Back contact cell, cell assembly and photovoltaic system

Abstract

The invention 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, first bus grid lines and first connecting grid lines are continuous at a first edge serial connection area and a second edge serial connection area, the first connecting grid line is located between the two first bus grid lines, and the second connecting grid line is located between the two first bus grid lines. The first insulating layer is arranged on the portion, corresponding to the first edge serial connection area, of the first bus grid line, the second insulating layer is arranged on the portion, corresponding to the second edge serial connection area, of the first connecting grid line, and the first auxiliary connecting line is connected with at least two second grid lines located on the same side of the first bus grid line set. The second auxiliary connecting line is connected with the first bus grid line located on one side of the first connecting grid line and at least one first grid line adjacent to the first bus grid line. Therefore, through special design of the electrode structure, the cold solder joint influence caused by the insulating layer can be reduced or even eliminated, so that the electrical performance of the back contact battery is improved.

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 assembly and a photovoltaic system. Background Art

[0002] A back-contact cell is a cell in which both the P-type doped layer and the N-type doped layer are arranged on the back of the silicon wafer. There is no metal electrode blocking the front, and it has a higher short-circuit current and conversion efficiency.

[0003] In the related art, the back of the back-contact solar cell is provided with alternately arranged grid lines. In order to reduce the use of slurry and transmission loss, a welding strip can be directly used in the battery assembly to form an electrical connection with the grid lines of the battery to achieve the current convergence output. However, in such a technical solution, since it is necessary to set an insulating glue at the grid lines of opposite polarity that cross the welding strip to avoid leakage, the setting of the insulating glue can easily cause the welding strip to have a cold weld during the welding process, resulting in the inability to collect the current of some grid lines, affecting the efficiency of the back-contact battery. Summary of the invention

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

[0005] The present application is implemented in this way. The back contact battery of the embodiment of the present application includes: 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.

[0006] In some embodiments, among several of the 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 of the 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.

[0007] In some embodiments, 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.

[0008] In some embodiments, 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.

[0009] In some embodiments, the first auxiliary connection line connects 2-20 of the second gate lines.

[0010] In some embodiments, the number of the first busbar line groups is multiple, and the multiple 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.

[0011] In some embodiments, there are multiple first busbar line groups, the multiple first busbar line groups are spaced apart 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.

[0012] In some embodiments, the number of the first busbar line groups is multiple, the multiple 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.

[0013] In some embodiments, 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.

[0014] In some embodiments, 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.

[0015] In some embodiments, the first busbar line includes a first bus 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.

[0016] In some embodiments, the width of the first bus layer is greater than the width of a portion of the first bus lines other than the first bus line that is located outside the second series connection region.

[0017] In some embodiments, the width of the first edge 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.

[0018] In some embodiments, 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 region.

[0019] In some embodiments, 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.

[0020] In some embodiments, the second auxiliary connection line located between two adjacent groups of the first bus gate lines connects all of the first gate lines located between two adjacent groups of the first bus gate lines.

[0021] In some embodiments, 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.

[0022] In some embodiments, the plurality of first serial connection areas further include a third edge serial connection area adjacent to the second edge serial connection area, and the third edge serial connection area is located on a side of the second edge serial 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.

[0023] In some embodiments, the width of the third auxiliary connecting line is greater than the width of a portion of the second gate line located outside the first series connection region.

[0024] In some embodiments, 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.

[0025] In some embodiments, 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.

[0026] In some embodiments, the fourth auxiliary connection line connects 2-20 of the first gate lines.

[0027] In some embodiments, the number of the second busbar line groups is multiple, and the multiple 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.

[0028] In some embodiments, the number of the second busbar line groups is multiple, 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 busbar line group closest to the third edge connects all the first busbar lines located between the third edge and the second busbar 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.

[0029] In some embodiments, 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.

[0030] In some embodiments, 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.

[0031] In some embodiments, 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.

[0032] In some embodiments, 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.

[0033] In some embodiments, 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.

[0034] In some embodiments, 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.

[0035] In some embodiments, the width of the fourth auxiliary connecting line is greater than the width of a portion of the first gate line located outside the second series connection region.

