Back contact cells, battery modules and photovoltaic systems

Abstract

The present application relates to the technical field of solar cells, and provides a back-contact cell, a cell assembly, and a photovoltaic system. In the back-contact cell, the first busbar and the first connecting grid are both continuous at the first edge series connection area and the second edge series connection area, the first connecting grid is located between two first busbars, the first insulating layer is arranged on the portion of the first busbar corresponding to the first edge series connection area, the second insulating layer is arranged on the portion of the first connecting grid corresponding to the second edge series connection area, the first auxiliary connecting wire connects at least two second grids located on the same side of the first busbar group, and the second auxiliary connecting wire is connected to the first busbar located on one side of the first connecting grid and at least one first grid adjacent to the first busbar. In this way, by specially designing the electrode structure, the influence of the cold solder joint caused by the insulating layer can be reduced or even eliminated, thereby improving the electrical performance of the back-contact cell.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular, to a back-contact cell, a cell module, and a photovoltaic system. Background Art

[0002] A back-contact cell is a cell in which both the P-type doping layer and the N-type doping layer are disposed on the back surface of a silicon wafer, and there is no shielding of metal electrodes on the front surface, and it has a higher short-circuit current and conversion efficiency.

[0003] In the related art, the back surface of a back-contact solar cell is provided with alternately arranged grid lines. In order to reduce the use of paste and transmission loss, a solder ribbon can be directly used in a cell module to form an electrical connection with the grid lines of the cell to achieve current collection and output. However, in such a technical solution, since it is necessary to provide an insulating adhesive at the grid lines of opposite polarities that cross the solder ribbon to avoid leakage of electricity, however, the setting of the insulating adhesive easily causes the phenomenon of poor soldering during the soldering process of the solder ribbon, resulting in the inability to collect the current of some grid lines and affecting the efficiency of the back-contact cell. Summary of the Invention

[0004] The present application provides a back-contact cell, a cell module, and a photovoltaic system.

[0005] The present application is implemented as follows. The back-contact cell according to an embodiment of the present application includes:

[0006] A substrate, the back surface of the substrate has opposite first and second edges in a first direction, and the back surface also has a plurality of first series connection regions and a plurality of second series connection regions alternately arranged in the first direction. The first series connection region includes a first edge series connection region closest to the first edge, and there is no second series connection region between the first edge series connection region and the first edge. The second series connection region includes a second edge series connection region adjacent to the first edge series connection region;

[0007] A plurality of first grid lines and a plurality of second grid lines alternately arranged along a second direction on the back surface, the second direction intersects the first direction, and both the first grid lines and the second grid lines intersect with the first series connection regions and the second series connection regions; a plurality of the first grid lines include at least one first current collection grid line group, the first current collection grid line group includes two adjacent first current collection grid lines, and the first current collection grid lines are continuous at both the first edge series connection region and the second edge series connection region; a plurality of the second grid lines include at least one first connection grid line, the first connection grid line is located between the two first current collection grid lines in the first current collection grid line group and is continuous at both the first edge series connection region and the second edge series connection region;

[0008] A first edge connection line closer to the first edge than the first edge series connection region, the first edge connection line being electrically connected to the first bus bar line and at least some of the remaining first gate lines;

[0009] A first insulating layer provided on a portion of the first bus bar line corresponding to the first edge series connection region;

[0010] A second insulating layer provided on a portion of the first connection gate line corresponding to the second edge series connection region; and

[0011] A first auxiliary connection line provided in the first edge series connection region and a second auxiliary connection line provided in the second edge series connection region. In the second direction, the first auxiliary connection line is provided on at least one side of the first bus bar line group, and the first auxiliary connection line connects at least two of the second gate lines located on the same side of the first bus bar line group; In the second direction, the second auxiliary connection line is provided on at least one side of the first bus bar line group, and the second auxiliary connection line is connected to the first bus bar line located on one side of the first connection gate line and at least one of the first gate lines adjacent to the first bus bar line.

[0012] In some embodiments, among the plurality of first gate lines, at least some of the remaining first gate lines other than the first bus bar line are discontinuous at the first edge series connection region and continuous at the second edge series connection region; Among the plurality of second gate lines, at least some of the remaining second gate lines other than the first connection gate line are continuous at the first edge series connection region and discontinuous at the second edge series connection region.

[0013] In some embodiments, at least two of the second gate lines connected to the first auxiliary connection line include the second gate line adjacent to the first bus bar line.

[0014] In some embodiments, the first edge connection line is electrically connected to all the first gate lines; or

[0015] The first edge connection line is electrically connected to some of the remaining first gate lines other than the first bus bar line, and the number of the first gate lines not electrically connected to the first edge connection line is less than or equal to 4.

[0016] In some embodiments, the first auxiliary connection line connects 2-20 second gate lines.

[0017] In some embodiments, the number of the first bus bar line groups is multiple, and the multiple first bus bar line groups are spaced apart in the second direction;

[0018] In the second direction, the first auxiliary connection lines are provided on both sides of the first bus bar line group, and the first auxiliary connection lines are also provided between adjacent first bus bar line groups. The first auxiliary connection lines between adjacent first bus bar line groups are connected to all the second grid lines between adjacent first bus bar line groups.

[0019] In some embodiments, the number of the first bus bar line groups is multiple, and the multiple first bus bar line groups are arranged at intervals in the second direction. The first auxiliary connection lines are provided on both sides of the first bus bar line group. The substrate has a third edge and a fourth edge in the second direction.

[0020] The first auxiliary connection line between the third edge and the first bus bar line group closest to the third edge is connected to all the second grid lines between the third edge and the first bus bar line group closest to the third edge; and / or

[0021] The first auxiliary connection line between the fourth edge and the first bus bar line group closest to the fourth edge is connected to all the second grid lines between the fourth edge and the first bus bar line group closest to the fourth edge.

[0022] In some embodiments, the number of the first bus bar line groups is multiple, and the multiple first bus bar line groups are arranged at intervals in the second direction. The substrate has a third edge and a fourth edge in the second direction.

[0023] A plurality of the first grid lines further include a first edge bus bar line. Among the first grid lines and the second grid lines, the first edge bus bar line is the grid line closest to the third edge. The first edge bus bar line is continuous at the first edge series connection area and the second edge series connection area and is electrically connected to the first edge connection line; and / or

[0024] A plurality of the first grid lines further include a second edge bus bar line. Among the first grid lines and the second grid lines, the second edge bus bar line is the grid line closest to the fourth edge. The second edge bus bar line is continuous at the first edge series connection area and the second edge series connection area and is electrically connected to the first edge connection line.

[0025] In some embodiments, the substrate has a third edge and a fourth edge in the second direction.

[0026] At the junction where the first edge bus bar line is connected to the first edge connection line, the first edge connection line has a first convex portion protruding toward the third edge side; and / or

[0027] At the junction where the second edge busbar is connected to the first edge connection line, the first edge connection line has a second convex portion protruding toward the fourth edge side.

[0028] In some embodiments, the width of the first busbar is greater than the width of the portions of the remaining first grid lines other than the first busbar that are located outside the second series connection region.

[0029] In some embodiments, the first busbar includes a first busbar segment located between the second edge series connection region and the first edge;

[0030] wherein, the width of the first busbar segment is greater than the width of the portions of the remaining parts of the first busbar that are located outside the second series connection region; and / or

[0031] A first busbar layer is provided on the first busbar segment.

[0032] In some embodiments, the width of the first busbar layer is greater than the width of the portions of the remaining first grid lines other than the first busbar that are located outside the second series connection region.

[0033] In some embodiments, the width of the first edge connection line is greater than the width of the portions of the remaining first grid lines other than the first busbar that are located outside the second series connection region.

[0034] In some embodiments, the width of the first auxiliary connection line is greater than the width of the portions of the second grid lines that are located outside the first series connection region.

[0035] In some embodiments, the number of the first connection grid lines is multiple, and the multiple first connection grid lines are arranged at intervals along the second direction, and each first connection grid line corresponds to a first busbar group;

[0036] In the second edge series connection region, second auxiliary connection lines are provided on both sides of the first busbar group, and two first busbar lines in the first busbar group are respectively connected to one second auxiliary connection line.

[0037] In some embodiments, the second auxiliary connection lines located between adjacent two first busbar groups connect all the first grid lines located between adjacent two first busbar groups.

[0038] In some embodiments, the width of the second auxiliary connection line is greater than the width of the portions of the remaining first grid lines other than the first busbar that are located outside the second series connection region.

[0039] In some embodiments, some of the first connection regions further include a third edge connection region adjacent to the second edge connection region, and the third edge connection region is located on a side of the second edge connection region away from the first edge;

[0040] The first connection gate line is continuous at the third edge connection region, and a third auxiliary connection line is provided in the third edge connection region. In the second direction, the third auxiliary connection line connects the first connection gate line and at least one of the second gate lines on both sides of the first connection gate line.

[0041] In some embodiments, the width of the third auxiliary connection line is greater than the width of the portion of the second gate line outside the first connection region.

[0042] In some embodiments, some of the second connection regions include a fourth edge connection region closest to the second edge, and there is no first connection region between the fourth edge connection region and the second edge. Some of the first connection regions further include a fifth edge connection region adjacent to the fourth edge connection region;

[0043] Some of the second gate lines include at least one second busbar gate line group, and the second busbar gate line group includes two adjacent second busbar gate lines. Among the second gate lines, the second busbar gate lines are continuous at both the fourth edge connection region and the fifth edge connection region, and at least some of the remaining second gate lines are discontinuous at the fourth edge connection region and continuous at the fifth edge connection region;

[0044] Some of the first gate lines include at least one second connection gate line, and the second connection gate line is located between the two second busbar gate lines in the second busbar gate line group. Among the first gate lines, the second connection gate line is continuous at both the fourth edge connection region and the fifth edge connection region, and the remaining first gate lines are continuous at the fourth edge connection region and discontinuous at the fifth edge connection region;

[0045] The back contact battery further includes:

[0046] A second edge connection line, which is closer to the second edge than the fourth edge connection region. The second edge connection line is electrically connected to the second busbar gate line and is also electrically connected to at least some of the remaining second gate lines other than the second busbar gate line;

[0047] A third insulating layer and a fourth insulating layer. The third insulating layer is disposed on a portion of the second busbar gate line corresponding to the fourth edge connection region, and the fourth insulating layer is disposed on a portion of the second connection gate line corresponding to the fifth edge connection region; and

[0048] A fourth auxiliary connection line and a fifth auxiliary connection line, the fourth auxiliary connection line is disposed in the fourth edge connection area. In the second direction, the fourth auxiliary connection line is provided on at least one side of the second bus bar line group. The fourth auxiliary connection line connects at least two of the first grid lines located on the same side of the second bus bar line group. Among them, at least two of the first grid lines connected to the fourth auxiliary connection line include the first grid line adjacent to the second bus bar line group;

[0049] The fifth auxiliary connection line is disposed in the fifth edge connection area. In the second direction, the fifth auxiliary connection line is provided on at least one side of the second bus bar line group. The fifth auxiliary connection line is connected to the second bus bar line located on one side of the second connection grid line and at least one of the second grid lines adjacent to the second bus bar line.

[0050] In some embodiments, the second edge connection line is electrically connected to all of the second grid lines; or

[0051] The second edge connection line is electrically connected to some of the second grid lines other than the second bus bar line, and the number of the second grid lines not electrically connected to the second edge connection line is less than or equal to 4.

[0052] In some embodiments, the fourth auxiliary connection line connects 2 to 20 of the first grid lines.

[0053] In some embodiments, the number of the second bus bar line groups is multiple, and the multiple second bus bar line groups are spaced apart in the second direction;

[0054] In the second direction, the fourth auxiliary connection lines are provided on both sides of the second bus bar line group, and the fourth auxiliary connection lines are provided between adjacent two of the second bus bar line groups. The fourth auxiliary connection line between adjacent two of the second bus bar line groups connects all of the first grid lines between adjacent two of the second bus bar line groups.

[0055] In some embodiments, the number of the second bus bar line groups is multiple, and the multiple second bus bar line groups are spaced apart in the second direction. The fourth auxiliary connection lines are provided on both sides of the second bus bar line group. The substrate has a third edge and a fourth edge in the second direction;

[0056] The fourth auxiliary connection line between the third edge and the second bus bar line group closest to the third edge connects all of the first grid lines between the third edge and the second bus bar line group closest to the third edge; and / or

[0057] The fourth auxiliary connection line between the fourth edge and the second busbar gate line group closest to the fourth edge connects all the first gate lines between the fourth edge and the second busbar gate line group closest to the fourth edge.

[0058] In some embodiments, the substrate has a third edge and a fourth edge in the second direction;

[0059] A plurality of the second gate lines further include a third-edge busbar gate line located between the third edge and the second busbar gate line group closest to the third edge. The third-edge busbar gate line is continuous at both the fourth-edge connection area and the fifth-edge connection area and is electrically connected to the second-edge connection line; and / or

[0060] A plurality of the first gate lines further include a fourth-edge busbar gate line located between the fourth edge and the second busbar gate line group closest to the fourth edge. The fourth-edge busbar gate line is continuous at both the fourth-edge connection area and the fifth-edge connection area and is electrically connected to the second-edge connection line.

[0061] In some embodiments, the substrate has a third edge and a fourth edge in the second direction. The second-edge connection line includes an intermediate busbar section, a first-edge busbar section, and a second-edge busbar section. The intermediate busbar section, the first-edge busbar section, and the second-edge busbar section all extend along the second direction. The intermediate busbar section is closer to the second edge than the first-edge busbar section and the second-edge busbar section. The first-edge busbar section is disposed close to the third edge, and the second-edge busbar section is disposed close to the fourth edge;

[0062] The second-edge connection line further includes a first connection section and a second connection section. The first connection section and the second connection section both extend along the first direction. The first connection section connects the intermediate busbar section and the first-edge busbar section, and the second connection section connects the intermediate busbar section and the second-edge busbar section;

[0063] Wherein, the first-edge busbar section connects two of the second gate lines closest to the third edge. At the junction of the first-edge busbar section and the first connection section, the first-edge busbar section has a third convex portion protruding toward the fourth-edge side, and the first connection section has a fourth convex portion protruding toward the first-edge side. At the junction of the intermediate busbar section and the first connection section, the intermediate busbar section has a fifth convex portion protruding toward the third-edge side, and the first connection section has a sixth convex portion protruding toward the second-edge side; and / or

[0064] The second edge bus bar section is connected to the two second gate lines closest to the fourth edge. At the junction of the second edge bus bar section and the second connection section, the second edge bus bar section has a seventh convex portion protruding toward the third edge side, and the second connection section has an eighth convex portion protruding toward the first edge side. At the junction of the middle bus bar section and the second connection section, the middle bus bar section has a ninth convex portion protruding toward the fourth edge side, and the second connection section has a tenth convex portion protruding toward the second edge.

