Back contact cell assembly and photovoltaic system

Abstract

The application is suitable for the technical field of solar cells, and provides a back contact cell assembly and a photovoltaic system. In the back contact cell assembly, one of two back contact cells adjacent to each other in a cell string partially overlaps the other at one end of a first edge to form an overlapping area. The overlapping area covers a part of a second busbar line on one of the two adjacent back contact cells, and the ratio between the length of the part of the second busbar line covered by the overlapping area in a first direction and the total length of the second busbar line in the first direction is A, and A is less than 15%. In this way, the power generation efficiency per unit area of the back contact cell assembly can be improved, the length of the overlapping area can be effectively prevented from being too long to cause virtual welding or even welding failure between the interconnection solder strip and the solder pad, the risk of virtual welding can be reduced, the welding performance can be ensured, and the phenomenon that the interconnection solder strip and the solder pad are in poor contact when the assembly is subjected to external force impact can be effectively avoided.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and more particularly to a back-contact battery module and photovoltaic system. Background Technology

[0002] In solar cell technology, back-contact solar cells have high power generation efficiency because they place both the emitter and base contact electrodes on the back of the cell, eliminating any metal electrodes that obstruct the light-receiving surface. These cells typically have a doped layer and electrode structure on the back, and are connected in series via solder ribbons. Back-contact solar cell modules consist of arrays of cell strings, where each string comprises several back-contact cells connected in series.

[0003] In related technologies, the back contact cells in the battery string are all arranged at intervals in one direction, and there are gaps between adjacent back contact cells. In this case, on the one hand, the gaps are ineffective areas, and the efficiency per unit area of ​​the back contact cell module is low. On the other hand, due to the existence of the gaps, the solder ribbons set on the back side will be exposed from the gaps, affecting the aesthetics of the module. Summary of the Invention

[0004] This application provides a back-contact battery module and a photovoltaic system.

[0005] This application is implemented as follows: the back contact battery assembly of this application embodiment includes a plurality of battery strings, the battery strings including a plurality of back contact batteries arranged along a first direction, the back contact batteries having a first edge and a second edge opposite to each other in the first direction;

[0006] The back contact battery has a plurality of first fine grids, a plurality of second fine grids, a plurality of first solder pads and a plurality of second solder pads on its back side. The first fine grids and the second fine grids are arranged alternately along the first direction and both extend along the second direction, which intersects the first direction.

[0007] Both the first pad and the second pad are located close to the first edge. A first bus gate line is connected to the first pad. The first bus gate line is located between the first pad and the first edge and is connected to the first fine gate. A second bus gate line is connected to the second pad. The second bus gate line is located between the second pad and the first edge and is connected to the second fine gate. The second bus gate line is closer to the first edge than the first bus gate line.

[0008] In the battery string, one of two adjacent back contact batteries has one end of the first edge and the other has one end of the second edge, forming an overlapping region. The overlapping region covers a portion of the second busbar on one of the two adjacent back contact batteries. The ratio A between the length of the portion of the second busbar covered by the overlapping region in the first direction and the total length of the second busbar in the first direction is less than 15%.

[0009] In some embodiments, the absolute value of the difference between the lengths of the portions of any two second busbars covered by the overlapping region in the first direction is less than 0.5 mm.

[0010] In some embodiments, the overlapping region does not cover the first busbar.

[0011] In some embodiments, the overlapping region also covers a portion of the first busbar, and the ratio of the length of the portion of the first busbar covered by the overlapping region in the first direction to the total length of the first busbar in the first direction is B, where B is less than A.

[0012] In some embodiments, in a back-contact battery assembly, B is less than 7%.

[0013] In some embodiments, the absolute value of the difference between the lengths of the portions of any two first busbars covered by the overlapping region in the first direction is less than 0.5 mm.

[0014] In some embodiments, in a back-contact battery assembly, the absolute value of the difference between the lengths of any two overlapping regions in the first direction is less than 1 mm.

[0015] In some embodiments, the back side of the back contact battery also has a plurality of third pads and a plurality of fourth pads, the third pads and the fourth pads are both disposed close to the second edge, the third pads and the first pads are collinearly disposed in the first direction, and the fourth pads and the second pads are collinearly disposed in the first direction;

[0016] A third bus line is connected to the third pad, the third bus line is located between the third pad and the second edge and is connected to the first fine gate; a fourth bus line is connected to the fourth pad, the fourth bus line is located between the fourth pad and the second edge and is connected to the second fine gate, and the fourth bus line is closer to the second edge than the third bus line.

[0017] In the battery string, the overlapping region also covers a portion of the fourth busbar on another of the two adjacent back contact batteries, and the ratio of the length of the portion of the fourth busbar covered by the overlapping region in the first direction to the total length of the fourth busbar in the first direction is C, where C is less than 15%.

[0018] In some embodiments, in a back-contact battery assembly, C is less than A.

[0019] In some embodiments, C is less than 13%.

[0020] In some embodiments, the overlapping region does not cover the third busbar.

[0021] In some embodiments, the overlapping region also covers a portion of the third busbar, and the ratio of the length of the portion of the third busbar covered by the overlapping region in the first direction to the total length of the third busbar in the first direction is D, where D is less than C.

[0022] In some embodiments, in a back-contact battery assembly, D is less than 7%.

[0023] In some embodiments, the overlapping region also covers a portion of the first busbar, and the ratio of the length of the portion of the first busbar covered by the overlapping region in the first direction to the total length of the first busbar in the first direction is B, where D is less than B.

[0024] This application also provides a photovoltaic system, which includes the aforementioned back contact battery assembly.

[0025] In the back-contact battery module and photovoltaic system of this application embodiment, in the battery string, one end of two adjacent back-contact batteries facing a first edge partially overlaps with the other end facing a second edge to form an overlapping region. The overlapping region covers a portion of the second busbar on one of the two adjacent back-contact batteries. The ratio A between the length of the portion of the second busbar covered by the overlapping region in a first direction and the total length of the second busbar in the first direction is less than 15%. Thus, overlapping the opposite ends of two adjacent back-contact batteries to form an overlapping region can eliminate the gap between the two adjacent back-contact batteries, improve the power generation efficiency per unit area of ​​the back-contact battery module, and also avoid the interconnect solder ribbons from being exposed between the two back-contact batteries, thereby improving the aesthetics of the module. Furthermore, by optimizing the design of the proportion of the length of the second busbar covered by the overlapping region and setting it to a specific range of less than 15%, the length of the overlapping region can be effectively prevented from being too long, which could lead to poor soldering or even failure to solder between the interconnect solder ribbons and the pads, reducing the risk of poor soldering, ensuring soldering performance, and effectively preventing poor contact between the interconnect solder ribbons and the pads when the module is subjected to external impact.

[0026] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a photovoltaic system module provided in an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the planar structure of the back contact battery assembly provided in an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of a planar structure with interconnecting solder strips on the back contact battery provided in an embodiment of this application;

[0030] Figure 4 This is a schematic diagram of a planar structure of a back contact battery with interconnecting solder strips and adhesive dispensing provided in an embodiment of this application;

[0031] Figure 5 yes Figure 4 A magnified schematic diagram of the back contact battery at point V;

[0032] Figure 6 yes Figure 4 Another enlarged schematic diagram of the back contact battery at point V;

[0033] Figure 7 yes Figure 4A partially enlarged structural diagram of the back contact battery at point VII;

[0034] Figure 8 yes Figure 4 Another enlarged schematic diagram of the back contact battery at point VII;

[0035] Figure 9 This is a schematic diagram of the stacking of two adjacent back contact batteries in the battery string of the back contact battery assembly provided in this application embodiment;

[0036] Figure 10 yes Figure 9 A schematic diagram of the cross-sectional structure of XX along the central line;

[0037] Figure 11 yes Figure 9 A schematic diagram of the cross-sectional structure along line XI-XI. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0039] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "top", "bottom", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "several," "multiple," and "more than" mean two (roots) or more, unless otherwise explicitly specified.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0044] Please see Figure 1 and Figure 2 The photovoltaic system 1000 in this embodiment may include the back-contact battery module 100, which may include a plurality of battery strings 10. The plurality of battery strings 10 form a battery string array. In some embodiments, the back-contact battery module 100 may further include a plurality of first busbars 20 and a plurality of second busbars 30. In a first direction, one end of each battery string 10 is provided with a first busbar 20, and the other end is provided with a second busbar 30. The two ends of the battery string 10 are respectively connected to the first busbar 20 and the second busbar 30. Each battery string 10 in the back-contact battery module 100 can be connected in series and in parallel through the first busbars 20 and the second busbars 30 to achieve current collection and output.

[0045] The battery string 10 may include a plurality of back contact batteries 11, a plurality of first interconnecting solder strips 12 and a plurality of second interconnecting solder strips 13. In the battery string 10, the plurality of back contact batteries 11 are arranged along a first direction, which is the stringing direction of the battery string 10.

[0046] Please see Figure 3 The back contact battery 11 has a first edge 101 and a second edge 102 opposite to each other in a first direction, and the back side of the back contact battery 11 has a plurality of first fine grids 14, a plurality of second fine grids 15, a plurality of first pads 16 and a plurality of second pads 17.

[0047] A plurality of first fine grids 14 and a plurality of second fine grids 15 are arranged alternately at intervals along a first direction and all extend along a second direction, the second direction intersecting the first direction.

[0048] Both the first pad 16 and the second pad 17 are disposed close to the first edge 101. Each of the first pad 16 and the second pad 17 has a plurality of first fine gates 14 and a plurality of second fine gates 15 between itself and the first edge 101. The plurality of first pads 16 and the plurality of second pads 17 are arranged alternately at intervals along a second direction. The first pad 16 is connected to a portion of the first fine gates 14 and is insulated from the second fine gates 15. The second pad 17 is connected to a portion of the second fine gates 15 and is insulated from the first fine gates 14.

[0049] Specifically, such as Figure 2 As shown, the first direction can be the longitudinal direction of the back-contact battery assembly 100, that is, the stringing direction of the battery string 10, and the second direction can be the transverse direction of the back-contact battery assembly 100, and the two are perpendicular to each other.

[0050] like Figure 3 As shown, a first busbar 18 is connected to the first pad 16. The first busbar 18 extends along a first direction and is located between the first pad 16 and the first edge 101. The first busbar 18 is connected to a first fine gate 14 located between the first pad 16 and the first edge 101 and is insulated from the second fine gate 15. Figure 3 As shown, in some embodiments, the first bus gate line 18 is connected to all the first fine gates 14 located between the first pad 16 and the first edge 101.

[0051] A second busbar 19 is connected to the second pad 17. The second busbar 19 extends along a first direction and is located between the second pad 17 and the first edge 101. The second busbar 19 is connected to a second fine gate 15 located between the second pad 17 and the first edge 101 and is insulated from the first fine gate 14. Figure 3 As shown, in some embodiments, the second bus gate 19 is connected to all the second fine gates 15 located between the second pad 17 and the first edge 101.

