same time, it also reduces the consumption of paste, thereby helping to reduce the production cost of the solar cell 100.
[0068] To avoid or reduce the risk of microcracks and breakage of the solar cell 100 caused by lamination and tension applied to the solder strip 201 during welding, thereby ensuring the welding performance of the battery module and the integrity of the solar cell 100, in order to further reduce the consumption of paste, in some possible embodiments, the edge of the end of the solar cell semi-finished product 10 where the first solder pad 221 is provided is not provided with a harpoon 23.
[0069] Since the solar cell semi-finished product 10 has a first solder pad 221 at one end, when it is welded to the solder ribbon 201, the solder ribbon 201 extends towards the second solder pad 222 and extends outward to the other solar cell 100 without being subjected to the tension caused by the bending and extension of the solder ribbon 201. Therefore, it is sufficient to connect the solder ribbon 201 through the first solder pad 221. This arrangement can reduce the obstruction of sunlight without affecting the welding performance of the first solder pad and the solder ribbon 201, thereby improving the photoelectric conversion effect, and can also take into account the consumption of paste, thus helping to reduce production costs.
[0070] In this embodiment of the application, only one end of the solar cell semi-finished product 100 is provided with a harpoon 23, while the other end is not provided with a harpoon 23.
[0071] In some possible implementations, the pad group 22 consists of a first pad 221 and a second pad 222. That is, only the pads at both ends are retained on the surface of the solar cell 100. While meeting the welding performance requirements, this can further reduce the wet weight of the solar cell 100, reduce the shading area of the solar cell 100, increase the conversion efficiency of the solar cell 100, and further reduce the consumption of paste.
[0072] It should be noted that, in combination Figure 2 The solar cell 100 in this embodiment may include a first unit 101 and a second unit 102 arranged adjacent to each other from top to bottom along the first direction X. Figure 2 The first unit 101 and the second unit 102 are separated by a dashed line 103 extending from the left-right direction of the paper. Along the vertical direction of the paper, the portion above the dashed line 103 is the first unit 101, and the portion below the dashed line 103 is the second unit 102. Both the first unit 101 and the second unit 102 have a first end 100a and a second end 100b along the first direction X. The first end 100a is the end closer to the chamfer O, and the second end 100b is the end farther from the chamfer O.
[0073] Both the first unit 101 and the second unit 102 have electrode structures 20. Specifically, both the first unit 101 and the second unit 102 have multiple sub-gates 21, pad groups 22, and harpoons 23 spaced apart along a first direction X, with each sub-gate 21 extending along a second direction Y. A first pad 221 is located at a first end 100a, a second pad 222 is located at a second end 100b, and the harpoon 23 is located at the second end 100b (the end away from the chamfer O) and is connected to the second pad 222.
[0074] In other words, when the solar cell 100 includes a first unit 101 and a second unit 102, each region is provided with a harpoon 23 only at one end, and the harpoon 23 is provided at the end away from the chamfer O of the solar cell 100. That is, the harpoons 23 in the first unit 101 and the second unit 102 are arranged opposite to each other along the first direction X. When slicing, each half of the solar cell 100 is provided with a harpoon 23 only at the end away from the chamfer O at both ends along the first direction X.
[0075] Continue reading Figure 4 and Figure 5In some possible implementations, the first pad 221 has a dimension L1 in the first direction X, and the second pad 222 has a dimension D1 in the first direction X, where D1 > L1. It can be understood that the first direction X is the length direction of the solder ribbon 201. By limiting the dimension of the second pad 222 in the first direction X to be greater than the dimension of the first pad 221 in the first direction X, the contact dimension between the second pad 222 and the solder ribbon 201 in the first direction X can be made greater than the contact dimension between the first pad 221 and the solder ribbon 201, thereby effectively ensuring the soldering performance between the solder ribbon 201 and the second pad 222 and further reducing the risk of solder microcracks.
[0076] It should be noted that the dimensions of the first pad 221 and the second pad 222 in the second direction Y can be equal or unequal, as long as the welding is satisfied in the width direction of the solder strip 201.