[0065] In some embodiments, the width of the second bus bar gate line is greater than the width of the portions of the other second gate lines outside the first series connection area except the second bus bar gate line.

[0066] In some embodiments, the second bus bar gate line includes a second bus bar section located between the fifth edge series connection area and the second edge;

[0067] Wherein, the width of the second bus bar section is greater than the width of the portions of the other parts of the second bus bar gate line outside the first series connection area; and / or

[0068] A second bus bar layer is provided on the second bus bar section.

[0069] In some embodiments, the width of the second bus bar layer is greater than the width of the portions of the other second gate lines outside the first series connection area except the second bus bar gate line.

[0070] In some embodiments, the width of the second edge connection line is greater than the width of the portions of the other second gate lines outside the first series connection area except the second bus bar gate line.

[0071] In some embodiments, the width of the fourth auxiliary connection line is greater than the width of the portions of the first gate line outside the second series connection area.

[0072] In some embodiments, the number of the second connection gate lines is multiple, and the multiple second connection gate lines are arranged at intervals along the second direction, and each second connection gate line corresponds to a second bus bar gate line group;

[0073] In the fifth edge series connection area, fifth auxiliary connection lines are provided on both sides of the second bus bar gate line group, and the two second bus bar gate lines in the second bus bar gate line group are respectively connected to one fifth auxiliary connection line.

[0074] In some embodiments, the fifth auxiliary connection line located between two adjacent second bus bar gate line groups is connected to all the second gate lines located between two adjacent second bus bar gate line groups.

[0075] In some embodiments, the width of the fifth auxiliary connection line is greater than the width of the portion of the second gate lines other than the second bus gate line that is located outside the first series connection area.

[0076] In some embodiments, the plurality of second serial connection areas further include a sixth edge serial connection area adjacent to the fifth edge serial connection area, and the sixth edge serial connection area is located on a side of the fifth edge serial connection area away from the second edge;

[0077] The second connection gate line is continuous at the sixth edge series connection area, and a sixth auxiliary connection line is provided in the sixth edge series connection area. In the second direction, the sixth auxiliary connection line connects the second connection gate line and at least one of the first gate lines located on both sides of the second connection gate line.

[0078] In some embodiments, 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 series connection area.

[0079] The present application also provides a battery assembly, which includes a plurality of back-contact batteries as described in any of the above items.

[0080] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0081] In the back-contact cell, cell assembly and photovoltaic system of the embodiment of the present application, by setting the first edge connection line and the first bus grid line group, the current collected by at least part of the isolated section of the first grid line between the first edge series connection area and the first edge can be converged to the welding strip of the same polarity in the second edge series connection area adjacent to the first edge series connection area, which can effectively avoid welding at the first edge of the back-contact cell and cause hidden cracks while ensuring the efficiency of the back-contact cell. The setting of the first insulating layer can achieve insulation between the welding strip in the first edge series connection area and the first bus grid line. Through the setting of the first auxiliary connection line, even if a cold weld occurs between the second grid line and the welding strip near the first insulating layer due to the setting of the first insulating layer, due to the existence of the first auxiliary connection line, the second grid line with a cold weld can also realize the current convergence output through the first auxiliary connection line, reducing or even eliminating the cold weld effect caused by the first insulating layer, thereby ensuring the efficiency of the back-contact cell.

[0082] ​​The first busbar group is set to include two adjacent first busbars, and the first insulating layers on the two first busbars are adjacent, which can reduce the radiation area of the soldering defect caused by the first insulating layer and further reduce the risk of soldering defect. Through the continuous design of the first connecting busbar in the second edge series connection area, it can be avoided that the current of the first connecting busbar cannot be collected due to soldering defect. The design of the second insulating layer can insulate the first connecting busbar. Through the design of the second auxiliary connecting wire, even if soldering defect occurs between the second busbar near the second insulating layer and the solder strip due to the setting of the second insulating layer, due to the existence of the second auxiliary connecting wire, the second busbar with soldering defect can also realize the current convergence output through the second auxiliary connecting wire, reducing and even eliminating the influence of soldering defect brought by the second insulating layer, so as to ensure the efficiency of the back contact battery.

[0083] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figure 1 is a schematic diagram of a module of a photovoltaic system provided by an embodiment of the present application;

[0085] Figure 2 is a schematic diagram of a module of a battery assembly provided by an embodiment of the present application;

[0086] Figure 3 is a schematic plan view of a back contact battery provided by an embodiment of the present application;

[0087] Figure 4 is Figure 3 a partial enlarged schematic view of the back contact battery in

[0088] Figure 5 is Figure 4 a sectional structural schematic view of the back contact battery along line V-V in

[0089] Figure 6 is Figure 4 a sectional structural schematic view of the back contact battery along line VI-VI in

[0090] Figure 7 is Figure 4 a partial enlarged schematic view of the back contact battery in

[0091] Figure 8 is Figure 4 another sectional structural schematic view of the back contact battery along line VI-VI in

[0092] Figure 9 is Figure 4Another schematic cross-sectional structure diagram along line VI-VI of the back-contact battery in

[0093] Figure 10 is Figure 4 Another partial enlarged schematic diagram of the back-contact battery in

[0094] Figure 11 is Figure 4 Another partial enlarged schematic diagram of the back-contact battery in

[0095] Figure 12 is Figure 3 Another partial enlarged schematic diagram of the back-contact battery in

[0096] Figure 13 is Figure 12 Schematic cross-sectional structure diagram along line XIII-XIII of the back-contact battery in

[0097] Figure 14 is Figure 12 Schematic cross-sectional structure diagram along line XIV-XIV of the back-contact battery in

[0098] Figure 15 is Figure 12 Partial enlarged schematic diagram of the back-contact battery in

[0099] Figure 16 is Figure 12 Another schematic cross-sectional structure diagram along line XIV-XIV of the back-contact battery in

[0100] Figure 17 is Figure 12 Another schematic cross-sectional structure diagram along line XIV-XIV of the back-contact battery in

[0101] Figure 18 is Figure 12 Another partial enlarged schematic diagram of the back-contact battery in

[0102] Figure 19 is Figure 12 Another partial enlarged schematic diagram of the back-contact battery in Detailed implementation manners

[0103] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, in which 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 only for explaining the present application and should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0104] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

[0105] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a number of" is two or more unless otherwise specifically defined.

[0106] In the present application, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0107] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use scenarios of other materials.

[0108] Please refer to Figure 1 and Figure 2 In the embodiment of the present application, the photovoltaic system 1000 may include the battery module 200 in the embodiment of the present application, and the battery module 200 in the embodiment of the present application may include a plurality of back-contact batteries 100 in the embodiment of the present application. In the embodiment of the present application, a plurality of back-contact batteries 100 in the battery module 200 may be connected in series to form a plurality of battery strings, and each battery string may be connected in series, in parallel, or in a series-parallel combination to achieve the current confluence output. For example, the connection between each battery cell may be achieved by welding a welding tape, and the connection between each battery string may be achieved by a bus bar. In some embodiments, each battery string may form a battery cell array, and then be encapsulated together with a front plate, a front encapsulant film, a back encapsulant film, and a back plate to form the battery module 200.

[0109] In the embodiment of the present application, the back-contact battery 100 is a main-gridless back-contact battery. Please refer to Figures 3 - 6 In the embodiment of the present application, the back-contact battery 100 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.

[0110] As Figures 3 - 6 shown, the substrate 10 has opposite front 11 and back 12 surfaces. The back 12 surface of the substrate 10 has opposite first 121 and second 122 edges in a first direction, and the back 12 surface has a plurality of first series connection regions 13 and a plurality of second series connection regions 14. The first series connection regions 13 and the second series connection regions 14 are respectively used for setting positive and negative welding tapes. That is to say, one of the first series connection regions 13 and the second series connection regions 14 is a positive series connection region, and the other is a negative welding region.

[0111] As Figure 3 and Figure 4 shown, in the first direction, the first series connection regions 13 and the second series connection regions 14 are alternately arranged. The plurality of first series connection regions 13 includes a first edge series connection region 131 closest to the first edge 121, and there is no second series connection region 14 between the first edge series connection region 131 and the first edge 121. That is to say, as Figure 3 shown, among the first series connection regions 13 and the second series connection regions 14, the series connection region closest to the first edge 121 is the first series connection region 13, and this first series connection region 13 is represented as the first edge series connection region 131, and there are no other series connection regions between the first edge series connection region 131 and the first edge 121.

[0112] The plurality of second series connection regions 14 includes a second edge series connection region 141 adjacent to the first edge series connection region 131 (i.e., Figure 3 andFigure 4 the second series connection region 14 closest to the first edge 121 therein.

[0113] As Figure 3 shown, a plurality of first grid lines 20 and a plurality of second grid lines 30 are alternately arranged along a second direction on the back surface 12, and the second direction intersects with the first direction. All the first grid lines 20 and all the second grid lines 30 are cross - arranged with the first series connection region 13 and the second series connection region 14, that is, both the first series connection region 13 and the second series connection region 14 extend along the second direction to intersect with the first grid lines 20 and the second grid lines 30.

[0114] 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 the two are perpendicular to each other. For example, in Figure 3 the example shown, 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 two diagonal directions of the back - contact battery 100, and specific details are not limited herein.

[0115] Among them, the plurality of first grid lines 20 include at least one first bus - bar grid line group 210. The first bus - bar grid line group 210 includes two adjacent first bus - bar grid lines 22. Among the plurality of first grid lines 20, the first bus - bar grid lines 22 are continuous at both the first edge series connection region 131 and the second edge series connection region 141, while at least some of the remaining first grid lines 20 are discontinuous at the first edge series connection region 131 and continuous at the second edge series connection region 141. For example, in some embodiments, among the plurality of first grid lines 20, except for the first bus - bar grid lines 22, all the remaining first grid lines 20 are discontinuous at the first edge series connection region 131 and continuous at the second edge series connection region 141. Another example is that in some embodiments, among the first grid lines 20, it can also be that except for the first bus - bar grid lines 22 and the first edge bus - bar grid lines 203 described below, all the remaining first grid lines 20 are discontinuous at the first edge series connection region 131 and continuous at the second edge series connection region 141.

[0116] As Figure 3 and Figure 4 shown, the plurality of second grid lines 30 include at least one first connection grid line 32. The first connection grid line 32 is located between two first bus - bar grid lines 22 in the first bus - bar grid line group 210. Among the plurality of second grid lines 30, the first connection grid line 32 is continuous at both the first edge series connection region 131 and the second edge series connection region 141, while the remaining second grid lines 30 are continuous at the first edge series connection region 131 and discontinuous at the second edge series connection region 141. The number of the first bus - bar grid line group 210 corresponds to the number of the first connection grid lines 32.

[0117] The back-contact battery 100 is a main-gridless back-contact battery. In the battery module 200, the solder tapes in the first series connection region 13 (including the first edge series connection region 131) are used to connect to the second grid line 30 to achieve the current collection output of the second grid line 30, and the solder tapes in the second series connection region 14 are used to be welded to the first grid line 20 to achieve the current collection output of the first grid line 20.

[0118] As Figure 3 shown, the first edge connection line 40 is closer to the first edge 121 than the first edge series connection region 131. The first edge connection line 40 is electrically connected to the first current collection grid line 22, and the first edge connection line 40 is also electrically connected to at least some of the remaining first grid lines 20 in the first grid line 20 other than the first current collection grid line 22. Specifically, in order to avoid the battery from having a hidden crack due to welding at the edge position of the first edge 121, the first edge connection line 40 is not used for welding. It is used to collect the current of the isolated part formed between the first edge series connection region 131 and the first edge 121 of the remaining first grid lines 20 in the first grid line 20 other than the first current collection grid line 22, and then collect the current through the first current collection grid line 22 to the solder tape of the same polarity in the second edge series connection region 141 adjacent to the first edge series connection region 131, so as to collect 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 connection line 40 and the first current collection grid line 22 are not provided, it will cause the remaining first grid lines 20 in the first grid line 20 other than the first current collection grid line 22 to form isolated grid line segments between the first edge series connection region 131 and the first edge 121, resulting in the inability to collect the current of this part.

[0119] As Figure 3 shown, the first insulating layer 51 is disposed on the first edge series connection region 131 and on the first current collection grid line 22, that is, the first insulating layer 51 is disposed on the part corresponding to the first current collection grid line 22 and the first edge series connection region 131. The first insulating layer 51 is provided to insulate the solder tapes of different polarities in the first edge series connection region 131 from the first current collection grid line 22 to avoid short circuit.

[0120] The second insulating layer 52 is disposed in the second edge series connection region 141 and on the first connection grid line 32, that is, the second insulating layer 52 is disposed on the part corresponding to the first connection grid line 32 and the second edge series connection region 141. The second insulating layer 52 is provided to insulate the solder tapes of different polarities in the second edge series connection region 141 from the first connection grid line 32 to avoid short circuit.

[0121] As Figure 3 and Figure 4As shown, the first auxiliary connection line 61 is disposed within the first edge series connection region 131. In the second direction, the first auxiliary connection line 61 is provided on at least one side of the first bus bar line 22. The first auxiliary connection line 61 connects at least two second grid lines 30 located on the same side of the first bus bar line group 210. Among them, as Figure 4 and Figure 6 shown, in some embodiments, the at least two second grid lines 30 connected to the first auxiliary connection line 61 preferably include the second grid lines 30 adjacent to the first bus bar line group 210 (i.e., Figure 3 and Figure 4 the second grid line 30 closest to the first bus bar line group 210 in

[0122] ). That is to say, in some embodiments, the first auxiliary connection line 61 preferably connects to the second grid line 30 closest to the first bus bar line group 210, and the first auxiliary connection line 61 also connects to at least one of the remaining second grid lines 30 located on the same side as the second grid line 30. That is, the first auxiliary connection line 61 preferably connects at least to the second grid line 30 adjacent to the first bus bar line group 210 and at least one of the remaining second grid lines 30 on the same side.

[0123] In the back-contact battery 100, battery module 200, and photovoltaic system 1000 according to the embodiments of the present application, by providing the first edge connection line 40 and the first busbar grid line group 210, the current collected by at least part of the isolated segment of the first grid line 20 located between the first edge series connection region 131 and the first edge 121 can be collected and fed into the same-polarity solder strip within the second edge series connection region 141 adjacent to the first edge series connection region 131, effectively avoiding the occurrence of hidden cracks 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 provision of the first insulating layer 51 can achieve insulation between the solder strip within the first edge series connection region 131 and the first busbar grid line 22. Through the provision of the first auxiliary connection line 61, even if there is a poor solder joint between the second grid line 30 near the first insulating layer 51 and the solder strip due to the provision of the first insulating layer 51, due to the presence of the first auxiliary connection line 61, the second grid line 30 with the poor solder joint can also achieve current collection and output through the first auxiliary connection line 61, reducing or even eliminating the impact of poor soldering caused by the first insulating layer 51, thereby ensuring the efficiency of the back-contact battery 100.