[0052] Among them, such as Figure 3 As shown, each back contact battery 11 has a plurality of first interconnect solder strips 12 and a plurality of second interconnect solder strips 13 on its back side. The plurality of first interconnect solder strips 12 and the plurality of second interconnect solder strips 13 are arranged alternately along the second direction and all extend along the first direction. The first interconnect solder strips 12 are soldered to the first solder pad 16, and the second interconnect solder strips 13 are soldered to the second solder pad 17.

[0053] like Figure 3 As shown, in the thickness direction of the back contact battery 11 (i.e. the stacking direction of the interconnecting ribbons and the battery cells), the first interconnecting ribbon 12 completely covers the first busbar 18, and the second interconnecting ribbon 13 covers a portion of the second busbar 19. That is, the first interconnecting ribbon 12 completely covers the first busbar 18, and the second interconnecting ribbon 13 partially covers the second busbar 19.

[0054] It is easy to understand that in some embodiments, the width of the first busbar 18 is smaller than the width of the first interconnect solder strip 12, and the width of the second busbar 19 is smaller than the width of the second interconnect solder strip 13. Overall, the width of the busbars is smaller than the width of the interconnect solder strips.

[0055] In embodiments of this application, the current collected by the first fine gate 14 located between the first pad 16 and the first edge 101 can be channeled through the first bus gate line 18 to the first interconnect solder strip 12 soldered to the first pad 16, thereby achieving current collection on the first fine gate 14 between the first pad 16 and the first edge 101. The current collected by the second fine gate 15 located between the second pad 17 and the first edge 101 can be channeled through the second bus gate line 19 to the second interconnect solder strip 13 soldered to the second pad 17, thereby achieving current collection on the second fine gate 15 between the second pad 17 and the first edge 101.

[0056] Each first pad 16 corresponds to a first busbar 18, and the number of first busbars 18 corresponds to the number of first pads 16. Each second pad 17 corresponds to a second busbar 19, and the number of second busbars 19 corresponds to the number of second pads 17. The number of first interconnect solder ribbons 12 on each back contact battery 11 also corresponds to the number of first pads 16 and first busbars 18, and the number of second interconnect solder ribbons 13 on each back contact battery 11 also corresponds to the number of second pads 17 and second busbars 19.

[0057] In the back-contact battery assembly 100 and photovoltaic system 1000 of this application embodiment, a first busbar 18 is connected to a first pad 16. The first busbar 18 extends along a first direction and is located between the first pad 16 and a first edge 101. The first busbar 18 is connected to a first fine grid 14 located between the first pad 16 and the first edge 101 and is insulated from a second fine grid 15. A second busbar 19 is connected to a second pad 17. The second busbar 19 extends along a first direction and is located between the second pad 17 and the first edge 101. The second busbar 19 is connected to a second fine grid 15 located between the second pad 17 and the first edge 101 and is insulated from a first fine grid 14. A first interconnect solder ribbon 12 is soldered to the first pad 16, and a second interconnect solder ribbon 13 is soldered to the second pad 17. The first interconnect solder ribbon 12 completely covers the first busbar 18, and the second interconnect solder ribbon 13 covers a portion of the second busbar 19. In this way, the second interconnect solder ribbon 13 is soldered to the second solder pad 17 and only covers a portion of the second busbar 19, which can reduce the area on the back side of the back contact battery 11 that is blocked by the second interconnect solder ribbon 13, thereby improving the light absorption efficiency on the back side, increasing the bifaciality of the back contact battery assembly 100, and also reducing the cost of the second interconnect solder ribbon 13. Furthermore, due to the presence of the first busbar 18 and the second busbar 19, the first interconnect solder ribbon 12 can collect the current on the first fine gate 14 located near the first edge 101 without soldering it to the first fine gate 14 between the first pad 16 and the first edge 101. Similarly, the second interconnect solder ribbon 13 can collect the current on the second fine gate 15 located near the first edge 101 without soldering it to the solder ribbon between the second pad 17 and the first edge 101. There are no soldering points on the first fine gate 14 between the first pad 16 and the first edge 101, and there are no soldering points on the second fine gate 15 between the second pad 17 and the first edge 101. This effectively reduces the risk of microcracks in the edge region while ensuring current collection efficiency, thus guaranteeing the quality of the component.

[0058] In other words, in the back contact battery module 100 of this application embodiment, the risk of microcracks in the edge area can be reduced while ensuring current collection efficiency, and the bifaciality of the back contact battery module 100 can be increased and the cost of solder strips can be reduced.

[0059] Specifically, in the embodiments of this application, the back contact cell 11 may be a gridless back contact cell. The back contact cell 11 includes a silicon substrate (not shown) and a first doped layer (not shown) and a second doped layer (not shown) stacked on the back side of the silicon substrate and alternately arranged along a first direction. Both the first and second doped layers have a back passivation layer. The first fine gate 14 corresponds one-to-one with the first doped layer and at least partially penetrates the passivation layer to form an ohmic contact with the first doped layer. The second fine gate 15 corresponds one-to-one with the second doped layer and at least partially penetrates the back passivation layer to form an ohmic contact with the second doped layer. In some possible embodiments, a doped layer with the same polarity as the first doped layer may be provided below the region corresponding to the first pad 16 and the first bus line 18, and the second doped layer is disconnected at the location of this region. Similarly, a doped layer with the same polarity as the second doped layer may be provided below the region corresponding to the second pad 17 and the second bus line 19, and the first doped layer is disconnected at the location of this region. No specific limitations are imposed here.

[0060] Furthermore, in this application, in the back contact battery assembly 100, the number of battery strings 10 is several strings, such as... Figure 2 As shown, Figure 2 The diagram shows 12 battery strings 10. The back-contact battery assembly 100 is divided into upper and lower halves in the first direction, and each half includes 6 battery strings 10 arranged along the second direction.

[0061] The first busbar 20 can be an end busbar, which is disposed at the upper and lower ends of the back contact battery assembly 100 in the first direction, and is used to connect adjacent battery strings 10 in the second direction. The second busbar 30 can be an intermediate busbar, which can be disposed between the upper and lower halves, and is used to connect the upper and lower halves together in parallel.

[0062] like Figure 2As shown, in the upper half, from left to right, the first battery string 10 and the second battery string 10 are connected in series via a first bus bar 20, the third battery string 10 and the fourth battery string 10 are connected in series via a first bus bar 20, and the fifth battery string 10 and the sixth battery string 10 are connected in series via a first bus bar 20. Similarly, in the lower half, from left to right, the first battery string 10 and the second battery string 10 are connected in series via a first bus bar 20, the third battery string 10 and the fourth battery string 10 are connected in series via a first bus bar 20, and the fifth battery string 10 and the sixth battery string 10 are connected in series via a first bus bar 20. In this case, there can be four second busbars 30. From left to right, the first battery string 10 in the upper half and the first battery string 10 in the lower half are connected to the first second busbar 30. The second and third battery strings in the upper half and the second and third battery strings in the lower half are connected to the second second busbar 30. The fourth and fifth battery strings in the upper half and the fourth and fifth battery strings in the lower half are connected to the third second busbar 30. The sixth battery string 10 in the upper half and the sixth battery string 10 in the lower half are connected to the fourth second busbar 30. A bypass diode can be provided between two adjacent second busbars 30.

[0063] In addition, such as Figure 2 As shown, it is easy to understand that in the battery string 10, two adjacent back contact batteries 11 are connected in series through a first interconnecting solder strip 12 and a second interconnecting solder strip 13. For example, in some embodiments, the first interconnecting solder strip 12 on the first back contact battery 11 closest to the first busbar 20 in the battery string 10 is an independent solder strip and is connected to the first busbar 20. Then, the second interconnecting solder strip 13 on the first back contact battery 11 is connected to the first interconnecting solder strip 12 on the second back contact battery 11, the second interconnecting solder strip 13 on the second back contact battery 11 is connected to the first interconnecting solder strip 12 on the third back contact battery 11, and so on. The second interconnecting solder strip on the last back contact battery 11 is an independent solder strip and is connected to the second busbar 30, and the second interconnecting solder strip 13 on the second-to-last back contact battery 11 is connected to the first interconnecting solder strip 12 on the last back contact battery 11. That is, in the battery string 10, if the interconnecting solder strip connected to the first bus bar 20 is the first interconnecting solder strip 12, then the interconnecting solder strip connected to the second bus bar 30 is the second interconnecting solder strip 13; if the interconnecting solder strip connected to the first bus bar 20 is the second interconnecting solder strip 13, then the interconnecting solder strip connected to the second bus bar 30 is the first interconnecting solder strip 12.

[0064] In some embodiments, in two adjacent back contact batteries 11 of the battery string 10, the first pad 16 of one battery and the second pad 17 of the other battery are collinearly arranged in a first direction. That is, in two adjacent back contact batteries 11, the first interconnect solder strip 12 of one battery and the second interconnect solder strip 13 of the other battery are collinearly arranged in a first direction. In this case, the first interconnect solder strip 12 and the second interconnect solder strip 13 connected to each other can be a single long solder strip, while the isolated first interconnect solder strip 12 and the second interconnect solder strip 13 are short solder strips.

[0065] Furthermore, it should be noted that in some embodiments, the battery strings 10 in the upper and lower halves of the back contact battery assembly 100 can be symmetrical. That is, the lower half battery string 10 can be obtained by rotating the upper half battery string 10 by 180°. Therefore, it is easy to understand that in the back contact battery assembly 100, the back contact batteries 11 in the two corresponding battery strings 10 in the upper and lower halves in the first direction are oriented in opposite directions. For example, taking the first battery string 10 in the upper half and the first battery string 10 in the lower half as examples, the first edge 101 of the back contact battery 11 in the first battery string 10 in the upper half can be the edge of the back contact battery 11 facing upward (i.e., facing the first busbar 20 in the upper half), and the second edge 102 of the back contact battery 11 in the first battery string 10 in the upper half is the edge of the back contact battery 11 facing downward (i.e., facing the second busbar 30). In this case, the first edge 101 and the second edge 102 of the back contact battery 11 in the first battery string 10 in the lower half are opposite, that is, the first edge 101 of the back contact battery 11 in the first battery string 10 in the lower half is the edge of the back contact battery 11 facing downward (i.e., facing the first busbar 20 in the lower half), and the second edge 102 of the back contact battery 11 in the first battery string 10 in the lower half is the edge of the back contact battery 11 facing upward (i.e., facing the second busbar 30).

[0066] Furthermore, it is easy to understand that in some embodiments, in the back contact battery assembly 100, since two adjacent battery strings 10 connected to the same first busbar 20 need to be connected in series, and two adjacent battery strings 10 connected to the same second busbar 30 also need to be connected in series, in any half-region, in the two adjacent battery strings 10 in the second direction, one battery string 10 is obtained by rotating the other battery string 10 by 180°. That is, in the two adjacent battery strings 10 in the second direction, the orientation of the back contact battery 11 in one battery string 10 is opposite to the orientation of the other back contact battery 11. In other words, the first edge 101 of the back contact battery 11 in one battery string 10 is the upper edge, and the first edge 101 of the back contact battery 11 in the other battery string 10 is the lower edge.

