Back-contact cell, cell assembly, and photovoltaic system

Abstract

The present application is applicable to the technical field of solar cells, and provides a back-contact cell (100), a cell assembly (200), and a photovoltaic system (1000). In the back-contact cell (100), a back surface (12) is provided with a plurality of first series-connection regions (13) and a plurality of second series-connection regions (14), a plurality of first grid lines (20) comprise at least one first bus grid line group (210), the first bus grid line group (210) comprises two adjacent first bus grid lines (22), a first insulating layer (51) is arranged in a first edge series-connection region (131) and located on the first bus grid lines (22), a second insulating layer (52) is arranged in a second edge series-connection region (141) and located on a first connecting grid line (32), a first auxiliary connecting line (61) is arranged in the first edge series-connection region (131), in a second direction, at least one side of each first bus grid line (22) is provided with the first auxiliary connecting line (61), the first auxiliary connecting line (61) connects at least two second grid lines (30) located on the same side of the first bus grid line group (210), a second auxiliary connecting line (62) is arranged in the second edge series-connection region (141), in the second direction, at least one side of the first bus grid line group (210) is provided with the second auxiliary connecting line (62), and the second auxiliary connecting line (62) connects the first bus grid line (22) located on one side of the first connecting grid line (32) and at least one first grid line (20) adjacent to the first bus grid line (22).

Description

Back contact batteries, battery modules and photovoltaic systems

[0001] Priority information

[0002] This application claims priority and benefits to patent application No. 202510101743.6, filed with the China National Intellectual Property Administration on January 22, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of solar cell technology, and more particularly to a back-contact cell, a cell module, and a photovoltaic system. Background Technology

[0004] A back-contact battery is a type of battery in which both P-type and N-type doped layers are placed on the back of a silicon wafer, with no metal electrodes obstructing the front. It has higher short-circuit current and conversion efficiency.

[0005] In related technologies, the back of a back-contact solar cell has alternating grid lines. In order to reduce the use of paste and transmission loss, solder ribbons can be directly used to form an electrical connection with the grid lines of the cell in the cell module to achieve current collection and output. Summary of the Invention

[0006] This application provides a back-contact battery, a battery module, and a photovoltaic system.

[0007] This application is implemented as follows: the back contact battery in the embodiments of this application includes:

[0008] The substrate has a back surface with opposing first and second edges in a first direction. The back surface also has a plurality of first interconnection areas and a plurality of second interconnection areas arranged alternately in the first direction. The first interconnection area includes a first edge interconnection area closest to the first edge. There is no second interconnection area between the first edge interconnection area and the first edge. The second interconnection area includes a second edge interconnection area adjacent to the first edge interconnection area.

[0009] A plurality of first grid lines and a plurality of second grid lines are alternately arranged on the back side along a second direction, the second direction intersecting the first direction, and both the first grid lines and the second grid lines intersecting the first concatenation area and the second concatenation area; the plurality of first grid lines include at least one first bus grid line group, the first bus grid line group including two adjacent first bus grid lines, the first bus grid lines being continuous at both the first edge concatenation area and the second edge concatenation area; the plurality of second grid lines include at least one first connecting grid line, the first connecting grid line being located between two first bus grid lines in the first bus grid line group and being continuous at both the first edge concatenation area and the second edge concatenation area;

[0010] The first edge connection line, which is closer to the first edge than the first edge serialization area, is electrically connected to the first bus gate line and to at least a portion of the remaining first gate lines.

[0011] A first insulating layer is disposed on the portion of the first busbar corresponding to the first edge connection area;

[0012] A second insulating layer is disposed on the portion of the first connecting gate line corresponding to the second edge serial connection area; and

[0013] A first auxiliary connecting line is disposed in the first edge concatenation area and a second auxiliary connecting line is disposed in the second edge concatenation area. In the second direction, at least one side of the first busbar group is provided with the first auxiliary connecting line, and the first auxiliary connecting line connects at least two second grid lines located on the same side of the first busbar group. In the second direction, at least one side of the first busbar group is provided with the second auxiliary connecting line, and the second auxiliary connecting line connects to the first busbar line located on one side of the first connecting grid line and at least one first grid line adjacent to the first busbar line.

[0014] This application also provides a battery assembly comprising a plurality of back contact batteries as described in any of the preceding claims.

[0015] This application also provides a photovoltaic system, which includes the aforementioned battery components. Attached Figure Description

[0016] Figure 1 is a schematic diagram of the photovoltaic system provided in an embodiment of this application;

[0017] Figure 2 is a schematic diagram of the battery assembly provided in an embodiment of this application;

[0018] Figure 3 is a schematic diagram of the planar structure of the back contact battery provided in an embodiment of this application;

[0019] Figure 4 is a partially enlarged schematic diagram of the back contact battery in Figure 3;

[0020] Figure 5 is a schematic cross-sectional view of the back contact battery along line VV in Figure 4.

[0021] Figure 6 is a schematic cross-sectional view of the back contact battery along line VI-VI in Figure 4.

[0022] Figure 7 is a partially enlarged schematic diagram of the back contact battery in Figure 4;

[0023] Figure 8 is another cross-sectional view of the back contact battery along line VI-VI in Figure 4.

[0024] Figure 9 is another cross-sectional structural diagram of the back contact battery along line VI-VI in Figure 4.

[0025] Figure 10 is another enlarged schematic diagram of the back contact battery in Figure 4;

[0026] Figure 11 is another partially enlarged schematic diagram of the back contact battery in Figure 4;

[0027] Figure 12 is another enlarged schematic diagram of the back contact battery in Figure 3;

[0028] Figure 13 is a schematic cross-sectional view of the back contact battery along line XIII-XIII in Figure 12.

[0029] Figure 14 is a schematic cross-sectional view of the back contact battery along line XIV-XIV in Figure 12.

[0030] Figure 15 is a partially enlarged schematic diagram of the back contact battery in Figure 12;

[0031] Figure 16 is another cross-sectional view of the back contact battery along line XIV-XIV in Figure 12.

[0032] Figure 17 is another cross-sectional structural diagram of the back contact battery along line XIV-XIV in Figure 12.

[0033] Figure 18 is another enlarged schematic diagram of the back contact battery in Figure 12;

[0034] Figure 19 is another partially enlarged schematic diagram of the back contact battery in Figure 12. Detailed Implementation

[0035] 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. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. It should be noted that 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 for explaining this application and are not intended to limit this application.

[0036] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.

[0037] 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "several" means two or more, unless otherwise explicitly specified.

[0038] 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.

[0039] 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.

[0040] Referring to Figures 1 and 2, the photovoltaic system 1000 in this embodiment may include the battery module 200 in this embodiment, and the battery module 200 may include several back-contact cells 100 in this embodiment. In this embodiment, multiple back-contact cells 100 in the battery module 200 may be connected in series to form multiple battery strings. Each battery string may be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output. For example, the connection between each cell can be achieved by welding solder strips, or the connection between each battery string can be achieved by busbars. In some embodiments, each battery string may form a cell array, and then be encapsulated together by a front panel, a front encapsulating film, a rear encapsulating film, and a back panel to form the battery module 200.

[0041] In the embodiments of this application, the back contact battery 100 is a back contact battery without a main grid. Please refer to Figures 3-6. The back contact battery 100 in the embodiments of this application may include a substrate 10, a plurality of first grid lines 20, a plurality of second grid lines 30, a first edge connection line 40, a first insulating layer 51, a second insulating layer 52, a first auxiliary connection line 61, and a second auxiliary connection line 62.

[0042] As shown in Figures 3-6, the substrate 10 has a front side 11 and a back side 12. The back side 12 of the substrate 10 has a first edge 121 and a second edge 122 in a first direction. The back side 12 has a plurality of first series connection areas 13 and a plurality of second series connection areas 14. The first series connection areas 13 and the second series connection areas 14 are used to set the positive electrode solder strip and the negative electrode solder strip, respectively. That is to say, one of the first series connection areas 13 and the second series connection area 14 is the positive electrode series connection area, and the other is the negative electrode soldering area.

[0043] As shown in Figures 3 and 4, in the first direction, the first connecting area 13 and the second connecting area 14 are arranged alternately. The plurality of first connecting areas 13 include a first edge connecting area 131 closest to the first edge 121. There is no second connecting area 14 between the first edge connecting area 131 and the first edge 121. That is, as shown in Figure 3, among the first connecting areas 13 and the second connecting areas 14, the connecting area closest to the first edge 121 is the first connecting area 13, and this first connecting area 13 is referred to as the first edge connecting area 131. There are no other connecting areas between the first edge connecting area 131 and the first edge 121.

[0044] Several second concatenation areas 14 include a second edge concatenation area 141 adjacent to the first edge concatenation area 131 (i.e. the second concatenation area 14 closest to the first edge 121 in Figures 3 and 4).

[0045] As shown in Figure 3, a plurality of first grid lines 20 and a plurality of second grid lines 30 are alternately arranged on the back surface 12 along a second direction, which intersects with the first direction. All first grid lines 20 and all second grid lines 30 are intersected with the first serial connection area 13 and the second serial connection area 14, that is, the first serial connection area 13 and the second serial connection area 14 both extend along the second direction to intersect with the first grid lines 20 and the second grid lines 30.

[0046] In some embodiments, the first direction and the second direction can be the longitudinal direction and the transverse direction of the back contact battery 100, respectively, and they are perpendicular to each other. For example, in the example shown in FIG3, the first direction is the transverse direction of the back contact battery 100, and the second direction is the longitudinal direction of the back contact battery 100. Of course, in other embodiments, the first direction and the second direction can also be other directions, such as the two diagonal directions of the back contact battery 100, and there is no specific limitation here.

[0047] The plurality of first gate lines 20 includes at least one first bus gate line group 210, and the first bus gate line group 210 includes two adjacent first bus gate lines 22. Among the plurality of first gate lines 20, the first bus gate lines 22 are continuous at both the first edge concatenation region 131 and the second edge concatenation region 141, and at least some of the remaining first gate lines 20 are discontinuous at the first edge concatenation region 131 and continuous at the second edge concatenation region 141. For example, in some embodiments, among the plurality of first gate lines 20, except for the first bus gate line 22, all the remaining first gate lines 20 are discontinuous at the first edge concatenation region 131 and continuous at the second edge concatenation region 141. As another example, in some embodiments, among the first gate lines 20, except for the first bus gate line 22 and the first edge bus gate line 203 described below, all the remaining first gate lines 20 may be discontinuous at the first edge concatenation region 131 and continuous at the second edge concatenation region 141.

[0048] As shown in Figures 3 and 4, the plurality of second grid lines 30 includes at least one first connecting grid line 32. The first connecting grid line 32 is located between two first bus grid lines 22 in the first bus grid group 210. Among the plurality of second grid lines 30, the first connecting grid line 32 is continuous at both the first edge concatenation region 131 and the second edge concatenation region 141, while the remaining second grid lines 30 are continuous at the first edge concatenation region 131 and discontinuous at the second edge concatenation region 141. The number of first bus grid groups 210 corresponds to the number of first connecting grid lines 32.

[0049] The back contact battery 100 is a gridless back contact battery. In the battery assembly 200, the solder strip in the first series connection area 13 (including the first edge series connection area 131) is used to connect with the second grid line 30 to realize the current output of the second grid line 30, and the solder strip in the second series connection area 14 is used to weld and connect with the first grid line 20 to realize the current output of the first grid line 20.

[0050] As shown in Figure 3, the first edge connection line 40 is closer to the first edge 121 than the first edge serial region 131. The first edge connection line 40 is electrically connected to the first bus gate line 22, and the first edge connection line 40 is also electrically connected to at least some of the gate lines in the other first gate lines 20 besides the first bus gate line 22. Specifically, to avoid microcracks in the battery caused by welding at the edge of the first edge 121, the first edge connecting line 40 is not used for welding. Instead, it is used to collect the current of the isolated portion of the first grid line 20 (excluding the first bus grid line 22) located between the first edge series connection area 131 and the first edge 121. The current is then collected through the first bus grid line 22 onto the same polarity solder strip in the second edge series connection area 141 adjacent to the first edge series connection area 131. This collects the current of the isolated grid line segments in the edge region of the first grid line 20 located at the first edge 121, improving the efficiency of the back contact battery 100. If the first edge connecting line 40 and the first bus grid line 22 are not provided, the portion of the first grid line 20 (excluding the first bus grid line 22) located between the first edge series connection area 131 and the first edge 121 will form an isolated grid line segment, and the current in that portion cannot be collected.

[0051] As shown in Figure 3, the first insulating layer 51 is disposed in the first edge serial connection area 131 and located on the first bus gate line 22. That is, the first insulating layer 51 is disposed on the portion of the first bus gate line 22 corresponding to the first edge serial connection area 131. The first insulating layer 51 is disposed to insulate and separate the opposite polarity solder strip in the first edge serial connection area 131 from the first bus gate line 22 to avoid short circuit.

[0052] The second insulating layer 52 is disposed within the second edge serialization area 141 and located on the first connecting gate line 32. That is, the second insulating layer 52 is disposed on the portion of the first connecting gate line 32 corresponding to the second edge serialization area 141. The second insulating layer 52 is disposed to insulate and separate the opposite polarity solder strips in the second edge serialization area 141 from the first connecting gate line 32 to avoid short circuit.