[0124] The first busbar grid line group 210 is provided to include two adjacent first busbar grid lines 22, and the first insulating layers 51 on the two first busbar grid lines 22 are adjacent, which can reduce the radiation area of poor soldering caused by the first insulating layer 51 and further reduce the risk of poor soldering. Through the continuous design of the first connection grid line 32 in the second edge series connection region 141, it is possible to avoid the occurrence of a poor solder joint in the first connection grid line 32 resulting in the inability to collect its current. The design of the second insulating layer 52 can insulate the first connection grid line 32. Through the design of the second auxiliary connection line 62, even if there is a poor solder joint between the second grid line 30 near the second insulating layer 52 and the solder strip due to the provision of the second insulating layer 52, due to the presence of the second auxiliary connection line 62, the second grid line 30 with the poor solder joint can also achieve current collection and output through the second auxiliary connection line 62, reducing or even eliminating the impact of poor soldering caused by the second insulating layer 52, thereby ensuring the efficiency of the back-contact battery 100.

[0125] That is to say, through the special design of the electrode structure on the back surface of the back-contact battery 100 near the first edge 121 in the present application, it is possible to reduce or even eliminate the impact 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.

[0126] As shown above, it is not difficult to understand that in the present application, the first edge connection line 40 is not used for welding, but only for current transmission and collection, and the function of the first busbar grid line 22 is for collection and transmission. Figure 3 and Figure 4 It can be seen that inFigure 3 and Figure 4 In the example shown, if the first edge connection line 40 and the first bus bar 22 are not provided, some of the first grid lines 20 are disconnected at the first edge series connection area 131. The current of the partial grid line segments of the disconnected first grid lines 20 located between the first edge series connection area 131 and the first edge 121 cannot be collected. Therefore, by providing the first edge connection line 40 and the first bus bar 22, the current of at least part of the isolated grid line segments of the first grid line 20 in this edge area can be collected and transmitted to the solder tape provided in the adjacent second edge series connection area 141, thereby effectively avoiding efficiency loss.

[0127] Since the first bus bar 22 is continuously provided in the first edge series connection area 131, in order to avoid short circuit caused by the contact between the solder tape on the first edge series connection area 131 and the first bus bar 22, a first insulating layer 51 (such as insulating glue) needs to be provided at the position corresponding to the first edge series connection area 131 of the first bus bar 22. The height of the first insulating layer 51 is higher than that of the second grid line 30 (including the first connection grid line 32). That is, in the thickness direction, the protruding height of the first insulating layer 51 is higher than the height of the second grid line 30. In such a case, the solder tape in the first edge series connection area 131 is likely to be poorly soldered to the second grid line 30 during the soldering process, resulting in the inability to effectively collect the current on some of the second grid lines 30 (especially the second grid line 30 adjacent to the first bus bar 22, which has the greatest possibility of poor soldering). Based on this, the present application connects at least two second grid lines 30 on the same side of the first bus bar 22 by providing a first auxiliary connection line 61, and preferably selects the second grid lines 30 connected thereto to include the one adjacent to the first bus bar 22. It can connect some of the second grid lines 30 into a whole at the first edge series connection area 131 through the first auxiliary connection line 61. Even if one of the second grid lines 30 is poorly soldered due to the presence of the first insulating layer 51, it can still output current through the first auxiliary connection line 61, thereby reducing or even completely eliminating the influence caused by poor soldering.

[0128] In addition, since the first connection grid line 32 is located between two first insulating layers 51, the risk of poor soldering is the greatest. If the first connection grid line 32 is discontinuous at the second edge series connection area 141, it is likely to have an isolated section, resulting in the inability to collect the current of this part. Therefore, setting the first connection grid line 32 to be continuous at the second edge series connection area 141 can avoid the problem that an isolated section causes the inability to collect part of the current.

[0129] Since the first connection grid line 32 is continuous at both the first edge series connection area 131 and the second edge series connection area 141, in order to avoid short circuit caused by the solder tape on the second edge series connection area 141 contacting the first connection grid line 32, a second insulating layer 52 (such as insulating glue) needs to be provided at the position corresponding to the second edge series connection area 141 of the first connection grid line 32. The height of the second insulating layer 52 is higher than that of the first grid line 20. That is, in the thickness direction, the protruding height of the second insulating layer 52 is higher than that of the first grid line 20. In such a case, the solder tape in the second edge series connection area 141 is likely to have poor soldering with the first grid line 20 during the soldering process, resulting in the current on some of the first grid lines 20 not being effectively collected. Especially for the first grid line 20 adjacent to the first connection grid line 32 (i.e., the first bus grid line 22), the possibility of poor soldering of this grid line is the greatest. Based on this, the present application connects the first bus grid line 22 on one side of the first connection grid line 32 and at least one first grid line 20 adjacent to the first bus grid line 22 by providing a second auxiliary connection line 62. It can connect the first bus grid line 22 and the remaining at least one first grid line 20 into a whole at the second edge series connection area 141 through the second auxiliary connection line 62. Even if poor soldering occurs in one of the second grid lines 30 due to the presence of the second insulating layer 52, the current can still be output through the second auxiliary connection line 62, thereby reducing or even completely eliminating the influence of poor soldering brought by the second insulating layer 52.

[0130] Further, in the embodiments of the present application, as Figure 5 and Figure 6 shown, the substrate 10 may include a silicon substrate 101, a plurality of first doping layers 102, a plurality of second doping layers 103, and a back passivation film layer 104. The silicon substrate 101 has opposite first surface 1011 and second surface 1012. The first doping layers 102 and the second doping layers 103 are both provided on the second surface 1012. The plurality of first doping layers 102 and the plurality of second doping layers 103 are alternately arranged along the second direction. The back passivation film layer 104 is at least stacked on the first doping layers 102 and the second doping layers 103. In some embodiments, the back passivation film layer 104 may cover the entire second surface 1012. That is, the first doping layers 102, the second doping layers 103, and the area of the second surface 1012 where no doping layer is provided are all stacked with the back passivation film layer 104.

[0131] It can be seen therefrom that in the substrate 10, the surface on the side where the first surface 1011 is located is the front surface 11 of the substrate 10, and the side where the second surface 1012 is located is the back surface of the substrate 10. Of course, in some embodiments, in the substrate 10, a first passivation layer (not shown in the figure) may be provided between the first doping layer 102 and the silicon substrate 101. The first passivation layer may be, for example, a tunneling layer, an intrinsic amorphous silicon layer, or other film layers. A second passivation layer (not shown in the figure) may also be provided between the second doping 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 layers.

[0132] In the back contact battery 100, the first gate line 20 corresponds to the first doping layer 102 one by one, and the second gate line 30 corresponds to the second doping layer 103 one by one. One of the first doping layer 102 and the second doping layer 103 may be a P-type doping layer, and the other may be an N-type doping layer. In some embodiments, the first gate line 20 may entirely penetrate the back surface passivation film layer 104 to form a full contact with the first doping layer 102, or the first gate line 20 may only partially penetrate the back surface passivation film layer 104 to form a local metallization contact with the first doping layer 102. Specific details are not limited herein.

[0133] That is to say, in the embodiments of the present application, the first gate line 20 is correspondingly arranged with the first doping layer 102 and at least partially penetrates the back surface passivation film layer 104 to make an electrically conductive contact with the first doping layer 102, and the second gate line 30 is correspondingly arranged with the second doping layer 103 and at least partially penetrates the back surface passivation film layer 104 to make an electrically conductive contact with the second doping layer 103.

[0134] Such as Figure 3 、 Figure 4 and Figure 7 As shown, in some embodiments, the first gate line 20 may be continuous at each second series connection region 14 and have a first welding section 201 for welding with a solder strip at the second series connection region 14. The second gate line 30 may be continuous at each first series connection region 13 and have a second welding section 301 for welding with a solder strip at the first series connection region 13.

[0135] In some embodiments, in the first gate line 20, the width of the first welding section 201 (i.e., the length in the second direction) may be greater than the width of the remaining part. In the second gate line 30, the width of the second welding section 301 (i.e., the length in the second direction) may also be greater than the width of the remaining part. In this way, the contact area between the first gate line 20 and the second gate line 30 and the solder strip can be increased, and the welding stability can be improved.

[0136] In some embodiments, the first welding 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 welding layer that is stacked on the first collection layer and does not penetrate the back passivation film layer 104. The first collection layer penetrates the back passivation film layer 104 and is in conductive contact with the first doping layer 102.

[0137] In some embodiments, the first collection layer may be continuous at the second series connection region 14 and discontinuous at the first series connection region 13. The first welding layer may be disposed at the second series connection region 14 and on the first collection layer. In such a case, in the first gate line 20, the portion corresponding to the first welding layer is the first welding segment 201.

[0138] Of course, in some other embodiments, the first welding segment 201 may be a single-layer structure. In such a case, the first collection layer is discontinuous at both the second series connection region 14 and the first series connection region 13. The first welding layer is disposed at the second series connection region 14 and is electrically connected to the two ends formed by the first collection layer at the second series connection region 14. It is not difficult to understand that in these cases, the portion corresponding to the first welding layer is the first welding segment 201.

[0139] In some embodiments, the width of the first welding layer may be set to be greater than the width of the first collection layer, where the width refers to the length of both in the second direction. In this way, the welding area during welding can be increased, and the welding reliability can be improved.

[0140] In some embodiments, the second welding 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 welding layer that is stacked on the second collection layer and does not penetrate the back passivation film layer 104. The second collection layer penetrates the back passivation film layer 104 and is in conductive contact with the second doping layer 103.

[0141] In some embodiments, the second collection layer may be continuous at the first series connection region 13 and discontinuous at the second series connection region 14. The second welding layer may be disposed at the first series connection region 13 and on the second collection layer. In such a case, in the second gate line 30, the portion corresponding to the second welding layer is the second welding segment 301.

[0142] Of course, in some other embodiments, the second collection layer may also be discontinuous at both the first series connection region 13 and the second series connection region 14. The second welding layer is disposed at the first series connection region 13 and is electrically connected to the two ends formed by the second collection layer at the first series connection region 13. It is not difficult to understand that in these cases, the portion corresponding to the second welding layer is the second welding segment 301.

[0143] In some embodiments, the width of the second welding layer may also be set to be greater than the width of the second collection layer, where the width refers to the length of both in the second direction.

[0144] As Figure 3 and Figure 4 shown, in the embodiments of the present application, in order to minimize the impact of poor soldering as much as possible, when there are at least two second grid lines 30 on both sides of the first bus grid line group 210, it is preferably that first auxiliary connection lines 61 are simultaneously provided on both sides of the first bus grid line group 210. Of course, if the first bus grid line group 210 is located at the outermost edge position in the second direction, the first auxiliary connection line 61 may be provided on one side of the first bus grid line group 210.

[0145] In some embodiments, the width of the first bus grid line 22 (i.e., the length in the second direction) may be greater than the width of the portion of the remaining first grid lines 20 other than the first bus grid line 22 that is outside the second series connection region 14 (i.e., the portion other than the first welding section 201) (i.e., the length in the second direction).

[0146] Thus, since the first bus grid line 22 needs to undertake the function of bus bar transmission, therefore, setting the width of the first bus grid line 22 wider can reduce the transmission loss during the bus bar transmission process and improve the efficiency. And the first welding section 201 is used for welding, setting the first welding section 201 wider can improve the reliability and stability of welding, and the width of the first bus grid line 22 may be the same as the width of the first welding section 201.

[0147] In addition, as Figure 3 , Figure 4 and Figure 7 shown, in some embodiments, in the first bus grid line 22, it is continuous only at the first edge series connection region 131, and is disconnected at other first series connection regions 13. Of course, in some embodiments, as described below, when the back contact battery 100 has a second connection grid line 23, the first bus grid line 22 may also be continuous at the fifth edge series connection region 133 described below. In such a case, the first bus grid line 22 and the second connection grid line 23 are the same grid line.

[0148] The first bus grid line 22 is continuous at the first edge series connection region 131, and only the section closest to the first edge 121 (i.e., the portion between the second edge series connection region 141 and the first edge 121) of the first bus grid line 22 undertakes the bus bar function. Therefore, in some embodiments, in order to save the paste to reduce the cost, only this part of the grid line segment may be set wider.

[0149] In such a case, please refer to Figure 3 , Figure 4 and Figure 7, the first bus bar 22 may include a first bus segment 221 located between the second edge series connection region 141 and the first edge 121. In some embodiments, the width of the first bus segment 221 (i.e., the length in the second direction) may be greater than the width of the remaining part of the first bus bar 22 outside the second series connection region 14 (i.e., the part other than the first bus segment 221 and other than the first welding segment 201).

[0150] In this way, only by setting the width of the first bus segment 221 wider, the use of paste can be reduced while reducing the bus bar transmission loss, thereby reducing costs.

[0151] Specifically, as described above, in such an embodiment, the first bus segment 221 can collect current to the solder tape provided at the second edge series connection region 141, and only setting a part of the first bus segment 221 wider can reduce the use of paste. In such a case, the first bus segment 221 penetrates the back passivation film layer 104 and contacts the first doping layer 102.

[0152] Please refer to Figure 7 , in some other embodiments, a first bus layer 70 may be provided on the first bus segment 221. In this way, by providing the first bus layer 70 on the first bus segment 221, it is equivalent to increasing the cross-sectional area of the first bus segment 221, which can also reduce the transmission loss. At the same time, the first bus layer 70 can be made of a paste with a lower cost than the first bus segment 221, which can reduce costs.

[0153] Specifically, in such an embodiment, the first bus bar 22 may be an ordinary bus bar, and the width of the rest of the positions may be the same except that it is wider at the first welding segment 201. And by providing the first bus layer 70 on the first bus segment 221, it is equivalent to increasing the cross-sectional area of the first bus segment 221. That is to say, since the first bus layer 70 is provided on the first bus segment 221, it is not necessary to widen the first bus segment 221, and it can also achieve the purpose of reducing the transmission loss. Of course, in some embodiments, the first bus segment 221 may also be widened, and specific details are not limited here.

[0154] 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 doping layer 102. The paste cost of the first bus layer 70 is lower than the paste cost of the first bus segment 221. For example, when neither the first bus layer 70 nor the first bus segment 221 is a silver paste layer, the silver content in the first bus layer 70 can be lower than the silver content in the first bus segment 221. Another example is that the first bus segment 221 can be a silver paste layer, and the first bus layer 70 can be a metal layer with a lower cost such as a copper layer or a silver-coated copper layer.