[0067] Please see Figure 3 In some embodiments, in the second direction, a plurality of first pads 16 are arranged collinearly, and a plurality of second pads 17 are also arranged collinearly.

[0068] Thus, the collinear arrangement of the first pad 16 allows the current collected by the first interconnect solder ribbon 12 to be evenly distributed in the second direction, and the collinear arrangement of the second pad 17 allows the current collected by the second interconnect solder ribbon 13 to be evenly distributed in the second direction, reducing series mismatch caused by pad position deviation.

[0069] Specifically, in such an embodiment, the collinear arrangement of the first pads 16 means that the first pads 16 are arranged in a straight line in the second direction, which can be achieved by aligning the center point of each first pad 16 with the same horizontal axis. The collinear arrangement of the second pads 17 means that the second pads 17 are arranged in another independent straight line in the second direction, which can also be achieved by aligning the center point of each first pad 16 with the same horizontal axis.

[0070] In some embodiments, the ratio of the length of the portion of the second busbar 19 covered by the second interconnect solder strip 13 in the first direction to the overall length of the second busbar 19 in the first direction is less than 0.4.

[0071] Thus, after lamination, the portion of the second interconnecting solder strip 13 that extends beyond the second solder pad 17 can form point or line contact with the second busbar 19 through partial coverage, thereby allowing more light to penetrate the back of the cell while reducing transmission loss and improving collection efficiency, thus increasing the bifaciality of the module.

[0072] Specifically, in this embodiment, a ratio less than 0.4 refers to the upper limit of the proportion of the area covered by the second busbar 19 to the total length of the busbar. This proportion setting ensures that more than 60% of the area of ​​the second busbar 19 remains unobstructed by the second interconnect solder ribbon 13. For example, when the total length of the second busbar 19 is 150mm in the second direction, the extension length of the area covered by the second interconnect solder ribbon 13 in the first direction is limited to within 60mm. That is to say, this embodiment reduces the length of the second busbar 19 not covered by the solder ribbon by more than 60% while ensuring current collection efficiency by precisely controlling the solder ribbon coverage ratio, thereby increasing the light-transmitting area on the back of the battery. It should be noted that in this application, the starting point of the first busbar 18 is the intersection of the first busbar 18 and the first pad 16, and the starting point of the second busbar 19 is the intersection of the second busbar 19 and the second pad 17.

[0073] In some embodiments, the difference in length between any two second busbars 19 covered by the second interconnecting solder strip 13 is less than or equal to 1 mm.

[0074] That is to say, among the multiple second busbars 19 and multiple second interconnecting ribbons 13, for any two second busbars 19 and two second interconnecting ribbons 13, the length of the overlapping portion of one first interconnecting ribbon 13 and the second busbar 19 is a, and the length of the overlapping portion of the other second interconnecting ribbon 13 and the second busbar 19 is b, wherein the absolute value of the difference between a and b is less than or equal to 1 mm.

[0075] Thus, by controlling the deviation between the overlap lengths of each second interconnect solder strip 13 and each second busbar 19 within 1 mm, the uniformity of current collection of different second interconnect solder strips 13 can be ensured, avoiding uneven resistance distribution of the current transmission path due to excessive differences in local coverage ratios, and improving the consistency of electrical performance. In other words, by limiting this range of difference, the uniformity of current can be ensured while reducing back-side shading, thereby improving the consistency of electrical performance.

[0076] Specifically, the difference in length between any two second busbars 19 covered by the second interconnecting solder strip 13 can be, for example, 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, 0.05 mm, or other values ​​less than 1 mm, without any specific limitation here.

[0077] In some embodiments, the length of the first busbar 18 in the first direction may be 2mm-10mm.

[0078] In this way, we can avoid the situation where the length of the first busbar 18 is too short, resulting in an insufficient distance between the first pad 16 and the first edge 101, which could easily lead to microcracks at the edge during soldering, thus reducing the risk of microcracks. We can also avoid the situation where the length of the first busbar 18 is too long, resulting in an excessively long busbar path in the edge region and excessive current loss. In other words, by optimizing the design of the length of the first busbar 18, we can reduce the risk of microcracks while avoiding excessive current loss.

[0079] Specifically, the length of the first busbar 18 in the first direction may be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or other values ​​between 2mm and 10mm, without any specific limitation.

[0080] In some embodiments, the length of the second busbar 19 in the first direction may be 2mm-10mm.

[0081] In this way, we can avoid the situation where the length of the second bus gate 19 is too short, resulting in an insufficient distance between the second pad 17 and the first edge 101, which could easily lead to microcracks at the edge during soldering, thus reducing the risk of microcracks. We can also avoid the situation where the length of the second bus gate 19 is too long, resulting in an excessively long bus path in the edge region and excessive losses. In other words, by optimizing the design of the length of the second bus gate 19, we can reduce the risk of microcracks while avoiding excessive bus losses.

[0082] Specifically, the length of the second busbar 19 in the first direction may be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or other values ​​between 2mm and 10mm, without any specific limitation.

[0083] In some embodiments, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction may be 2%-15%, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or other values ​​of 2%-15%, which are not limited here.

[0084] In this way, we can avoid the risk of microcracks appearing at the edge during welding due to the short length of the first busbar 18 being too small, and also avoid the risk of excessive busbar loss due to the long length of the first busbar 18 being too large.

[0085] In some embodiments, the ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction may also be 2%-15%, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or other values ​​of 2%-15%, which are not limited here.

[0086] In this way, we can avoid the risk of microcracks appearing at the edges during welding due to the length of the second busbar 19 being too small, and also avoid the risk of excessive busbar loss due to the length of the second busbar 19 being too long.

[0087] Specifically, in this application, the back contact battery 11 can be a full cell battery, a half cell battery, a one-third slice battery, or a one-quarter slice battery; no specific limitation is made here.

[0088] In some embodiments, when the back contact battery 11 is a full-cell battery, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction is preferably 2%-3%, such as 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, or other values ​​between 2% and 3%, without specific limitations. The ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 2%-3%, such as 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, or other values ​​between 2% and 3%, without specific limitations.

[0089] In some embodiments, when the back contact battery 11 is a half-cell battery, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction is preferably 3%-7%, such as 3%, 4%, 5%, 6%, 7%, or other values ​​between 3% and 7%, and is not specifically limited herein. The ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 3%-7%, such as 3%, 4%, 5%, 6%, 7%, or other values ​​between 3% and 7%, and is not specifically limited herein.

[0090] When the back contact battery 11 is a one-third slice battery, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction is preferably 5%-9%, such as 5%, 6%, 7%, 8%, 9%, or other values ​​between 5% and 9%, and is not specifically limited here. The ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 5%-9%, such as 5%, 6%, 7%, 8%, 9%, or other values ​​between 5% and 9%, and is not specifically limited here.

[0091] When the back contact battery 11 is a quarter-slice battery, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction is preferably 8%-15%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​between 8%-15%, and is not specifically limited here. The ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 8%-15%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​between 8%-15%, and is not specifically limited here.

[0092] Please see Figure 4 and Figure 5 In some embodiments, a first edge adhesive 40 is provided on the portion of the second busbar 19 covered by the second interconnect solder ribbon 13. The first edge adhesive 40 is used to fix the second interconnect solder ribbon 13 to the back contact battery 11 during the fabrication of the back contact battery assembly 100.

[0093] Please see Figure 5 In some embodiments, the end of the second interconnect solder strip 13 toward the first edge 101 extends onto the first edge adhesive 40 and beyond the first edge adhesive 40 in a first direction, and the distance between the end of the second interconnect solder strip 13 toward the first edge 101 and the first edge adhesive 40 is L1, wherein L1≤3mm.

[0094] In this way, the second interconnecting solder ribbon 13 can be stably pre-fixed by the first edge adhesive 40, effectively preventing the second interconnecting solder ribbon 13 from shifting during lamination, which could lead to inaccurate welding and short circuits. Simultaneously, setting the length L1 of the portion of the first interconnecting solder ribbon 13 extending beyond the first edge adhesive 40 to less than or equal to 3mm effectively prevents the second interconnecting solder ribbon 13 from extending too far beyond the first edge adhesive 40, resulting in an excessively long suspended section outside the first edge adhesive 40, which could easily shift during lamination and cause a short circuit. In other words, this arrangement ensures welding accuracy while preventing solder ribbon shifting and short circuits, thus improving component reliability.

[0095] Specifically, in such embodiments, the size of L1 may be, for example, 3mm, 2.8mm, 2.6mm, 2.4mm, 2.2mm, 2mm, 1.8mm, 1.6mm, 1.4mm, 1.2mm, 1mm, 0.8mm, 0.6mm, 0.4mm, 0.2mm, 0.1mm or other values ​​less than 3mm, and no specific limitation is made here.

[0096] Of course, such as Figure 6 As shown, in some embodiments, the end of the second interconnect solder strip 13 facing the first edge 101 may also extend onto the first edge adhesive 40 and not exceed the first edge adhesive 40 in the first direction.

[0097] In this way, the second interconnect solder strip 13 can be fixed while avoiding displacement of the second interconnect solder strip 13.

[0098] In this application, the preferred method is to use Figure 5The configuration allows the second interconnecting solder strip 13 to have sufficient bonding area with the first edge adhesive 40, preventing the second interconnecting solder strip 13 from having too small a bonding area due to only its end being located on the first edge adhesive 40, which would cause the solder strip to shift.

[0099] Specifically, after research and verification by the inventors of this application, it was found that if the following method is adopted... Figure 6 The design scheme in the text exhibits a problem where the second interconnecting solder strip 13 becomes unstable during the lamination process. However, by adopting... Figure 5 The design of L1 is specifically designed to ensure the stable fixation of the second interconnect solder strip 13 and to prevent the end of the second interconnect solder strip 13 from shifting and coming into contact with the nearby fine gate of opposite polarity, thus avoiding a short circuit.

[0100] Please see Figure 5 In some embodiments, a first edge adhesive 40 is provided on the portion of the second busbar 19 covered by the second interconnect solder strip 13, the end of the second interconnect solder strip 13 extending toward the first edge 101 onto the first edge adhesive 40 and beyond the first edge adhesive 40 in a first direction.

[0101] Wherein, the distance between the end of the second interconnect solder strip 13 facing the first edge 101 and the first edge adhesive dot 40 is L1, and the distance between the end of the second interconnect solder strip 13 facing the first edge 101 and the second pad 17 is L2, wherein 0 < L1: L2 ≤ 0.8.