[0053] As shown in Figures 3 and 4, a first auxiliary connection line 61 is disposed within the first edge serialization area 131. In the second direction, at least one side of the first busbar 22 is provided with the first auxiliary connection line 61, which connects at least two second gate lines 30 located on the same side of the first busbar group 210. As shown in Figures 4 and 6, in some embodiments, the at least two second gate lines 30 connected to the first auxiliary connection line 61 preferably include the second gate line 30 adjacent to the first busbar group 210 (i.e., the second gate line 30 closest to the first busbar group 210 in Figures 3 and 4). That is, in some embodiments, the first auxiliary connection line 61 preferably connects to the second gate line 30 closest to the first busbar group 210, and the first auxiliary connection line 61 also connects to at least one of the remaining second gate lines 30 located on the same side as the first gate line 30. That is, the first auxiliary connection line 61 preferably connects at least one of the second grid line 30 adjacent to the first busbar group 210 and the remaining second grid lines 30 on the same side.

[0054] The second auxiliary connection line 62 is disposed within the second edge serialization area 141. In the second direction, at least one side of the first busbar group 210 is provided with the second auxiliary connection line 62. The second auxiliary connection line 62 connects the first busbar 22 located on one side of the first connecting busbar 32 and at least one first busbar 20 adjacent to the first busbar 22. That is, in some embodiments, the second auxiliary connection line 62 is connected to the first busbar 22 located on one side of the first connecting busbar 32 and at least one first busbar 20 adjacent to the first busbar 22.

[0055] In related technologies, back-contact solar cells have alternating grid lines on their back side. To reduce paste usage and transmission losses, solder ribbons can be directly used to form an electrical connection with the grid lines in the cell module to achieve current collection and output. However, in this technical solution, insulating adhesive needs to be placed at the grid lines of opposite polarity where they intersect with the solder ribbon to prevent leakage. However, the application of insulating adhesive can easily lead to incomplete soldering during the soldering process, resulting in the current from some grid lines not being collected and affecting the efficiency of the back-contact cell.

[0056] In the back contact battery 100, battery module 200 and photovoltaic system 1000 of this application embodiment, by setting the first edge connection line 40 and the first busbar group 210, the current collected by at least part of the isolated segment of the first busbar 20 located between the first edge series region 131 and the first edge 121 can be channeled to the same polarity solder strip in the second edge series region 141 adjacent to the first edge series region 131. This can effectively avoid microcracks caused by welding at the first edge 121 of the back contact battery 100 while ensuring the efficiency of the back contact battery 100. The first insulating layer 51 can achieve insulation between the solder strip in the first edge series connection area 131 and the first busbar 22. With the first auxiliary connection line 61, even if the second grid line 30 near the first insulating layer 51 has a poor solder joint due to the setting of the first insulating layer 51, the poorly soldered second grid line 30 can still achieve current busbar output through the first auxiliary connection line 61, thereby reducing or even eliminating the effect of poor solder joint caused by the first insulating layer 51, thus ensuring the efficiency of the back contact battery 100.

[0057] The first busbar group 210 is configured to include two adjacent first busbars 22. The first insulating layers 51 on the two first busbars 22 are adjacent, which can reduce the radiation area of ​​the cold solder joint caused by the first insulating layer 51 and further reduce the risk of cold solder joint. The continuous design of the first connecting grid line 32 in the second edge series connection area 141 can avoid the failure of the first connecting grid line 32 to collect current due to cold solder joint. The design of the second insulating layer 52 can insulate the first connecting grid line 32. Through the design of the second auxiliary connecting line 62, even if the second grid line 30 near the second insulating layer 52 has a cold solder joint with the solder strip due to the setting of the second insulating layer 52, the second grid line 30 with a cold solder joint can still achieve current collection output through the second auxiliary connecting line 62, reducing or even eliminating the cold solder joint effect caused by the second insulating layer 52, thereby ensuring the efficiency of the back contact battery 100.

[0058] In other words, by making special designs on the electrode structure on the back side of the back contact battery 100 near the first edge 121, this application can reduce or even eliminate the effects of poor soldering caused by the first insulating layer 51 and the second insulating layer 52, thereby improving the electrical performance of the back contact battery 100 and ensuring the efficiency of the back contact battery 100.

[0059] As shown above, it is easy to understand that in this application, the first edge connection line 40 is not used for welding; it is only used for current transmission and merging. The function of the first bus gate line 22 is to collect and transmit current. As can be seen from Figures 3 and 4, in the examples shown in Figures 3 and 4, if the first edge connection line 40 and the first bus gate line 22 are not provided, part of the first gate line 20 will be broken at the first edge connection area 131. The current of the part of the gate line segment located between the first edge connection area 131 and the first edge 121 in the broken first gate line 20 cannot be collected. Therefore, by providing the first edge connection line 40 and the first bus gate line 22, the current of at least part of the isolated gate line segment of the first gate line 20 located in the edge region can be merged and transmitted to the solder strip provided in the adjacent second edge connection area 141, thereby effectively avoiding efficiency loss.

[0060] Because the first busbar 22 is continuously arranged in the first edge series connection area 131, in order to avoid short circuits caused by contact between the solder strip on the first edge series connection area 131 and the first busbar 22, a first insulating layer 51 (e.g., insulating adhesive) needs to be provided at the position corresponding to the first busbar 22 and the first edge series connection area 131. The height of the first insulating layer 51 is greater than the height of the second gate line 30 (including the first connecting gate line 32), that is, in the thickness direction, the protrusion height of the first insulating layer 51 is greater than the height of the second gate line 30. Under such circumstances, the solder strip in the first edge series connection area 131 is prone to poor soldering with the second gate line 30 during the soldering process, resulting in a lack of current on part of the second gate line 30. The current is effectively collected (especially the second gate line 30 adjacent to the first bus gate line 22, which is most likely to have a cold solder joint). Based on this, this application connects at least two second gate lines 30 on the same side of the first bus gate line 22 by setting a first auxiliary connection line 61, and preferably selects the second gate line 30 connected to it to include the one adjacent to the first bus gate line 22. It can connect part of the second gate lines 30 into a whole at the first edge serial connection area 131 through the first auxiliary connection line 61. Even if one of the second gate lines 30 has a cold solder joint due to the presence of the first insulating layer 51, it can still achieve current output through the first auxiliary connection line 61, thereby reducing or even completely eliminating the impact of the cold solder joint.

[0061] Furthermore, since the first connecting gate line 32 is located between the two first insulating layers 51, it is at the greatest risk of poor soldering. If the first connecting gate line 32 is interrupted at the second edge series connection area 141, isolated segments are likely to occur, causing the current in that part to be unable to be collected. Therefore, setting the first connecting gate line 32 to be continuous at the second edge series connection area 141 can avoid the problem of isolated segments causing some current to be unable to be collected.

[0062] Since the first connecting gate line 32 is continuous at both the first edge serialization area 131 and the second edge serialization area 141, a second insulating layer 52 (e.g., insulating adhesive) needs to be provided at the position corresponding to the first connecting gate line 32 and the second edge serialization area 141 to avoid short circuit caused by contact between the solder strip on the second edge serialization area 141 and the first connecting gate line 32. The height of the second insulating layer 52 is greater than the height of the first gate line 20; that is, in the thickness direction, the protrusion height of the second insulating layer 52 is greater than the height of the first gate line 20. Under such circumstances, the solder strip in the second edge serialization area 141 is prone to poor soldering with the first gate line 20 during the soldering process, resulting in some current on the first gate line 20 not being effectively collected, especially with the first... The first grid line 20 (i.e., the first bus grid line 22) adjacent to the first grid line 32 is most likely to have a cold solder joint. Based on this, this application connects the first bus grid line 22 on one side of the first connecting grid line 32 and at least one first grid line 20 adjacent to the first bus grid line 22 by setting a second auxiliary connecting line 62. The first bus grid line 22 and the remaining at least one first grid line 20 can be connected into a whole at the second edge series connection area 141 by the second auxiliary connecting line 62. Even if one of the second grid lines 30 has a cold solder joint due to the presence of the second insulating layer 52, it can still achieve current output through the second auxiliary connecting line 62, thereby reducing or even completely eliminating the cold solder joint effect caused by the second insulating layer 52.

[0063] Further, in embodiments of this application, as shown in Figures 5 and 6, the substrate 10 may include a silicon substrate 101, a plurality of first doped layers 102, a plurality of second doped layers 103, and a back passivation film layer 104. The silicon substrate 101 has opposing first surfaces 1011 and second surfaces 1012. The first doped layers 102 and second doped layers 103 are both disposed on the second surface 1012, and the plurality of first doped layers 102 and the plurality of second doped layers 103 are alternately arranged along a second direction. The back passivation film layer 104 is at least stacked on the first doped layers 102 and the second doped layers 103. In some embodiments, the back passivation film layer 104 may cover the entire second surface 1012, that is, the first doped layers 102 and the second doped layers 103, as well as the areas of the second surface 1012 where no doped layers are disposed, are all stacked with the back passivation film layer 104.

[0064] Therefore, in the substrate 10, the surface on the side where the first surface 1011 is located is the front side 11 of the substrate 10, and the side where the second surface 1012 is located is the back side of the substrate 10. Of course, in some embodiments, a first passivation layer (not shown) may also be provided between the first doped layer 102 and the silicon substrate 101 in the substrate 10. The first passivation layer may be, for example, a tunneling layer, an intrinsic amorphous silicon layer, or other film layer. A second passivation layer (not shown) may also be provided between the second doped layer 103 and the silicon substrate 101. The second passivation layer may be, for example, a tunneling layer, an intrinsic amorphous silicon layer, or other film layer.

[0065] In the back contact battery 100, the first gate line 20 corresponds one-to-one with the first doped layer 102, and the second gate line 30 corresponds one-to-one with the second doped layer 103. One of the first doped layer 102 and the second doped layer 103 can be a P-type doped layer, and the other can be an N-type doped layer. In some embodiments, the first gate line 20 can completely penetrate the back passivation film layer 104 to form a complete contact with the first doped layer 102, or the first gate line 20 can only partially penetrate the back passivation film layer 104 to form a localized metallized contact with the first doped layer 102. The specific method is not limited here.

[0066] That is to say, in the embodiments of this application, the first gate line 20 is correspondingly disposed with the first doped layer 102 and at least partially penetrates the back passivation film layer 104 and makes conductive contact with the first doped layer 102, and the second gate line 30 is correspondingly disposed with the second doped layer 103 and at least partially penetrates the back passivation film layer 104 and makes conductive contact with the second doped layer 103.

[0067] As shown in Figures 3, 4, and 7, in some embodiments, the first gate line 20 may be continuous at each second cascade region 14 and have a first welding segment 201 for welding with solder strip at each second cascade region 14. The second gate line 30 may be continuous at each first cascade region 13 and have a second welding segment 301 for welding with solder strip at each first cascade region 13.

[0068] In some embodiments, in the first gate line 20, the width (i.e., the length in the second direction) of the first welding segment 201 may be greater than the width of the remaining portion. In the second gate line 30, the width (i.e., the length in the second direction) of the second welding segment 301 may also be greater than the width of the remaining portion. This increases the contact area between the first gate line 20 and the second gate line 30 and the solder strip, improving welding stability.

[0069] In some embodiments, the first weld segment 201 may be a double-layer structure. Specifically, in some embodiments, the first gate line 20 may include a first collection layer that penetrates the back passivation film layer 104 and a first weld layer that is stacked on the first collection layer but does not penetrate the back passivation film layer 104, wherein the first collection layer penetrates the back passivation film layer 104 and makes conductive contact with the first doped layer 102.

[0070] In some embodiments, the first collection layer may be continuous at the second serial area 14 and discontinuous at the first serial area 13, and the first welding layer may be disposed at the second serial area 14 and located on the first collection layer. In such a case, the portion corresponding to the first welding layer in the first gate line 20 is the first welding segment 201.

[0071] Of course, in some other embodiments, the first welding segment 201 may be a single-layer structure. In this case, the first collecting layer is interrupted at both the second series connection area 14 and the first series connection area 13. The first welding layer is disposed at the second series connection area 14 and electrically connected to the two ends of the first collecting layer formed at the second series connection area 14. It is easy to understand that in these cases, the portion corresponding to the first welding layer is the first welding segment 201.

[0072] In some embodiments, the width of the first welding layer can be set to be greater than the width of the first collecting layer, where the width refers to the length of both in the second direction. This increases the welding area during welding and improves the reliability of the welding process.

[0073] In some embodiments, the second weld segment 301 may also be a double-layer structure. Specifically, in some embodiments, the second gate line 30 may include a second collection layer that penetrates the back passivation film layer 104 and a second weld layer that is stacked on the second collection layer but does not penetrate the back passivation film layer 104, wherein the second collection layer penetrates the back passivation film layer 104 and makes conductive contact with the second doped layer 103.

[0074] In some embodiments, the second collection layer may be continuous at the first serial area 13 and discontinuous at the second serial area 14, and the second welding layer may be disposed at the first serial area 13 and located on the second collection layer. In such a case, the portion corresponding to the second welding layer in the second gate line 30 is the second welding segment 301.

[0075] Of course, in other embodiments, the second collecting layer may also be interrupted at both the first series connection area 13 and the second series connection area 14, and the second welding layer is disposed at the first series connection area 13 and electrically connected to the two ends of the second collecting layer formed at the first series connection area 13. It is easy to understand that in these cases, the portion corresponding to the second welding layer is the second welding segment 301.

[0076] In some embodiments, the width of the second welding layer may also be set to be greater than the width of the second collecting layer, where the width refers to the length of both in the second direction.