[0155] Further, 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 portions of the remaining first grid lines 20 other than the first bus grid line 22 that are located outside the second series connection region 14 (i.e., the portions other than the first welding section 201). In this way, by increasing the width of the first bus layer 70, the transmission capacity can be further improved and the transmission loss can be reduced.

[0156] In such an embodiment, the width of the first bus layer 70 may be the same as the width of the first welding section 201. In this article, the width of the first welding section 201 refers to the length of the first welding section 201 in the second direction. As shown above, when the width of the first welding layer is greater than the width of the first collection layer, the width of the first welding section 201 is the width of the first welding layer (i.e., the length in the second direction). For similar descriptions hereinafter, this can be referred to for understanding.

[0157] In this way, it can be ensured that no large transmission loss will be caused during the bus process. At the same time, during the printing process, the first bus layer 70 can be printed simultaneously with the first welding layer at the first welding section 201. When using the same screen printing, there is no need to open screen slots of different sizes on the screen, saving manufacturing processes and reducing manufacturing difficulty.

[0158] Please refer 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 portions of the remaining first grid lines 20 other than the first bus grid line 22 that are located outside the second series connection region 14 (i.e., the portions other than the first welding section 201 among the remaining first grid lines 20 other than the first bus grid line 22).

[0159] In this way, since the first edge connection line 40 needs to undertake the bus transmission function, therefore, setting the width of the first edge connection line 40 wider can also reduce the transmission loss during the bus process and improve the efficiency.

[0160] Specifically, in such an embodiment, the width of the first edge connection line 40 may be the same as the width of the first welding section 201. In this way, it can be ensured that no large bus loss will be caused during the bus process.

[0161] In addition, please continue to refer to Figure 7 , 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 portions of the second grid lines 30 that are located outside the first series connection region 13 (the portions of the second grid lines 30 other than the second welding section 301).

[0162] Thus, since the first auxiliary connection line 61 plays the role of transmitting and converging current when a cold solder joint occurs, setting the width of the first auxiliary connection line 61 wider can also reduce the transmission loss in the converging process and improve efficiency.

[0163] In some embodiments, the width of the first auxiliary connection line 61 may be the same as the width of the first edge connection line 40, and the widths of both may also be the same as the widths of the first welding section 201 and the second welding section 301.

[0164] Please refer to Figure 3 and Figure 4 In some embodiments, the first edge connection line 40 is electrically connected to all the first gate lines 20.

[0165] In this way, all currents collected by the isolated gate line segments in the first gate line 20 except those located between the first edge series connection area 131 and the first edge 121 can be converged, thereby maximizing the efficiency of the back contact battery 100.

[0166] Of course, in some embodiments, the first edge connection line 40 may be electrically connected to only some of the remaining first gate lines 20 except the first bus gate line 22. In this case, the number of first gate lines 20 that are not electrically connected to the first edge connection line 40 is less than or equal to 4. In this way, even if some of the first gate lines 20 are not connected to the first edge connection line 40, the number is small and will not cause excessive efficiency loss and result in product defects.

[0167] In some embodiments, the first auxiliary connection line 61 is connected to 2-20 second gate lines 30. Thus, by setting the number of second gate lines 30 connected to the first auxiliary connection line 61 within this reasonable range, the influence of cold solder joints can be reduced as much as possible or even eliminated.

[0168] In the embodiment of the present application, the number of the first busbar line group 210 may be single. In this case, the first auxiliary connection line 61 may be provided only on one side of the first busbar line group 210, or may be provided on both sides of the first busbar line group 210, and the specific details are not limited here. When there are at least two second grid lines 30 on both sides of the first busbar line group 210, it is preferred to provide the first auxiliary connection line 61 on both sides.

[0169] ​​​​In addition, it should be noted that in the present application, when the number of the first bus bar groups 210 is multiple, the first auxiliary connection lines 61 may be provided on one side or both sides of only some of the first bus bar groups 210, while the first auxiliary connection lines 61 may not be provided on both sides of the remaining first bus bar groups 210. In such a case, the problem of virtual soldering at some positions can also be solved. In the present application, it is preferred that the first auxiliary connection lines 61 are provided on both sides of each first bus bar group 210. Of course, if the first bus bar group 210 is located at the third edge 123, only the first auxiliary connection line 61 needs to be provided on one side of the first bus bar 22.

[0170] Of course, please refer to Figure 3 and Figure 4 , in some embodiments, the number of the first bus bar groups 210 is multiple, and the multiple first bus bar groups 210 are arranged at intervals in the second direction. In this way, arranging multiple first bus bar groups 210 can shorten the current bus bar path, effectively reduce the bus bar transmission loss, and improve the efficiency.

[0171] In such a case, the first auxiliary connection lines 61 are provided on both sides of the first bus bar group 210, and the first auxiliary connection lines 61 are also provided between adjacent two first bus bar groups 210. The first auxiliary connection lines 61 located between adjacent two first bus bar groups 210 are connected to all the second grid lines 30 located between adjacent two first bus bar groups 210.

[0172] In this way, connecting the first auxiliary connection lines 61 to all the second grid lines 30 between adjacent two first bus bar groups 210 can basically completely eliminate the influence brought by virtual soldering and improve the efficiency of the back contact battery 100 as much as possible.

[0173] Specifically, in such an embodiment, the number of the first bus bar groups 210 in the back contact battery 100 can be selected according to the actual situations such as the size of the battery chip and the loss during the transmission process, and no limitation is made here.

[0174] Please refer to Figure 3 and Figure 4 , in some embodiments, the number of the first bus bar groups 210 is multiple, the multiple first bus bar groups 210 are arranged at intervals in the second direction, the first auxiliary connection lines 61 are provided on both sides of the first bus bar group 210, and the substrate 10 has a third edge 123 and a fourth edge 124 in the second direction;

[0175] Some of the first grid lines 20 further include a first edge bus grid line 203. Among the first grid lines 20 and the second grid lines 30, the first edge bus grid line 203 is the grid line closest to the third edge 123. The first edge bus grid line 203 is continuous at both the first edge series connection area 131 and the second edge series connection area 141 and is electrically connected to the first edge connection line 40; and / or

[0176] Some of the first grid lines 20 further include a second edge bus grid line 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 series connection area 131 and the second edge series connection area 141 and is electrically connected to the first edge connection line 40.

[0177] Thus, by providing the first edge bus grid line 203 and the second edge bus grid line 204, the bus bar path can be further shortened and the bus bar transmission loss can be reduced. It is not difficult to understand that since the first edge bus grid line 203 and the second edge bus grid line 204 are continuous at the first edge series connection area 131, an insulating layer also needs to be provided thereon. Therefore, through the above design, the virtual soldering effect caused by the insulating layers on the first edge bus grid line 203 and the second edge bus grid line 204 can be basically reduced or even eliminated.

[0178] Of course, it can be understood that in some embodiments, the first edge bus grid line 203 and the second edge bus grid line 204 may not be provided.

[0179] In such a case, a first auxiliary connection line 61 between the third edge 123 and the first bus grid line group 210 closest to the third edge 123 can connect all the second grid lines 30 between the third edge 123 and the first bus grid line group 210 closest to the third edge 123. And / or a first auxiliary connection line 61 between the fourth edge 124 and the first bus grid line group 210 closest to the fourth edge 124 connects all the second grid lines 30 between the fourth edge 124 and the first bus grid line group 210 closest to the fourth edge 124.

[0180] Thus, through such a design, it is possible to avoid performance degradation caused by virtual soldering at the starting solder joints and ending solder joints at the upper and lower ends of the first edge series connection area 131 of the solder tape.

[0181] Please refer to Figure 7 and 8 , as described above, the first grid line 20 may include a first welding section 201 corresponding to the second series connection area 14, and the second grid line 30 includes a second welding section 301 corresponding to the first edge series connection area 131.

[0182] In some embodiments, within the first edge connection region 131, a first groove 15 is formed on the substrate 10. A portion of the first busbar grid line 22 is located within the first groove 15, and the 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 in which the front surface 11 faces the back surface 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.

[0183] Thus, by forming the first groove 15 on the substrate 10 and disposing the first insulating layer 51 within 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 is greater than the height of the second welding segment 301 and the height difference between the two is less than or equal to 15 μm, thereby further reducing the risk of false soldering caused by the first insulating layer 51.

[0184] In some embodiments, the first groove 15 may penetrate through the back surface passivation film layer 104 and the first doping layer 102, so that the silicon substrate 101 is exposed from the first groove 15, and the portion of the first busbar grid line 22 located within the first groove 15 is in contact with the silicon substrate 101. In this way, after the substrate 10 is fabricated, the first groove 15 can be directly formed on the substrate 10 by etching (such as laser etching, etc.), without inserting an etching and grooving process during the preparation of the substrate 10.

[0185] Specifically, in such a case, a complete substrate 10 can be provided first, and then grooving treatment can be directly performed at the position on the substrate 10 where the first insulating layer 51 needs to be placed, and then the first grid line 20 and the second grid line 30 are printed, and then the first insulating layer 51 is disposed at the first groove 15.

[0186] Of course, in some other embodiments, it may also be that at the position corresponding to the first busbar grid line 22 in the first edge connection region 131, a first indentation groove is formed on the silicon substrate 101, and both the first doping layer 102 and the back surface passivation film layer 104 are recessed toward the side where the front surface 11 is located at the first indentation groove, so as to form the first groove 15 on the substrate 10.

[0187] Specifically, in such a case, during the manufacturing process, before preparing the first doped layer 102, a first recessed groove may be opened at the position in the silicon substrate 101 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 opened on the silicon substrate 101, the above-mentioned first groove 15 can be correspondingly formed on the substrate 10. Then, the first gate line 20 and the second gate line 30 are printed, and then the first insulating layer 51 is disposed at the first groove 15.

[0188] Please refer to Figure 9 , in some embodiments, at the first edge series connection region 131, a first auxiliary connection layer 80 may be disposed on the second gate line 30. The first auxiliary connection layer 80 is used for welding with a 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.

[0189] Thus, by disposing the first auxiliary connection layer 80 on the portion of the second gate line 30 corresponding to the first edge series connection region 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 is flush with the first auxiliary connection layer 80, or the height of the first insulating layer 51 is greater than the height of the first auxiliary connection layer 80 and the height difference between the two is less than or equal to 15 μm, thereby reducing the risk of false soldering caused by the first insulating layer 51.

[0190] Specifically, in such an embodiment, the first auxiliary connection layer 80 may be stacked on the second welding section 301. The first auxiliary connection layer 80 may be a conductive material layer such as a solder paste layer, which is used for welding with a solder strip during the welding process, and is not specifically limited herein.

[0191] Please refer to Figure 4 and Figure 10 , in some embodiments, the substrate 10 has a third edge 123 and a fourth edge 124 in the second direction. At the junction where the first edge busbar gate line 203 is connected to the first edge connection line 40, the first edge connection line 40 has a first convex portion 41 protruding toward the third edge 123.

[0192] Please refer to Figure 4 and Figure 11 , in some embodiments, at the junction where the second edge busbar gate line 204 is connected to the first edge connection line 40, the first edge connection line 40 has a second convex portion 42 protruding toward the fourth edge 124.

[0193] Thus, the provision of the first convex portion 41 and the second convex portion 42 can provide redundancy for the first edge connection line 40 at the corner of the back contact battery 100 located at the first edge 121, avoiding poor contact between the first edge connection line 40 and the first edge busbar line 203 and the second edge busbar line 204 due to inaccurate printing during the printing process, which may result in incomplete filling of the paste at the corner.

[0194] Specifically, in such a case, in some embodiments, a busbar layer may be provided on a portion of the first edge busbar line 203 and the second edge busbar line 204 located between the second edge series connection region 141 and the first edge 121, which can reduce the busbar loss.

[0195] In addition, as Figure 10 and Figure 11 shown, in some embodiments, in the back contact battery 100, chamfers are formed at the intersections of the first edge 121 with the third edge 123 and the fourth edge 124, and the first grid line 20 is correspondingly provided at the chamfer. Therefore, as Figure 10 and Figure 11 shown, in order to realize the connection between the first edge connection line 40 and the first grid line 20, the first edge connection line 40 has bending portions at both chamfers. Of course, it can be understood that in some embodiments, if the back contact battery 100 does not have chamfers, there is no need to provide bending portions.

[0196] Please refer to Figure 10 and Figure 11 , in some embodiments, at the junction of the first grid line 20 and the first edge connection line 40, at least a part of the first grid line 20 has a first grid line convex portion 202 that protrudes toward the first edge 121 side compared with the first edge connection line 40.

[0197] Thus, through the provision of the first grid line convex portion 202, the stability of the electrical connection between the first grid line 20 and the first edge connection line 40 can be ensured, effectively avoiding the phenomenon that some of the first grid lines 20 cannot form a stable contact with the first edge connection line 40 due to printing accuracy during the printing process.

[0198] Please refer to Figure 3 and Figure 4, in some embodiments, the number of the first connecting gate lines 32 is multiple, and the number of the first connecting gate lines 32 is the same as and corresponds one by one to the number of the first busbar gate line groups 210. The multiple first connecting gate lines 32 are arranged at intervals in the second direction, and each first connecting gate line 32 corresponds to a first busbar gate line group 210. In the second edge series connection region 141, second auxiliary connection lines 62 are provided on both sides of the first busbar gate line group 210, and two first busbar gate lines 22 in the first busbar gate line group 210 are respectively connected to one second auxiliary connection line 62. In this way, the virtual soldering influence brought by the second insulating layer 52 on both sides can be reduced.

[0199] Please refer to Figure 3 and Figure 4 , in such an embodiment, the second auxiliary connection lines 62 located between two adjacent first busbar gate line groups 210 are connected to all the first gate lines 20 located between two adjacent first busbar gate line groups 210. In this way, the virtual soldering influence brought by the second insulating layer 52 can be completely and basically eliminated.

[0200] Of course, it can be understood that, in some embodiments, the second auxiliary connection lines 62 can also be provided on one side of the first connecting gate lines 32, and the virtual soldering influence in some areas can also be reduced. Of course, in the present application, it is preferably to provide the second auxiliary connection lines 62 on both sides of the first connecting gate lines 32.

[0201] In addition, in some alternative embodiments, when the first connecting gate lines 32 are multiple, the second auxiliary connection lines 62 can also be provided on at least one of some of the first connecting gate lines 32, and the second auxiliary connection lines 62 can not be provided on both sides of the remaining first connecting gate lines 32. In this way, the virtual soldering influence in some areas can also be reduced.

[0202] In some embodiments, the width (the length in the first direction) of the second auxiliary connection lines 62 is greater than the width (the length in the second direction) of the portion (i.e., the first welding segment 201) of the remaining first gate lines 20 other than the first busbar gate lines 22 located outside the second series connection region 14.