[0036] In some embodiments, the number of the second connecting grid lines is multiple, the multiple second connecting grid lines are arranged at intervals along the second direction, and each of the second connecting 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.

[0037] In some embodiments, 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.

[0038] In some embodiments, 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.

[0039] In some embodiments, the plurality of second serial connection regions further include a sixth edge serial connection region adjacent to the fifth edge serial connection region, and the sixth edge serial connection region is located on a side of the fifth edge serial connection region 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.

[0040] In some embodiments, the width of the sixth auxiliary connecting line is greater than the width of a portion of the first gate line located outside the second series connection region.

[0041] The present application also provides a battery assembly, which includes several back-contact batteries as described in any of the above items.

[0042] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0043] 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.

[0044] The first bus grid line group is arranged to include two adjacent first bus grid lines, and the first insulating layers on the two first bus grid lines are adjacent, which can reduce the radiation area of ​​the cold solder joint caused by the first insulating layer, and further reduce the risk of cold solder joint. The continuous design of the first connecting grid line in the second edge series connection area can avoid the first connecting grid line from having a cold solder joint and causing its current to be unable to be collected. The design of the second insulating layer can insulate the first connecting grid line. Through the design of the second auxiliary connecting line, even if a cold solder joint occurs between the second grid line and the welding strip near the second insulating layer due to the setting of the second insulating layer, due to the existence of the second auxiliary connecting line, the second grid line with a cold solder joint can also realize the current bus output through the second auxiliary connecting line, thereby reducing or even eliminating the cold solder joint influence caused by the second insulating layer, thereby ensuring the efficiency of the back contact battery.

[0045] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a module schematic diagram of a photovoltaic system provided in an embodiment of the present application; Figure 2 is a module schematic diagram of a battery assembly provided in an embodiment of the present application; Figure 3 is a schematic diagram of the planar structure of a back contact battery provided in an embodiment of the present application; Figure 4 yes Figure 3 A partial enlarged schematic diagram of the back contact battery in FIG. Figure 5 yes Figure 4 Schematic diagram of the cross-sectional structure of the back contact battery along line VV; Figure 6 yes Figure 4 Schematic diagram of the cross-sectional structure of the back contact battery along line VI-VI; Figure 7 yes Figure 4 A partial enlarged schematic diagram of the back contact battery in FIG. Figure 8 yes Figure 4 Another schematic cross-sectional structure diagram of the back contact battery along line VI-VI; Fig. 9 yes Figure 4 Another schematic cross-sectional structure diagram of the back contact battery along line VI-VI; Fig.10 yes Figure 4 Another partial enlarged schematic diagram of the back contact battery in FIG. Fig.11 yes Figure 4 Another partial enlarged schematic diagram of the back contact battery in FIG. Fig.12 yes Figure 3 Another partial enlarged schematic diagram of the back contact battery in FIG. Fig.13 yes Fig.12 Schematic diagram of the cross-sectional structure of the back contact battery along line XIII-XIII; Fig.14 yes Fig.12 Schematic diagram of the cross-sectional structure of the back contact battery along line XIV-XIV; Fig.15 yes Fig.12 A partial enlarged schematic diagram of the back contact battery in FIG. Fig.16 yes Fig.12 Another schematic diagram of the cross-sectional structure of the back contact battery along line XIV-XIV; Fig.17 yes Fig.12 Another schematic cross-sectional structure diagram of the back contact battery along line XIV-XIV; Fig.18 yes Fig.12 Another partial enlarged schematic diagram of the back contact battery in FIG. Fig.19 yes Fig.12 Another partially enlarged schematic diagram of the back contact battery. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, in which the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. It should be noted that the embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot 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.

[0048] In the description of the present application, it should be understood that the terms "up", "down", "left", "right", "horizontal", "vertical", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and 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 therefore should not be understood as a limitation on the present application.

[0049] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0050] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0051] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the various specific processes and examples of materials provided by the present application, but those of ordinary skill in the art can be aware of the application of other processes and / or the use scenarios of other materials.