[0102] Thus, by optimizing the ratio between L1 and L2, it is possible to effectively avoid the second interconnect solder ribbon 13 from being too close to the second pad 17, which would result in a cold solder joint at the second pad 17. It is also possible to avoid the first edge adhesive 40 being too far from the second pad 17, which would result in the first edge adhesive 40 being too close to the first edge 101, leading to excessive edge stress concentration and reducing the risk of edge microcracks.

[0103] Specifically, during the lamination process, the height of the first edge adhesive dot 40 is typically higher than the height of the second pad 17. If the first edge adhesive dot 40 and the second pad 17 are too close, the height difference between them can easily lead to cold solder joints between the second interconnect solder strip 13 and the second pad 17, resulting in poor soldering reliability. Conversely, if the distance between the first edge adhesive dot 40 and the second pad 17 is too far, the first edge adhesive dot 40 may be too close to the first edge 101, increasing the risk of microcracks at the edge. Based on this consideration, the inventors of this application have discovered through research and demonstration that setting the ratio between L1 and L2 within the aforementioned specific range can reduce the risk of cold solder joints and improve soldering stability while simultaneously reducing the risk of microcracks at the edge.

[0104] Specifically, in such an embodiment, the ratio of L1 to L2 may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or other values ​​less than 0.8, without any specific limitation herein.

[0105] Please continue reading. Figure 5 In some embodiments, the distance between the first edge adhesive dot 40 and the second pad 17 is L3, where 1mm ≤ L3 ≤ 3mm.

[0106] Thus, by optimizing the design of the distance between the first edge adhesive 40 and the second pad 17 and controlling it within a reasonable range of 1mm-3mm, it is possible to avoid the risk of poor soldering caused by the distance between the first edge adhesive 40 and the second pad 17 being too close, and also to avoid the risk of edge microcracks caused by the first edge adhesive 40 being too close to the first edge 101.

[0107] Specifically, in such an embodiment, the distance L3 between the first edge adhesive dot 40 and the second pad 17 can be, for example, 3mm, 2.8mm, 2.6mm, 2.4mm, 2.2mm, 2mm, 1.8mm, 1.6mm, 1.4mm, 1.2mm, 1mm or other values ​​between 1mm and 3mm, without any specific limitation.

[0108] Please continue reading. Figure 5 In some embodiments, the distance between the first edge adhesive 40 and the second pad 17 is L3, and the distance between the end of the second interconnect solder ribbon 13 facing the first edge 101 and the first edge adhesive 40 is L1, wherein -4mm≤L3-L1≤5mm.

[0109] Thus, by optimizing the design of the difference between L3 and L1, the spacing between the first edge adhesive dot 40 and the second solder pad 17 can be controlled within a reasonable range, reducing the risk of cold solder joints and improving the stability of the soldering.

[0110] Specifically, in this embodiment, a negative value indicates that L3 is smaller than L1, and a positive value indicates that L3 is larger than L1. The difference between L3 and L1 can be, for example, 5mm, 4.5mm, 4mm, 3.5mm, 3mm, 2.5mm, 2mm, 1.5mm, 1mm, 0mm, -0.5mm, -1mm, -1.5mm, -2mm, -2.5mm, -3mm, -3.5mm, -4mm, or other values ​​between -4mm and 5mm, without any specific limitation. That is to say, in this embodiment, when L3 is larger than L1, L3 is at most 5mm longer than L1, and when L1 is larger than L3, L1 is at most 4mm longer than L3.

[0111] In some embodiments, L1:L3 is less than 1, that is, L1 is less than L3, and the ratio of L1 to L3 is less than 1. The ratio between the two can be, for example, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 or other values ​​less than 1, and no specific limitation is made here.

[0112] Therefore, setting L1 to be less than L3 can prevent the second interconnect solder strip 13 from extending too far beyond the first edge dispensing 40, which would make it prone to displacement.

[0113] Please see Figure 5 In some embodiments, the distance between the first edge adhesive dot 40 and the first edge 101 is L4, and the distance between the first edge adhesive dot 40 and the second pad 17 is L3, wherein L4 ≥ L3.

[0114] This configuration ensures sufficient distance between the first edge adhesive 40 and the first edge 101, effectively reducing the risk of microcracks appearing in the area of ​​the back contact battery 11 near the first edge 101 due to the presence of the first edge adhesive 40.

[0115] Please continue reading. Figure 5 In some embodiments, the distance between the end of the second interconnect solder strip 13 facing the first edge 101 and the first edge 101 is L5, and the distance between the end of the second interconnect solder strip 13 facing the first edge 101 and the second pad 17 is L2, wherein 0.2≤L5:L2≤4.

[0116] Thus, by optimizing the ratio of L5 to L2, it is possible to effectively avoid the second interconnect solder ribbon 13 extending too short beyond the second pad 17 (i.e., the length of the portion overlapping with the second busbar 19), which would cause the distance between the first edge dispensing 40 and the second pad 17 to be too close when the first edge dispensing 40 is applied to the second interconnect solder ribbon 13, resulting in poor soldering. It is also possible to avoid the second interconnect solder ribbon 13 extending too long beyond the second pad 17 (i.e., the length of the portion overlapping with the second busbar 19), which would cause the area on the back of the back contact battery 11 to be covered by the second interconnect solder ribbon 13 to be too large, resulting in a reduced bifaciality. At the same time, it is also possible to reduce the cost of the second interconnect solder ribbon 13.

[0117] Specifically, in such an embodiment, the ratio of L5 to L2 can be, for example, 0.2, 0.3, 0.5, 1, 1.5, 2, 2.5, 3, 3.4, 4 or other values ​​between 0.2 and 4, without any specific limitation.

[0118] In some embodiments, the size of L5 is in the range of 1.5mm-5mm, that is, 1.5mm≤L5≤5mm. The size of L5 can be, for example, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm or other values ​​between 1.5mm and 5mm, and there is no specific limitation here.

[0119] Specifically, on the one hand, if L5 is too small, the distance between the end of the second interconnect solder ribbon 13 facing the first edge 101 and the second pad 17 will be relatively large. In this case, if the first edge dispensing 40 is too close to the first edge 101, although it can effectively prevent the end of the second interconnect solder ribbon 13 from shifting, it is prone to causing edge microcracks in the back contact battery 11. On the other hand, if the first edge dispensing 40 is set too far from the first edge 101, the portion of the second interconnect solder ribbon 13 extending beyond the first edge dispensing 40 may become too long and prone to shifting, increasing the risk of short circuit. On the other hand, if L5 is too large, the distance between the end of the second interconnect solder ribbon 13 facing the first edge 101 and the second pad 17 will be relatively small. In this case, the distance between the first edge dispensing 40 and the second pad 17 will be too small, increasing the risk of poor soldering. Therefore, after careful research and verification, the inventors of this application found that optimizing L5 within the range of 1.5mm-5mm can reduce the risk of edge microcracks and short circuits while also reducing the risk of poor soldering.

[0120] Please see Figure 4 and Figure 5 In some embodiments, a second edge adhesive 50 may be provided on the first busbar 18. The second edge adhesive 50 is used to fix the first interconnecting solder ribbon 12 to the back contact battery 11 during the fabrication of the back contact battery assembly 100.

[0121] Please see Figure 3 and Figure 4 In some embodiments, the back contact battery 11 also has a plurality of third pads 110 and a plurality of fourth pads 111 on the back side.

[0122] The third pad 110 and the fourth pad 111 are both located close to the second edge 102. A plurality of third pads 110 and a plurality of fourth pads 111 are arranged alternately along the second direction. A plurality of first fine gates 14 and a plurality of second fine gates 15 are provided between the third pad 110 and the fourth pad 111 and the second edge 102.

[0123] The third pad 110 and the first pad 16 are arranged collinearly in the first direction and are soldered to the same first interconnect solder strip 12. The fourth pad 111 and the second pad 17 are arranged collinearly in the first direction and are soldered to the same second interconnect solder strip 13.

[0124] A third busbar 112 is connected to the third pad 110. The third busbar 112 extends continuously along a first direction and is located between the third pad 110 and the second edge 102. The third busbar 112 is connected to the first fine gate 14 located between the third pad 110 and the second edge 102 and is insulated from the second fine gate 15. Figure 3 As shown, in some embodiments, the third bus gate line 112 may be connected to all the first fine gates 14 located between the third pad 110 and the second edge 102.

[0125] A fourth busbar 113 is connected to the fourth pad 111. The fourth busbar 113 extends continuously along a first direction and is located between the fourth pad 111 and the second edge 102. The fourth busbar 113 is connected to the second fine gate 15 located between the fourth pad 111 and the second edge 102 and is insulated from the first fine gate 14. Figure 3 As shown, in some embodiments, the fourth bus gate line 113 may be connected to all the second fine gates 15 located between the fourth pad 111 and the second edge 102.

[0126] In the thickness direction of the back contact battery 11 (i.e., the stacking direction of the interconnecting ribbons and the battery cells), the first interconnecting ribbon 12 covers a portion of the third busbar 112, and the second interconnecting ribbon 13 completely covers the fourth busbar 113.

[0127] It is easy to understand that in some embodiments, the width of the third busbar 112 is smaller than the width of the first interconnect solder strip 12, and the width of the fourth busbar 113 is smaller than the width of the second interconnect solder strip 13. Overall, the width of the busbars is smaller than the width of the interconnect solder strips.

[0128] In embodiments of this application, the current collected by the first fine gate 14 located between the third pad 110 and the second edge 102 can be channeled through the third bus gate line 112 to the first interconnect solder strip 12 soldered to the third pad 110, thereby achieving current collection on the first fine gate 14 between the third pad 110 and the second edge 102. The current collected by the second fine gate 15 located between the fourth pad 111 and the second edge 102 can be channeled through the fourth bus gate line 113 to the second interconnect solder strip 13 soldered to the fourth pad 111, thereby achieving current collection on the second fine gate 15 between the fourth pad 111 and the second edge 102.

[0129] Each third pad 110 corresponds to one third busbar 112, and the number of third busbars 112 corresponds to the number of third pads 110. Each fourth pad 111 corresponds to one fourth busbar 113, and the number of fourth busbars 113 corresponds to the number of fourth pads 111. The number of first interconnect solder ribbons 12 on each back contact battery 11 also corresponds to the number of third pads 110 and third busbars 112, and the number of second interconnect solder ribbons 13 on each back contact battery 11 also corresponds to the number of fourth pads 111 and fourth busbars 113.

[0130] Thus, by soldering the first interconnect solder ribbon 12 to the fourth pad 111 and covering only a portion of the fourth busbar 113, the area on the back side of the back contact battery 11 that is blocked by the first interconnect solder ribbon 12 can be reduced, thereby improving the light absorption efficiency on the back side and increasing the bifaciality of the back contact battery assembly 100. This also reduces the cost of the first interconnect solder ribbon 12. Furthermore, due to the presence of the third busbar 112 and the fourth busbar 113, the first interconnect solder ribbon 12 can collect current on the first fine gate 14 in the area near the second edge 102 without soldering to the third pad 110 and the first fine gate 14 between the second edge 102. Similarly, the second interconnect solder ribbon 13 can collect current on the second fine gate 15 in the area near the second edge 102 without soldering to the solder ribbon between the fourth pad 111 and the second edge 102. There are no soldering points on the first fine gate 14 between the third pad 110 and the second edge 102, and there are no soldering points on the second fine gate 15 between the fourth pad 111 and the second edge 102. This can effectively reduce the risk of microcracks in the edge area while ensuring the current collection efficiency, thus ensuring the quality of the component.