[0203] In this way, since the second auxiliary connection lines 62 play a role in transmitting and collecting current when virtual soldering occurs, therefore, setting the width of the second auxiliary connection lines 62 wider can also reduce the transmission loss during the current collection process and improve the efficiency.

[0204] Specifically, in such an embodiment, the width of the second auxiliary connection lines 62 can be the same as the width of the first welding segment 201.

[0205] Please refer to Figure 3 , Figure 4 and Figure 7, in some embodiments, several first connection regions 13 further include a third edge connection region 132 adjacent to the second edge connection region 141. The third edge connection region 132 is located on a side of the second edge connection region 141 away from the first edge 121.

[0206] The first connection grid line 32 is continuous at the third edge connection region 132. A third auxiliary connection line 90 is provided in the third edge connection region 132. In the second direction, the third auxiliary connection line 90 connects the first connection grid line 32 and at least one second grid line 30 on both sides of the first connection grid line 32.

[0207] Thus, by providing the third auxiliary connection line 90 in the third edge connection region 132, it is possible to effectively avoid the phenomenon that the solder tape in the third edge connection region 132 is poorly soldered or has poor contact at the first connection grid line 32, resulting in the inability to collect the current transmitted from the first connection grid line 32.

[0208] Specifically, as Figure 4 and Figure 7 shown, in such an embodiment, the number of the third auxiliary connection lines 90 may be the same as the number of the first connection grid lines 32, and the two correspond one by one. The third auxiliary connection line 90 connects the first connection grid line 32 and also connects two second grid lines 30 adjacent to the first connection grid line 32.

[0209] In some embodiments, the width of the third auxiliary connection line 90 (the length in the first direction) may be greater than the width of the portion of the second grid line 30 other than the part located in the first connection region 13 (i.e., other than the second welding section 301) (the length in the second direction). Thus, by setting the width of the third auxiliary connection line 90 wider, it is also possible to reduce the transmission loss during the current collection process and improve the efficiency.

[0210] In some embodiments, the distance between the first edge connection region 131 and the first edge 121 is greater than or equal to 2 mm and less than or equal to 20 mm.

[0211] Thus, it is possible to avoid the distance between the first edge connection region 131 and the first edge 121 being too small, resulting in the welding position being too close to the first edge 121 and causing a hidden crack in the back contact battery 100, reducing the risk of hidden cracks. It is also possible to avoid the distance between the first edge connection region 131 and the first edge 121 being too large, resulting in the length of the isolated grid line segment between the first edge connection region 131 and the first edge 121 being too long and causing excessive loss during the transmission path.

[0212] Specifically, in such an embodiment, the distance between the first edge connection area 131 and the first edge 121 can be, for example, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, or any value between 2 mm and 20 mm, and specifically there is no limitation here.

[0213] Please refer to Figure 3 and Figures 12 - 15 , in some embodiments, several second connection areas 14 further include a fourth edge connection area 142 closest to the second edge 122, and there is no first connection area 13 between the fourth edge connection area 142 and the second edge 122. That is to say, as Figure 3 and Figure 12 shown, among the second connection area 14 and the first connection area 13, the connection area closest to the second edge 122 is the second connection area 14, and this second connection area 14 is represented as the fourth edge connection area 142, and there are no other connection areas between the fourth edge connection area 142 and the second edge 122.

[0214] Several first connection areas 13 further include a fifth edge connection area 133 adjacent to the fourth edge connection area 142 (that is, Figure 3 and Figure 12 the first connection area 13 closest to the second edge 122 in

[0215] Among them, several second gate lines 30 include at least one second bus gate line group 310, and the second bus gate line group 310 includes two adjacent second bus gate lines 33. Among several second gate lines 30, the second bus gate lines 33 are continuous at both the fourth edge connection area 142 and the fifth edge connection area 133, while at least some of the other second gate lines 30 are discontinuous at the fourth edge connection area 142 and continuous at the fifth edge connection area 133. For example, in some embodiments, among the second gate lines 30, except for the second bus gate lines 33, all the other second gate lines 30 (including the second connection gate lines 23 mentioned above) are discontinuous at the fourth edge connection area 142 and continuous at the fifth edge connection area 133. Another example is that in some embodiments, among the second gate lines 30, it can also be that except for the second bus gate lines 33 and the third edge bus gate lines 303 described below, all the other second gate lines 30 are discontinuous at the fourth edge connection area 142 and continuous at the fifth edge connection area 133.

[0216] As Figure 3 , Figure 4 and Figure 12As shown, in the embodiments of the present application, all the first gate lines 20 are discontinuous at all the first connection regions 13 except for the first edge connection region 131 and the fifth edge connection region 133, and all the first gate lines 20 are continuous at all the second connection regions 14. All the second gate lines 30 are discontinuous at all the other second connection regions 14 except for the second edge connection region 141 and the fourth edge connection region 142, and all the second gate lines 30 are continuous at all the first connection regions 13.

[0217] As Figure 3 and Figure 12 shown, several first gate lines 20 include at least one second connection gate line 23, and the second connection gate line 23 is located between two second bus gate lines 33 in the second bus gate line group 310. Among the several first gate lines 20, the second connection gate line 23 is continuous at both the fourth edge connection region 142 and the fifth edge connection region 133, and the remaining first gate lines 20 are continuous at the fourth edge connection region 142 and discontinuous at the fifth edge connection region 133. The number of the second bus gate line groups 310 corresponds to the number of the second connection gate lines 23.

[0218] It should be noted that, as Figure 3 , Figure 4 and Figure 12 shown, in the illustrated embodiment, the first connection gate line 32 and the second bus gate line 33 are different gate lines. It can be understood that, in some embodiments, the first connection gate line 32 and the second bus gate line 33 may also be the same gate line, that is, the first connection gate line 32 serves as a second bus gate line 33, and specific details are not limited herein.

[0219] In addition, in the illustrated embodiment, the second connection gate line 23 and the first bus gate line 22 are different gate lines. It can be understood that, in some embodiments, the second connection gate line 23 and the first bus gate line 22 may also be the same gate line, that is, a first bus gate line 22 serves as a second connection gate line 23.

[0220] The back contact battery 100 further includes a second edge connection line 110, a third insulating layer 120, a fourth insulating layer 1210, a fourth auxiliary connection line 130, and a fifth auxiliary connection line 1310.

[0221] As Figure 3 and Figure 12As shown, the second edge connection line 110 is closer to the second edge 122 than the fourth edge connection area 142. The second edge connection line 110 is electrically connected to the second busbar gate line 33, and the second edge connection line 110 is also electrically connected to at least some of the other second gate lines 30 in the second gate lines 30 except the second busbar gate line 33. Specifically, in order to avoid the battery from having hidden cracks caused by welding at the edge position of the second edge 122, the second edge connection line 110 is not used for welding. It is used to collect the current of the isolated part formed between the fourth edge connection area 142 and the second edge 122 in the other second gate lines 30 in the second gate lines 30 except the second busbar gate line 33, and then the current is collected by the second busbar gate line 33 and flows to the same-polarity solder tape in the fifth edge connection area 133 adjacent to the fourth edge connection area 142, so as to collect the current of the isolated gate line segments in the edge area of the second gate lines 30 located at the second edge 122, improving the efficiency of the back-contact battery 100. If the second edge connection line 110 and the second busbar gate line 33 are not provided, it will cause the other second gate lines 30 in the second gate lines 30 except the second busbar gate line 33 to form isolated gate line segments between the fourth edge connection area 142 and the second edge 122, resulting in the inability to collect the current of this part.

[0222] As Figure 3 shown, the third insulating layer 120 is disposed on the fourth edge connection area 142 and located on the second busbar gate line 33, that is, the third insulating layer 120 is disposed on the part corresponding to the second busbar gate line 33 and the fourth edge connection area 142. The setting of the third insulating layer 120 is used to insulate and separate the different-polarity solder tape in the fourth edge connection area 142 from the second busbar gate line 33 to avoid short circuit.

[0223] The fourth insulating layer 1210 is disposed in the fifth edge connection area 133 and located on the second connection gate line 23, that is, the fourth insulating layer 1210 is disposed on the part corresponding to the second connection gate line 23 and the fifth edge connection area 133. The setting of the fourth insulating layer 1210 is used to insulate and separate the different-polarity solder tape in the fifth edge connection area 133 from the second connection gate line 23 to avoid short circuit.

[0224] As Figure 3 and Figure 12 shown, the fourth auxiliary connection line 130 is disposed in the fourth edge connection area 142. In the second direction, at least one side of the second busbar gate line 33 is provided with the fourth auxiliary connection line 130, and the fourth auxiliary connection line 130 connects at least two first gate lines 20 located on the same side of the second busbar gate line group 310. Among them, as Figure 4 and Figure 15As shown, in some embodiments, at least two first gate lines 20 connected to the fourth auxiliary connection line 130 preferably include the first gate lines 20 adjacent to the second bus gate line group 310 (i.e., Figure 3 and Figure 12 the first gate line 20 closest to the second bus gate line group 310 in Figure 12 ), that is to say, in some embodiments, the fourth auxiliary connection line 130 preferably connects to the first gate line 20 closest to the second bus gate line group 310, and the fourth auxiliary connection line 130 also connects to at least one of the remaining first gate lines 20 on the same side as this first gate line 20. That is, the fourth auxiliary connection line 130 preferably connects at least to the first gate line 20 adjacent to the second bus gate line group 310 and at least one of the remaining first gate lines 20 on the same side.

[0225] The fifth auxiliary connection line 1310 is disposed in the fifth edge series connection area 133. In the second direction, the fifth auxiliary connection line 1310 is provided on at least one side of the second bus gate line group 310. The fifth auxiliary connection line 1310 connects the second bus gate line 33 on one side of the second connection gate line 23 and at least one second gate line 30 adjacent to the second bus gate line 33. That is to say, in some embodiments, the fifth auxiliary connection line 1310 is connected to the second bus gate line 33 on one side of the second connection gate line 23 and at least one second gate line 30 adjacent to the second bus gate line 33.

[0226] In this way, by providing the second edge connection line 110 and the second bus gate line group 310, the current collected by at least part of the isolated segment of the second gate line 30 located between the fourth edge series connection area 142 and the second edge 122 can be converged to the same-polarity solder tape in the fifth edge series connection area 133 adjacent to the fourth edge series connection area 142, which can effectively avoid causing hidden cracks due to welding at the second edge 122 of the back-contact battery 100 while ensuring the efficiency of the back-contact battery 100. The setting of the third insulating layer 120 can achieve insulation between the solder tape in the fourth edge series connection area 142 and the second bus gate line 33. Through the setting of the fourth auxiliary connection line 130, even if there is a virtual solder between the first gate line 20 near the third insulating layer 120 and the solder tape due to the setting of the third insulating layer 120, due to the existence of the fourth auxiliary connection line 130, the first gate line 20 with virtual solder can also achieve current convergence output through the fourth auxiliary connection line 130, reducing or even eliminating the virtual solder influence brought by the third insulating layer 120, thereby ensuring the efficiency of the back-contact battery 100.

[0227] The second busbar line group 310 is arranged to include two adjacent second busbar lines 33. The third insulating layer 120 on the two second busbar lines 33 is adjacent, which can reduce the radiation area of virtual soldering caused by the first insulating layer 51, further reducing the risk of virtual soldering. Through the continuous design of the second connecting busbar 23 in the fifth edge series connection area 133, it is possible to avoid virtual soldering of the second connecting busbar 23, resulting in the inability to collect its current. The design of the fourth insulating layer 1210 can insulate the second connecting busbar 23. Through the design of the fifth auxiliary connecting line 1310, even if virtual soldering occurs between the first busbar line 20 near the fourth insulating layer 1210 and the solder strip due to the setting of the fourth insulating layer 1210, due to the existence of the fifth auxiliary connecting line 1310, the virtual soldered first busbar line 20 can also achieve current confluence output through the fifth auxiliary connecting line 1310, reducing or even eliminating the impact caused by virtual soldering brought by the fourth insulating layer 1210, thereby ensuring the efficiency of the back-contact battery 100.

[0228] That is to say, through the special design of the electrode structure on the back of the back-contact battery 100 near the second edge 122 in this application, the influence of virtual soldering brought by the third insulating layer 120 and the fourth insulating layer 1210 can be reduced or even eliminated, thereby improving the electrical performance of the back-contact battery 100 and ensuring the efficiency of the back-contact battery 100.

[0229] As shown above, it is not difficult to understand that in this application, the second edge connecting line 110 is not used for soldering, but only for current transmission and confluence. The function of the second busbar line 33 is for collection and transmission. Figure 3 and Figure 12 It can be seen that in Figure 3 and Figure 12 In the shown example, if the second edge connecting line 110 and the second busbar line 33 are not provided, some of the second busbar lines 30 are disconnected at the fourth edge series connection area 142. The current of the partial busbar line segments of the disconnected second busbar lines 30 between the fourth edge series connection area 142 and the second edge 122 cannot be collected. Therefore, by providing the second edge connecting line 110 and the second busbar line 33, the current of at least part of the isolated busbar line segments of the second busbar line 30 in this edge area can be confluently transmitted to the solder strip arranged in the adjacent fourth edge series connection area 142, thereby effectively avoiding efficiency loss.

[0230] Since the second busbar 33 is continuously provided in the fourth edge connection area 142, in order to prevent the solder tape on the fourth edge connection area 142 from contacting the second busbar 33 and causing a short circuit, a third insulating layer 120 (such as insulating glue) needs to be provided at the position corresponding to the second busbar 33 and the fourth edge connection area 142. The height of the third insulating layer 120 is higher than that of the first grid line 20 (including the second connecting grid line 23). That is, in the thickness direction, the protruding height of the third insulating layer 120 is higher than the height of the first grid line 20. In such a case, the solder tape in the fourth edge connection area 142 is likely to be poorly soldered to the first grid line 20 during the soldering process, resulting in the inability to effectively collect the current on some of the first grid lines 20 (especially the first grid line 20 adjacent to the second busbar 33, which has the highest probability of poor soldering). Based on this, the present application connects at least two first grid lines 20 on the same side of the second busbar 33 by providing a fourth auxiliary connection line 130, and preferably selects the first grid lines 20 connected thereto to include the one adjacent to the second busbar 33. It can connect some of the first grid lines 20 into a whole through the fourth auxiliary connection line 130 at the fourth edge connection area 142. Even if one of the first grid lines 20 is poorly soldered due to the presence of the third insulating layer 120, it can still output current through the fourth auxiliary connection line 130, thereby reducing or even completely eliminating the influence caused by poor soldering.