[0077] As shown in Figures 3 and 4, in the embodiments of this application, in order to minimize the impact of poor soldering, when at least two second gate lines 30 are provided on both sides of the first busbar group 210, it is preferable to simultaneously provide a first auxiliary connection line 61 on both sides of the first busbar group 210. Of course, if the first busbar group 210 is located at the outermost edge in the second direction, the first auxiliary connection line 61 can be provided on one side of the first busbar group 210.

[0078] In some embodiments, the width (i.e. the length in the second direction) of the first bus gate 22 may be greater than the width (i.e. the length in the second direction) of the portion of the remaining first gates 20 other than the first bus gate 22 located outside the second serial area 14 (i.e. the portion other than the first solder section 201).

[0079] Thus, since the first bus gate 22 needs to undertake the function of current collection and transmission, setting the width of the first bus gate 22 to be wider can reduce transmission loss during the current collection process and improve efficiency. The first welding section 201 is used for welding; setting the width of the first welding section 201 to be wider can improve the reliability and stability of the welding. The width of the first bus gate 22 can be the same as the width of the first welding section 201.

[0080] Furthermore, as shown in Figures 3, 4, and 7, in some embodiments, the first busbar 22 is continuous only at the first edge connection area 131, and is broken at other first connection areas 13. Of course, in some embodiments, as described below, when the back contact battery 100 has a second connection grid line 23, the first busbar 22 may also be continuous at the fifth edge connection area 133 as described below. In such cases, the first busbar 22 and the second connection grid line 23 are the same grid line.

[0081] The first busbar 22 is continuous at the first edge junction area 131, and only the segment of the first busbar 22 closest to the first edge 121 (i.e., the portion located between the second edge junction area 141 and the first edge 121) performs the busbar function. Therefore, in some embodiments, in order to save slurry and reduce costs, only this portion of the busbar segment can be made wider.

[0082] In this case, referring to Figures 3, 4, and 7, the first bus gate 22 may include a first bus segment 221 located between the second edge concatenation region 141 and the first edge 121. In some embodiments, the width of the first bus segment 221 (i.e., its length in the second direction) may be greater than the width of the remaining portion of the first bus gate 22 located outside the second concatenation region 14 (i.e., the portion other than the first weld segment 201 in the portion other than the first bus segment 221).

[0083] Thus, by simply making the width of the first busbar 221 wider, the amount of slurry used can be reduced while reducing busbar transmission loss, thereby reducing costs.

[0084] Specifically, as described above, in such an embodiment, the first bus 221 can channel current to the solder strip located at the second edge series region 141, and making only a portion of the first bus 221 wider can reduce the amount of paste used. In this case, the first bus 221 penetrates the back passivation film layer 104 and contacts the first doped layer 102.

[0085] Referring to Figure 7, in some embodiments, a first bus layer 70 may be provided on the first bus segment 221. Thus, by providing the first bus layer 70 on the first bus segment 221, the cross-sectional area of ​​the first bus segment 221 is effectively increased, which can also reduce transmission losses. Furthermore, the first bus layer 70 can be manufactured using a lower-cost paste than the first bus segment 221, thereby reducing costs.

[0086] Specifically, in such an embodiment, the first busbar 22 can be a regular busbar, with the width being the same at all positions except for the wider width at the first welding section 201. By providing the first bus layer 70 on the first bus section 221, the cross-sectional area of ​​the first bus section 221 is effectively increased. That is, because the first bus layer 70 is provided on the first bus section 221, it is not necessary to widen the first bus section 221 to achieve the same purpose of reducing transmission loss. Of course, in some embodiments, the first bus section 221 may be widened; this is not limited here.

[0087] The first bus layer 70 can be made of a non-burn-through paste. The first bus layer 70 does not penetrate the back passivation film layer 104 and contact the first doped layer 102. The paste cost of the first bus layer 70 is lower than that of the paste cost of the first bus section 221. For example, when neither the first bus layer 70 nor the first bus section 221 has a silver paste layer, the silver content in the first bus layer 70 can be lower than that in the first bus section 221. Alternatively, the first bus section 221 can be a silver paste layer, while the first bus layer 70 can be a copper layer, a silver-coated copper layer, or other lower-cost metal layers.

[0088] Furthermore, in such an embodiment, the width (length in the second direction) of the first bus layer 70 may be greater than the width (length in the second direction) of the portion of the remaining first gate lines 20 other than the first bus gate line 22 that is located outside the second serial area 14 (i.e., the portion other than the first solder section 201). Thus, by increasing the width of the first bus layer 70, the transmission capacity can be further improved and the transmission loss can be reduced.

[0089] In such an embodiment, the width of the first busbar 70 may be the same as the width of the first weld segment 201. In this document, the width of the first weld segment 201 refers to its length in the second direction. As shown above, when the width of the first weld layer is greater than the width of the first collection layer, the width of the first weld segment 201 is the width of the first weld layer (i.e., its length in the second direction). Similar descriptions will appear below and can be understood by referring to this document.

[0090] This ensures that there will be no significant transmission loss during the convergence process. Simultaneously, during printing, the first convergence layer 70 can be printed simultaneously with the first welding layer at the first welding section 201. When using the same screen printing plate, there is no need to create screen slots of different sizes on the screen, saving manufacturing steps and reducing manufacturing difficulty.

[0091] Referring to Figure 7, in some embodiments, the width (length in the first direction) of the first edge connection line 40 is greater than the width (length in the second direction) of the portion of the remaining first gate lines 20 other than the first bus gate line 22 located outside the second serial area 14 (i.e., the portion of the remaining first gate lines 20 other than the first bus gate line 22 excluding the first weld segment 201).

[0092] Therefore, since the first edge connection line 40 needs to undertake the function of bus transmission, setting the width of the first edge connection line 40 to be wider can also reduce transmission loss during the bus process and improve efficiency.

[0093] Specifically, in such an embodiment, the width of the first edge connecting line 40 can be the same as the width of the first welding segment 201. This ensures that no significant current loss occurs during the merging process.

[0094] Furthermore, referring to FIG7, in some embodiments, the width (length in the first direction) of the first auxiliary connection line 61 is greater than the width (length in the second direction) of the portion of the second gate line 30 located outside the first serial area 13 (the portion of the second gate line 30 excluding the second solder section 301).

[0095] Thus, since the first auxiliary connection line 61 serves to transmit and combine current when a cold solder joint occurs, setting the width of the first auxiliary connection line 61 to be wider can also reduce transmission loss during the current combining process and improve efficiency.

[0096] In some embodiments, the width of the first auxiliary connecting line 61 may be the same as the width of the first edge connecting line 40, and the widths of both may be the same as the widths of the first welding segment 201 and the second welding segment 301.

[0097] Please refer to Figures 3 and 4. In some embodiments, the first edge connection line 40 is electrically connected to all the first gate lines 20.

[0098] In this way, all the current collected by the isolated grid line segments located between the first edge series region 131 and the first edge 121 in the first grid line 20 can be combined, thereby maximizing the efficiency of the back contact battery 100.

[0099] Of course, in some embodiments, the first edge connection line 40 may only be electrically connected to a portion of the remaining first gate lines 20, excluding the first bus gate line 22. In such cases, the number of first gate lines 20 not electrically connected to the first edge connection line 40 is less than or equal to four. Thus, even if some of the first gate lines 20 are not connected to the first edge connection line 40, their number is very small and will not cause excessive efficiency loss or product defects.

[0100] In some embodiments, the first auxiliary connection line 61 connects 2 to 20 second gate lines 30. By setting the number of second gate lines 30 connected to the first auxiliary connection line 61 within this reasonable range, the impact of poor soldering can be minimized or even eliminated.

[0101] In embodiments of this application, the number of first busbar groups 210 may be single. In such cases, the first auxiliary connecting line 61 may be provided only on one side of the first busbar group 210, or the first auxiliary connecting line 61 may be provided on both sides of the first busbar group 210; the specific provision is not limited here. When at least two second gate lines 30 are provided on both sides of the first busbar group 210, it is preferable to provide the first auxiliary connecting line 61 on both sides.

[0102] Furthermore, it should be noted that in this application, when there are multiple first busbar groups 210, the first auxiliary connection line 61 can be provided only on one or both sides of some of the first busbar groups 210, while the first auxiliary connection line 61 can be omitted on both sides of the remaining first busbar groups 210. In this case, the problem of cold solder joints in some locations can still be solved. In this application, it is preferable that the first auxiliary connection line 61 is provided on both sides of each first busbar group 210. Of course, if the first busbar group 210 is located at the third edge 123, then the first auxiliary connection line 61 only needs to be provided on one side of the first busbar 22.

[0103] Of course, referring to Figures 3 and 4, in some embodiments, there are multiple first bus gate groups 210, which are spaced apart in the second direction. Thus, setting multiple first bus gate groups 210 can shorten the current confluence path, effectively reduce current transmission losses, and improve efficiency.

[0104] In this case, a first auxiliary connecting line 61 is provided on both sides of the first busbar group 210, and a first auxiliary connecting line 61 is provided between two adjacent first busbar groups 210. The first auxiliary connecting line 61 located between two adjacent first busbar groups 210 connects all the second grid lines 30 located between two adjacent first busbar groups 210.

[0105] In this way, by connecting the first auxiliary connection line 61 to all the second grid lines 30 between two adjacent first busbar groups 210, the influence of poor soldering can be basically completely eliminated, and the efficiency of the back contact battery 100 can be improved as much as possible.

[0106] Specifically, in such an embodiment, the number of the first busbar group 210 in the back contact battery 100 can be selected according to the actual situation such as the size of the battery cell and the loss during the transmission process, and is not limited here.

[0107] Please refer to Figures 3 and 4. In some embodiments, there are multiple first busbar groups 210. The multiple first busbar groups 210 are spaced apart in the second direction. First auxiliary connecting lines 61 are provided on both sides of the first busbar group 210. The substrate 10 has a third edge 123 and a fourth edge 124 in the second direction.

[0108] The plurality of first gate lines 20 also include a first edge bus gate line 203, wherein the first edge bus gate line 203 is the gate line closest to the third edge 123 in the first gate line 20 and the second gate line 30, and the first edge bus gate line 203 is continuous at both the first edge series region 131 and the second edge series region 141 and electrically connected to the first edge connection line 40; and / or

[0109] The first grid lines 20 also include second edge bus grid lines 204. Among the first grid lines 20 and the second grid lines 30, the second edge bus grid line 204 is the grid line closest to the fourth edge 124. The second edge bus grid line 204 is continuous at both the first edge connection area 131 and the second edge connection area 141 and is electrically connected to the first edge connection line 40.

[0110] Thus, by setting the first edge bus gate 203 and the second edge bus gate 204, the bus path can be further shortened and the bus transmission loss reduced. It is easy to understand that since the first edge bus gate 203 and the second edge bus gate 204 are continuous at the first edge connection area 131, an insulating layer also needs to be set on them. Therefore, through the above design, the effect of poor soldering caused by the insulating layer on the first edge bus gate 203 and the second edge bus gate 204 can be substantially reduced or even eliminated.

[0111] Of course, it is understood that in some embodiments, the first edge busbar 203 and the second edge busbar 204 may not be provided.

[0112] In this case, the first auxiliary connection line 61 located between the third edge 123 and the first busbar group 210 closest to the third edge 123 can connect all the second busbars 30 located between the third edge 123 and the first busbar group 210 closest to the third edge 123. And / or the first auxiliary connection line 61 located between the fourth edge 124 and the first busbar group 210 closest to the fourth edge 124 connects all the second busbars 30 located between the fourth edge 124 and the first busbar group 210 closest to the fourth edge 124.

[0113] In this way, the design can avoid the occurrence of poor solder joints at the starting and ending points of the solder strip at the upper and lower ends of the first edge connection area 131, which would otherwise lead to performance degradation.

[0114] Please refer to Figures 7 and 8. As described above, the first gate line 20 may include a first weld segment 201 corresponding to the second serial connection area 14, and the second gate line 30 may include a second weld segment 301 corresponding to the first edge serial connection area 131.

[0115] In some embodiments, a first groove 15 is formed on the substrate 10 within the first edge connection area 131, a first busbar 22 is partially located within the first groove 15, and a first insulating layer 51 is at least partially disposed within the first groove 15. In the thickness direction of the back contact battery 100 (i.e., the direction from the front side 11 to the back side 12), the height of the first insulating layer 51 is flush with the height of the second welding segment 301, or the height of the first insulating layer 51 is less than the height of the second welding segment 301, or the height of the first insulating layer 51 is greater than the height of the second welding segment 301, and the height difference between the first insulating layer 51 and the second welding segment 301 is less than or equal to 15 μm.

[0116] Thus, by forming a first groove 15 on the substrate 10 and placing the first insulating layer 51 in the groove, the height of the first insulating layer 51 can be less than the height of the second welding segment 301, or the first insulating layer 51 can be flush with the second welding segment 301, or the height of the first insulating layer 51 can be greater than the second welding segment 301 and the height difference between the two can be less than or equal to 15um, thereby further reducing the risk of poor soldering caused by the first insulating layer 51.

[0117] In some embodiments, the first groove 15 may penetrate the back passivation film layer 104 and the first doped layer 102, so that the silicon substrate 101 is exposed from the first groove 15, and the portion of the first bus gate line 22 located in the first groove 15 contacts the silicon substrate 101. In this way, the first groove 15 can be directly formed on the substrate 10 by etching (e.g., laser etching) after the substrate 10 is fabricated, without the need to insert an etching and grooving process during the fabrication of the substrate 10.