[0131] Please see Figure 3 and Figure 4 In some embodiments, in the second direction, a plurality of third pads 110 are arranged collinearly, and a plurality of fourth pads 111 are also arranged collinearly.

[0132] Thus, the collinear arrangement of the third pad 110 allows the current collected by the first interconnect solder strip 12 to be evenly distributed in the second direction, and the collinear arrangement of the fourth pad 111 allows the current collected by the second interconnect solder strip 13 to be evenly distributed in the second direction, reducing series mismatch caused by pad position deviation.

[0133] Specifically, in such an embodiment, the collinear arrangement of the third pads 110 means that the third pads 110 are arranged in a straight line in the second direction, which can be achieved by aligning the center point of each third pad 110 with the same horizontal axis. The collinear arrangement of the fourth pads 111 means that the fourth pads 111 are arranged in another independent straight line in the second direction, which can also be achieved by aligning the center point of each third pad 110 with the same horizontal axis.

[0134] In some embodiments, the ratio of the length of the portion of the third busbar 112 covered by the first interconnect solder strip 12 in the first direction to the overall length of the third busbar 112 in the first direction is less than 0.4.

[0135] Thus, after lamination, the portion of the first interconnect solder strip 12 that extends beyond the fourth solder pad 111 can form point or line contact with the third busbar 112 through partial coverage, thereby allowing more light to penetrate the back of the cell while reducing transmission loss and improving collection efficiency, thus increasing the bifaciality of the module.

[0136] Specifically, in this embodiment, a ratio less than 0.4 refers to the upper limit of the proportion of the covered area to the total length of the busbar. This proportion setting ensures that more than 60% of the surface of the third busbar 112 remains unobstructed by the first interconnect solder ribbon 12. For example, when the total length of the third busbar 112 is 150mm in the second direction, the extension length of the area covered by the first interconnect solder ribbon 12 in the first direction is limited to within 60mm. That is to say, this embodiment, by precisely controlling the solder ribbon coverage ratio, reduces the length of the third busbar 112 not covered by the solder ribbon by more than 60% while ensuring current collection efficiency, significantly increasing the light-transmitting area on the back of the battery. It should be noted that in this application, the starting point of the third busbar 112 is the intersection of the third busbar 112 and the third pad 110, and the starting point of the fourth busbar 113 is the intersection of the fourth busbar 113 and the fourth pad 111.

[0137] In some embodiments, the difference in length between any two third busbars 112 covered by the first interconnect solder strip 12 is less than or equal to 1 mm.

[0138] That is to say, among the multiple third bus gates 112 and multiple first interconnect solder strips 12, for any two third bus gates 112 and two first interconnect solder strips 12, the length of the overlapping portion of one first interconnect solder strip 13 and the third bus gate 112 is c, and the length of the overlapping portion of the other first interconnect solder strip 12 and the third bus gate 112 is d, wherein the absolute value of the difference between c and d is less than or equal to 1 mm.

[0139] Thus, by controlling the deviation between the overlap lengths of each first interconnect solder strip 12 and each third busbar 112 within 1 mm, the uniformity of current collection of different first interconnect solder strips 12 can be ensured, avoiding uneven resistance distribution of the current transmission path due to excessive differences in local coverage ratios. In other words, by limiting this range of difference, the uniformity of current can be ensured while reducing back-side shading, thereby improving the consistency of electrical performance.

[0140] Specifically, the difference in length between any two third busbars 112 covered by the first interconnecting solder strip 12 can be, for example, 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, 0.05 mm, or other values ​​less than 1 mm, without any specific limitation here.

[0141] In some embodiments, the length of the third busbar 112 in the first direction may be 2mm-10mm.

[0142] In this way, the length of the third busbar 112 can be optimized to avoid the situation where the distance between the fourth pad 111 and the second edge 102 is too small due to an excessively short length, which could easily lead to microcracks at the edge during soldering, thus reducing the risk of microcracks. Conversely, the length of the third busbar 112 can also be optimized to avoid excessive current loss due to an excessively long busbar path in the edge region. In other words, by optimizing the length of the third busbar 112, the risk of microcracks can be reduced while avoiding excessive current loss.

[0143] Specifically, the length of the third busbar 112 in the first direction can be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or other values ​​between 2mm and 10mm, without any specific limitation here.

[0144] In some embodiments, the length of the fourth busbar 113 in the first direction may be 2mm-10mm.

[0145] In this way, the length of the fourth bus gate 113 can be optimized to avoid the situation where the distance between the third pad 110 and the second edge 102 is too small due to an excessively short length, which could easily lead to microcracks at the edge during soldering, thus reducing the risk of microcracks. Conversely, the length of the fourth bus gate 113 can also be optimized to avoid excessive current loss due to an excessively long bus path in the edge region. In other words, by optimizing the design of the length of the fourth bus gate 113, the risk of microcracks can be reduced while avoiding excessive current loss.

[0146] Specifically, the length of the fourth busbar 113 in the first direction can be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or other values ​​between 2mm and 10mm, without any specific limitation.

[0147] In some embodiments, the ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction may be 2%-15%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or other values ​​of 2%-15%, which are not limited here.

[0148] In this way, we can avoid the risk of microcracks appearing at the edge during welding due to the excessively small length of the fourth bus gate line 113, and also avoid the risk of excessive bus loss due to the excessively long length of the fourth bus gate line 113.

[0149] In some embodiments, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction may also be 2%-15%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or other values ​​of 2%-15%, which are not limited here.

[0150] In this way, we can avoid the risk of microcracks appearing at the edge during welding due to the excessively small length of the third busbar 112, and also avoid the risk of excessive busbar loss due to the excessively long length of the third busbar 112.

[0151] Specifically, in this application, the back contact battery 11 can be a full cell battery, a half cell battery, a one-third slice battery, or a one-quarter slice battery; no specific limitation is made here.

[0152] In some embodiments, when the back contact battery 11 is a full-cell battery, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction is preferably 2%-3%, such as 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, or other values ​​between 2% and 3%, without specific limitations. The ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 2%-3%, such as 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, or other values ​​between 2% and 3%, without specific limitations.

[0153] In some embodiments, when the back contact battery 11 is a half-cell battery, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction is preferably 3%-7%, such as 3%, 4%, 5%, 6%, 7%, or other values ​​between 3% and 7%, and is not specifically limited herein. The ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 3%-7%, such as 3%, 4%, 5%, 6%, 7%, or other values ​​between 3% and 7%, and is not specifically limited herein.

[0154] When the back contact battery 11 is a one-third slice battery, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction is preferably 5%-9%, such as 5%, 6%, 7%, 8%, 9%, or other values ​​between 5% and 9%, and is not specifically limited here. The ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 5%-9%, such as 5%, 6%, 7%, 8%, 9%, or other values ​​between 5% and 9%, and is not specifically limited here.

[0155] When the back contact battery 11 is a quarter-slice battery, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction is preferably 8%-15%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​between 8% and 15%, and is not specifically limited here. The ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 8%-15%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​between 8% and 15%, and is not specifically limited here.

[0156] Please see Figure 4 and Figure 7 In some embodiments, a third edge adhesive 60 is provided on the portion of the third busbar 112 covered by the first interconnect solder ribbon 12. The third edge adhesive 60 is used to fix the first interconnect solder ribbon 12 to the back contact battery 11 during the fabrication of the back contact battery assembly 100. Specifically, the first interconnect solder ribbon 12 can be fixed to the back contact battery 11 by the first edge adhesive 40 and the third edge adhesive 60.

[0157] Please see Figure 7In some embodiments, the end of the first interconnect solder strip 12 toward the second edge 102 extends onto the third edge adhesive 60 and beyond the third edge adhesive 60 in a first direction, and the distance between the end of the first interconnect solder strip 12 toward the second edge 102 and the third edge adhesive 60 is L6, wherein L6≤3mm.

[0158] In this way, the first interconnect solder ribbon 12 can be stably pre-fixed by the third edge adhesive 60, effectively preventing the first interconnect solder ribbon 12 from shifting during lamination, which could lead to inaccurate welding and short circuits. Simultaneously, setting the length L6 of the portion of the first interconnect solder ribbon 13 extending beyond the third edge adhesive 60 to less than or equal to 3mm effectively prevents the first interconnect solder ribbon 12 from extending too far beyond the third edge adhesive 60, which could result in an excessively long suspended section outside the third edge adhesive 60, making it prone to shifting during lamination and causing short circuits. In other words, this setup ensures welding accuracy while preventing solder ribbon shifting and short circuits, thus improving component reliability.

[0159] Specifically, in such embodiments, the size of L6 may be, for example, 3mm, 2.8mm, 2.6mm, 2.4mm, 2.2mm, 2mm, 1.8mm, 1.6mm, 1.4mm, 1.2mm, 1mm, 0.8mm, 0.6mm, 0.4mm, 0.2mm, 0.1mm or other values ​​less than 3mm, and no specific limitation is made here.

[0160] Of course, such as Figure 8 As shown, in some embodiments, the end of the first interconnect solder strip 12 toward the second edge 102 may also extend onto the third edge adhesive 60 and not exceed the third edge adhesive 60 in the first direction.

[0161] In this way, the first interconnect solder strip 12 can be fixed while avoiding displacement of the first interconnect solder strip 12.

[0162] In this application, the preferred method is to use Figure 7 The configuration allows the first interconnecting solder strip 12 to have sufficient bonding area with the third edge adhesive 60, preventing the first interconnecting solder strip 12 from having too small a bonding area due to only its end being located on the third edge adhesive 60, which would cause the solder strip to shift.

[0163] Specifically, after research and verification by the inventors of this application, it was found that if the following method is adopted... Figure 8 The design scheme in the text suffers from unstable fixation of the first interconnect solder strip 12 during the lamination process. However, by adopting... Figure 7The design of L6 is specifically designed to ensure the stable fixation of the first interconnect solder strip 12 and to prevent the end of the first interconnect solder strip 12 from shifting and coming into contact with the nearby fine gate of opposite polarity, thus avoiding a short circuit.

[0164] Please see Figure 4 In some embodiments, there is no adhesive dot between the first pad 16 and the third pad 110. This avoids the adhesive dotting between the first pad 16 and the third pad 110, which would block the first fine gate 14 between them, preventing the first interconnect solder ribbon 12 from making contact with the first fine gate 14 blocked by the adhesive and thus causing efficiency loss.