[0231] In addition, since the second connecting grid line 23 is located between two third insulating layers 120, the risk of its poor soldering is the greatest. If the second connecting grid line 23 is discontinuous at the fifth edge connection area 133, it is likely to have an isolated segment, resulting in the inability to collect the current in this part. Therefore, setting the second connecting grid line 23 to be continuous at the fifth edge connection area 133 can avoid the problem that an isolated segment causes the inability to collect some of the current.

[0232] Since the second connection grid line 23 is continuous at both the fourth edge series connection area 142 and the fifth edge series connection area 133, in order to prevent the solder tape on the fifth edge series connection area 133 from contacting the second connection grid line 23 and causing a short circuit, a fourth insulating layer 1210 (such as insulating glue) needs to be provided at the position corresponding to the fifth edge series connection area 133 of the second connection grid line 23. The height of the fourth insulating layer 1210 is higher than that of the second grid line 30. That is, in the thickness direction, the protruding height of the fourth insulating layer 1210 is higher than that of the second grid line 30. In such a case, the solder tape in the fifth edge series connection area 133 is likely to have a poor solder joint with the second grid line 30 during the soldering process, resulting in the inability to effectively collect the current on some of the second grid lines 30. Especially for the second grid line 30 adjacent to the second connection grid line 23 (i.e., the second busbar grid line 33), the possibility of a poor solder joint on this grid line is the greatest. Based on this, the present application connects the second busbar grid line 33 on one side of the second connection grid line 23 and at least one second grid line 30 adjacent to the second busbar grid line 33 by providing a fifth auxiliary connection line 1310. It can connect the second busbar grid line 33 and the at least one other second grid line 30 into a whole at the fifth edge series connection area 133 through the fifth auxiliary connection line 1310. Even if a poor solder joint occurs on one of the first grid lines 20 due to the presence of the fourth insulating layer 1210, the current can still be output through the fifth auxiliary connection line 1310, thereby reducing or even completely eliminating the influence of the poor solder joint caused by the fourth insulating layer 1210.

[0233] As Figure 3 and Figure 12 shown, in the embodiments of the present application, in order to minimize the influence of poor solder joints as much as possible, when there are at least two first grid lines 20 on both sides of the second busbar grid line group 310, it is preferably to simultaneously provide fourth auxiliary connection lines 130 on both sides of the second busbar grid line group 310. Of course, if the second busbar grid line group 310 is located at the outermost edge position in the second direction, the fourth auxiliary connection line 130 can be provided on one side of the second busbar grid line group 310

[0234] In some embodiments, the width of the second busbar grid line 33 (i.e., the length in the second direction) can be greater than the width of the part of the other second grid lines 30 outside the first series connection area 13 (i.e., the part other than the second soldering section 301) (i.e., the length in the second direction).

[0235] Thus, since the second bus bar 33 needs to undertake the function of bus bar transmission, the width of the second bus bar 33 is set wider, which can reduce the transmission loss during the bus bar process and improve the efficiency. The second welding section 301 is used for welding. Setting the second welding section 301 wider can improve the reliability and stability of welding. The width of the second bus bar 33 can be the same as the width of the second welding section 301.

[0236] In addition, as Figure 3 , Figure 12 and Figure 15 shown, in some embodiments, in the second bus bar 33, it is continuous only at the fourth edge series connection area 142, and is disconnected at other second series connection areas 14. Of course, in some embodiments, as described above, when the second bus bar 33 and the first connection bus bar 32 are the same bus bar, the second bus bar 33 is continuous at the second edge series connection area 141.

[0237] The second bus bar 33 is continuous at the fourth edge series connection area 142. Only one section of the second bus bar 33 closest to the second edge 122 (i.e., the part between the fifth edge series connection area 133 and the second edge 122) undertakes the bus bar function. Therefore, in some embodiments, in order to save paste to reduce costs, only this part of the bus bar section can be set wider.

[0238] In such a case, please refer to Figure 3 , Figure 12 and Figure 15 , the second bus bar 33 may include a second bus bar section 331 located between the fifth edge series connection area 133 and the second edge 122. In some embodiments, the width of the second bus bar section 331 (i.e., the length in the second direction) may be greater than the width of the remaining part of the second bus bar 33 outside the first series connection area 13 (i.e., the part other than the second bus bar section 331 and other than the second welding section 301).

[0239] Thus, only setting the width of the second bus bar section 331 wider can reduce the use of paste while reducing the bus bar transmission loss, thereby reducing costs.

[0240] Specifically, as described above, in such an embodiment, the second bus bar section 331 can bus bar the current to the solder strip provided at the fifth edge series connection area 133, and only setting a part of the second bus bar section 331 wider can reduce the use of paste. In such a case, the second bus bar section 331 penetrates through the back passivation film layer 104 and contacts the first doping layer 102.

[0241] Please refer to Figure 15, in some other embodiments, a second busbar layer 140 may be disposed on the second busbar segment 331. Thus, by disposing the second busbar layer 140 on the second busbar segment 331, it is equivalent to increasing the cross-sectional area of the second busbar segment 331, which can also reduce transmission losses. At the same time, the second busbar layer 140 can be made of a paste with a lower cost compared to the second busbar segment 331, which can reduce costs.

[0242] Specifically, in such an embodiment, the second busbar grid line 33 may be an ordinary grid line. Except for being wider at the second welding segment 301, the widths at other positions may be the same. And disposing the second busbar layer 140 on the second busbar segment 331 is equivalent to increasing the cross-sectional area of the second busbar segment 331. That is to say, since the second busbar layer 140 is disposed on the second busbar segment 331, it is not necessary to widen the second busbar segment 331, and the same purpose of reducing transmission losses can be achieved. Of course, in some embodiments, the second busbar segment 331 may also be widened, and specific details are not limited herein.

[0243] The second busbar layer 140 may be made of a non-burn-through paste. The second busbar layer 140 does not penetrate the back passivation film layer 104 to contact the first doping layer 102. The paste cost of the second busbar layer 140 is lower than that of the second busbar segment 331. For example, when neither the second busbar layer 140 nor the second busbar segment 331 has a silver paste layer, the silver content in the second busbar layer 140 may be lower than that in the second busbar segment 331. Another example is that the second busbar segment 331 may be a silver paste layer, and the second busbar layer 140 may be a metal layer with a lower cost such as a copper layer or a silver-coated copper layer.

[0244] Furthermore, in such an embodiment, the width (length in the second direction) of the second busbar layer 140 may be greater than the width (length in the second direction) of the portions of the other second grid lines 30 located outside the first series connection region 13 (i.e., the portions other than the second welding segment 301) except the second busbar grid line 33. Thus, by increasing the width of the second busbar layer 140, the transmission capacity can be further improved and the transmission loss can be reduced.

[0245] In such an embodiment, the width of the second busbar layer 140 may be the same as the width of the second welding segment 301. In this article, the width of the second welding segment 301 refers to the length of the second welding segment 301 in the second direction. As shown above, when the width of the first welding layer is greater than the width of the first collection layer, the width of the second welding segment 301 is the width of the first welding layer (i.e., the length in the second direction). For similar descriptions that appear later, this understanding can be referred to.

[0246] In this way, it can be ensured that there will be no significant transmission loss during the current collecting process. At the same time, during the printing process, the second current collecting 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 open screen printing slots of different sizes on the screen printing plate, which saves manufacturing processes and reduces manufacturing difficulty.

[0247] Please refer 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 portions of the remaining second grid lines 30 other than the second current collecting grid line 33 that are located outside the first series connection region 13 (i.e., the portions of the remaining second grid lines 30 other than the second current collecting grid line 33 that are other than the second welding section 301).

[0248] In this way, since the second edge connection line 110 needs to undertake the function of current collecting and transmission, setting the width of the second edge connection line 110 wider can also reduce the transmission loss during the current collecting process and improve efficiency.

[0249] Specifically, in such an embodiment, the width of the second edge connection line 110 can be the same as the width of the second welding section 301. In this way, it can be ensured that there will be no significant current collecting loss during the current collecting process.

[0250] In addition, please continue to refer to Figure 15 , 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 portions of the first grid lines 20 that are located outside the second series connection region 14 (the portions of the first grid lines 20 other than the first welding section 201).

[0251] In this way, since the fourth auxiliary connection line 130 functions to transmit and collect current when virtual soldering occurs, setting the width of the fourth auxiliary connection line 130 wider can also reduce the transmission loss during the current collecting process and improve efficiency.

[0252] In some embodiments, the width of the fourth auxiliary connection line 130 can be the same as the width of the second edge connection line 110, and the widths of both can also be the same as the widths of the second welding section 301 and the first welding section 201.

[0253] Please refer to Figure 3 and Figure 12 , in some embodiments, the second edge connection line 110 is electrically connected to all the second grid lines 30.

[0254] In this way, the current collected by all the isolated grid line segments of the second grid lines 30 that are located between the fourth edge series connection region 142 and the second edge 122 can be collected, and the efficiency of the back contact battery 100 can be improved to the greatest extent.

[0255] Of course, in some embodiments, the second edge connection line 110 may also be electrically connected only to some of the remaining second gate lines 30 other than the second bus gate line 33. In such a case, the number of second gate lines 30 not electrically connected to the second edge connection line 110 is less than or equal to 4. Thus, even if some of the second gate lines 30 are not connected to the second edge connection line 110, the number is small and will not cause excessive efficiency loss and product defects.

[0256] In some embodiments, the fourth auxiliary connection line 130 is connected to 2 - 20 first gate lines 20. Thus, setting the number of first gate lines 20 connected to the fourth auxiliary connection line 130 within this reasonable range can minimize or even eliminate the impact of false soldering.

[0257] In the embodiments of the present application, the number of the second bus gate line groups 310 may be single. In such a case, the fourth auxiliary connection line 130 may be provided only on one side of the second bus gate line group 310, or may be provided on both sides of the second bus gate line group 310. Specifically, there is no limitation here. When there are at least two first gate lines 20 on both sides of the second bus gate line group 310, it is preferred to provide the fourth auxiliary connection line 130 on both sides.

[0258] In addition, it should be noted that in the present application, when the number of the second bus gate line groups 310 is multiple, the fourth auxiliary connection line 130 may also be provided only on one side or both sides of some of the second bus gate line groups 310, while the fourth auxiliary connection line 130 may not be provided on both sides of the remaining second bus gate line groups 310. In such a case, it can also solve the problem of false soldering at some positions. In the present application, it is preferred that the fourth auxiliary connection line 130 is provided on both sides of each second bus gate line group 310. Of course, if the second bus gate line group 310 is located at the third edge 123, only the fourth auxiliary connection line 130 needs to be provided on one side of the second bus gate line 33.

[0259] Of course, please refer to Figure 3 and Figure 12 , in some embodiments, the number of the second bus gate line groups 310 is multiple, and the multiple second bus gate line groups 310 are arranged at intervals in the second direction. Thus, arranging multiple second bus gate line groups 310 can shorten the current bus path, effectively reduce the bus transmission loss, and improve the efficiency.

[0260] In such a case, fourth auxiliary connection lines 130 are provided on both sides of the second busbar line group 310, and fourth auxiliary connection lines 130 are provided between adjacent second busbar line groups 310. The fourth auxiliary connection lines 130 between adjacent second busbar line groups 310 are connected to all the first grid lines 20 between adjacent second busbar line groups 310.

[0261] In this way, by connecting the fourth auxiliary connection lines 130 to all the first grid lines 20 between adjacent second busbar line groups 310, the influence caused by virtual soldering can be basically completely eliminated, and the efficiency of the back contact battery 100 can be improved as much as possible.

[0262] Specifically, in such an embodiment, the number of the second busbar line groups 310 in the back contact battery 100 can be selected according to the actual situation such as the size of the battery chip and the loss during the transmission process, and no limitation is made here.

[0263] Please refer to Figure 3 and Figure 12 , in some embodiments, the number of the second busbar line groups 310 is multiple, and the multiple second busbar line groups 310 are arranged at intervals in the second direction. Fourth auxiliary connection lines 130 are provided on both sides of the second busbar line group 310. The substrate 10 has a third edge 123 and a fourth edge 124 in the second direction;

[0264] Some of the second grid lines 30 further include a third-edge busbar line 303, and the third-edge busbar line 303 is located between the third edge 123 and the second busbar line group 310 closest to the third edge 123. The third-edge busbar line 303 is continuous at the fourth-edge connection area 142 and the fifth-edge connection area 133 and is electrically connected to the second-edge connection line 110; and / or

[0265] Some of the second grid lines 30 further include a fourth-edge busbar line 304, and the fourth-edge busbar line 304 is located between the fourth edge 124 and the second busbar line group 310 closest to the fourth edge 124. The fourth-edge busbar line 304 is continuous at the fourth-edge connection area 142 and the fifth-edge connection area 133 and is electrically connected to the second-edge connection line 110.

[0266] In this way, by providing the third-edge busbar line 303 and the fourth-edge busbar line 304, the busbar path can be further shortened, and the busbar transmission loss can be reduced.

[0267] Specifically, it is not difficult to understand that since the third-edge busbar line 303 and the fourth-edge busbar line 304 are continuous at the fourth-edge connection area 142, an insulating layer also needs to be provided thereon. Therefore, as Figure 3 and Figure 12As shown, within the fourth edge connection region 142, auxiliary connection lines may also be provided between the third edge bus bar 303 and the third edge 123. These auxiliary connection lines can connect all the first grid lines 20 between the third edge bus bar 303 and the third edge 123. Similarly, within the fourth edge connection region 142, auxiliary connection lines may also be provided between the fourth edge bus bar 304 and the fourth edge 124. These auxiliary connection lines can connect all the first grid lines 20 between the fourth edge bus bar 304 and the fourth edge 124. Thus, through such a design, the soldering void effect caused by the insulating layers on the third edge bus bar 303 and the fourth edge bus bar 304 can be basically reduced or even eliminated.

[0268] Of course, it can be understood that in some embodiments, the third edge bus bar 303 and the fourth edge bus bar 304 may not be provided.

[0269] In such a case, the fourth auxiliary connection line 130 between the third edge 123 and the second bus bar group 310 closest to the third edge 123 can connect all the first grid lines 20 between the third edge 123 and the second bus bar group 310 closest to the third edge 123. And / or the fourth auxiliary connection line 130 between the fourth edge 124 and the second bus bar group 310 closest to the fourth edge 124 connects all the first grid lines 20 between the fourth edge 124 and the second bus bar group 310 closest to the fourth edge 124.

[0270] Thus, through such a design, it is possible to avoid the soldering void at the starting and ending solder joints at the upper and lower ends of the fourth edge connection region 142, which may cause performance degradation.

[0271] Please refer to Figure 15 and 16 , as described above, the second grid line 30 may include a second welding section 301 corresponding to the first connection region 13, and the first grid line 20 includes a first welding section 201 corresponding to the fourth edge connection region 142.