[0118] Specifically, in this case, a complete substrate 10 can be provided first, and then a groove can be made directly on the substrate 10 at the position where the first insulating layer 51 needs to be placed. Then, the first grid line 20 and the second grid line 30 are printed, and the first insulating layer 51 is set at the first groove 15.

[0119] Of course, in other embodiments, a first recessed groove may be formed on the silicon substrate 101 at the position corresponding to the first edge serial area 131 and the first bus gate line 22. The first doped layer 102 and the back passivation film layer 104 are both recessed at the first recessed groove toward the side where the front side 11 is located, so as to form a first groove 15 on the substrate 10.

[0120] Specifically, in this case, during the fabrication process, before preparing the first doped layer 102, a first recessed groove can be formed in the silicon substrate 101 at the location where the first doped layer 102 needs to be prepared and the first insulating layer 51 needs to be placed. Then, the first doped layer 102 and the back passivation film layer 104 are prepared to form the substrate 10. Since the first recessed groove is provided on the silicon substrate 101, the first groove 15 mentioned above can be formed on the substrate 10. Then, the first gate line 20 and the second gate line 30 are printed, and the first insulating layer 51 is placed at the first groove 15.

[0121] Referring to Figure 9, in some embodiments, at the first edge serial connection area 131, a first auxiliary connection layer 80 may be provided on the second grid line 30. The first auxiliary connection layer 80 is used for welding with the solder strip. In the thickness direction of the back contact battery 100, the first insulating layer 51 is flush with the first auxiliary connection layer 80, or the height of the first insulating layer 51 is less than the height of the first auxiliary connection layer 80, or the height difference between the first insulating layer 51 and the first auxiliary connection layer 80 is less than or equal to 15 μm.

[0122] Thus, by providing the first auxiliary connection layer 80 on the portion corresponding to the second gate line 30 and the first edge serial connection area 131, the height of the first insulating layer 51 can be less than the height of the first auxiliary connection layer 80, or the first insulating layer 51 can be flush with the first auxiliary connection layer 80, or the height of the first insulating layer 51 can be greater than the first auxiliary connection layer 80 and the height difference between the two can be less than or equal to 15um, thereby reducing the risk of poor soldering caused by the first insulating layer 51.

[0123] Specifically, in such an embodiment, the first auxiliary connection layer 80 may be stacked on the second soldering section 301. The first auxiliary connection layer 80 may be a conductive material layer such as solder paste layer, which is used to solder with the solder strip during the soldering process. No specific limitation is made here.

[0124] Referring to Figures 4 and 10, in some embodiments, the substrate 10 has a third edge 123 and a fourth edge 124 in a second direction. At the junction where the first edge busbar 203 connects to the first edge connecting line 40, the first edge connecting line 40 has a first protrusion 41 protruding toward the third edge 123.

[0125] Referring to Figures 4 and 11, in some embodiments, at the junction where the second edge busbar 204 connects to the first edge connecting line 40, the first edge connecting line 40 has a second protrusion 42 protruding toward the fourth edge 124.

[0126] Thus, the arrangement of the first protrusion 41 and the second protrusion 42 can provide redundancy for the first edge connecting line 40 at the corner of the back contact battery 100 located at the first edge 121, avoiding inaccurate printing during the printing process, which would prevent the paste from forming a complete fill at the corner and cause poor contact between the first edge connecting line 40 and the first edge busbar 203 and the second edge busbar 204.

[0127] Specifically, in some embodiments, a bus layer may be provided on the portion of the first edge bus line 203 and the second edge bus line 204 located between the second edge concatenation region 141 and the first edge 121, which can reduce bus losses.

[0128] Furthermore, as shown in Figures 10 and 11, in some embodiments, chamfers are formed at the intersections of the first edge 121, the third edge 123, and the fourth edge 124 in the back contact battery 100. A first grid line 20 is correspondingly provided at each chamfer. Therefore, as shown in Figures 10 and 11, in order to connect the first edge connecting line 40 to the first grid line 20, the first edge connecting line 40 has a bend at both chamfers. Of course, it is understood that in some embodiments, if the back contact battery 100 does not have chamfers, then a bend is unnecessary.

[0129] Referring to Figures 10 and 11, in some embodiments, at the junction of the first gate line 20 and the first edge connection line 40, at least a portion of the first gate line 20 has a first gate line protrusion 202 that protrudes toward the first edge 121 relative to the first edge connection line 40.

[0130] Thus, by setting the first grid line protrusion 202, the stability of the electrical connection between the first grid line 20 and the first edge connecting line 40 can be guaranteed, effectively avoiding the phenomenon that some of the first grid lines 20 cannot form a stable contact with the first edge connecting line 40 due to printing accuracy issues during the printing process.

[0131] Referring to Figures 3 and 4, in some embodiments, there are multiple first connecting gate lines 32. The number of first connecting gate lines 32 is the same as the number of first bus gate groups 210 and they correspond one-to-one. The multiple first connecting gate lines 32 are spaced apart along the second direction, and each first connecting gate line 32 corresponds to one first bus gate group 210. In the second edge serial connection area 141, second auxiliary connecting lines 62 are provided on both sides of the first bus gate group 210. Two first bus gate lines 22 in the first bus gate group 210 are respectively connected to one second auxiliary connecting line 62. In this way, the impact of the second insulating layer 52 on the two sides of the poor solder joint can be reduced.

[0132] Referring to Figures 3 and 4, in this embodiment, a second auxiliary connection line 62 located between two adjacent first busbar groups 210 connects all the first gate lines 20 located between two adjacent first busbar groups 210. This effectively eliminates the effects of poor soldering caused by the second insulating layer 52.

[0133] Of course, it is understood that in some embodiments, a second auxiliary connection line 62 may also be provided on one side of the first connecting gate line 32, which can also reduce the impact of poor soldering in some areas. Of course, in this application, it is preferable to provide the second auxiliary connection line 62 on both sides of the first connecting gate line 32.

[0134] In addition, in some alternative embodiments, when there are multiple first connecting gate lines 32, a second auxiliary connecting line 62 may be provided on at least one of some of the first connecting gate lines 32, while the second auxiliary connecting lines 62 may not be provided on both sides of the remaining first connecting gate lines 32. This can also reduce the impact of poor soldering in some areas.

[0135] In some embodiments, the width (length in the first direction) of the second auxiliary connection line 62 is greater than the width (length in the second direction) of the portion of the remaining first grid lines 20 other than the first busbar 22 located outside the second serial connection area 14 (i.e., the first solder section 201).

[0136] Thus, since the second auxiliary connection line 62 serves to transmit and combine current when a cold solder joint occurs, making the width of the second auxiliary connection line 62 wider can reduce transmission losses during the current combining process and improve efficiency.

[0137] Specifically, in such an embodiment, the width of the second auxiliary connecting line 62 may be the same as the width of the first welding segment 201.

[0138] Please refer to Figures 3, 4 and 7. In some embodiments, the plurality of first connecting regions 13 further include a third edge connecting region 132 adjacent to the second edge connecting region 141, the third edge connecting region 132 being located on the side of the second edge connecting region 141 away from the first edge 121.

[0139] The first connecting grid line 32 is continuous at the third edge concatenation area 132. The third edge concatenation area 132 is provided with a third auxiliary connecting line 90. In the second direction, the third auxiliary connecting line 90 connects the first connecting grid line 32 and at least one second grid line 30 located on both sides of the first connecting grid line 32.

[0140] Thus, by setting a third auxiliary connection line 90 in the third edge series connection area 132, the phenomenon that the current transmitted from the first connection grid line 32 cannot be collected can be effectively avoided by the solder strip in the third edge series connection area 132 having poor soldering or contact at the first connection grid line 32.

[0141] Specifically, as shown in Figures 4 and 7, in such an embodiment, the number of third auxiliary connecting lines 90 can be the same as the number of first connecting gate lines 32, with a one-to-one correspondence between the two. The third auxiliary connecting lines 90 connect to the first connecting gate lines 32, and also connect to the two second gate lines 30 adjacent to the first connecting gate lines 32.

[0142] In some embodiments, the width (length in the first direction) of the third auxiliary connection line 90 may be greater than the width (length in the second direction) of the portion of the second gate line 30 other than the portion located in the first serial area 13 (i.e., the portion other than the second solder section 301). Thus, setting the width of the third auxiliary connection line 90 to be wider can also reduce transmission losses during the bus operation and improve efficiency.

[0143] In some embodiments, the distance between the first edge concatenation area 131 and the first edge 121 is greater than or equal to 2 mm and less than or equal to 20 mm.

[0144] This avoids the situation where the distance between the first edge serial connection area 131 and the first edge 121 is too small, causing the welding position to be too close to the first edge 121 and resulting in microcracks in the back contact battery 100, thus reducing the risk of microcracks. It also avoids the situation where the distance between the first edge serial connection area 131 and the first edge 121 is too large, resulting in excessively long isolated grid line segments between the first edge serial connection area 131 and the first edge 121, leading to excessive losses during the transmission path.

[0145] Specifically, in such an embodiment, the distance between the first edge connecting area 131 and the first edge 121 can be, for example, any value between 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm or 2mm-20mm, and is not limited here.

[0146] Referring to Figures 3 and 12-15, in some embodiments, the plurality of second connecting regions 14 further include a fourth edge connecting region 142 closest to the second edge 122, and there is no first connecting region 13 between the fourth edge connecting region 142 and the second edge 122. That is, as shown in Figures 3 and 12, among the second connecting regions 14 and the first connecting regions 13, the connecting region closest to the second edge 122 is the second connecting region 14, and this second connecting region 14 is represented as the fourth edge connecting region 142, and there are no other connecting regions between the fourth edge connecting region 142 and the second edge 122.

[0147] The first serial connection area 13 also includes a fifth edge serial connection area 133 adjacent to the fourth edge serial connection area 142 (i.e. the first serial connection area 13 closest to the second edge 122 in Figures 3 and 12).

[0148] The plurality of second gate lines 30 includes at least one second bus gate line group 310, which includes two adjacent second bus gate lines 33. Among the plurality of second gate lines 30, the second bus gate line 33 is continuous at both the fourth edge concatenation region 142 and the fifth edge concatenation region 133, while at least a portion of the remaining second gate lines 30 are discontinuous at the fourth edge concatenation region 142 and continuous at the fifth edge concatenation region 133. For example, in some embodiments, all the second gate lines 30 except the second bus gate line 33 (including the second connecting gate line 23 mentioned above) are discontinuous at the fourth edge concatenation region 142 and continuous at the fifth edge concatenation region 133. For example, in some embodiments, the second gate line 30 may be discontinuous at the fourth edge concatenation region 142 and continuous at the fifth edge concatenation region 133, except for the second bus gate line 33 and the third edge bus gate line 303 described below.

[0149] As shown in Figures 3, 4, and 12, in the embodiments of this application, all first gate lines 20 are discontinuous at all first concatenation regions 13 except for the first edge concatenation region 131 and the fifth edge concatenation region 133, and all first gate lines 20 are continuous at all second concatenation regions 14. All second gate lines 30 are discontinuous at all other second concatenation regions 14 except for the second edge concatenation region 141 and the fourth edge concatenation region 142, and all second gate lines 30 are continuous at all first concatenation regions 13.

[0150] As shown in Figures 3 and 12, a plurality of first grid lines 20 include at least one second connecting grid line 23. The second connecting grid line 23 is located between two second bus grid lines 33 in the second bus grid group 310. Among the plurality of first grid lines 20, the second connecting grid line 23 is continuous at both the fourth edge concatenation region 142 and the fifth edge concatenation region 133, while the remaining first grid lines 20 are continuous at the fourth edge concatenation region 142 and discontinuous at the fifth edge concatenation region 133. The number of second bus grid groups 310 corresponds to the number of second connecting grid lines 23.

[0151] It should be noted that, as shown in Figures 3, 4, and 12, in the illustrated embodiments, the first connecting gate line 32 and the second bus gate line 33 are different gate lines. It is understood that in some embodiments, the first connecting gate line 32 and the second bus gate line 33 may also be the same gate line; that is, the first connecting gate line 32 can serve as a second bus gate line 33. This is not specifically limited here.

[0152] Furthermore, in the illustrated embodiment, the second connecting gate line 23 and the first bus gate line 22 are different gate lines. It is understood that in some embodiments, the second connecting gate line 23 and the first bus gate line 22 may also be the same gate line, that is, one first bus gate line 22 serves as one second connecting gate line 23.

[0153] The back contact battery 100 also includes a second edge connecting line 110, a third insulating layer 120, a fourth insulating layer 1210, a fourth auxiliary connecting line 130, and a fifth auxiliary connecting line 1310.

[0154] As shown in Figures 3 and 12, the second edge connection line 110 is closer to the second edge 122 than the fourth edge serial region 142. The second edge connection line 110 is electrically connected to the second bus gate line 33, and the second edge connection line 110 is also electrically connected to at least some of the gate lines in the other second gate lines 30 besides the second bus gate line 33. Specifically, to avoid microcracks in the battery caused by welding at the edge of the second edge 122, the second edge connecting line 110 is not used for welding. Instead, it is used to collect the current of the isolated portion of the second grid lines 30 (excluding the second bus grid line 33) located between the fourth edge series region 142 and the second edge 122. The current is then collected through the second bus grid line 33 onto the same polarity solder strip in the fifth edge series region 133 adjacent to the fourth edge series region 142. This collects the current of the isolated grid line segments in the edge region of the second grid lines 30 located at the second edge 122, improving the efficiency of the back contact battery 100. If the second edge connecting line 110 and the second bus grid line 33 are not provided, the portion of the second grid lines 30 (excluding the second bus grid line 33) located between the fourth edge series region 142 and the second edge 122 will form an isolated grid line segment, and the current in that portion will not be collected.