[0165] Please see Figure 7 In some embodiments, a third edge adhesive 60 is provided on the portion of the third busbar 112 covered by the first interconnect solder strip 12, the end of the first interconnect solder strip 12 extending toward the second edge 102 to the third edge adhesive 60 and extending beyond the third edge adhesive 60 in a first direction.

[0166] Wherein, the distance between the end of the first interconnect solder strip 12 facing the second edge 102 and the adhesive dot 60 at the third edge is L6, and the distance between the end of the first interconnect solder strip 12 facing the second edge 102 and the third pad 110 is L7, wherein 0 < L6: L7 ≤ 0.8.

[0167] Thus, by optimizing the ratio between L6 and L7, it is possible to effectively avoid the first interconnect solder strip 12 from having a poor solder joint at the third solder pad 110 due to the distance between the third edge adhesive 60 and the third solder pad 110 being too close, and also to avoid the third edge adhesive 60 being too far from the third solder pad 110, which would cause the third edge adhesive 60 to be too close to the second edge 102 and result in excessive edge stress concentration, thereby reducing the risk of edge microcracks.

[0168] Specifically, during the lamination process, the height of the third edge adhesive dot 60 is typically higher than the height of the third pad 110. If the third edge adhesive dot 60 and the third pad 110 are too close, the height difference between them can easily lead to cold solder joints between the first interconnect solder strip 12 and the third pad 110, resulting in poor soldering reliability. Conversely, if the distance between the third edge adhesive dot 60 and the third pad 110 is too great, the third edge adhesive dot 60 may become too close to the second edge 102, increasing the risk of microcracks at the edge. Based on this consideration, the inventors of this application have researched and demonstrated that setting the ratio between L6 and L7 within the aforementioned specific range can reduce the risk of cold solder joints and improve soldering stability while simultaneously reducing the risk of microcracks at the edge.

[0169] Specifically, in such an embodiment, the ratio of L6 to L7 may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or other values ​​less than 0.8, without any specific limitation.

[0170] Please see Figure 7 In some embodiments, the distance between the third edge adhesive dot 60 and the third pad 110 is L8, where 1mm ≤ L8 ≤ 3mm.

[0171] Thus, by optimizing the design of the distance between the third edge adhesive dispensing 60 and the third pad 110 and controlling it within a reasonable range of 1mm-3mm, it is possible to avoid the risk of poor soldering caused by the distance between the third edge adhesive dispensing 60 and the third pad 110 being too close, and also to avoid the risk of edge microcracks caused by the distance between the third edge adhesive dispensing 60 and the second edge 102 being too close.

[0172] Specifically, in such an embodiment, the distance L8 between the third edge adhesive dot 60 and the third pad 110 can be, for example, 3mm, 2.8mm, 2.6mm, 2.4mm, 2.2mm, 2mm, 1.8mm, 1.6mm, 1.4mm, 1.2mm, 1mm or other values ​​between 1mm and 3mm, without any specific limitation.

[0173] Please continue reading. Figure 7 In some embodiments, the distance between the third edge adhesive 60 and the third pad 110 is L8, and the distance between the end of the first interconnect solder ribbon 12 facing the second edge 102 and the third edge adhesive 60 is L6, wherein -4mm≤L8-L6≤5mm.

[0174] Thus, by optimizing the design of the difference between L8 and L6, the spacing between the third edge adhesive dot 60 and the third solder pad 110 can be controlled within a reasonable range, reducing the risk of poor soldering and improving the stability of the soldering.

[0175] Specifically, in this embodiment, a negative value indicates that L8 is smaller than L6, and a positive value indicates that L8 is larger than L6. The difference between L8 and L6 can be, for example, 5mm, 4.5mm, 4mm, 3.5mm, 3mm, 2.5mm, 2mm, 1.5mm, 1mm, 0mm, -0.5mm, -1mm, -1.5mm, -2mm, -2.5mm, -3mm, -3.5mm, -4mm, or other values ​​between -4mm and 5mm, without any specific limitation. That is to say, in this embodiment, when L8 is larger than L6, L8 is at most 5mm longer than L6, and when L6 is larger than L8, L6 is at most 4mm longer than L8.

[0176] In some embodiments, L6:L8 is less than 1, that is, L6 is less than L8, and the ratio of L6 to L8 is less than 1. The ratio between the two can be, for example, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1 or other values ​​less than 1, and no specific limitation is made here.

[0177] Therefore, setting L6 to be less than L8 can prevent the first interconnect solder strip 12 from extending too far beyond the third edge dispensing 60, which would make it prone to displacement.

[0178] Please see Figure 5 In some embodiments, the distance between the third edge adhesive 60 and the second edge 102 is L9, and the distance between the third edge adhesive 60 and the third pad 110 is L8, wherein L9 ≥ L8.

[0179] This configuration ensures sufficient distance between the third edge adhesive 60 and the second edge 102, effectively reducing the risk of microcracks appearing in the area of ​​the back contact battery 11 near the second edge 102 due to the presence of the third edge adhesive 60.

[0180] Please continue reading. Figure 7 In some embodiments, the distance between the end of the first interconnect solder strip 12 facing the second edge 102 and the second edge 102 is L10, and the distance between the end of the first interconnect solder strip 12 facing the second edge 102 and the third pad 110 is L7, wherein 0.2≤L10:L7≤4.

[0181] Thus, by optimizing the ratio of L10 to L7, it is possible to effectively avoid the first interconnect solder ribbon 12 extending too far beyond the third pad 110 (i.e., the length of the part overlapping with the third busbar 112) from being too short, which would cause the distance between the third edge dispensing 60 and the third pad 110 to be too close when the third edge dispensing 60 is applied to the first interconnect solder ribbon 12, resulting in poor soldering. It is also possible to avoid the first interconnect solder ribbon 12 extending too far beyond the third pad 110 (i.e., the length of the part overlapping with the third busbar 112) from being too long, which would cause the area on the back of the back contact battery 11 to be too large and result in a reduced bifaciality. At the same time, it is also possible to reduce the cost of the first interconnect solder ribbon 12.

[0182] Specifically, in such an embodiment, the ratio of L10 to L7 can be, for example, 0.2, 0.3, 0.5, 1, 1.5, 2, 2.5, 3, 3.4, 4 or other values ​​between 0.2 and 4, without any specific limitation.

[0183] In some embodiments, the size of L10 is in the range of 1.5mm-5mm, that is, 1.5mm≤L10≤5mm. The size of L10 can be, for example, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm or other values ​​between 1.5mm and 5mm, and there is no specific limitation here.

[0184] Specifically, on the one hand, if L10 is too small, the distance between the end of the first interconnect solder ribbon 12 facing the second edge 102 and the third pad 110 will be relatively large. In this case, if the third edge dispensing 60 is set too close to the second edge 102, although it can effectively prevent the end of the first interconnect solder ribbon 12 from shifting, it is easy to cause microcracks at the edge of the back contact battery 11. On the other hand, if the third edge dispensing 60 is set too far from the second edge 102, the portion of the first interconnect solder ribbon 12 extending beyond the third edge dispensing 60 will be too long and prone to shifting, increasing the risk of short circuit. On the other hand, if L10 is too large, the distance between the end of the first interconnect solder ribbon 12 facing the second edge 102 and the third pad 110 will be relatively small. In this case, the distance between the third edge dispensing 60 and the third pad 110 will be too small, increasing the risk of poor soldering. Therefore, after careful research and verification, the inventors of this application found that optimizing the L10 design within the range of 1.5mm-5mm can reduce the risk of edge microcracks and short circuits, while also reducing the risk of poor soldering.

[0185] Please see Figure 4 and Figure 7 In some embodiments, a fourth edge adhesive 70 may be provided on the fourth busbar 113, which is used to fix the second interconnecting ribbon 13 to the back contact battery 11 during the fabrication of the back contact battery assembly 100.

[0186] Please see Figure 4 In some embodiments, there is no adhesive dot between the second pad 17 and the fourth pad 111. This avoids the adhesive dotting between the second pad 17 and the fourth pad 111 from blocking the second fine gate 15 between them, which would prevent the second interconnect solder ribbon 13 from making contact with the second fine gate 15 blocked by the adhesive and thus causing efficiency loss.

[0187] Please see Figure 3 and Figure 9 In some embodiments, in the back contact battery 11, the second busbar 19 is closer to the first edge 101 than the first busbar 18. In such a case, of the first fine gate 14 and the second fine gate 15, the fine gate closest to the first edge 101 is the second fine gate 15.

[0188] Please see Figure 9 and Figure 10 In the battery string 100, one of the two adjacent back contact batteries 11 partially overlaps with one end of the first edge 101 and the other end of the second edge 102 to form an overlapping area 105.

[0189] The overlapping region 105 covers a portion of the second busbar 19 on one of the two adjacent back contact batteries 11. The ratio of the length H2 of the portion of the second busbar 19 covered by the overlapping region 105 in the first direction to the total length H1 of the second busbar 19 in the first direction is A, where A is less than 15%, that is, the ratio of H2 to H1 is less than 15%. For example, it can be 14.5%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, or other values ​​less than 15%.

[0190] Thus, by overlapping the opposite ends of two adjacent back contact cells 11 to form an overlapping area 105, the gap between two adjacent back contact cells 11 can be eliminated, which can improve the power generation efficiency per unit area of ​​the back contact cell module 100. At the same time, it can also avoid the interconnecting solder strips from being exposed between the two back contact cells 11, thereby improving the aesthetics of the module.

[0191] Furthermore, by optimizing the length ratio of the second busbar 19 covered by the overlapping region 105, and setting it to less than 15%, it is possible to effectively prevent the overlapping region 105 from being too long, which would cause the end of one back contact battery 11 to be too far from the pad on the other back contact battery 11 (e.g., Figure 10 The third pad 110 shown is too close, which may cause poor soldering or even failure to solder between the interconnect solder ribbon and the pad. This reduces the risk of poor soldering, ensures soldering performance, and effectively avoids poor contact between the interconnect solder ribbon and the pad when the component is subjected to external impact.

[0192] Specifically, such as Figure 10 As shown, it is easy to understand that, since adjacent back contact batteries 11 have overlapping areas 105, there is a height difference between the back sides of the two back contact batteries 11 in the thickness direction of the back contact battery assembly 100. If the proportion of the second busbar 19 covered is too large, the length of the overlapping area 105 will be too large, resulting in the end of one back contact battery 11 being too far from the pad on the other back contact battery 11 (e.g., ...). Figure 10The third pad 110 shown is too close to the back contact battery 11. In this case, when the back contact battery 11 is connected in series by solder strips, due to the height difference and the distance between the overlapping area 105 and the solder pad (e.g., the third pad 110) on the lower back contact battery 11, a poor solder joint may occur between the solder strip and the solder pad on the lower back contact battery 11. Based on this, the inventors of this application have found through research and investigation that by optimizing the design of the length ratio of the second busbar 19 covered by the overlapping area 105, and setting its ratio to less than 15%, this phenomenon can be effectively avoided.