[0077] The relevant parameters of the first pad 221 and the second pad 222 will be further explained below.
[0078] In some possible implementations, the dimension L1 of the first pad 221 in the first direction X is 0.3 mm to 1 mm. It is understood that the dimension L1 of the first pad 221 in the first direction X includes any range within this numerical range. Optionally, L1 can be 0.3 mm to 0.5 mm, 0.4 mm to 0.8 mm, or 0.8 mm to 1 mm, etc. Accordingly, the dimension L1 of the first pad 221 in the first direction X includes any point value within this numerical range; for example, L1 can be 0.3 mm, 0.5 mm, or 0.8 mm, etc.
[0079] In some possible implementations, the dimension L2 of the first pad 221 in the second direction Y is 0.5mm to 1.2mm. It is understood that the dimension L2 of the first pad 221 in the second direction Y includes any range within this value range; optionally, L2 can be 0.5mm to 0.8mm, 0.8mm to 1mm, or 1mm to 1.2mm, etc. Correspondingly, the dimension L2 of the first pad 221 in the second direction Y includes any point value within this value range; for example, L2 can be 0.5mm, 0.8mm, or 1mm, etc.
[0080] In some possible implementations, the dimension D1 of the second pad 222 in the first direction X is 0.3 mm to 1 mm. It is understood that the dimension D1 of the second pad 222 in the first direction X includes any range within this value range; optionally, D1 can be 0.3 mm to 0.5 mm, 0.4 mm to 0.8 mm, or 0.8 mm to 1 mm, etc. Correspondingly, the dimension D1 of the second pad 222 in the first direction X includes any point value within this value range; for example, D1 can be 0.3 mm, 0.5 mm, or 0.8 mm, etc.
[0081] In some possible implementations, the dimension D2 of the second pad 222 in the second direction Y is 0.5mm to 1.2mm. It is understood that the dimension D2 of the second pad 222 in the second direction Y includes any range within this value range; optionally, D2 can be 0.5mm to 0.8mm, 0.8mm to 1mm, or 1mm to 1.2mm, etc. Correspondingly, the dimension D2 of the second pad 222 in the second direction Y includes any point value within this value range; for example, D2 can be 0.5mm, 0.8mm, or 1.2mm, etc.
[0082] Wherein, the first direction X can be the length direction of the solder strip 201, and the second direction Y can be the length extension direction of the sub-gate 21.
[0083] The solar cell 100 disclosed in this application, while achieving good performance (including the absence of poor soldering, false soldering, solder strip 201 detachment, and welding microcracks or fragments), effectively reduces the metallization area of the electrode structure 20 by reducing the size of the first solder pad 221 and the second solder pad 222. This is beneficial for improving photoelectric conversion efficiency and reducing the cost of the solar cell 100. Furthermore, the smaller solder pad size in this application provides a smaller metallization area, which not only reduces metal contact recombination but also reduces sunlight shading, improving photoelectric conversion efficiency in two ways and effectively controlling production costs.
[0084] In the embodiments of this application, the solar cell 100 can be OBB (Zero Busbar), MBB (MultiBusbar), SMBB (Super Multi Busbar), etc. The OBB technology mainly eliminates the main busbar connection line 24 and uses solder ribbon 201 to directly connect the sub-busbar 21 to collect and conduct current. This significantly reduces the metal shading area on the surface of the solar cell semi-finished product 10, increases the light-receiving area, and thus improves the power generation efficiency of the solar cell 100. The MBB and SMBB technologies mainly collect the current of the sub-busbar 21 through the main busbar connection line 24 and conduct the current through solder ribbon 201.
[0085] The following explanation will take the multi-busbar solar cell 100 as an example.
[0086] Because the current gridless design is still limited by the current battery module manufacturing process, problems such as broken grids, open welds, or poor welds are very likely to occur when welding 0BB solar cells 100.