[0052] See also Figure 1 and Figure 2 , the photovoltaic system 1000 in the embodiment of the present application may include the battery assembly 200 in the embodiment of the present application, and the battery assembly 200 in the embodiment of the present application may include several back-contact batteries 100 in the embodiment of the present application. In the embodiment of the present application, multiple back-contact batteries 100 in the battery assembly 200 can be connected in series to form multiple battery strings, and each battery string can be connected in series, in parallel, or in series and parallel combination to realize the current bus output. For example, the connection between each battery cell can be realized by welding a welding strip, and the connection between each battery string can be realized by a bus bar. In some embodiments, each battery string can form a battery cell array, and then be packaged together by a front plate, a front adhesive film, a rear adhesive film and a back plate to form a battery assembly 200.

[0053] In the embodiment of the present application, the back contact cell 100 is a busbar-free back contact cell. Figure 3-Figure 6 The back contact battery 100 in the embodiment of the present application may include a substrate 10, a plurality of first gate lines 20, a plurality of second gate 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.

[0054] like Figure 3-Figure 6 As shown, the substrate 10 has a front side 11 and a back side 12 opposite to each other. The back side 12 of the substrate 10 has a first edge 121 and a second edge 122 opposite to each other in a first direction. The back side 12 has a plurality of first series connection areas 13 and a plurality of second series connection areas 14. The first series connection areas 13 and the second series connection areas 14 are used to set positive electrode welding strips and negative electrode welding strips, respectively. In other words, one of the first series connection areas 13 and the second series connection areas 14 is a positive electrode series connection area, and the other is a negative electrode welding area.

[0055] like Figure 3 and Figure 4 As shown, in the first direction, the first serial connection areas 13 and the second serial connection areas 14 are arranged alternately, and the first serial connection areas 13 include a first edge serial connection area 131 closest to the first edge 121, and there is no second serial connection area 14 between the first edge serial connection area 131 and the first edge 121. In other words, Figure 3 As shown, in the first series connection area 13 and the second series connection area 14 , the series connection area closest to the first edge 121 is the first series connection area 13 , and the first series connection area 13 is represented as a first edge series connection area 131 . There is no other series connection area between the first edge series connection area 131 and the first edge 121 .

[0056] The plurality of second serial connection areas 14 include a second edge serial connection area 141 (ie, Figure 3 and Figure 4 The second series connection area 14 closest to the first edge 121).

[0057] like Figure 3 As shown, a plurality of first gate lines 20 and a plurality of second gate lines 30 are alternately arranged along the second direction on the back surface 12, and the second direction intersects with the first direction. All first gate lines 20 and all second gate lines 30 are arranged to intersect with the first series connection area 13 and the second series connection area 14, that is, the first series connection area 13 and the second series connection area 14 extend along the second direction to intersect with the first gate lines 20 and the second gate lines 30.

[0058] In some embodiments, the first direction and the second direction may be the longitudinal direction and the lateral direction of the back contact battery 100, respectively, and the two directions are perpendicular to each other. Figure 3 In the example shown, the first direction is the lateral 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 may also be other directions, such as two diagonal directions of the back contact battery 100, which is not specifically limited here.

[0059] Among them, the plurality of first gate lines 20 include at least one first bus gate line group 210, and the first bus gate line group 210 includes two adjacent first bus gate lines 22. Among the plurality of first gate lines 20, the first bus gate line 22 is continuous at the first edge series connection area 131 and the second edge series connection area 141, and at least part of the remaining first gate lines 20 is discontinuous at the first edge series connection area 131 and continuous at the second edge series connection area 141. For example, in some embodiments, among the plurality of first gate lines 20, except for the first bus gate line 22, all the remaining first gate lines 20 are discontinuous at the first edge series connection area 131 and continuous at the second edge series connection area 141. For another example, in some embodiments, among the first gate lines 20, except for the first bus gate line 22 and the first edge bus gate line 203 described below, all the remaining first gate lines 20 are discontinuous at the first edge series connection area 131 and continuous at the second edge series connection area 141.