[0155] As shown in Figure 3, the third insulating layer 120 is disposed in the fourth edge serial connection area 142 and located on the second bus gate line 33. That is, the third insulating layer 120 is disposed on the part of the second bus gate line 33 corresponding to the fourth edge serial connection area 142. The third insulating layer 120 is disposed to insulate and separate the opposite polarity solder strip in the fourth edge serial connection area 142 from the second bus gate line 33 to avoid short circuit.

[0156] The fourth insulating layer 1210 is disposed within the fifth edge serial connection area 133 and located on the second connecting gate line 23. That is, the fourth insulating layer 1210 is disposed on the portion of the second connecting gate line 23 corresponding to the fifth edge serial connection area 133. The fourth insulating layer 1210 is disposed to insulate and separate the opposite polarity solder strips in the fifth edge serial connection area 133 from the second connecting gate line 23 to avoid short circuit.

[0157] As shown in Figures 3 and 12, a fourth auxiliary connection line 130 is disposed within the fourth edge concatenation area 142. In the second direction, at least one side of the second busbar 33 is provided with the fourth auxiliary connection line 130, which connects at least two first grid lines 20 located on the same side of the second busbar group 310. As shown in Figures 4 and 15, in some embodiments, the at least two first grid lines 20 connected to the fourth auxiliary connection line 130 preferably include the first grid line 20 adjacent to the second busbar group 310 (i.e., the first grid line 20 closest to the second busbar group 310 in Figures 3 and 12). That is, in some embodiments, the fourth auxiliary connection line 130 preferably connects to the first grid line 20 closest to the second busbar group 310, and the fourth auxiliary connection line 130 also connects to at least one of the remaining first grid lines 20 located on the same side as the first grid line 20. That is, the fourth auxiliary connection line 130 preferably connects at least one of the first grid line 20 adjacent to the second bus grid line group 310 and the remaining first grid lines 20 on the same side.

[0158] A fifth auxiliary connection line 1310 is disposed within the fifth edge concatenation area 133. In the second direction, at least one side of the second busbar group 310 is provided with a fifth auxiliary connection line 1310. The fifth auxiliary connection line 1310 connects the second busbar 33 located on one side of the second connecting busbar 23 and at least one second busbar 30 adjacent to the second busbar 33. That is, in some embodiments, the fifth auxiliary connection line 1310 is connected to the second busbar 33 located on one side of the second connecting busbar 23 and at least one second busbar 30 adjacent to the second busbar 33.

[0159] Thus, by setting the second edge connection line 110 and the second busbar group 310, the current collected by at least a portion of the isolated segment of the second grid line 30 located between the fourth edge series region 142 and the second edge 122 can be channeled to the same polarity solder strip in the fifth edge series region 133 adjacent to the fourth edge series region 142. This can effectively avoid microcracks caused by soldering at the second edge 122 of the back contact battery 100 while ensuring the efficiency of the back contact battery 100. The third insulating layer 120 can achieve insulation between the solder strip in the fourth edge series area 142 and the second busbar 33. With the fourth auxiliary connection line 130, even if the first grid line 20 near the third insulating layer 120 has a poor solder joint due to the setting of the third insulating layer 120, the poorly soldered first grid line 20 can still achieve current busbar output through the fourth auxiliary connection line 130, thereby reducing or even eliminating the poor solder joint effect caused by the third insulating layer 120, and thus ensuring the efficiency of the back contact battery 100.

[0160] The second busbar group 310 is configured to include two adjacent second busbars 33, with the third insulating layers 120 on the two second busbars 33 being adjacent. This reduces the radiation area of ​​the cold solder joint caused by the first insulating layer 51, further reducing the risk of cold solder joints. The continuous design of the second connecting grid line 23 in the fifth edge series connection area 133 can prevent the second connecting grid line 23 from having a cold solder joint, which would prevent its current from being collected. The design of the fourth insulating layer 1210 can insulate the second connecting grid line 23. Through the design of the fifth auxiliary connecting line 1310, even if the first grid line 20 near the fourth insulating layer 1210 has a cold solder joint with the solder strip due to the setting of the fourth insulating layer 1210, the first grid line 20 with a cold solder joint can still achieve current collection and output through the fifth auxiliary connecting line 1310, reducing or even eliminating the impact of the cold solder joint caused by the fourth insulating layer 1210, thereby ensuring the efficiency of the back contact battery 100.

[0161] In other words, by making a special design to the electrode structure on the back side of the back contact battery 100 near the second edge 122, this application can reduce or even eliminate the effects of poor soldering caused by the third insulating layer 120 and the fourth insulating layer 1210, thereby improving the electrical performance of the back contact battery 100 and ensuring the efficiency of the back contact battery 100.

[0162] As shown above, it is easy to understand that in this application, the second edge connection line 110 is not used for welding; it is only used for current transmission and merging. The function of the second bus gate line 33 is to collect and transmit current. As can be seen from Figures 3 and 12, in the examples shown in Figures 3 and 12, if the second edge connection line 110 and the second bus gate line 33 are not provided, part of the second gate line 30 will be broken at the fourth edge connection area 142. The current of the part of the gate line segment of the broken second gate line 30 located between the fourth edge connection area 142 and the second edge 122 cannot be collected. Therefore, by providing the second edge connection line 110 and the second bus gate line 33, the current of at least part of the isolated gate line segment of the second gate line 30 located in the edge region can be merged and transmitted to the solder strip provided in the adjacent fourth edge connection area 142, thereby effectively avoiding efficiency loss.

[0163] Because the second busbar 33 is continuously arranged in the fourth edge series connection area 142, in order to avoid short circuits caused by contact between the solder strips on the fourth edge series connection area 142 and the second busbar 33, a third insulating layer 120 (e.g., insulating adhesive) needs to be provided at the position corresponding to the second busbar 33 and the fourth edge series connection area 142. The height of the third insulating layer 120 is greater than the height of the first gate line 20 (including the second connecting gate line 23), that is, in the thickness direction, the protrusion height of the third insulating layer 120 is greater than the height of the first gate line 20. Under such circumstances, the solder strips in the fourth edge series connection area 142 are prone to poor soldering with the first gate line 20 during the soldering process, resulting in some of the current on the first gate line 20 not being able to flow. Effective collection (especially of the first grid line 20 adjacent to the second bus grid line 33, which is most likely to have a cold solder joint). Based on this, this application connects at least two first grid lines 20 on the same side of the second bus grid line 33 by setting a fourth auxiliary connection line 130, and preferably selects the first grid line 20 connected to it to include the one adjacent to the second bus grid line 33. It can connect part of the first grid lines 20 into a whole at the fourth edge series connection area 142 through the fourth auxiliary connection line 130. Even if one of the first grid lines 20 has a cold solder joint due to the presence of the third insulating layer 120, it can still achieve current output through the fourth auxiliary connection line 130, thereby reducing or even completely eliminating the impact of the cold solder joint.

[0164] Furthermore, since the second connecting gate line 23 is located between the two third insulating layers 120, it is at the greatest risk of poor soldering. If the second connecting gate line 23 is interrupted at the fifth edge series connection area 133, isolated segments are likely to occur, causing the current in that part to be unable to be collected. Therefore, by making the second connecting gate line 23 continuous at the fifth edge series connection area 133, the problem of isolated segments causing some current to be unable to be collected can be avoided.

[0165] Since the second connecting gate line 23 is continuous in both the fourth edge series region 142 and the fifth edge series region 133, a fourth insulating layer 1210 (e.g., insulating adhesive) is required at the positions corresponding to the second connecting gate line 23 and the fifth edge series region 133 to prevent short circuits caused by contact between the solder strip on the fifth edge series region 133 and the second connecting gate line 23. The height of the fourth insulating layer 1210 is greater than the height of the second gate line 30; that is, in the thickness direction, the protrusion height of the fourth insulating layer 1210 is greater than the height of the second gate line 30. Under these circumstances, the solder strip in the fifth edge series region 133 is prone to poor soldering with the second gate line 30 during the soldering process, resulting in some current on the second gate line 30 not being effectively collected, especially with the second connecting gate line 23. The second gate line 30 (i.e., the second bus gate line 33) adjacent to the gate line 23 is most likely to have a cold solder joint. Based on this, this application connects the second bus gate line 33 on one side of the second connecting gate line 23 and at least one second gate line 30 adjacent to the second bus gate line 33 by setting a fifth auxiliary connecting line 1310. The fifth auxiliary connecting line 1310 can connect the second bus gate line 33 and the remaining at least one second gate line 30 into a whole at the fifth edge series connection area 133. Even if the presence of the fourth insulating layer 1210 causes a cold solder joint in one of the first gate lines 20, it can still achieve current output through the fifth auxiliary connecting line 1310, thereby reducing or even completely eliminating the cold solder joint effect caused by the fourth insulating layer 1210.

[0166] As shown in Figures 3 and 12, in the embodiments of this application, in order to minimize the impact of poor soldering, when at least two first grid lines 20 are provided on both sides of the second busbar group 310, it is preferable to simultaneously provide a fourth auxiliary connection line 130 on both sides of the second busbar group 310. Of course, if the second busbar group 310 is located at the outermost edge in the second direction, the fourth auxiliary connection line 130 can be provided on one side of the second busbar group 310.

[0167] In some embodiments, the width (i.e. the length in the second direction) of the second bus gate 33 may be greater than the width (i.e. the length in the second direction) of the portion of the remaining second gates 30 other than the second bus gate 33 located outside the first serial area 13 (i.e. the portion other than the second solder section 301).

[0168] Therefore, since the second bus gate 33 needs to undertake the function of current collection and transmission, setting the width of the second bus gate 33 to be wider can reduce transmission loss during the current collection process and improve efficiency. The second welding section 301 is used for welding; setting the width of the second welding section 301 to be wider can improve the reliability and stability of the welding process. The width of the second bus gate 33 can be the same as the width of the second welding section 301.

[0169] Furthermore, as shown in Figures 3, 12, and 15, in some embodiments, the second bus gate line 33 is continuous only at the fourth edge concatenation region 142, and is broken at other second concatenation regions 14. Of course, in some embodiments, as described above, when the second bus gate line 33 and the first connecting gate line 32 are the same gate line, the second bus gate line 33 is continuous at the second edge concatenation region 141.

[0170] The second busbar 33 is continuous at the fourth edge junction area 142, and only the segment of the second busbar 33 closest to the second edge 122 (i.e., the portion located between the fifth edge junction area 133 and the second edge 122) performs the busbar function. Therefore, in some embodiments, in order to save slurry and reduce costs, only this portion of the busbar segment can be made wider.

[0171] In this case, referring to Figures 3, 12, and 15, the second busbar 33 may include a second bus segment 331 located between the fifth edge concatenation region 133 and the second edge 122. In some embodiments, the width of the second bus segment 331 (i.e., its length in the second direction) may be greater than the width of the remaining portion of the second busbar 33 located outside the first concatenation region 13 (i.e., the portion other than the second bus segment 331 excluding the second weld segment 301).

[0172] Thus, by simply making the width of the second busbar 331 wider, the amount of slurry used can be reduced while reducing busbar transmission loss, thereby reducing costs.

[0173] Specifically, as described above, in such an embodiment, the second bus 331 can channel current to the solder strip located at the fifth edge series region 133, and making only a portion of the second bus 331 wider can reduce the amount of paste used. In this case, the second bus 331 penetrates the back passivation film layer 104 and contacts the first doped layer 102.

[0174] Referring to Figure 15, in some embodiments, a second bus layer 140 may be provided on the second bus section 331. Thus, by providing the second bus layer 140 on the second bus section 331, the cross-sectional area of ​​the second bus section 331 is effectively increased, which can also reduce transmission losses. Furthermore, the second bus layer 140 can be manufactured using a lower-cost paste than the second bus section 331, thereby reducing costs.

[0175] Specifically, in such an embodiment, the second busbar 33 can be a regular busbar, with the width being the same at all positions except for the wider width at the second welding section 301. By providing the second bus layer 140 on the second bus section 331, the cross-sectional area of ​​the second bus section 331 is effectively increased. That is, because the second bus layer 140 is provided on the second bus section 331, it is not necessary to widen the second bus section 331 to achieve the same goal of reducing transmission loss. Of course, in some embodiments, the second bus section 331 may be widened; this is not limited here.

[0176] The second bus layer 140 can be made of a non-burn-through paste. The second bus layer 140 does not penetrate the back passivation film layer 104 and contact the first doped layer 102. The paste cost of the second bus layer 140 is lower than that of the second bus section 331. For example, when neither the second bus layer 140 nor the second bus section 331 has a silver paste layer, the silver content in the second bus layer 140 can be lower than that in the second bus section 331. Alternatively, the second bus section 331 can be a silver paste layer, while the second bus layer 140 can be a copper layer, a silver-coated copper layer, or other lower-cost metal layers.

[0177] Furthermore, in such an embodiment, the width (length in the second direction) of the second bus layer 140 may be greater than the width (length in the second direction) of the portion of the remaining second gate lines 30 other than the second bus gate line 33 located outside the first serial area 13 (i.e., the portion other than the second solder section 301). Thus, by increasing the width of the second bus layer 140, the transmission capacity can be further improved and the transmission loss reduced.