[0272] In some embodiments, within the fourth edge connection region 142, a second groove 16 is formed on the substrate 10. The second bus bar 33 is partially located within the second groove 16, and the 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 towards the back side 12), the height of the third insulating layer 120 is flush with the height of the first welding section 201, or the height of the third insulating layer 120 is less than the height of the first welding section 201, or the height of the third insulating layer 120 is greater than the height of the first welding section 201, and the height difference between the third insulating layer 120 and the first welding section 201 is less than or equal to 15um.

[0273] Thus, by forming the second groove 16 on the substrate 10 and disposing the third insulating layer 120 in the groove, the height of the third insulating layer 120 can be made less than the height of the first welding section 201, or the third insulating layer 120 can be flush with the first welding section 201, or the height of the third insulating layer 120 is greater than that of the first welding section 201 and the height difference between the two is less than or equal to 15 μm, thereby further reducing the risk of false soldering caused by the third insulating layer 120.

[0274] In some embodiments, the second groove 16 can penetrate through the back passivation film layer 104 and the second doping layer 103, so that the silicon substrate 101 is exposed from the second groove 16, and the part of the second busbar grid line 33 located in the second groove 16 is in contact with the silicon substrate 101. In this way, after the substrate 10 is manufactured, the second groove 16 can be directly formed on the substrate 10 by etching (such as laser etching, etc.), without inserting an etching and grooving process during the preparation process of the substrate 10.

[0275] Specifically, in such a case, a complete substrate 10 can be provided first, and then grooving treatment is directly performed at the position on the substrate 10 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 disposed at the second groove 16.

[0276] Of course, in some other embodiments, a second indentation groove may be formed on the silicon substrate 101 at a position corresponding to the fourth edge series connection region 142 and the second busbar grid line 33, and both the second doping layer 103 and the back passivation film layer 104 are recessed toward the side where the front surface 11 is located at the second indentation groove, so as to form the second groove 16 on the substrate 10.

[0277] Specifically, in such a case, during the manufacturing process, before preparing the first doping layer 102, a second indentation groove can be formed first at the position in the silicon substrate 101 where the second doping layer 103 needs to be prepared and the third insulating layer 120 needs to be placed, and then the first doping layer 102 and the back passivation film layer 104 are prepared, thereby forming the substrate 10. Since the second indentation groove is formed on the silicon substrate 101, the above-mentioned second groove 16 can be correspondingly formed on the substrate 10, then the second grid line 30 and the first grid line 20 are printed, and then the third insulating layer 120 is disposed at the second groove 16.

[0278] Please refer to Figure 17, in some embodiments, at the fourth edge connection area 142, a second auxiliary connection layer 150 may be provided on the first grid line 20. The second auxiliary connection layer 150 is used for welding with a 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 um.

[0279] Thus, by providing the second auxiliary connection layer 150 on the part of the first grid line 20 corresponding to the fourth edge 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 is greater than the height of the second auxiliary connection layer 150 and the height difference between the two is less than or equal to 15 um, thereby reducing the risk of false soldering caused by the third insulating layer 120.

[0280] Specifically, in such an embodiment, the second auxiliary connection layer 150 may be stacked on the first welding section 201. The second auxiliary connection layer 150 may be a conductive material layer such as a solder paste layer, which is used for welding with a solder strip during the welding process, and is not specifically limited herein.

[0281] Please refer to Figure 12 、 Figure 18 and Figure 19 , in some embodiments, the second edge connection line 110 may include an intermediate bus section 113, a first edge bus section 111, and a second edge bus section 112. The intermediate bus section 113, the first edge bus section 111, and the second edge bus section 112 all extend along the second direction. As Figure 12 shown, the three may be arranged in parallel at intervals along the first direction. The intermediate bus section 113 is closer to the second edge 122 than the first edge bus section 111 and the second edge bus section 112.

[0282] The first edge bus section 111 is arranged close to the third edge 123, and the second edge bus section 112 is arranged close to the fourth edge 124. The second edge connection line 110 further includes a first connection section 114 and a second connection section 115. The first connection section 114 and the second connection section 115 both extend along the first direction. The first connection section 114 connects the intermediate bus section 113 and the first edge bus section 111, and the second connection section 115 connects the intermediate bus section 113 and the second edge bus section 112;

[0283] Among them, the first edge busbar segment 111 is connected to the two second gate lines 30 closest to the third edge 123. At the junction of the first edge busbar segment 111 and the first connection segment 114, the first edge busbar segment 111 has a third convex portion 1101 protruding toward the fourth edge 124, and the first connection segment 114 has a fourth convex portion 1102 protruding toward the first edge 121. At the junction of the middle busbar segment 113 and the first connection segment 114, the middle busbar segment 113 has a fifth convex portion 1103 protruding toward the third edge 123, and the first connection segment 114 has a sixth convex portion 1104 protruding toward the second edge 122; and / or

[0284] The second edge busbar segment 112 is connected to the two second gate lines 30 closest to the fourth edge 124. At the junction of the second edge busbar segment 112 and the second connection segment 115, the second edge busbar segment 112 has a seventh convex portion 1105 protruding toward the third edge 123, and the second connection segment 115 has an eighth convex portion 1106 protruding toward the first edge 121. At the junction of the middle busbar segment 113 and the second connection segment 115, the middle busbar segment 113 has a ninth convex portion 1107 protruding toward the fourth edge 124, and the second connection segment 115 has a tenth convex portion 1108 protruding toward the second edge 122.

[0285] In this way, when there are chamfers at the junctions of the second edge 122 with the third edge 123 and the fourth edge 124, by setting the second edge connection line 110 into a structure of 3 vertical segments + 2 horizontal segments, the chamfers can be avoided, reducing the printing difficulty. At the same time, by setting corresponding convex portions at the junctions of each busbar segment, redundancy can be set at the corners of the second edge 122, avoiding poor contact between each busbar segment caused by inaccurate printing during the printing process, resulting in incomplete filling of the slurry at the corners.

[0286] Of course, it can be understood that in some embodiments, when there are chamfers formed at the intersections of the second edge 122 with the third edge 123 and the fourth edge 124, the second edge connection line 110 can also be set in the same way as the first edge connection line 40 (for example, there are bending portions), and specific details are not limited here. Of course, it can be understood that in some embodiments, if there are no chamfers in the back-contact battery 100, only a second edge connection line 110 extending vertically and continuously along the second direction needs to be set.

[0287] Please refer to Figure 18 and Figure 19 , in some embodiments, at the junction of the second gate line 30 and the second edge connection line 110, at least part of the second gate line 30 has a second gate line convex portion 302 protruding toward the second edge 122 compared to the second edge connection line 110.

[0288] In this way, by providing the second gate line convex portion 302, the stability of the electrical connection between the second gate line 30 and the second edge connection line 110 can be ensured, effectively avoiding the phenomenon that some of the second gate lines 30 cannot form a stable contact with the second edge connection line 110 due to printing accuracy during the printing process.

[0289] Please refer to Figure 3 and Figure 12 , in some embodiments, the number of the second connection gate lines 23 is multiple, the number of the second connection gate lines 23 is the same as and corresponds to that of the second bus gate line group 310 one by one, the multiple second connection gate lines 23 are arranged at intervals along the second direction, and each second connection gate line 23 corresponds to a second bus gate line group 310. In the fifth edge series connection area 133, fifth auxiliary connection lines 1310 are provided on both sides of the second bus gate line group 310, and two second bus gate lines 33 in the second bus gate line group 310 are respectively connected to one fifth auxiliary connection line 1310. In this way, the virtual soldering influence brought by the fourth insulating layer 1210 on both sides can be reduced.

[0290] Please refer to Figure 3 and Figure 12 , in such an embodiment, the fifth auxiliary connection lines 1310 located between two adjacent second bus gate line groups 310 are connected to all the second gate lines 30 located between two adjacent second bus gate line groups 310. In this way, the virtual soldering influence brought by the fourth insulating layer 1210 can be basically eliminated completely.

[0291] Of course, it can be understood that, in some embodiments, the fifth auxiliary connection lines 1310 can also be provided on one side of the second connection gate lines 23, which can also reduce the virtual soldering influence in some areas. Of course, in the present application, it is preferred to provide the fifth auxiliary connection lines 1310 on both sides of the second connection gate lines 23.

[0292] In addition, in some alternative embodiments, when the second connection gate lines 23 are multiple, the fifth auxiliary connection lines 1310 can also be provided on at least one of some of the second connection gate lines 23, while the fifth auxiliary connection lines 1310 are not provided on both sides of the remaining second connection gate lines 23, which can also reduce the virtual soldering influence in some areas.

[0293] In some embodiments, the width (the length in the first direction) of the fifth auxiliary connection lines 1310 is greater than the width (the length in the second direction) of the portions (i.e., the second welding segments 301) of the remaining second gate lines 30 other than the second bus gate lines 33 located outside the first series connection area 13.

[0294] Thus, since the fifth auxiliary connection line 1310 functions to transmit and converge current when a soldering defect occurs, setting the width of the fifth auxiliary connection line 1310 wider can also reduce transmission losses during the current convergence process and improve efficiency.

[0295] Specifically, in such an embodiment, the width of the fifth auxiliary connection line 1310 may be the same as the width of the second soldering section 301.

[0296] Please refer to Figure 3 、 Figure 12 and Figure 15 In some embodiments, several second series connection regions 14 further include a sixth edge series connection region 143 adjacent to the fifth edge series connection region 133. The sixth edge series connection region 143 is located on a side of the fifth edge series connection region 133 away from the second edge 122.

[0297] The second connection gate line 23 is continuous at the sixth edge series connection region 143. A sixth auxiliary connection line 160 is provided in the sixth edge series connection region 143. In the second direction, the sixth auxiliary connection line 160 connects the second connection gate line 23 and at least one first gate line 20 located on both sides of the second connection gate line 23.

[0298] Thus, by providing the sixth auxiliary connection line 160 in the sixth edge series connection region 143, it is possible to effectively avoid the phenomenon that the current transmitted from the second connection gate line 23 cannot be collected due to a soldering defect or poor contact of the solder tape in the sixth edge series connection region 143 at the second connection gate line 23.

[0299] Specifically, as Figure 12 and Figure 15 shown, in such an embodiment, the number of the sixth auxiliary connection lines 160 may be the same as the number of the second connection gate lines 23, and they correspond to each other one by one. The sixth auxiliary connection line 160 connects the second connection gate line 23 and also connects two adjacent first gate lines 20 of the second connection gate line 23.

[0300] In some embodiments, the width of the sixth auxiliary connection line 160 (the length in the first direction) may be greater than the width (the length in the second direction) of the part of the first gate line 20 other than the part located in the second series connection region 14 (i.e., other than the first soldering section 201). Thus, setting the width of the sixth auxiliary connection line 160 wider can also reduce transmission losses during the current convergence process and improve efficiency.

[0301] In some embodiments, the distance between the fourth edge series connection region 142 and the second edge 122 is greater than or equal to 2 mm and less than or equal to 20 mm.

[0302] In this way, it is possible to avoid the distance between the fourth edge connection region 142 and the second edge 122 being too small, which may cause the welding position to be too close to the second edge 122, resulting in hidden cracks in the back-contact battery 100 and reducing the risk of hidden cracks. It is also possible to avoid the distance between the fourth edge connection region 142 and the second edge 122 being too large, which may cause the length of the isolated gate line segment located between the fourth edge connection region 142 and the second edge 122 to be too long, resulting in excessive loss during the transmission path.

[0303] Specifically, in such an embodiment, the distance between the fourth edge connection region 142 and the second edge 122 can be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, or any value between 2mm and 20mm, and specific values are not limited here.

[0304] In the above embodiment, the polarities of the fourth edge connection region 142 and the first edge connection region 131 are opposite, the polarities of the fifth edge connection region 133 and the second edge connection region 141 are opposite, and the polarities of the sixth edge connection region 143 and the third edge connection region 132 are opposite. The click structures of the two edges of the back-contact battery 100 in the first direction are different and asymmetric.

[0305] It can be understood that in some possible embodiments, the polarities of the fourth edge connection region 142 and the first edge connection region 131 can also be the same, the polarities of the fifth edge connection region 133 and the second edge connection region 141 can also be the same, and the polarities of the sixth edge connection region 143 and the third edge connection region 132 can also be the same. In such a case, the structures of the two edges of the back-contact battery 100 in the first direction are the same and symmetric. That is to say, in such a case, in the back-contact battery 100, the three connection regions closest to the second edge 122 are symmetric with the first edge connection region 131, the second edge connection region 141, and the third edge connection region 132. Structures such as edge connection lines and auxiliary connection lines are also provided on one side of the second edge 122, which are completely symmetric with one side of the first edge 121. To avoid redundancy, the specific structure is not described in detail here.

[0306] Please refer to Figure 3, in some embodiments, the substrate 10 has a third edge 123 and a fourth edge 124 in the second direction. In the first connection area 13 except for the first edge connection area 131 and the fifth edge connection area 133, a seventh auxiliary connection line 170 and an eighth auxiliary connection line 180 may also be provided. The seventh auxiliary connection line 170 connects N second gate lines 30 closest to the third edge 123, and the eighth auxiliary connection line 180 connects M second gate lines 30 closest to the fourth edge 124, where both N and M are greater than or equal to 2 and less than or equal to 8.

[0307] In some embodiments, in the second connection area 14 except for the second edge connection area 141 and the fourth edge connection area 142, a ninth auxiliary connection line 190 and a tenth auxiliary connection line 1100 may also be provided. The ninth auxiliary connection line 190 connects P first gate lines closest to the third edge, and the tenth auxiliary connection line 1100 connects Q first gate lines closest to the fourth edge, where both P and Q are greater than or equal to 2 and less than or equal to 8.

[0308] In this way, by respectively arranging the seventh auxiliary connection line 170 and the eighth auxiliary connection line 180 at the head and tail ends of the solder tape in the first connection area 13 of the middle area, the problem that the solder tape on the first connection area 13 is prone to virtual soldering at the starting solder point and the ending solder point positions, resulting in the inability to collect the current of some gate lines, can be effectively avoided. Similarly, by respectively arranging the ninth auxiliary connection line 190 and the tenth auxiliary connection line 1100 at the positions close to the third edge 123 and the fourth edge 124 in the second connection area 14 of the middle area, that is, by respectively arranging the ninth auxiliary connection line 190 and the tenth auxiliary connection line 1100 at the head and tail ends of the solder tape in the second connection area 14, the problem that the solder tape on the second connection area 14 is prone to virtual soldering at some positions of the starting solder point and the ending solder point, resulting in the inability to collect the current of some gate lines, can be effectively avoided.