[0060] like Figure 3 and Figure 4 As shown, the plurality of second gate lines 30 include at least one first connecting gate line 32, and the first connecting gate line 32 is located between two first bus gate lines 22 in the first bus gate line group 210. Among the plurality of second gate lines 30, the first connecting gate line 32 is continuous at the first edge series connection area 131 and the second edge series connection area 141, and the remaining second gate lines 30 are continuous at the first edge series connection area 131 and interrupted at the second edge series connection area 141. The number of the first bus gate line group 210 corresponds to the number of the first connecting gate lines 32.

[0061] The back contact cell 100 is a main grid-free back contact cell. In the battery assembly 200, the welding strip in the first series connection area 13 (including the first edge series connection area 131) is used to connect with the second grid line 30 to realize the busbar output of the second grid line 30, and the welding strip in the second series connection area 14 is used to weld and connect with the first grid line 20 to realize the busbar output of the first grid line 20.

[0062] like Figure 3 As shown, the first edge connection line 40 is closer to the first edge 121 than the first edge series area 131 , and the first edge connection line 40 is electrically connected to the first bus grid line 22 , and the first edge connection line 40 is also electrically connected to at least part of the remaining first grid lines 20 except the first bus grid line 22 . Specifically, in order to avoid welding at the edge position of the first edge 121 and causing hidden cracks in the battery, the first edge connecting line 40 is not used for welding, but is used to collect the current of the isolated part formed by the remaining first grid lines 20 except the first bus grid line 22 located between the first edge series area 131 and the first edge 121, and then converge through the first bus grid line 22 to the same polarity welding strip in the second edge series area 141 adjacent to the first edge series area 131, so as to collect the current of the isolated grid line segment of the edge area of ​​the first grid line 20 located at the first edge 121, thereby improving the efficiency of the back contact battery 100. If the first edge connecting line 40 and the first bus grid line 22 are not provided, the remaining first grid lines 20 except the first bus grid line 22 located between the first edge series area 131 and the first edge 121 will form an isolated grid line segment, and the current of this part cannot be collected.

[0063] like Figure 3 As shown, the first insulating layer 51 is arranged in the first edge series area 131 and is located on the first bus bar 22, that is, the first insulating layer 51 is arranged on the portion of the first bus bar 22 corresponding to the first edge series area 131. The first insulating layer 51 is arranged to insulate and separate the opposite polarity welding strip in the first edge series area 131 from the first bus bar 22 to avoid short circuit.

[0064] The second insulating layer 52 is arranged in the second edge series area 141 and is located on the first connecting gate line 32, that is, the second insulating layer 52 is arranged on the portion corresponding to the first connecting gate line 32 and the second edge series area 141. The second insulating layer 52 is arranged to insulate and separate the opposite polarity welding strip in the second edge series area 141 from the first connecting gate line 32 to avoid short circuit.

[0065] like Figure 3 and Figure 4As shown, the first auxiliary connection line 61 is disposed in the first edge series connection area 131. In the second direction, at least one side of the first busbar line 22 is provided with the first auxiliary connection line 61, and the first auxiliary connection line 61 connects at least two second busbar lines 30 located on the same side of the first busbar line group 210. Figure 4 and Figure 6 As shown, in some embodiments, the at least two second gate lines 30 connected to the first auxiliary connection line 61 preferably include the second gate lines 30 adjacent to the first bus gate line group 210 (ie Figure 3 and Figure 4 That is, in some embodiments, the first auxiliary connection line 61 is preferably connected to the second grid line 30 closest to the first bus grid line group 210, and the first auxiliary connection line 61 is also connected to at least one of the remaining second grid lines 30 on the same side as the second grid line 30. That is, the first auxiliary connection line 61 is preferably connected to at least the second grid line 30 adjacent to the first bus grid line group 210 and at least one of the remaining second grid lines 30 on the same side.

[0066] The second auxiliary connection line 62 is disposed in the second edge series connection area 141. In the second direction, at least one side of the first bus grid line group 210 is provided with the second auxiliary connection line 62, and the second auxiliary connection line 62 connects the first bus grid line 22 located 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. That is, in some embodiments, the second auxiliary connection line 62 is connected to the first bus grid line 22 located 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.