[0178] In such an embodiment, the width of the second busbar 140 may be the same as the width of the second weld segment 301. Hereinafter, the width of the second weld segment 301 refers to its length in the second direction. As shown above, when the width of the first weld layer is greater than the width of the first collection layer, the width of the second weld segment 301 is the width of the first weld layer (i.e., its length in the second direction). Similar descriptions will appear below and can be understood here.

[0179] This ensures that there will be no significant transmission loss during the convergence process. Simultaneously, during printing, the second convergence layer 140 can be printed simultaneously with the first welding layer at the second welding section 301. When using the same screen printing plate, there is no need to create screen slots of different sizes on the screen, saving manufacturing steps and reducing manufacturing difficulty.

[0180] Referring to Figure 15, in some embodiments, the width (length in the first direction) of the second edge connection line 110 is greater than the width (length in the second direction) of the portion of the remaining second gate lines 30 other than the second bus gate line 33 located outside the first serial area 13 (i.e., the portion of the remaining second gate lines 30 other than the second bus gate line 33 excluding the second weld segment 301).

[0181] Therefore, since the second edge connection line 110 needs to undertake the function of bus transmission, setting the width of the second edge connection line 110 to be wider can also reduce transmission loss during the bus process and improve efficiency.

[0182] Specifically, in such an embodiment, the width of the second edge connecting line 110 can be the same as the width of the second welding segment 301. This ensures that no significant current loss occurs during the merging process.

[0183] Furthermore, referring to FIG15, in some embodiments, the width (length in the first direction) of the fourth auxiliary connection line 130 is greater than the width (length in the second direction) of the portion of the first gate line 20 located outside the second serial area 14 (the portion of the first gate line 20 excluding the first solder segment 201).

[0184] Thus, since the fourth auxiliary connection line 130 serves to transmit and combine current when a cold solder joint occurs, making the width of the fourth auxiliary connection line 130 wider can reduce transmission losses during the current combining process and improve efficiency.

[0185] In some embodiments, the width of the fourth auxiliary connecting line 130 may be the same as the width of the second edge connecting line 110, and the widths of both may be the same as the widths of the second welding segment 301 and the first welding segment 201.

[0186] Referring to Figures 3 and 12, in some embodiments, the second edge connection line 110 is electrically connected to all the second gate lines 30.

[0187] In this way, the current collected by all isolated grid line segments except the second grid line 30 located between the fourth edge series region 142 and the second edge 122 can be combined to maximize the efficiency of the back contact battery 100.

[0188] Of course, in some embodiments, the second edge connection line 110 may only be electrically connected to a portion of the remaining second gate lines 30, excluding the second bus gate line 33. In such cases, the number of second gate lines 30 not electrically connected to the second edge connection line 110 is less than or equal to four. Thus, even if some of the second gate lines 30 are not connected to the second edge connection line 110, their number is very small and will not cause excessive efficiency loss or product defects.

[0189] In some embodiments, the fourth auxiliary connection line 130 connects 2 to 20 first gate lines 20. Thus, by setting the number of first gate lines 20 connected to the fourth auxiliary connection line 130 within this reasonable range, the impact of poor soldering can be minimized or even eliminated.

[0190] In embodiments of this application, the number of second busbar groups 310 may be single. In such cases, the fourth auxiliary connection line 130 may be provided only on one side of the second busbar group 310, or the fourth auxiliary connection line 130 may be provided on both sides of the second busbar group 310; no specific limitation is imposed here. When at least two first grid lines 20 are provided on both sides of the second busbar group 310, it is preferable to provide the fourth auxiliary connection line 130 on both sides.

[0191] Furthermore, it should be noted that in this application, when there are multiple second busbar groups 310, the fourth auxiliary connection line 130 may only be provided on one or both sides of some of the second busbar groups 310, while the fourth auxiliary connection line 130 may not be provided on both sides of the remaining second busbar groups 310. In this case, the problem of cold solder joints in some locations can still be solved. In this application, it is preferable that the fourth auxiliary connection line 130 is provided on both sides of each second busbar group 310. Of course, if the second busbar group 310 is located at the third edge 123, then the fourth auxiliary connection line 130 only needs to be provided on one side of the second busbar group 33.

[0192] Of course, referring to Figures 3 and 12, in some embodiments, there are multiple second bus gate groups 310, which are spaced apart in the second direction. Thus, providing multiple second bus gate groups 310 can shorten the current bus path, effectively reduce bus transmission losses, and improve efficiency.

[0193] In this case, a fourth auxiliary connection line 130 is provided on both sides of the second busbar group 310, and a fourth auxiliary connection line 130 is provided between two adjacent second busbar groups 310. The fourth auxiliary connection line 130 located between two adjacent second busbar groups 310 connects all the first grid lines 20 located between two adjacent second busbar groups 310.

[0194] In this way, by connecting the fourth auxiliary connection line 130 to all the first grid lines 20 between two adjacent second busbar groups 310, the influence of poor soldering can be basically completely eliminated, and the efficiency of the back contact battery 100 can be improved as much as possible.

[0195] Specifically, in such an embodiment, the number of the second busbar group 310 in the back contact battery 100 can be selected according to the actual situation such as the size of the battery cell and the loss during the transmission process, and is not limited here.

[0196] Please refer to Figures 3 and 12. In some embodiments, there are multiple second busbar groups 310. The multiple second busbar groups 310 are spaced apart in the second direction. A fourth auxiliary connecting line 130 is provided on both sides of the second busbar group 310. The substrate 10 has a third edge 123 and a fourth edge 124 in the second direction.

[0197] The second gate lines 30 also include a third edge bus gate line 303, which is located between the third edge 123 and the second bus gate line group 310 closest to the third edge 123. The third edge bus gate line 303 is continuous at both the fourth edge series region 142 and the fifth edge series region 133 and is electrically connected to the second edge connection line 110; and / or

[0198] The second grid lines 30 also include a fourth edge bus grid line 304, which is located between the fourth edge 124 and the second bus grid line group 310 closest to the fourth edge 124. The fourth edge bus grid line 304 is continuous at both the fourth edge series region 142 and the fifth edge series region 133 and is electrically connected to the second edge connection line 110.

[0199] Thus, by setting the third edge bus gate 303 and the fourth edge bus gate 304, the bus path can be further shortened and the bus transmission loss can be reduced.

[0200] Specifically, it is easy to understand that since the third edge busbar 303 and the fourth edge busbar 304 are continuous at the fourth edge junction area 142, an insulating layer also needs to be provided on them. Therefore, as shown in Figures 3 and 12, an auxiliary connecting line can also be provided between the third edge busbar 303 and the third edge 123 within the fourth edge junction area 142. This auxiliary connecting line can connect all the first gate lines 20 between the third edge busbar 303 and the third edge 123. Similarly, an auxiliary connecting line can also be provided between the fourth edge busbar 304 and the fourth edge 124 within the fourth edge junction area 142. This auxiliary connecting line can connect all the first gate lines 20 between the fourth edge busbar 304 and the fourth edge 124. In this way, through such a design, the effect of poor soldering caused by the insulating layer on the third edge busbar 303 and the fourth edge busbar 304 can be basically reduced or even eliminated.

[0201] Of course, it is understood that in some embodiments, the third edge busbar 303 and the fourth edge busbar 304 may not be provided.

[0202] In this configuration, a fourth auxiliary connection line 130 located between the third edge 123 and the second busbar group 310 closest to the third edge 123 can connect all the first grid lines 20 located between the third edge 123 and the second busbar group 310 closest to the third edge 123. And / or a fourth auxiliary connection line 130 located between the fourth edge 124 and the second busbar group 310 closest to the fourth edge 124 can connect all the first grid lines 20 located between the fourth edge 124 and the second busbar group 310 closest to the fourth edge 124.

[0203] In this way, the design can avoid the occurrence of poor solder joints at the starting and ending points of the solder strip at the upper and lower ends of the fourth edge serial connection area 142, which would otherwise lead to performance degradation.

[0204] Please refer to Figures 15 and 16. As described above, the second gate line 30 may include a second weld segment 301 corresponding to the first serial connection area 13, and the first gate line 20 includes a first weld segment 201 corresponding to the fourth edge serial connection area 142.

[0205] In some embodiments, a second groove 16 is formed on the substrate 10 within the fourth edge serial connection area 142, a second busbar 33 is partially located within the second groove 16, and a third insulating layer 120 is at least partially disposed within the second groove 16. In the thickness direction of the back contact battery 100 (i.e., the direction from the front side 11 to the back side 12), the height of the third insulating layer 120 is flush with the height of the first welding segment 201, or the height of the third insulating layer 120 is less than the height of the first welding segment 201, or the height of the third insulating layer 120 is greater than the height of the first welding segment 201, and the height difference between the third insulating layer 120 and the first welding segment 201 is less than or equal to 15 μm.

[0206] Thus, by forming a second groove 16 on the substrate 10 and placing the third insulating layer 120 inside the groove, the height of the third insulating layer 120 can be less than the height of the first welding segment 201, or the third insulating layer 120 can be flush with the first welding segment 201, or the height of the third insulating layer 120 can be greater than the first welding segment 201 and the height difference between the two can be less than or equal to 15um, thereby further reducing the risk of poor soldering caused by the third insulating layer 120.

[0207] In some embodiments, the second groove 16 may penetrate the back passivation film layer 104 and the second doped layer 103, so that the silicon substrate 101 is exposed from the second groove 16, and the portion of the second bus gate line 33 located within the second groove 16 contacts the silicon substrate 101. Thus, after the substrate 10 is fabricated, the second groove 16 can be directly formed on the substrate 10 by etching (e.g., laser etching), without needing to insert an etching and grooving process during the fabrication of the substrate 10.

[0208] Specifically, in this case, a complete substrate 10 can be provided first, and then a groove can be made directly on the substrate 10 at the position where the third insulating layer 120 needs to be placed. Then, the second grid line 30 and the first grid line 20 are printed, and then the third insulating layer 120 is set at the second groove 16.

[0209] Of course, in other embodiments, a second recessed groove may be formed on the silicon substrate 101 at the position corresponding to the fourth edge serial region 142 and the second bus gate line 33. The second doped layer 103 and the back passivation film layer 104 are both recessed at the second recessed groove toward the side where the front side 11 is located, so as to form a second groove 16 on the substrate 10.

[0210] Specifically, in this case, during the fabrication process, before preparing the first doped layer 102, a second recessed groove can be formed in the silicon substrate 101 at the location where the second doped layer 103 needs to be prepared and the third insulating layer 120 needs to be placed. Then, the first doped layer 102 and the back passivation film layer 104 are prepared to form the substrate 10. Since the second recessed groove is formed on the silicon substrate 101, the second groove 16 mentioned above can be formed on the substrate 10. Then, the second gate line 30 and the first gate line 20 are printed, and the third insulating layer 120 is placed at the second groove 16.

[0211] Referring to Figure 17, in some embodiments, a second auxiliary connection layer 150 may be provided on the first grid line 20 at the fourth edge serial connection area 142. The second auxiliary connection layer 150 is used for welding with the solder strip. In the thickness direction of the back contact battery 100, the third insulating layer 120 is flush with the second auxiliary connection layer 150, or the height of the third insulating layer 120 is less than the height of the second auxiliary connection layer 150, or the height of the third insulating layer 120 is greater than the height of the second auxiliary connection layer 150, and the height difference between the third insulating layer 120 and the second auxiliary connection layer 150 is less than or equal to 15 μm.

[0212] Thus, by providing a second auxiliary connection layer 150 on the portion corresponding to the first gate line 20 and the fourth edge serial connection area 142, the height of the third insulating layer 120 can be less than the height of the second auxiliary connection layer 150, or the third insulating layer 120 can be flush with the second auxiliary connection layer 150, or the height of the third insulating layer 120 can be greater than the second auxiliary connection layer 150 and the height difference between the two can be less than or equal to 15um, thereby reducing the risk of poor soldering caused by the third insulating layer 120.

[0213] Specifically, in such an embodiment, the second auxiliary connection layer 150 may be stacked on the first soldering section 201. The second auxiliary connection layer 150 may be a conductive material layer such as solder paste layer, which is used to solder with the solder strip during the soldering process. No specific limitation is made here.

[0214] Referring to Figures 12, 18, and 19, in some embodiments, the second edge connecting line 110 may include an intermediate busbar 113, a first edge busbar 111, and a second edge busbar 112. All three extend along the second direction, as shown in Figure 12, and may be arranged parallel to each other at intervals along the first direction. The intermediate busbar 113 is closer to the second edge 122 than the first edge busbar 111 and the second edge busbar 112.

[0215] The first edge merging segment 111 is disposed near the third edge 123, and the second edge merging segment 112 is disposed near the fourth edge 124. The second edge connecting line 110 also includes a first connecting segment 114 and a second connecting segment 115, both of which extend along a first direction. The first connecting segment 114 connects the intermediate merging segment 113 and the first edge merging segment 111, and the second connecting segment 115 connects the intermediate merging segment 113 and the second edge merging segment 112.