[0193] In other words, in such an embodiment, by optimizing the length ratio of the second busbar 19 covered by the overlapping area 105, the probability of cold solder joints can be effectively reduced, the welding performance of the module can be improved, and the stability and reliability of the module can be guaranteed, while improving the power generation efficiency per unit area and the aesthetics of the module.

[0194] In the embodiments of this application, in the battery string, all back contact batteries 11 can be stacked sequentially along a first direction, and the first edges 101 of all back contact batteries 11 face the same side. In this application, the end of the Nth back contact battery 11 located on the side of the second edge 102 may overlap with the end of the (N+1)th back contact battery sheet 11 located on the side of the first edge 101, where N is a positive integer.

[0195] In a battery string, the back contact batteries 11 can be stacked sequentially from one end of the battery string to the other. That is, the (M+1)th back contact battery 11 is stacked on top of the Mth back contact battery 11, where M is a positive integer. In other words, from one end of the battery string to the other, the second back contact battery 11 is stacked on top of the first back contact battery 11, the third back contact battery 11 is stacked on top of the second back contact battery 11, and so on.

[0196] Of course, in some possible embodiments, the back contact batteries 11 may be stacked in such a way that the even-numbered back contact batteries 11 are stacked on top of two adjacent odd-numbered batteries. For example, the second back contact battery 11 may be stacked on top of the first and third back contact batteries 11, while the first and third back contact batteries 11 are both located below the second back contact battery 11.

[0197] Furthermore, in such an embodiment, the size of A is preferably greater than 1%, that is, 1% < A < 15%. In this way, the length of the overlapping region 105 can be avoided from being too short, thereby preventing the formation of gaps between cells due to a small displacement of the cell during the lamination process.

[0198] In some embodiments, the absolute value of the difference between the lengths of the portions of any two second busbars 19 covered by the overlapping region 105 in the first direction is less than 0.5 mm. For example, among a plurality of second busbars 19, if the length of one second busbar 19 covered by the overlapping region 105 is 1 mm, then the lengths of the other second busbars 19 covered by the overlapping region must be at least greater than 0.5 mm and less than 1.5 mm.

[0199] In this way, the excessive difference in the length of the second busbar 19 being covered can be avoided, which would lead to a large difference in the coverage length of the overlapping area 105 at various locations, resulting in excessive battery adaptation and affecting the efficiency of the module.

[0200] Specifically, in such an embodiment, the absolute value of the difference between the lengths of the portions covered by the overlapping region 105 in any two second busbars 19 in the first direction can be, for example, 0.48 mm, 0.45 mm, 0.4 mm, 0.35 mm, 0.3 mm, 0.25 mm, 0.2 mm, 0.15 mm, 0.1 mm, or other values ​​less than 0.5 mm, without any specific limitation herein.

[0201] In some embodiments, the overlapping region 105 also covers a portion of the first busbar 18, and the ratio between the length H4 of the portion of the first busbar 18 covered by the overlapping region 105 in the first direction and the total length H3 of the first busbar 18 in the first direction is B, where B is less than A, that is, H4:H3 < H2:H1.

[0202] Thus, since the second busbar 19 is closer to the first edge 101 than the first busbar 18, the proportion of the length covered by the first busbar 18 is smaller than the proportion of the length covered by the second busbar 19. Simultaneously, setting B to a smaller value also avoids the overlap area 105 being too far from the pads on the back contact battery 11 below (e.g., Figure 10 The fourth pad (111)

[0203] Specifically, in the embodiments of this application, the length of the first bus gate 18 may be the same as the length of the second bus gate 19.

[0204] In some embodiments, in the back contact battery assembly 100, B is less than 7%, that is, H4:H3 < 7%.

[0205] For example, it can be 7%, 6%, 5%, 4%, 3%, 2%, 1%, or other values ​​less than 7%.

[0206] Thus, by optimizing the length ratio of the first busbar 18 covered by the overlapping region 105, and setting it to less than 7%, it is possible to effectively avoid the overlapping region 105 being too long, which would cause the end of one back contact battery 11 to be too far from the pad on the other back contact battery 11 (e.g., Figure 11 The fourth pad 111 shown is too close, which can cause poor soldering or even failure to solder between the interconnect solder ribbon and the pad, thus affecting the soldering performance of the component and causing poor contact between the interconnect solder ribbon and the pad when the component is subjected to external impact.

[0207] In some embodiments, the absolute value of the difference between the lengths of the portions of any two first busbars 18 covered by the overlapping region 105 in the first direction is less than 0.5 mm. For example, among a plurality of first busbars 18, if the length of one first busbar 18 covered by the overlapping region 105 is 1 mm, then the lengths of the other first busbars 18 covered by the overlapping region must be at least greater than 0.5 mm and less than 1.5 mm.

[0208] In this way, the excessive difference in the length of the first busbar 18 being covered can be avoided, which would lead to a large difference in the coverage length of the overlapping area 105 at various locations, resulting in excessive battery adaptation and affecting the efficiency of the module.

[0209] Specifically, in such an embodiment, the absolute value of the difference between the lengths of the portions covered by the overlapping region 105 in any two first busbars 18 in the first direction can be, for example, 0.48 mm, 0.45 mm, 0.4 mm, 0.35 mm, 0.3 mm, 0.25 mm, 0.2 mm, 0.15 mm, 0.1 mm, or other values ​​less than 0.5 mm, without any specific limitation herein.

[0210] Of course, in some possible embodiments, the overlapping region 105 may not cover the first bus gate 18, and there are no specific limitations here.

[0211] In some embodiments, the difference in length between any two overlapping regions 105 in the first direction is less than 1 mm.

[0212] In this way, the excessive length difference of different overlapping regions 105 can be avoided, which would lead to excessive serial adaptation and affect efficiency.

[0213] Specifically, the difference between the lengths of any two overlapping regions 105 in the first direction can be, for example, 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, or other values ​​less than 1 mm, without any specific limitation.

[0214] Please see Figure 3 and Figure 9 In some embodiments, in the back contact battery 11, the fourth busbar 113 is closer to the second edge 102 than the third busbar 112. In such a case, among the first fine gate 14 and the second fine gate 15, the fine gate closest to the second edge 102 is also the second fine gate 15.

[0215] Please see Figure 9 and Figure 10 In the battery string 100, the overlapping region 105 also covers a portion of the fourth busbar 113 on another back contact battery 11 of the two adjacent back contact batteries 11. The ratio between the length H6 of the portion of the fourth busbar 113 covered by the overlapping region 105 in the first direction and the total length H5 of the fourth busbar 113 in the first direction is C, where C is less than 15%, that is, the ratio between H6 and H5 is less than 15%. For example, it can be 14.5%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, or other values ​​less than 15%.

[0216] Thus, by optimizing the length ratio of the fourth busbar 113 covered by the overlapping region 105, and setting its ratio to less than 15%, it is possible to effectively avoid the overlapping region 105 being too long, which would cause the end of one back contact battery 11 to be too far from the pad on the other back contact battery 11 (e.g., Figure 11 The fourth pad 111 shown is too close, which may cause poor soldering between the interconnect solder ribbon and the pad or even prevent soldering. This reduces the risk of poor soldering, ensures soldering performance, and effectively avoids the phenomenon of poor contact between the interconnect solder ribbon and the pad when the component is subjected to external impact.

[0217] Specifically, such as Figure 11 As shown, it is easy to understand that, since adjacent back contact batteries 11 have overlapping areas 105, there is a height difference between the back sides of the two back contact batteries 11 in the thickness direction of the back contact battery assembly 100. If the fourth busbar 113 is covered by too much, the length of the overlapping area 105 will be too large, resulting in the end of one back contact battery 11 being too far from the pad on the other back contact battery 11 (e.g., ...). Figure 11The fourth pad 111 shown is too close to the back contact battery 11. In this case, when the back contact battery 11 is connected in series by solder strips, due to the height difference and the distance between the overlapping area 105 and the solder pad (e.g., the fourth pad 111) on the lower back contact battery 11, a poor solder joint may occur between the solder strip and the solder pad on the lower back contact battery 11. Based on this, the inventors of this application have found through research and investigation that by optimizing the design of the proportion of the length of the fourth busbar 113 covered by the overlapping area 105, setting its proportion to less than 15%, this phenomenon can be effectively avoided.

[0218] In other words, in such an embodiment, by optimizing the length ratio of the fourth busbar 113 covered by the overlapping area 105, the probability of cold solder joints can be effectively reduced, the welding performance of the module can be improved, and the stability and reliability of the module can be guaranteed, while improving the power generation efficiency per unit area and the aesthetics of the module.

[0219] In some embodiments, in the back contact battery assembly 100, C is less than A. Thus, setting C to be less than A can control the distance between the end of the upper back contact battery 11 and the fourth pad 111, reducing the risk of poor soldering of the interconnecting solder strips at the fourth pad 111.

[0220] Furthermore, in such embodiments, C is preferably less than 13%, for example 12.5%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, or other values ​​less than 13%.

[0221] In some embodiments, the size of C is preferably greater than 1%, that is, 1% < C < 13%. In this way, the length of the overlapping area 105 can be avoided from being too short, thereby avoiding the formation of gaps between cells due to small displacement of the cells during the lamination process.

[0222] In some embodiments, the absolute value of the difference between the lengths of the portions covered by the overlapping region 105 in any two fourth bus gates 113 in the first direction is less than 0.5 mm. For example, in a plurality of fourth bus gates 113, if the length of one fourth bus gate 113 covered by the overlapping region 105 is 1 mm, then the lengths of the other fourth bus gates 113 covered by the overlapping region must be at least greater than 0.5 mm and less than 1.5 mm.

[0223] In this way, the excessive difference in the length of the fourth busbar 113 being covered can be avoided, which would lead to a large difference in the coverage length of the overlapping area 105 at various locations, resulting in excessive battery adaptation and affecting the efficiency of the module.

[0224] Specifically, in such an embodiment, the absolute value of the difference between the lengths of the portions covered by the overlapping region 105 in any two fourth busbars 113 in the first direction can be, for example, 0.48 mm, 0.45 mm, 0.4 mm, 0.35 mm, 0.3 mm, 0.25 mm, 0.2 mm, 0.15 mm, 0.1 mm, or other values ​​less than 0.5 mm, without any specific limitation herein.

[0225] In some embodiments, the overlapping region 105 also covers a portion of the third busbar 112, and the ratio between the length H8 of the portion of the third busbar 112 covered by the overlapping region 105 in the first direction and the total length H7 of the third busbar 112 in the first direction is D, where D is less than C, that is, H8:H7 < H6:H5.

[0226] Thus, since the fourth busbar 113 is closer to the second edge 102 than the third busbar 112, the proportion of the length covered by the third busbar 112 is smaller than the proportion of the length covered by the fourth busbar 113. At the same time, setting D to a smaller value also avoids the overlap area 105 being too far from the pads on the back contact battery 11 below (e.g., Figure 11 The fourth pad (111)

[0227] Specifically, in the embodiments of this application, the length of the third bus gate 112 may be the same as the length of the fourth bus gate 113.