[0067] In the back-contact cell 100, the cell assembly 200 and the photovoltaic system 1000 of the embodiment of the present application, by providing the first edge connecting line 40 and the first bus bar group 210, the current collected by at least part of the isolated section of the first bus bar 20 between the first edge series connection area 131 and the first edge 121 can be converged to a welding strip of the same polarity in the second edge series connection area 141 adjacent to the first edge series connection area 131, thereby effectively avoiding hidden cracks caused by welding at the first edge 121 of the back-contact cell 100 while ensuring the efficiency of the back-contact cell 100. The setting of the first insulating layer 51 can achieve insulation between the welding strip in the first edge series area 131 and the first bus grid line 22. Through the setting of the first auxiliary connecting line 61, even if a cold solder joint occurs between the second grid line 30 and the welding strip near the first insulating layer 51 due to the setting of the first insulating layer 51, due to the existence of the first auxiliary connecting line 61, the second grid line 30 with a cold solder joint can also realize current bus output through the first auxiliary connecting line 61, thereby reducing or even eliminating the cold solder joint effect caused by the first insulating layer 51, thereby ensuring the efficiency of the back contact battery 100.

[0068] The first bus grid line group 210 is configured to include two adjacent first bus grid lines 22, and the first insulating layers 51 on the two first bus grid lines 22 are adjacent, which can reduce the radiation area of ​​the cold solder joint caused by the first insulating layer 51, and further reduce the risk of cold solder joint. The design of the first connecting grid line 32 being continuous in the second edge series connection area 141 can avoid the first connecting grid line 32 from having a cold solder joint and causing its current to be unable to be collected. The design of the second insulating layer 52 can insulate the first connecting grid line 32. Through the design of the second auxiliary connecting line 62, even if a cold solder joint occurs between the second grid line 30 near the second insulating layer 52 and the welding strip due to the setting of the second insulating layer 52, due to the existence of the second auxiliary connecting line 62, the second grid line 30 with a cold solder joint can also realize the current bus output through the second auxiliary connecting line 62, thereby reducing or even eliminating the cold solder joint effect caused by the second insulating layer 52, thereby ensuring the efficiency of the back contact battery 100.

[0069] That is to say, the present application can reduce or even eliminate the effects of cold solder joints caused by the first insulating layer 51 and the second insulating layer 52 by specially designing the electrode structure on the back side of the back-contact battery 100 near the first edge 121, thereby improving the electrical performance of the back-contact battery 100 and ensuring the efficiency of the back-contact battery 100.

[0070] 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 is only used for current transmission and collection, and the function of the first busbar line 22 is to collect and transmit. Figure 3 and Figure 4 It is known that in Figure 3 and Figure 4 In the example shown, if the first edge connecting line 40 and the first bus grid line 22 are not provided, part of the first grid line 20 is disconnected at the first edge series connection area 131, and the current of part of the grid line segments of the disconnected first grid line 20 located between the first edge series connection area 131 and the first edge 121 cannot be collected. Therefore, by providing the first edge connecting line 40 and the first bus grid line 22, the current of at least part of the isolated grid line segments of the first grid line 20 located in the edge area can be transferred to the welding strip provided in the adjacent second edge series connection area 141, thereby effectively avoiding efficiency loss.

[0071] Since the first bus grid lines 22 are continuously arranged in the first edge series connection area 131, in order to prevent the welding strip on the first edge series connection area 131 from contacting the first bus grid lines 22 and causing a short circuit, a first insulating layer 51 (such as insulating glue) needs to be arranged at the position corresponding to the first bus grid lines 22 and the first edge series connection area 131, and the height of the first insulating layer 51 is higher than the height of the second grid lines 30 (including the first connecting grid lines 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 lines 30. In this case, the welding strip in the first edge series connection area 131 is prone to have a cold solder joint with the second grid lines 30 during the welding process, resulting in a current loss on part of the second grid lines 30. The method is to effectively collect the second gate lines 30 adjacent to the first bus grid line 22, which is most likely to have a cold solder joint. Based on this, the present application sets a first auxiliary connecting line 61 to connect at least two second gate lines 30 on the same side of the first bus grid line 22, and preferably selects the second gate line 30 connected thereto to include the one adjacent to the first bus grid line 22. The first auxiliary connecting line 61 can connect part of the second gate lines 30 into a whole at the first edge series connection area 131. Even if one of the second gate lines 30 has a cold solder joint due to the presence of the first insulating layer 51, the first auxiliary connecting line 61 can be used to output current, thereby reducing or even completely eliminating the impact of the cold solder joint.