[0216] Wherein, the first edge merging segment 111 connects the two second gate lines 30 closest to the third edge 123; at the junction of the first edge merging segment 111 and the first connecting segment 114, the first edge merging segment 111 has a third protrusion 1101 protruding towards the fourth edge 124; the first connecting segment 114 has a fourth protrusion 1102 protruding towards the first edge 121; at the junction of the intermediate merging segment 113 and the first connecting segment 114, the intermediate merging segment 113 has a fifth protrusion 1103 protruding towards the third edge 123; and the first connecting segment 114 has a sixth protrusion 1104 protruding towards the second edge 122; and / or

[0217] The second edge merging segment 112 connects the two second grid lines 30 closest to the fourth edge 124. At the junction of the second edge merging segment 112 and the second connecting segment 115, the second edge merging segment 112 has a seventh protrusion 1105 protruding towards the third edge 123. The second connecting segment 115 has an eighth protrusion 1106 protruding towards the first edge 121. At the junction of the intermediate merging segment 113 and the second connecting segment 115, the intermediate merging segment 113 has a ninth protrusion 1107 protruding towards the fourth edge 124. The second connecting segment 115 has a tenth protrusion 1108 protruding towards the second edge 122.

[0218] Thus, when there is a chamfer at the connection between the second edge 122 and the third edge 123 and the fourth edge 124, the chamfer can be avoided by setting the connecting line 110 of the second edge into a structure of 3 vertical segments + 2 horizontal segments, reducing the printing difficulty. At the same time, setting corresponding protrusions at the junctions of each confluence segment can provide redundancy at the corners of the second edge 122, avoiding inaccurate printing during the printing process that would prevent the paste from forming a complete fill at the corners and cause poor contact between the confluence segments.

[0219] Of course, it is understood that in some embodiments, when a chamfer is formed at the intersection of the second edge 122, the third edge 123, and the fourth edge 124, the second edge connecting line 110 can also be configured in the same way as the first edge connecting line 40 (e.g., with a bend), and no specific limitation is made here. Of course, it is understood that in some embodiments, if the back contact battery 100 does not have a chamfer, then only a second edge connecting line 110 extending vertically continuously along the second direction needs to be provided.

[0220] Referring to Figures 18 and 19, in some embodiments, at the junction of the second gate line 30 and the second edge connection line 110, at least a portion of the second gate line 30 has a second gate line protrusion 302 that protrudes toward the second edge 122 relative to the second edge connection line 110.

[0221] Thus, by setting the second grid line protrusion 302, the stability of the electrical connection between the second grid line 30 and the second edge connecting line 110 can be guaranteed, effectively avoiding the phenomenon that some of the second grid lines 30 cannot form a stable contact with the second edge connecting line 110 due to printing accuracy issues during the printing process.

[0222] Referring to Figures 3 and 12, in some embodiments, there are multiple second connecting gate lines 23. The number of second connecting gate lines 23 is the same as the number of second bus gate groups 310 and they correspond one-to-one. The multiple second connecting gate lines 23 are spaced apart along the second direction, and each second connecting gate line 23 corresponds to one second bus gate group 310. In the fifth edge serial connection area 133, fifth auxiliary connecting lines 1310 are provided on both sides of the second bus gate group 310. Two second bus gate lines 33 in the second bus gate group 310 are respectively connected to one fifth auxiliary connecting line 1310. In this way, the impact of the fourth insulating layer 1210 on the cold solder joints on both sides can be reduced.

[0223] Referring to Figures 3 and 12, in this embodiment, a fifth auxiliary connection line 1310 located between two adjacent second busbar groups 310 connects all the second gate lines 30 located between two adjacent second busbar groups 310. This effectively eliminates the solder joint effects caused by the fourth insulating layer 1210.

[0224] Of course, it is understood that in some embodiments, a fifth auxiliary connection line 1310 may also be provided on one side of the second connection gate line 23, which can also reduce the impact of poor soldering in some areas. Of course, in this application, it is preferable to provide the fifth auxiliary connection line 1310 on both sides of the second connection gate line 23.

[0225] In addition, in some alternative embodiments, when there are multiple second connecting gate lines 23, a fifth auxiliary connecting line 1310 may be provided on at least one of some of the second connecting gate lines 23, while the fifth auxiliary connecting line 1310 may not be provided on both sides of the remaining second connecting gate lines 23. This can also reduce the impact of poor soldering in some areas.

[0226] In some embodiments, the width (length in the first direction) of the fifth auxiliary connection line 1310 is greater than the width (length in the second direction) of the portion of the remaining second grid lines 30 other than the second busbar 33 located outside the first serial area 13 (i.e., the second solder section 301).

[0227] Thus, since the fifth auxiliary connection line 1310 serves to transmit and combine current when a cold solder joint occurs, making the width of the fifth auxiliary connection line 1310 wider can reduce transmission losses during the current combining process and improve efficiency.

[0228] Specifically, in such an embodiment, the width of the fifth auxiliary connecting line 1310 may be the same as the width of the second welding segment 301.

[0229] Please refer to Figures 3, 12 and 15. In some embodiments, the plurality of second serialization areas 14 further include a sixth edge serialization area 143 adjacent to the fifth edge serialization area 133, the sixth edge serialization area 143 being located on the side of the fifth edge serialization area 133 away from the second edge 122.

[0230] The second connecting grid line 23 is continuous at the sixth edge concatenation area 143. The sixth edge concatenation area 143 is provided with a sixth auxiliary connecting line 160. In the second direction, the sixth auxiliary connecting line 160 connects the second connecting grid line 23 and at least one first grid line 20 located on both sides of the second connecting grid line 23.

[0231] Thus, by setting a sixth auxiliary connection line 160 in the sixth edge series connection area 143, the phenomenon that the current transmitted from the second connection grid line 23 cannot be collected can be effectively avoided by the solder strip in the sixth edge series connection area 143 having poor soldering or contact at the second connection grid line 23.

[0232] Specifically, as shown in Figures 12 and 15, in such an embodiment, the number of sixth auxiliary connecting lines 160 can be the same as the number of second connecting gate lines 23, with a one-to-one correspondence between the two. The sixth auxiliary connecting line 160 connects to the second connecting gate line 23, and also connects to the two first gate lines 20 adjacent to the second connecting gate line 23.

[0233] In some embodiments, the width (length in the first direction) of the sixth auxiliary connection line 160 may be greater than the width (length in the second direction) of the portion of the first gate line 20 excluding the portion located in the second serial area 14 (i.e., the portion excluding the first solder section 201). Thus, setting the width of the sixth auxiliary connection line 160 to be wider can also reduce transmission losses during the bus operation and improve efficiency.

[0234] In some embodiments, the distance between the fourth edge concatenation area 142 and the second edge 122 is greater than or equal to 2 mm and less than or equal to 20 mm.

[0235] This avoids the situation where the distance between the fourth edge series connection area 142 and the second edge 122 is too small, causing the welding position to be too close to the second edge 122 and resulting in microcracks in the back contact battery 100, thus reducing the risk of microcracks. It also avoids the situation where the distance between the fourth edge series connection area 142 and the second edge 122 is too large, resulting in excessively long isolated grid line segments between the fourth edge series connection area 142 and the second edge 122, leading to excessive losses during the transmission path.

[0236] Specifically, in such an embodiment, the distance between the fourth edge connecting area 142 and the second edge 122 can be, for example, any value between 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm or 2mm-20mm, and is not limited here.

[0237] In the above embodiments, the fourth edge connection region 142 has the opposite polarity to the first edge connection region 131, the fifth edge connection region 133 has the opposite polarity to the second edge connection region 141, and the sixth edge connection region 143 has the opposite polarity to the third edge connection region 132. The contact structures of the two edges of the back contact battery 100 in the first direction are different and asymmetrical.

[0238] It is understood that in some possible embodiments, the polarity of the fourth edge connection area 142 may be the same as that of the first edge connection area 131, the polarity of the fifth edge connection area 133 may be the same as that of the second edge connection area 141, and the polarity of the sixth edge connection area 143 may be the same as that of the third edge connection area 132. In this case, the structures of the two edges of the back contact battery 100 in the first direction are the same and symmetrical. That is to say, in this case, in the back contact battery 100, the three connection areas closest to the second edge 122 are symmetrical to the first edge connection area 131, the second edge connection area 141 and the third edge connection area 132. The edge connecting line, auxiliary connecting line and other structures are also provided on one side of the second edge 122, which is completely symmetrical to one side of the first edge 121. To avoid being verbose, the specific structure will not be described in detail here.

[0239] Referring to Figure 3, in some embodiments, the substrate 10 has a third edge 123 and a fourth edge 124 in the second direction. A seventh auxiliary connection line 170 and an eighth auxiliary connection line 180 may also be provided in the first connection area 13 other than the first edge connection area 131 and the fifth edge connection area 133. The seventh auxiliary connection line 170 connects the N second gate lines 30 closest to the third edge 123, and the eighth auxiliary connection line 180 connects the M second gate lines 30 closest to the fourth edge 124, wherein N and M are both greater than or equal to 2 and less than or equal to 8.

[0240] In some embodiments, a ninth auxiliary connection line 190 and a tenth auxiliary connection line 1100 may be provided in the second serial connection area 14 other than the second edge serial connection area 141 and the fourth edge serial connection area 142. The ninth auxiliary connection line 190 connects to the P first gate lines closest to the third edge, and the tenth auxiliary connection line 1100 connects to the Q first gate lines closest to the fourth edge, wherein P and Q are both greater than or equal to 2 and less than or equal to 8.

[0241] Thus, by setting the seventh auxiliary connecting line 170 and the eighth auxiliary connecting line 180 at the beginning and end of the solder strip in the first series-connection area 13 of the intermediate zone, the problem of some grid lines' current not being collected can be effectively avoided due to poor soldering at the start and end points of the solder strip in the first series-connection area 13. Similarly, by setting the ninth auxiliary connecting line 190 and the tenth auxiliary connecting line 1100 at the positions near the third edge 123 and the fourth edge 124 of the second series-connection area 14 of the intermediate zone, that is, by setting the ninth auxiliary connecting line 190 and the tenth auxiliary connecting line 1100 at the beginning and end of the solder strip in the second series-connection area 14, the problem of some grid lines' current not being collected can be effectively avoided due to poor soldering at some positions of the start and end points of the solder strip in the second series-connection area 14.

[0242] Referring to Figure 3, in some embodiments, within the first serial connection region 13, the X first gate lines 20 closest to the third edge 123 are interrupted at the first serial connection region 13, and the Y first gate lines 20 closest to the fourth edge 124 are interrupted at the first serial connection region 13. The width of the interrupted region formed by the X first gate lines 20 closest to the third edge 123 gradually increases in the direction towards the third edge 123, and the width of the interrupted region formed by the Y first gate lines 20 closest to the fourth edge 124 gradually increases in the direction towards the fourth edge 124, wherein both X and Y are greater than or equal to 2. That is, in such an embodiment, in the first serial connection region 13, among the at least two second gate lines 30 closest to the third edge 123, the second weld segment 301 on the second gate line 30 closest to the third edge 123 is wider in the second direction. In the at least two second gate lines 30 closest to the fourth edge 124, the second weld segment 301 on the second gate line 30 closest to the fourth edge 124 is wider in the second direction.

[0243] Within the second serial connection region 14, the W second gate lines 30 closest to the third edge 123 are interrupted at the second serial connection region 14, and the Z second gate lines 30 closest to the fourth edge 124 are interrupted at the second serial connection region 14. The width of the interrupted region formed by the W second gate lines 30 closest to the third edge 123 gradually increases in the direction towards the third edge 123, and the width of the interrupted region formed by the Z second gate lines 30 closest to the fourth edge 124 gradually increases in the direction towards the fourth edge 124, wherein both W and Z are greater than or equal to 2. That is to say, in this embodiment, in the second serial connection region 14, among the at least two first gate lines 20 closest to the third edge 123, the first weld segment 201 on the first gate line 20 closest to the third edge 123 is wider in the second direction. In the at least two first gate lines 20 closest to the fourth edge 124, the first weld segment 201 on the first gate line 20 closest to the fourth edge 124 is wider in the second direction.

[0244] In the description of this specification, the references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an 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.

[0245] Furthermore, the above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A back-contact battery, characterized in that, include: The substrate has a back surface with opposing first and second edges in a first direction. The back surface also has a plurality of first interconnection areas and a plurality of second interconnection areas arranged alternately in the first direction. The first interconnection area includes a first edge interconnection area closest to the first edge. There is no second interconnection area between the first edge interconnection area and the first edge. The second interconnection area includes a second edge interconnection area adjacent to the first edge interconnection area. A plurality of first grid lines and a plurality of second grid lines are alternately arranged on the back side along a second direction, the second direction intersecting the first direction, and both the first grid lines and the second grid lines intersecting the first concatenation area and the second concatenation area; the plurality of first grid lines include at least one first bus grid line group, the first bus grid line group including two adjacent first bus grid lines, the first bus grid lines being continuous at both the first edge concatenation area and the second edge concatenation area; the plurality of second grid lines include at least one first connecting grid line, the first connecting grid line being located between two first bus grid lines in the first bus grid line group and being continuous at both the first edge concatenation area and the second edge concatenation area; The first edge connection line, which is closer to the first edge than the first edge serialization area, is electrically connected to the first bus gate line and to at least a portion of the remaining first gate lines. A first insulating layer is disposed on the portion of the first busbar corresponding to the first edge connection area; A second insulating layer is disposed on the portion corresponding to the first connecting gate line and the second edge serial connection area; and A first auxiliary connecting line is disposed in the first edge concatenation area and a second auxiliary connecting line is disposed in the second edge concatenation area. In the second direction, at least one side of the first busbar group is provided with the first auxiliary connecting line, and the first auxiliary connecting line connects at least two second grid lines located on the same side of the first busbar group. In the second direction, at least one side of the first busbar group is provided with the second auxiliary connecting line, and the second auxiliary connecting line connects to the first busbar line located on one side of the first connecting grid line and at least one first grid line adjacent to the first busbar line.