[0087] Therefore, in combination Figures 2 to 5 In some possible embodiments, the electrode structure 20 further includes a main grid connection line 24, which extends along a first direction X. The main grid connection line 24 has a first pad 221 and a second pad 222 at its two ends. By providing the main grid connection line 24 on the solar cell semi-finished product 10, the current formed by the sub-grid 21 collecting charge carriers is concentrated on the main grid connection line 24 and welded to the solder ribbon 201 through the main grid connection line 24, thus discharging the current. This effectively ensures the welding area between the solder ribbon 201 and the main grid connection line 24, thereby effectively improving the welding performance of the OBB design in the cell module and reducing problems such as broken grids, open welds, and incomplete welds.
[0088] Taking the first unit 101 as an example, the first unit 101 has multiple sub-gates 21 spaced apart along a first direction X, each sub-gate 21 extending along a second direction Y. The first unit 101 also has multiple main gate connection lines 24 spaced apart along the second direction Y, each main gate connection line 24 extending along the first direction X. Each main gate connection line 24 has a first pad 221 and a second pad 222 at its two ends. Specifically, each main gate connection line 24 has a first end 100a and a second end 100b arranged opposite each other along the first direction X. The first pad 221 is located at the first end 100a, and the second pad 222 is located at the second end 100b. The second end 100b (the end away from the chamfer O) of the main gate connection line 24 has a fork 23 connected to the second pad 222, while the first end 100a (the end near the chamfer O) does not have a fork 23.
[0089] Correspondingly, the second unit 102 also has the same sub-gate 21 and main gate connecting line 24, with a harpoon 23 only provided at the end of the main gate connecting line 24 away from the chamfer O.
[0090] It is worth noting that, in the process of welding multiple solar cells together, taking the series welding of two adjacent solar cells 100 as an example, the solder ribbon 201 extends from the front side of the first solar cell 100 to the back side of the second solar cell 100, and the solder ribbon bends between the two solar cells 100. Since the second end 100b of the solar cell 100 (the end away from the chamfer O) is provided with the second solder pad 222 and the fork 23, when welding with another solar cell 100, the second end 100b is positioned close to the other solar cell 100.
[0091] Taking the extension of the solder strip 201 from the front of the first solar cell 100 to the back of the second solar cell 100 as an example, the second end 100b of the front of the first solar cell 100 is provided with the second solder pad 222 and the harpoon 23. Then, the second solder pad 222 and the harpoon 23 are provided on the back of the second solar cell 100 near the end of the first solar cell 100. Because of the difference in thermal expansion coefficients between the solder ribbon 201 and the solar cell 100 after welding, the two ends of the two solar cells 100 that are close to each other are subjected to large tensile forces. After interconnection, the solar cells 100 are prone to bending, microcracks or fragmentation. Therefore, in order to save paste and reduce costs, only the harpoon 23 is retained to weld the solar cell 100 to the solder ribbon 201 and make the solder ribbon 201 bend and extend to the other end of the solar cell 100. This can also avoid or reduce the risk of microcracks and fragmentation of the solar cell 100 caused by lamination and the tensile force applied to the solder ribbon 201 during welding. This is conducive to ensuring the welding performance of the battery module and the integrity of the solar cell 100, so as to comprehensively meet the market demand for high efficiency and low cost of solar cell 100.
[0092] In related technologies, in order to reduce the cost of solar cell 100 and improve the overall process efficiency of solar cell 100, a technique of narrowing the line width of sub-grid 21 is adopted, mainly by optimizing the screen. However, due to the low transfer rate and uneven printing of the slurry caused by the steel wire screen, problems such as broken grids, false printing, and poor flatness are caused.
[0093] Based on this, the inventors attempted to introduce a new process screen, which includes a substrate with printing holes on the substrate, so that the printing holes are unobstructed and achieve a 100% opening rate at the printing holes. Thus, during printing, the ink can pass through the printing holes of the screen without obstruction, making the ink flow more smoothly and evenly, thereby achieving ultra-fine line printing. This can narrow the line width of the grid lines, resulting in low-wet-weight solar cells. While reducing conductive ink loss, it can also reduce defects such as grid line breakage, incomplete printing, and poor flatness.