[0072] In addition, since the first connection gate line 32 is located between the two first insulating layers 51, the risk of cold soldering is the greatest. If the first connection gate line 32 is interrupted at the second edge series connection area 141, an isolated section is likely to appear, resulting in the inability to collect the current of that part. Therefore, the first connection gate line 32 is set to be continuous at the second edge series connection area 141, which can avoid the problem of an isolated section resulting in the inability to collect part of the current.

[0073] Since the first connecting gate line 32 is continuous at the first edge series connection area 131 and the second edge series connection area 141, in order to avoid the welding strip on the second edge series connection area 141 from contacting the first connecting gate line 32 and causing a short circuit, a second insulating layer 52 (such as insulating glue) needs to be provided at the position corresponding to the first connecting gate line 32 and the second edge series connection area 141, and the height of the second insulating layer 52 is higher than the height of the first gate line 20, that is, in the thickness direction, the protruding height of the second insulating layer 52 is higher than the height of the first gate line 20. In this case, the welding strip in the second edge series connection area 141 is prone to have a cold solder joint with the first gate line 20 during the welding process, resulting in that the current on part of the first gate line 20 cannot be effectively collected, especially with the first gate line 20. A first gate line 20 (i.e., a first bus gate line 22) adjacent to a connecting gate line 32 is most likely to have a cold solder joint. Based on this, the present application sets a second auxiliary connecting line 62 to connect the first bus gate line 22 on one side of the first connecting gate line 32 and at least one first gate line 20 adjacent to the first bus gate line 22. The first bus gate line 22 can be connected to the remaining at least one first gate line 20 as a whole at the second edge series connection area 141 through the second auxiliary connecting line 62. Even if one of the second gate lines 30 has a cold solder joint due to the presence of the second insulating layer 52, the current can be output through the second auxiliary connecting line 62, thereby reducing or even completely eliminating the cold solder joint effect caused by the second insulating layer 52.

[0074] Further, in the embodiments of the present application, Figure 5 and Figure 6 As shown, the substrate 10 may include a silicon substrate 101, a plurality of first doped layers 102, a plurality of second doped layers 103 and a back passivation film layer 104. The silicon substrate 101 has a first surface 1011 and a second surface 1012 opposite to each other, the first doped layers 102 and the second doped layers 103 are both arranged on the second surface 1012, and the plurality of first doped layers 102 and the plurality of second doped layers 103 are alternately arranged along the second direction. The back passivation film layer 104 is at least stacked on the first doped layer 102 and the second doped layer 103. In some embodiments, the back passivation film layer 104 may cover the entire second surface 1012, that is, the first doped layer 102 and the second doped layer 103 and the area of ​​the second surface 1012 where no doping layer is arranged are stacked with the back passivation film layer 104.

[0075] It can be seen that in the substrate 10, the surface on the side where the first surface 1011 is located is the front side 11 of the substrate 10, and the side where the second surface 1012 is located is the back side of the substrate 10. Of course, in some embodiments, in the substrate 10, a first passivation layer (not shown in the figure) may be further provided between the first doped layer 102 and the silicon substrate 101, and 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 further provided between the second doped layer 103 and the silicon substrate 101, and the second passivation layer may be, for example, a tunneling layer, an intrinsic amorphous silicon layer, or other film layers.

[0076] In the back contact cell 100, the first gate line 20 corresponds to the first doped layer 102, and the second gate line 30 corresponds to the second doped layer 103. One of the first doped layer 102 and the second doped layer 103 may be a P-type doped layer, and the other may be an N-type doped layer. In some embodiments, the first gate line 20 may completely penetrate the back passivation film layer 104 to form a full contact with the first doped layer 102, or the first gate line 20 may only partially penetrate the back passivation film layer 104 to form a localized metallization contact with the first doped layer 102, and the specific details are not limited here.