[0309] Please refer to Figure 3, in some embodiments, within the first connection region 13, X first gate lines 20 closest to the third edge 123 are discontinuous at the first connection region 13, and Y first gate lines 20 closest to the fourth edge 124 are discontinuous at the first connection region 13. The width of the discontinuous 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 discontinuous 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, where both X and Y are greater than or equal to 2. That is to say, in such an embodiment, within the first connection region 13, among at least two second gate lines 30 closest to the third edge 123, the length of the second welding segment 301 on the second gate line 30 closer to the third edge 123 is wider in the second direction. Among at least two second gate lines 30 closest to the fourth edge 124, the length of the second welding segment 301 on the second gate line 30 closer to the fourth edge 124 is wider in the second direction.

[0310] Within the second connection region 14, W second gate lines 30 closest to the third edge 123 are discontinuous at the second connection region 14, and Z second gate lines 30 closest to the fourth edge 124 are discontinuous at the second connection region 14. The width of the discontinuous 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 discontinuous 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, where both W and Z are greater than or equal to 2. That is to say, in such an embodiment, within the second connection region 14, among at least two first gate lines 20 closest to the third edge 123, the length of the first welding segment 201 on the first gate line 20 closer to the third edge 123 is wider in the second direction. Among at least two first gate lines 20 closest to the fourth edge 124, the length of the first welding segment 201 on the first gate line 20 closer to the fourth edge 124 is wider in the second direction.

[0311] In the description of this specification, the descriptions with reference to terms such as "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0312] In addition, the above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A back contact battery, characterized in that: include: A substrate, wherein the back side of the substrate has a first edge and a second edge opposite to each other in a first direction, and the back side further has a plurality of first series connection areas and a plurality of second series connection areas alternately arranged in the first direction, wherein the first series connection area includes a first edge series connection area closest to the first edge, there is no second series connection area between the first edge series connection area and the first edge, and the second series connection area includes a second edge series connection area adjacent to the first edge series connection area; A plurality of first grid lines and a plurality of second grid lines arranged on the back side are alternately arranged along a second direction, the second direction intersects with the first direction, and the first grid lines and the second grid lines both intersect with the first series connection area and the second series connection area; the plurality of first grid lines include at least one first bus grid line group, the first bus grid line group includes two adjacent first bus grid lines, and the first bus grid lines are continuous at the first edge series connection area and the second edge series connection area; the plurality of second grid lines include at least one first connecting grid line, the first connecting grid line is located between two first bus grid lines in the first bus grid line group and is continuous at the first edge series connection area and the second edge series connection area; A first edge connection line closer to the first edge than the first edge series region, the first edge connection line being electrically connected to the first bus grid line and to at least part of the remaining first grid lines; A first insulating layer disposed on a portion of the first busbar line corresponding to the first edge series connection region; A second insulating layer disposed on a portion of the first connecting gate line corresponding to the second edge series connection region; and A first auxiliary connecting line is arranged in the first edge series area and a second auxiliary connecting line is arranged in the second edge series area. In the second direction, the first auxiliary connecting line is arranged on at least one side of the first bus grid line group, and the first auxiliary connecting line connects at least two of the second grid lines located on the same side of the first bus grid line group; in the second direction, the second auxiliary connecting line is arranged on at least one side of the first bus grid line group, and the second auxiliary connecting line is connected to the first bus grid line located on one side of the first connecting grid line and at least one of the first grid lines adjacent to the first bus grid line.

2. The back contact cell according to claim 1, characterized in that: Among several first gate lines, at least some of the remaining first gate lines except the first bus gate line are discontinuous at the first edge series area and continuous at the second edge series area; among several second gate lines, at least some of the remaining second gate lines except the first connecting gate line are continuous at the first edge series area and discontinuous at the second edge series area.

3. The back contact cell 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 cell 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 some of the first gate lines except the first bus gate line, and the number of the first gate lines not electrically connected to the first edge connection line is less than or equal to four.

5. The back contact cell according to claim 1, characterized in that: The first auxiliary connection line is connected to 20 of the second gate lines.

6. The back contact cell according to claim 1, characterized in that: There are a plurality of first busbar line groups, and the plurality of first busbar line groups are arranged at intervals in the second direction; In the second direction, the first auxiliary connecting lines are provided on both sides of the first bus bar group, and the first auxiliary connecting lines are provided between two adjacent first bus bar groups, and the first auxiliary connecting lines located between two adjacent first bus bar groups connect all the second bus bar lines located between two adjacent first bus bar groups.

7. The back contact cell according to claim 1, characterized in that: There are a plurality of first busbar line groups, the plurality of first busbar line groups are arranged at intervals in the second direction, both sides of the first busbar line groups are provided with the first auxiliary connection lines, and the substrate has a third edge and a fourth edge in the second direction; The first auxiliary connection line located between the third edge and the first busbar line group closest to the third edge connects all the second busbar lines located between the third edge and the first busbar line group closest to the third edge; and / or The first auxiliary connection line located between the fourth edge and the first bus bar line group closest to the fourth edge connects all the second bus bar lines located between the fourth edge and the first bus bar line group closest to the fourth edge.

8. The back contact cell according to claim 1, characterized in that: There are a plurality of first busbar line groups, the plurality of first busbar line groups are spaced apart in the second direction, and the substrate has a third edge and a fourth edge in the second direction; The plurality of first gate lines further include 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 the first edge series connection area and the second edge series connection area and is electrically connected to the first edge connection line; and / or Several of the first gate lines also include a second edge bus gate line. Among the first gate lines and the second gate lines, the second edge bus gate line is the gate line closest to the fourth edge. The second edge bus gate line is continuous at the first edge series connection area and the second edge series connection area and is electrically connected to the first edge connection line.

9. The back contact cell 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 is connected to the first edge connection line, the first edge connection line has a first protrusion protruding toward the third edge; and / or At the junction where the second edge busbar line is connected to the first edge connection line, the first edge connection line has a second protrusion protruding toward the fourth edge.

10. The back contact cell according to claim 1, characterized in that: The width of the first bus gate line is greater than the width of a portion of the first gate lines other than the first bus gate line that is located outside the second series connection region.

11. The back contact cell according to claim 1, characterized in that: The first busbar line includes a first busbar segment located between the second edge series connection region and the first edge; Wherein, the width of the first bus segment is greater than the width of the remaining portion of the first bus grid line located outside the second series connection area; and / or A first busbar layer is provided on the first busbar segment.

12. The back contact cell according to claim 11, characterized in that: The width of the first bus layer is greater than the width of the portion of the first bus line other than the first bus line that is located outside the second series connection region.

13. The back contact cell according to claim 1, characterized in that: The width of the first edge connection line is greater than the width of the remaining first gate lines except the first bus gate line and located outside the second series connection area.

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

15. The back contact cell according to claim 1, characterized in that: There are a plurality of first connecting gate lines, the plurality of first connecting gate lines are arranged at intervals along the second direction, and each of the first connecting gate lines corresponds to one of the first bus gate line groups; In the second edge series connection region, the second auxiliary connection lines are disposed on both sides of the first bus bar line group, and two of the first bus bar lines in the first bus bar line group are respectively connected to one corresponding second auxiliary connection line.

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

17. The back contact cell according to claim 1, characterized in that: The width of the second auxiliary connection line is greater than the width of a portion of the first gate lines other than the first bus gate line that is located outside the second series connection region.

18. The back contact cell according to claim 1, characterized in that: The first series connection areas further include a third edge series connection area adjacent to the second edge series connection area, and the third edge series connection area is located on a side of the second edge series connection area away from the first edge; The first connection gate line is continuous at the third edge series connection area. A third auxiliary connection line is provided in the third edge series connection area. In the second direction, the third auxiliary connection line connects the first connection gate line and at least one second gate line located on both sides of the first connection gate line.

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

20. The back contact cell according to claim 1, characterized in that The plurality of second serial connection areas include a fourth edge serial connection area closest to the second edge, and there is no first serial connection area between the fourth edge serial connection area and the second edge; and the plurality of first serial connection areas further include a fifth edge serial connection area adjacent to the fourth edge serial connection area; The plurality of second gate lines include at least one second bus gate line group, the second bus gate line group includes two adjacent second bus gate lines, and among the plurality of second gate lines, the second bus gate lines are continuous at the fourth edge series connection area and the fifth edge series connection area, and at least some of the remaining second gate lines are discontinuous at the fourth edge series connection area and continuous at the fifth edge series connection area; The plurality of first gate lines include at least one second connecting gate line, the second connecting gate line is located between two second bus gate lines in the second bus gate line group, and among the plurality of first gate lines, the second connecting gate line is continuous at the fourth edge series connection area and the fifth edge series connection area, and the remaining first gate lines are continuous at the fourth edge series connection area and discontinuous at the fifth edge series connection area; The back contact battery further comprises: a second edge connection line, the second edge connection line being closer to the second edge than the fourth edge series connection area, the second edge connection line being electrically connected to the second bus grid line, and the second edge connection line being electrically connected to at least part of the second grid lines other than the second bus grid line; a third insulating layer and a fourth insulating layer, wherein the third insulating layer is disposed on a portion of the second bus grid line corresponding to the fourth edge series connection region, and the fourth insulating layer is disposed on a portion of the second connection grid line corresponding to the fifth edge series connection region; and a fourth auxiliary connection line and a fifth auxiliary connection line, wherein the fourth auxiliary connection line is arranged in the fourth edge series connection area, and in the second direction, at least one side of the second bus grid line group is provided with the fourth auxiliary connection line, and the fourth auxiliary connection line connects at least two of the first grid lines located on the same side of the second bus grid line group, wherein the at least two of the first grid lines connected to the fourth auxiliary connection line include the first grid line adjacent to the second bus grid line group; The fifth auxiliary connecting line is arranged in the fifth edge series area. In the second direction, the fifth auxiliary connecting line is provided on at least one side of the second bus grid line group. The fifth auxiliary connecting line is connected to the second bus grid line located on one side of the second connecting grid line and at least one second grid line adjacent to the second bus grid line.

21. The back contact cell 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 some of the second gate lines except the second bus gate line, and the number of the second gate lines not electrically connected to the second edge connection line is less than or equal to four.

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

23. The back contact cell according to claim 20, characterized in that There are a plurality of second busbar line groups, and the plurality of second busbar line groups are arranged at intervals in the second direction; In the second direction, the fourth auxiliary connecting line is provided on both sides of the second bus grid line group, and the fourth auxiliary connecting line is provided between two adjacent second bus grid line groups. The fourth auxiliary connecting line located between two adjacent second bus grid line groups connects all the first grid lines located between two adjacent second bus grid line groups.

24. The back contact cell according to claim 20, characterized in that There are multiple second busbar line groups, the multiple second busbar line groups are arranged at intervals in the second direction, the fourth auxiliary connection lines are arranged on both sides of the second busbar line groups, and 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 bus grid line group closest to the third edge connects all the first grid lines located between the third edge and the second bus grid line group closest to the third edge; and / or The fourth auxiliary connection line located between the fourth edge and the second bus gate line group closest to the fourth edge connects all the first gate lines located between the fourth edge and the second bus gate line group closest to the fourth edge.

25. The back contact cell according to claim 20, characterized in that The substrate has a third edge and a fourth edge in the second direction; The plurality of second gate lines further include a third edge bus gate line, the third edge bus gate line is located between the third edge and the second bus gate line group closest to the third edge, the third edge bus gate line is continuous at the fourth edge series connection area and the fifth edge series connection area and is electrically connected to the second edge connection line; and / or Several of the first gate lines also include a fourth edge bus gate line, which is located between the fourth edge and the second bus gate line group closest to the fourth edge, and the fourth edge bus gate line is continuous at the fourth edge series connection area and the fifth edge series connection area and is electrically connected to the second edge connection line.

26. The back contact cell according to claim 20, characterized in that The substrate has a third edge and a fourth edge in the second direction, the second edge connection 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 arranged close to the third edge, and the second edge bus section is arranged close to the fourth edge; The second edge connection line further includes a first connection segment and a second connection segment, the first connection segment and the second connection segment both extend along the first direction, the first connection segment connects the middle bus segment and the first edge bus segment, and the second connection segment connects the middle bus segment and the second edge bus segment; Wherein, the first edge bus section connects two of the second grid lines closest to the third edge, and at the junction of the first edge bus section and the first connecting section, the first edge bus section has a third convex portion protruding toward the fourth edge, and the first connecting section has a fourth convex portion protruding toward the first edge, and at the junction of the middle bus section and the first connecting section, the middle bus section has a fifth convex portion protruding toward the third edge, and the first connecting section has a sixth convex portion protruding toward the second edge; and / or The second edge bus section connects the two second grid lines closest to the fourth edge. At the junction of the second edge bus section and the second connecting section, the second edge bus section 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 middle bus section and the second connecting section, the middle bus section 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 cell according to claim 20, characterized in that The width of the second bus gate line is greater than the width of a portion of the second bus gate lines other than the second bus gate line that is located outside the first series connection region.

28. The back contact cell according to claim 20, characterized in that The second busbar line includes a second bus segment located between the fifth edge series connection region and the second edge; Wherein, the width of the second bus segment is greater than the width of the remaining portion of the second bus grid line located outside the first series connection area; and / or A second bus layer is provided on the second bus section.

29. The back contact cell according to claim 28, characterized in that The width of the second bus layer is greater than the width of a portion of the second bus lines other than the second bus line that is located outside the first series connection region.

30. The back contact cell according to claim 20, characterized in that The width of the second edge connection line is greater than the width of a portion of the second gate lines other than the second bus gate line that is located outside the first series connection region.

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

32. The back contact cell according to claim 20, characterized in that There are a plurality of second connection grid lines, the plurality of second connection grid lines are arranged at intervals along the second direction, and each of the second connection grid lines corresponds to one second bus grid line group; In the fifth edge series connection region, the fifth auxiliary connection lines are disposed on both sides of the second bus bar line group, and two second bus bar lines in the second bus bar line group are respectively connected to one corresponding fifth auxiliary connection line.

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

34. The back contact cell according to claim 20, characterized in that The width of the fifth auxiliary connection line is greater than the width of a portion of the second gate lines other than the second bus gate line that is located outside the first series connection region.

35. The back contact cell according to claim 20, characterized in that The plurality of second serial connection areas further include a sixth edge serial connection area adjacent to the fifth edge serial connection area, and the sixth edge serial connection area is located on a side of the fifth edge serial connection area away from the second edge; The second connection gate line is continuous at the sixth edge series area. A sixth auxiliary connection line is provided in the sixth edge series area. In the second direction, the sixth auxiliary connection line connects the second connection gate line and at least one first gate line located on both sides of the second connection gate line.

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

37. A battery assembly, characterized in that: A back contact battery comprising any one of several claims 1-36.

38. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 37.

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