[0094] However, the inventors discovered that making 150 or more horizontal openings on the substrate would greatly damage the mechanical stability of the screen, making it very easy for the screen to burst during printing.
[0095] Based on this, in this embodiment, the printing holes on the screen corresponding to the printing sub-grids used for printing the sub-grids are segmented to enhance the mechanical properties of the screen. The sub-grids 21 formed by printing with this screen are characterized by breaks 212.
[0096] Specifically, each sub-gate 21 includes multiple second sub-gate lines 211, which are spaced apart along the second direction Y to form a break 212 between adjacent second sub-gate lines 211. This arrangement reduces the risk of grid failure from the perspective of the sub-gate screen; and from the perspective of the electrode structure 20, it reduces surface shading and conductive paste consumption without affecting the current collection of the sub-gate 21.
[0097] In order not to affect the transmission of current, a main grid is introduced. A connection structure 25 is formed by printing on the main grid and located at the break 212, so that the sub-grid 21 of the final electrode structure 20 forms a complete grid line.
[0098] Specifically, the electrode structure 20 also includes a connection structure 25, which is located at the break 212 to connect two adjacent second sub-gate lines 211. By providing the connection structure 25 at the break 212 and connecting it between the sub-gates 21 located on both sides of the break 212, current can be transmitted through the sub-gates 21, thus realizing the current transmission function of the sub-gates 21.
[0099] In some embodiments, the connection structure 25 can be a rectangular connection structure 25, the area of which is filled with slurry. The rectangular connection structure 25 is connected between the sub-grid lines located on both sides of the break 212, so that each sub-grid 21 extends as an uninterrupted grid line in the second direction Y.
[0100] Of course, in other embodiments, the connecting structure 25 may also be, for example, circular, near-circular, or other polygonal holes (e.g., triangular, pentagonal, or hexagonal, etc.).
[0101] Furthermore, in some embodiments, the shape of the connection structure 25 may include at least one of H-shape, N-shape, or inverted figure-eight shape. Using a connection structure 25 with these shapes can reduce slurry loss while ensuring effective connection between the connection structure 25 and the sub-grid lines located on both sides of the break 212.
[0102] Preferably, the connection structure 25 is H-shaped, which is more conducive to ensuring the connection between the formed connection structure 25 and the sub-grid 21, reducing paste loss, reducing the shading area, and thus improving the conversion efficiency of the solar cell 100.
[0103] In some possible implementations, the break 212 is located at the main grid connection line 24. That is, the main grid connection line 24 can pass through the break 212. Using this method, the connection structure 25 at the break 212 can be used to strengthen the connection between the main grid connection line 24 and the sub-grid 21. However, it should be noted that this method places requirements on the dimensions of the connection structure 25. Specifically, since the connection structure 25 is printed simultaneously with the main grid connection line 24, using the same paste printed on the main grid connection line 24, the final connection structure 25 has a low line height, which can easily lead to grid breakage during welding.
[0104] In some possible implementations, the break 212 is spaced apart from the main gate connection line 24 in the second direction Y. That is, the connection structure 25 located at the break 212 is also spaced apart from the main gate connection line 24. In this way, the break 212 and the main gate connection line 24 do not affect each other. The connection structure 25 is located at the break 212 and connects between the sub-gates 21 located on both sides of the break 212, so that current can be transmitted through the sub-gates 21, thereby allowing the current to be normally converged on the main gate connection line 24. Furthermore, the connection structure 25 here is not subject to strict size requirements.