[0077] That is to say, in the embodiment of the present application, the first gate line 20 is arranged corresponding to the first doped layer 102 and at least partially penetrates the back passivation film layer 104 and is in conductive contact with the first doped layer 102, and the second gate line 30 is arranged corresponding to the second doped layer 103 and at least partially penetrates the back passivation film layer 104 and is in conductive contact with the second doped layer 103.

[0078] like Figure 3 , Figure 4 as well as Figure 7 As shown, in some embodiments, the first gate line 20 may be continuous at each second series connection area 14 and have a first welding section 201 for welding with a welding ribbon at the second series connection area 14. The second gate line 30 may be continuous at each first series connection area 13 and have a second welding section 301 for welding with a welding ribbon at the first series connection area 13.

[0079] In some embodiments, in the first grid 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 portion. In the second grid 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 portion. In this way, the contact area between the first grid line 20 and the second grid line 30 and the welding strip can be increased, and the stability of welding can be improved.

[0080] In some embodiments, the first welding section 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, and the first collection layer penetrates the back passivation film layer 104 and is in conductive contact with the first doping layer 102.

[0081] In some embodiments, the first collection layer may be continuous at the second series connection area 14 and discontinuous at the first series connection area 13, and the first welding layer may be arranged at the second series connection area 14 and located on the first collection layer. In this case, in the first gate line 20, the portion corresponding to the first welding layer is the first welding segment 201.

[0082] Of course, in other embodiments, the first welding section 201 may be a single-layer structure. In this case, the first collection layer is interrupted at both the second series connection area 14 and the first series connection area 13, and the first welding layer is disposed at the second series connection area 14 and is electrically connected to the two ends of the first collection layer formed at the second series connection area 14. It is not difficult to understand that in these cases, the portion corresponding to the first welding layer is the first welding section 201.

[0083] In some embodiments, the width of the first welding layer can be set to be greater than the width of the first collection layer, where the width refers to the length of the two in the second direction, so that the welding area can be increased during welding and the reliability of welding can be improved.

[0084] In some embodiments, the second welding section 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, and the second collection layer penetrates the back passivation film layer 104 and is in conductive contact with the second doping layer 103.

[0085] In some embodiments, the second collection layer may be continuous at the first series connection area 13 and discontinuous at the second series connection area 14, and the second welding layer may be arranged at the first series connection area 13 and located on the second collection layer. In this case, in the second grid line 30, the part corresponding to the second welding layer is the second welding section 301.

[0086] Of course, in other embodiments, the second collection layer may also be interrupted at both the first series connection area 13 and the second series connection area 14, and the second welding layer is disposed at the first series connection area 13 and electrically connected to the two ends of the second collection layer formed at the first series connection area 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.

[0087] 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.

[0088] like Figure 3 and Figure 4 As shown, in the embodiment of the present application, in order to reduce the influence of cold soldering as much as possible, when at least two second grid lines 30 are provided on both sides of the first bus grid line group 210, first auxiliary connecting lines 61 are preferably 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 edge of the second direction, the first auxiliary connecting line 61 can be provided on one side of the first bus grid line group 210. In some embodiments, the width of the first busbar line 22 (i.e., the length in the second direction) may be greater than the width of the remaining first busbar line 20 outside the second series connection region 14 (i.e., the portion outside the first welding section 201 ) except the first busbar line 22 (i.e., the length in the second direction).

[0089] Thus, since the first busbar line 22 needs to bear the function of current transmission, setting the width of the first busbar line 22 wider can reduce the transmission loss during the current transmission process and improve efficiency. The first welding section 201 is used for welding, and setting the first welding section 201 wider can improve the reliability and stability of welding. The width of the first busbar line 22 can be the same as the width of the first welding section 201.