2. The back contact battery according to claim 1, characterized in that, In a plurality of the first gate lines, at least a portion of the remaining first gate lines, excluding the first bus gate line, are discontinuous at the first edge concatenation region and continuous at the second edge concatenation region; in a plurality of the second gate lines, at least a portion of the remaining second gate lines, excluding the first connecting gate line, are continuous at the first edge concatenation region and discontinuous at the second edge concatenation region.

3. The back contact battery according to claim 1, characterized in that, The at least two second gate lines connected to the first auxiliary connection line include the second gate line adjacent to the first bus gate line.

4. The back contact battery according to claim 1, characterized in that, The first edge connection line is electrically connected to all the first gate lines; or The first edge connection line is electrically connected to a portion of the remaining first gate lines, excluding the first bus gate line, and the number of first gate lines not electrically connected to the first edge connection line is less than or equal to four.

5. The back contact battery according to claim 1, characterized in that, The first auxiliary connection line connects 2-20 of the second gate lines.

6. The back contact battery according to claim 1, characterized in that, The number of the first busbar groups is multiple, and the multiple first busbar groups are spaced apart in the second direction; In the second direction, the first auxiliary connecting line is provided on both sides of the first busbar group, and the first auxiliary connecting line is provided between two adjacent first busbar groups. The first auxiliary connecting line located between two adjacent first busbar groups connects all the second grid lines located between two adjacent first busbar groups.

7. The back contact battery according to claim 1, characterized in that, The number of first busbar groups is multiple, and the multiple first busbar groups are spaced apart in the second direction. The first auxiliary connecting lines are provided on both sides of the first busbar group, and the substrate has a third edge and a fourth edge in the second direction. The first auxiliary connecting line located between the third edge and the first busbar group closest to the third edge connects all the second grid lines located between the third edge and the first busbar group closest to the third edge; and / or The first auxiliary connection line located between the fourth edge and the first busbar group closest to the fourth edge connects all the second grid lines located between the fourth edge and the first busbar group closest to the fourth edge.

8. The back contact battery according to claim 1, characterized in that, The number of the first busbar groups is multiple, and the multiple first busbar groups are spaced apart in the second direction. The substrate has a third edge and a fourth edge in the second direction. The plurality of first gate lines further includes a first edge bus gate line, wherein the first edge bus gate line is the gate line closest to the third edge among the first gate lines and the second gate lines, and the first edge bus gate line is continuous at both the first edge concatenation region and the second edge concatenation region and electrically connected to the first edge connection line; and / or The first grid lines further include second edge bus grid lines, wherein the second edge bus grid line is the grid line closest to the fourth edge in the first grid line and the second edge bus grid line is continuous in both the first edge connection area and the second edge connection area and electrically connected to the first edge connection line.

9. The back contact battery according to claim 8, characterized in that, The substrate has a third edge and a fourth edge in the second direction; At the junction where the first edge busbar line connects to the first edge connecting line, the first edge connecting line has a first protrusion extending toward the third edge; and / or At the junction where the second edge busbar connects to the first edge connecting line, the first edge connecting line has a second protrusion that protrudes toward the fourth edge.

10. The back contact battery according to claim 1, characterized in that, The width of the first busbar is greater than the width of the portion of the remaining first busbars outside the second cascading region.

11. The back contact battery according to claim 1, characterized in that, The first busbar includes a first bus segment located between the second edge concatenation area and the first edge; Wherein, the width of the first bus section is greater than the width of the remaining portion of the first bus gate line located outside the second serial connection area; and / or The first busbar section is provided with a first busbar layer.

12. The back contact battery according to claim 11, characterized in that, The width of the first bus layer is greater than the width of the portion of the remaining first gate lines outside the second serial area.

13. The back contact battery according to claim 1, characterized in that, The width of the first edge connection line is greater than the width of the portion of the remaining first grid lines outside the second serial connection area, excluding the first bus grid line.

14. The back contact battery according to claim 1, characterized in that, The width of the first auxiliary connecting line is greater than the width of the portion of the second gate line located outside the first serial area.

15. The back contact battery according to claim 1, characterized in that, The number of the first connecting grid lines is multiple, and the multiple first connecting grid lines are spaced apart along the second direction, with each first connecting grid line corresponding to a first busbar group; In the second edge connection area, the second auxiliary connection line is provided on both sides of the first busbar group, and the two first busbars in the first busbar group are respectively connected to one of the second auxiliary connection lines.

16. The back contact battery according to claim 15, characterized in that, The second auxiliary connection line located between two adjacent first busbar groups connects all the first grid lines located between two adjacent first busbar groups.

17. The back contact battery according to claim 1, characterized in that, The width of the second auxiliary connection line is greater than the width of the portion of the remaining first grid lines (excluding the first bus grid line) located outside the second serial connection area.

18. The back contact battery according to claim 1, characterized in that, The plurality of first concatenation areas further includes a third edge concatenation area adjacent to the second edge concatenation area, the third edge concatenation area being located on the side of the second edge concatenation area away from the first edge; The first connecting grid line is continuous at the third edge concatenation area, and a third auxiliary connecting line is provided in the third edge concatenation area. In the second direction, the third auxiliary connecting line connects the first connecting grid line and at least one second grid line located on both sides of the first connecting grid line.

19. The back contact battery according to claim 18, characterized in that, The width of the third auxiliary connecting line is greater than the width of the portion of the second gate line located outside the first serial connection area.

20. The back contact battery according to claim 1, characterized in that, The plurality of second serialization areas include a fourth edge serialization area closest to the second edge, wherein there is no first serialization area between the fourth edge serialization area and the second edge, and the plurality of first serialization areas also include a fifth edge serialization area adjacent to the fourth edge serialization area; The plurality of second grid lines include at least one second bus grid line group, the second bus grid line group including two adjacent second bus grid lines, wherein the second bus grid lines are continuous at both the fourth edge concatenation region and the fifth edge concatenation region, and at least a portion of the remaining second grid lines are discontinuous at the fourth edge concatenation region and continuous at the fifth edge concatenation region. The plurality of first gate lines includes at least one second connecting gate line located between two second bus gate lines in the second bus gate line group. Among the plurality of first gate lines, the second connecting gate line is continuous at both the fourth edge concatenation region and the fifth edge concatenation region, and the remaining first gate lines are continuous at the fourth edge concatenation region and discontinuous at the fifth edge concatenation region. The back contact battery also includes: The second edge connection line is closer to the second edge than the fourth edge serialization area. The second edge connection line is electrically connected to the second bus gate line and is electrically connected to at least a portion of the remaining second gate lines other than the second bus gate line. A third insulating layer and a fourth insulating layer, wherein the third insulating layer is disposed on the portion of the second busbar corresponding to the fourth edge serial connection area, and the fourth insulating layer is disposed on the portion of the second connection busbar corresponding to the fifth edge serial connection area; and A fourth auxiliary connection line and a fifth auxiliary connection line are provided. The fourth auxiliary connection line is disposed within the fourth edge serialization area. In the second direction, the fourth auxiliary connection line is provided on at least one side of the second busbar group. The fourth auxiliary connection line connects at least two first grid lines located on the same side of the second busbar group. The at least two first grid lines connected to the fourth auxiliary connection line include the first grid lines adjacent to the second busbar group. The fifth auxiliary connection line is disposed within the fifth edge serial connection area. In the second direction, the fifth auxiliary connection line is provided on at least one side of the second bus grid group. The fifth auxiliary connection line is connected to the second bus grid line located on one side of the second connection grid line and at least one second grid line adjacent to the second bus grid line.

21. The back contact battery according to claim 20, characterized in that, The second edge connection line is electrically connected to all the second gate lines; or The second edge connection line is electrically connected to a portion of the remaining second gate lines, excluding the second bus gate line, and the number of second gate lines not electrically connected to the second edge connection line is less than or equal to 4.

22. The back contact battery according to claim 20, characterized in that, The fourth auxiliary connection line connects 2-20 of the first grid lines.

23. The back contact battery according to claim 20, characterized in that, The number of the second busbar groups is multiple, and the multiple second busbar groups are spaced apart in the second direction; In the second direction, the fourth auxiliary connecting line is provided on both sides of the second busbar group, and the fourth auxiliary connecting line is provided between two adjacent second busbar groups. The fourth auxiliary connecting line located between two adjacent second busbar groups connects all the first grid lines located between two adjacent second busbar groups.

24. The back contact battery according to claim 20, characterized in that, The number of the second busbar groups is multiple, and the multiple second busbar groups are spaced apart in the second direction. The fourth auxiliary connecting line is provided on both sides of the second busbar group. The substrate has a third edge and a fourth edge in the second direction. The fourth auxiliary connection line located between the third edge and the second busbar group closest to the third edge connects all the first grid lines located between the third edge and the second busbar group closest to the third edge; and / or The fourth auxiliary connection line located between the fourth edge and the second busbar group closest to the fourth edge connects all the first grid lines located between the fourth edge and the second busbar group closest to the fourth edge.

25. The back contact battery according to claim 20, characterized in that, The substrate has a third edge and a fourth edge in the second direction; The second grid lines further include a third edge bus grid line located between the third edge and the group of second bus grid lines closest to the third edge, the third edge bus grid line being continuous at both the fourth edge concatenation region and the fifth edge concatenation region and electrically connected to the second edge connection line; and / or The plurality of first grid lines further includes a fourth edge bus grid line located between the fourth edge and the second bus grid line group closest to the fourth edge, the fourth edge bus grid line being continuous at both the fourth edge concatenation region and the fifth edge concatenation region and electrically connected to the second edge connection line.

26. The back contact battery according to claim 20, characterized in that, The substrate has a third edge and a fourth edge in the second direction. The second edge connecting line includes a middle bus section, a first edge bus section, and a second edge bus section. The middle bus section, the first edge bus section, and the second edge bus section all extend along the second direction. The middle bus section is closer to the second edge than the first edge bus section and the second edge bus section. The first edge bus section is located close to the third edge, and the second edge bus section is located close to the fourth edge. The second edge connecting line further includes a first connecting segment and a second connecting segment, both of which extend along the first direction. The first connecting segment connects the intermediate merging segment and the first edge merging segment, and the second connecting segment connects the intermediate merging segment and the second edge merging segment. Wherein, the first edge busbar connects the two second gate lines closest to the third edge; at the junction of the first edge busbar and the first connecting section, the first edge busbar has a third protrusion protruding towards the fourth edge, and the first connecting section has a fourth protrusion protruding towards the first edge; at the junction of the intermediate busbar and the first connecting section, the intermediate busbar has a fifth protrusion protruding towards the third edge, and the first connecting section has a sixth protrusion protruding towards the second edge; and / or The second edge busbar connects the two second gate lines closest to the fourth edge. At the junction of the second edge busbar and the second connecting section, the second edge busbar has a seventh protrusion protruding toward the third edge, and the second connecting section has an eighth protrusion protruding toward the first edge. At the junction of the intermediate busbar and the second connecting section, the intermediate busbar has a ninth protrusion protruding toward the fourth edge, and the second connecting section has a tenth protrusion protruding toward the second edge.

27. The back contact battery according to claim 20, characterized in that, The width of the second busbar is greater than the width of the portion of the remaining second busbars outside the first cascading region.

28. The back contact battery according to claim 20, characterized in that, The second busbar includes a second bus segment located between the fifth edge concatenation region and the second edge; Wherein, the width of the second bus section is greater than the width of the remaining portion of the second bus gate outside the first cascading area; and / or The second busbar section is provided with a second busbar layer.

29. The back contact battery according to claim 28, characterized in that, The width of the second bus layer is greater than the width of the portion of the remaining second gate lines outside the first cascading region, excluding the second bus gate line.

30. The back contact battery according to claim 20, characterized in that, The width of the second edge connection line is greater than the width of the portion of the remaining second gate lines outside the first serial connection area, excluding the second bus gate line.

31. The back contact battery according to claim 20, characterized in that, The width of the fourth auxiliary connection line is greater than the width of the portion of the first gate line located outside the second serial connection area.

32. The back contact battery according to claim 20, characterized in that, The number of the second connecting grid lines is multiple, and the multiple second connecting grid lines are spaced apart along the second direction, with each second connecting grid line corresponding to a second bus grid line group; In the fifth edge connection area, the second auxiliary connection line is provided on both sides of the second busbar group, and the two second busbars in the second busbar group are respectively connected to one of the fifth auxiliary connection lines.

33. The back contact battery according to claim 32, characterized in that, The fifth auxiliary connection line located between two adjacent second busbar groups connects all the second grid lines located between two adjacent second busbar groups.

34. The back contact battery according to claim 20, characterized in that, The width of the fifth auxiliary connection line is greater than the width of the portion of the remaining second grid lines (excluding the second bus grid line) located outside the first serial connection area.

35. The back contact battery according to claim 20, characterized in that, The plurality of second serialization areas further includes a sixth edge serialization area adjacent to the fifth edge serialization area, the sixth edge serialization area being located on the side of the fifth edge serialization area away from the second edge; The second connecting gate line is continuous at the sixth edge concatenation area, and a sixth auxiliary connecting line is provided in the sixth edge concatenation area. In the second direction, the sixth auxiliary connecting line connects the second connecting gate line and at least one of the first gate lines located on both sides of the second connecting gate line.

36. The back contact battery according to claim 35, characterized in that, The width of the sixth auxiliary connection line is greater than the width of the portion of the first gate line located outside the second serial connection area.

37. A battery assembly, characterized in that, Includes the back contact battery as described in any one of claims 1-36.

38. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 37.

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