[0105] In some possible implementations, the number of pad groups 22 is greater than or equal to the number of main gate connections 24. It is understood that when the number of pad groups 22 equals the number of main gate connections 24, there is a one-to-one correspondence between the pad groups 22 and the main gate connections 24. Thus, each solder ribbon 201 collects the current transmitted from the sub-gate 21 through the main gate before exporting it. When the number of pad groups 22 is greater than the number of main gate connections 24, part of the current transmitted from the sub-gate 21 can be collected by the main gate and then exported through the solder ribbon 201, while the other part can be directly exported through the solder ribbon 201. With the same number of pad groups 22, compared to the arrangement where each pad group 22 corresponds to one main gate connection 24, this reduces the number of main gate connections 24 while ensuring effective current conduction, thereby saving on ink consumption during printing the main gate connections 24 and ultimately reducing costs.
[0106] In one example, when there is one main gate connection line 24, there can be multiple pad groups 22. In this case, the main gate connection line 24 and the pad groups 22 are connected.
[0107] In another example, when there is one main gate connection line 24, there can be multiple pad groups 22. In this case, it is necessary to ensure that the main gate connection line 24 is connected to a pad group 22. That is, the first pad 221 and the second pad 222 of the pad group 22 are respectively connected to the two ends of the main gate connection line 24.
[0108] It should be noted that when there are multiple pad groups 22, the multiple pad groups 22 are spaced apart along the second direction Y, that is, the setting direction of the multiple pad groups 22 is consistent with the length extension direction of the subgate 21.
[0109] See Figure 6 and Figure 7 , Figure 6 This is another structural schematic diagram of the solar cell 100 according to an embodiment of this application. In this figure, the main grid connection lines 24 are arranged at intervals. Figure 7 yes Figure 6 Enlarged diagram of point D in the middle.
[0110] In some possible implementations, the number of main gate connection lines 24 includes multiple lines. When the number of pad groups 22 is greater than the number of main gate connection lines 24, there is also a pad group 22 between every two adjacent main gate connection lines 24. That is, when a certain number of solder ribbons 201 need to be soldered, the main gate connection lines 24 are arranged in an intermittent manner. For example, the first pad group, the second pad group to the fifth pad group are arranged intermittently along the second direction Y. In this case, a first main gate connection line, a second main gate connection line and a third main gate connection line can be provided. The first main gate connection line is set and connected to the first pad group, the second main gate connection line is set and connected to the third pad group, and the third main gate connection line is set and connected to the fifth pad group. That is, the purpose of having a pad group 22 between every two adjacent main gate connection lines 24 and the main gate connection lines 24 being arranged intermittently is achieved.
[0111] This setup allows for reduced wet weight and controlled production costs while ensuring electrical performance, EL (Electroluminescent) testing, and secondary sintering.
[0112] See Figure 8 and Figure 9 , Figure 8 This is another structural schematic diagram of the solar cell 100 according to an embodiment of this application. In this diagram, the main grid connection line 24 is intermittently arranged. Figure 9 yes Figure 8 Enlarged schematic diagram at point E. In some possible embodiments, the main gate connection line 24 includes multiple first sub-gate lines 241, which are spaced apart along a first direction X. Adjacent sub-gates 21 form gate line groups 210, and each gate line group 210 is spaced apart along the first direction X. Each first sub-gate line 241 is connected between two adjacent gate line groups 210. That is, by setting the main gate connection line 24 to be discontinuous, the sub-gate 21 is divided into multiple gate line groups 210 consisting of two sub-gates 21, and the first sub-gate lines 241 are connected between two gate line groups 210, so that the current transmitted by the sub-gate 21 can be collected normally while further reducing the wet weight.
[0113] Since a reasonable increase in the number of main gate connection lines 24 can reduce the transmission distance of the sub-gate 21, this application sets multiple main gate connection lines 24 to shorten the distance of the sub-gate 21 between two connected main gate connection lines 24, thereby reducing the gate line transmission resistance and series resistance, which is beneficial to improving the photoelectric conversion efficiency.
[0114] In some possible implementations, the number of main grid connection lines 24 is 0 to 24. Optionally, the number of main grid connection lines 24 can be 0 to 18, 18 to 24, or 12 to 24, etc., for example, 0, 18, or 24, which can result in a larger number of main grid connection lines 24 with smaller spacing. When there are 0 main grid connection lines 24, the solar cell 100 is a gridless cell.