[0228] In some embodiments, in the back contact battery assembly 100, D is less than 7%, that is, H8:H7 < 7%, for example, it can be 7%, 6%, 5%, 4%, 3%, 2%, 1% or other values ​​less than 7%.

[0229] Thus, by optimizing the length ratio of the third busbar 112 covered by the overlapping region 105, and setting its ratio to less than 7%, it is possible to effectively avoid the overlapping region 105 being too long, which would cause the end of one back contact battery 11 to be too far from the pad on the other back contact battery 11 (e.g., Figure 11 The fourth pad 111 shown is too close, which can cause poor soldering or even failure to solder between the interconnect solder ribbon and the pad, thus affecting the soldering performance of the component and causing poor contact between the interconnect solder ribbon and the pad when the component is subjected to external impact.

[0230] In some embodiments, the overlapping region 105 also covers a portion of the first busbar 18, and the ratio between the length of the portion of the first busbar 18 covered by the overlapping region 105 in the first direction and the total length of the first busbar 18 in the first direction is B, where D is less than B.

[0231] In other words, the length of the third busbar 112 covered by the overlapping region 105 is less than the length of the first busbar 18 covered by the overlapping region 105.

[0232] Thus, setting D to be less than B can control the distance between the end of the upper back contact battery 11 and the fourth pad 111, reducing the risk of poor soldering of the interconnect solder strip at the third pad 110.

[0233] In some embodiments, in two adjacent back contact batteries 11, the overlapping region 105 covers a portion of the first busbar 18 and a portion of the second busbar 19 of one back contact battery 11, and also covers a portion of the third busbar 112 and a portion of the fourth busbar 113 of the other back contact battery 11. The specific proportions of each busbar covered by the overlapping region 105 have been described above and will not be repeated here.

[0234] In some embodiments, the absolute value of the difference between the lengths of the portions covered by the overlapping region 105 in any two third bus gates 112 in the first direction is less than 0.5 mm. For example, in a plurality of third bus gates 112, if the length of one of the third bus gates 112 covered by the overlapping region 105 is 1 mm, then the lengths of the other third bus gates 112 covered by the overlapping region must be at least greater than 0.5 mm and less than 1.5 mm.

[0235] In this way, the excessive difference in the length of the third busbar 112 being covered can be avoided, which would lead to a large difference in the coverage length of the overlapping area 105 at various locations, resulting in excessive battery adaptation and affecting the efficiency of the module.

[0236] Specifically, in such an embodiment, the absolute value of the difference between the lengths of the portions covered by the overlapping region 105 in any two third busbars 112 in the first direction can be, for example, 0.48 mm, 0.45 mm, 0.4 mm, 0.35 mm, 0.3 mm, 0.25 mm, 0.2 mm, 0.15 mm, 0.1 mm, or other values ​​less than 0.5 mm, without any specific limitation herein.

[0237] Of course, in some possible embodiments, the overlapping region 105 may not cover the third bus gate 110, and there are no specific limitations here.

[0238] like Figures 9-11 As shown, in Figures 9-11In the illustrated embodiment, the overlapping region 105 may cover a portion of the first busbar 18 and a portion of the second busbar 19 on one of two adjacent back contact batteries 11. Simultaneously, the overlapping region 105 also covers the third busbar 110 and the fourth busbar 113 on the other back contact battery 11. In the two adjacent back contact batteries 11, the first busbar 18 on one battery is substantially aligned with the fourth busbar 113 on the other battery in a first direction, and the second busbar 19 on one battery is substantially aligned with the third busbar 110 on the other battery in a first direction.

[0239] It is easy to understand that in some possible embodiments, the overlapping region 105 may cover only a portion of the second busbar 19 on one of the two adjacent back contact batteries 11 without covering the first busbar 18. At the same time, the overlapping region 105 also covers the fourth busbar 113 on the other back contact battery 11 without covering the third busbar 110.

[0240] In summary, in some embodiments of this application, the back contact battery assembly 100 may include a plurality of battery strings 10, the battery strings 10 including a plurality of back contact batteries 11 arranged along a first direction and connected in series, and the back contact batteries 11 having opposing first edges 101 and second edges 102 in the first direction.

[0241] The back of the back contact battery 11 has a plurality of first fine grids 14, a plurality of second fine grids 15, a plurality of first solder pads 16 and a plurality of second solder pads 17. The plurality of first fine grids 14 and the plurality of second fine grids 15 are arranged alternately along a first direction and all extend along a second direction, and the second direction intersects the first direction.

[0242] Both the first pad 16 and the second pad 17 are located close to the first edge 101. Each pad 16 and the second pad 17 has a plurality of first fine gates 14 and a plurality of second fine gates 15 between itself and the first edge 101. The plurality of first pads 16 and the plurality of second pads 17 are arranged alternately along a second direction. A first busbar 18 is connected to the first pad 16. The first busbar 18 extends along the first direction and is located between the first pad 16 and the first edge 101. The first busbar 18 is connected to the first pad 16. A first fine gate 14 is connected between the pad 16 and the first edge 101 and is insulated from the second fine gate 15. A second bus gate 19 is connected to the second pad 17. The second bus gate 19 extends along a first direction and is located between the second pad 17 and the first edge 101. The second bus gate 19 is connected to the second fine gate 15 located between the second pad 17 and the first edge 101 and is insulated from the first fine gate 14. The second bus gate 19 is closer to the first edge 101 than the first bus gate 18.

[0243] In the battery string 10, one end of one of two adjacent back contact batteries 11 located at the first edge 101 partially overlaps with one end of the other back contact battery 11 located at the second edge 102 to form an overlapping region 105. The overlapping region 105 covers a portion of the second busbar 19 on one of the two adjacent back contact batteries 11, and the ratio between the length H2 of the portion of the second busbar 19 covered by the overlapping region 105 in the first direction and the total length H1 of the second busbar 19 in the first direction is A, where A is less than 15%.

[0244] In this embodiment, overlapping the opposite ends of two adjacent back contact cells 11 to form an overlapping region 105 eliminates the gap between the two adjacent back contact cells 11, improving the power generation efficiency per unit area of ​​the back contact cell assembly 100. It also prevents the interconnecting solder ribbon from being exposed between the two back contact cells 11, thus improving the assembly's aesthetics. Furthermore, by optimizing the proportion of the second busbar 19 covered by the overlapping region 105, setting it to less than 15%, it effectively prevents the overlapping region 105 from being too long, which could cause the end of one back contact cell 11 to be too close to the pad on the other back contact cell 11, leading to poor soldering or even failure to solder the interconnecting solder ribbon. This reduces the risk of poor soldering, ensures soldering performance, and effectively prevents poor contact between the interconnecting solder ribbon and the pad when the assembly is subjected to external impact.

[0245] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0246] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A back-contact battery assembly, characterized in that, It includes a plurality of battery strings, the battery strings including a plurality of back contact batteries arranged along a first direction, the back contact batteries having opposing first edges and second edges in the first direction; The back contact battery has a plurality of first fine grids, a plurality of second fine grids, a plurality of first solder pads and a plurality of second solder pads on its back side. The first fine grids and the second fine grids are arranged alternately along the first direction and both extend along the second direction, which intersects the first direction. Both the first pad and the second pad are located close to the first edge. A first bus gate line is connected to the first pad. The first bus gate line is located between the first pad and the first edge and is connected to the first fine gate. A second bus gate line is connected to the second pad. The second bus gate line is located between the second pad and the first edge and is connected to the second fine gate. The second bus gate line is closer to the first edge than the first bus gate line. In the battery string, one of two adjacent back contact batteries has one end of the first edge and the other has one end of the second edge, forming an overlapping region. The overlapping region covers a portion of the second busbar on one of the two adjacent back contact batteries. The ratio A between the length of the portion of the second busbar covered by the overlapping region in the first direction and the total length of the second busbar in the first direction is less than 15%.

2. The back contact battery assembly according to claim 1, characterized in that, The absolute value of the difference between the lengths of the portions of any two second busbars covered by the overlapping region in the first direction is less than 0.5 mm.

3. The back contact battery assembly according to claim 1, characterized in that, The overlapping area does not cover the first busbar.

4. The back contact battery assembly according to claim 1, characterized in that, The overlapping region also covers a portion of the first busbar, and the ratio of the length of the portion of the first busbar covered by the overlapping region in the first direction to the total length of the first busbar in the first direction is B, where B is less than A.

5. The back contact battery assembly according to claim 4, characterized in that, In back-contact battery assemblies, B is less than 7%.

6. The back contact battery assembly according to claim 4, characterized in that, The absolute value of the difference between the lengths of the portions of any two first busbars covered by the overlapping region in the first direction is less than 0.5 mm.

7. The back contact battery assembly according to claim 1, characterized in that, In the back-contact battery assembly, the absolute value of the difference between the lengths of any two overlapping regions in the first direction is less than 1 mm.

8. The back contact battery assembly according to claim 1, characterized in that, The back of the back contact battery also has a plurality of third solder pads and a plurality of fourth solder pads. The third solder pads and the fourth solder pads are both located close to the second edge. The third solder pads and the first solder pads are collinearly arranged in the first direction. The fourth solder pads and the second solder pads are collinearly arranged in the first direction. A third bus line is connected to the third pad, the third bus line is located between the third pad and the second edge and is connected to the first fine gate; a fourth bus line is connected to the fourth pad, the fourth bus line is located between the fourth pad and the second edge and is connected to the second fine gate, and the fourth bus line is closer to the second edge than the third bus line. In the battery string, the overlapping region also covers a portion of the fourth busbar on another of the two adjacent back contact batteries, and the ratio of the length of the portion of the fourth busbar covered by the overlapping region in the first direction to the total length of the fourth busbar in the first direction is C, where C is less than 15%.

9. The back contact battery assembly according to claim 8, characterized in that, In back-contact battery assemblies, C is less than A.

10. The back contact battery assembly according to claim 9, characterized in that, C is less than 13%.

11. The back contact battery assembly according to claim 8, characterized in that, The overlapping area does not cover the third busbar.

12. The back contact battery assembly according to claim 8, characterized in that, The overlapping region also covers a portion of the third busbar, and the ratio of the length of the portion of the third busbar covered by the overlapping region in the first direction to the total length of the third busbar in the first direction is D, where D is less than C.

13. The back contact battery assembly according to claim 12, characterized in that, In back-contact battery assemblies, D is less than 7%.

14. The back contact battery assembly according to claim 12, characterized in that, The overlapping region also covers a portion of the first busbar, and the ratio of the length of the portion of the first busbar covered by the overlapping region in the first direction to the total length of the first busbar in the first direction is B, where D is less than B.

15. A photovoltaic system, characterized in that, Includes the back contact battery assembly as described in any one of claims 1-14.

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