[0115] The increased number of main busbar connecting lines 24 improves compatibility with broken sub-busbars 21, allowing for further narrowing of the sub-busbars 21. For example, if the original number of main busbar connecting lines 24 was 18 and the distance between two main busbar connecting lines 24 was 11.29 mm, increasing the number of main busbar connecting lines 24 to 24 reduces this distance to 8.5 mm. Previously, the distance between two broken busbars needed to be greater than 11.29 mm for electroluminescence (EL), electrical performance testing, and secondary sintering to proceed. Now, with 24 connecting lines, this distance is reduced to 8.5 mm. Therefore, while ensuring the performance of the solar cell 100, the overall wet weight can be further reduced.
[0116] Of course, in other embodiments, the number of main grid connection lines 24 can be other numbers. In this embodiment, the number of main grid connection lines 24 is not specifically limited, as long as it meets the performance requirements of the solar cell.
[0117] The solar cells and photovoltaic modules disclosed in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the solar cells and photovoltaic modules of this application and their core ideas. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A solar cell, characterized in that, The solar cell is used in a photovoltaic module, the photovoltaic module including multiple solar cells, the solar cell including a solar cell semi-finished product and an electrode structure, the electrode structure including: Multiple sub-gates are arranged at intervals along a first direction, and each sub-gate extends along a second direction; A pad assembly, comprising a first pad and a second pad spaced apart along the first direction, wherein the first pad and the second pad are respectively disposed at both ends of the solar cell semi-finished product; and, A harpoon, which is located on the edge of one end of the solar cell semi-finished product and connected to the second pad; The harpoon and the second pad are configured to be welded to a solder strip such that the solder strip bends and extends from the connection point with the harpoon and the second pad to be welded to another solar cell; The first direction and the second direction intersect.
2. The solar cell according to claim 1, characterized in that, The first pad has a dimension L1 in the first direction, and the second pad has a dimension D1 in the first direction, where D1 > L1.
3. The solar cell according to claim 2, characterized in that, The dimension L1 of the first pad in the first direction is 0.3mm to 1mm, and the dimension L2 of the first pad in the second direction is 0.5mm to 1.2mm; and / or, The second pad has a dimension D1 of 0.3mm to 1mm in the first direction and a dimension D2 of 0.5mm to 1.2mm in the second direction.
4. The solar cell according to claim 1, characterized in that, The edge of the end of the solar cell semi-finished product where the first solder pad is located is not provided with the harpoon; and / or, The pad group consists of the first pad and the second pad.
5. The solar cell according to claim 1, characterized in that, The electrode structure further includes a main gate connection line, which extends along the first direction, and the two ends of the main gate connection line are respectively provided with the first pad and the second pad.
6. The solar cell according to claim 5, characterized in that, The number of pad groups is greater than or equal to the number of main gate connection lines.
7. The solar cell according to claim 6, characterized in that, The number of main gate connectors includes multiple lines. When the number of pad groups is greater than the number of main gate connectors, there is also a pad group between every two adjacent main gate connectors; and / or, The number of main gate connection lines is 0 to 24.
8. The solar cell according to claim 5, characterized in that, The main grid connection line includes multiple first sub-grid lines, which are spaced apart along the first direction. Two adjacent sub-grids form a grid line group, and each grid line group is spaced apart along the first direction. Each first sub-grid line is connected between two adjacent grid line groups.
9. The solar cell according to claim 5, characterized in that, Each of the sub-gates includes multiple second sub-gate lines, which are spaced apart along the second direction to form a break between two adjacent second sub-gate lines. The break is located at the main gate connection line, and / or the break is spaced apart from the main gate connection line in the second direction. The electrode structure also includes a connection structure located at the break point to connect two adjacent second sub-gate lines.
10. A photovoltaic module, characterized in that, Including the solar cell as described in any one of claims 1-9.