[0090] In addition, if Figure 3 , Figure 4 as well as Figure 7 As shown, in some embodiments, in the first bus bar 22, it is continuous only at the first edge series connection area 131, and is disconnected at other first series connection areas 13. Of course, in some embodiments, as described below, when the back contact battery 100 has a second connecting bar 23, the first bus bar 22 can also be continuous at the fifth edge series connection area 133 described below. In this case, the first bus bar 22 and the second connecting bar 23 are the same bar.

[0091] The first bus grid line 22 is continuous at the first edge series connection area 131, and only a section of the first bus grid line 22 closest to the first edge 121 (i.e., the section between the second edge series connection area 141 and the first edge 121) has a bus function. Therefore, in some embodiments, in order to save slurry and reduce costs, only this part of the grid line segment can be set to be wider.

[0092] In such cases, see Figure 3 , Figure 4 and Figure 7, the first busbar line 22 may include a first busbar segment 221 located between the second edge series connection region 141 and the first edge 121. In some embodiments, the width of the first busbar segment 221 (i.e., the length in the second direction) may be greater than the width of the rest of the first busbar line 22 located outside the second series connection region 14 (i.e., the portion other than the first welding segment 201 of the portion other than the first busbar segment 221).

[0093] In this way, only by setting the width of the first conduit segment 221 to be wider, the use of slurry can be reduced while reducing the conduit transmission loss, thereby reducing costs.

[0094] Specifically, as described above, in such an embodiment, the first bus section 221 can converge the current to the solder strip disposed at the second edge series connection area 141, and only a portion of the first bus section 221 is disposed wider to reduce the use of the slurry. In this case, the first bus section 221 penetrates the back passivation film layer 104 and contacts the first doping layer 102.

[0095] See also Figure 7 In other embodiments, a first bus layer 70 may be provided on the first bus segment 221. Thus, by providing the first bus layer 70 on the first bus segment 221, it is equivalent to increasing the cross-sectional area of ​​the first bus segment 221, which can also reduce transmission loss. At the same time, the first bus layer 70 can be made of a slurry with a lower cost than that of the first bus segment 221, which can reduce costs.

[0096] Specifically, in such an embodiment, the first busbar line 22 may be an ordinary busbar line, and except for being wider at the first welding section 201, the widths of the remaining positions may be the same. The first busbar layer 70 is provided on the first busbar section 221, which is equivalent to increasing the cross-sectional area of ​​the first busbar section 221. In other words, since the first busbar layer 70 is provided on the first busbar section 221, it is not necessary to widen the first busbar section 221, which can also achieve the purpose of reducing transmission loss. Of course, in some embodiments, the first busbar section 221 may also be widened, which is not specifically limited here.

[0097] The first bus layer 70 may be made of a non-burn-through slurry. The first bus layer 70 does not penetrate the back passivation film layer 104 and contacts the first doping layer 102. The slurry cost of the first bus layer 70 is lower than the slurry cost of the first bus segment 221. For example, when both the first bus layer 70 and the first bus segment 221 are silver paste layers, the silver content in the first bus layer 70 may be lower than the silver content in the first bus segment 221. For another example, the first bus segment 221 may be a silver paste layer, and the first bus layer 70 may be a copper layer, a silver-clad copper layer or other lower-cost metal layer.

[0098] Furthermore, in such an embodiment, the width (length in the second direction) of the first busbar layer 70 may be greater than the width (length in the second direction) of the portion of the first busbar line 20 other than the first busbar line 22 that is located outside the second series connection area 14 (i.e., the portion other than the first welding section 201). In this way, by increasing the width of the first busbar layer 70, the transmission capacity can be further improved and the transmission loss can be reduced.

[0099] In such an embodiment, the width of the first busbar layer 70 may be the same as the width of the first welding segment 201. In this article, the width of the first welding segment 201 refers to the length of the first welding segment 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 segment 201 is the width of the first welding layer (i.e., the length in the second direction). Similar descriptions appear below, which can be understood by referring to this.

[0100] In this way, it can be ensured that no large transmission loss will be caused during the convergence process. At the same time, during the printing process, the first convergence layer 70 can be printed simultaneously with the first welding layer at the first welding section 201. When the same screen is used for printing, there is no need to open screen slots of different sizes on the screen, which saves manufacturing processes and reduces manufacturing difficulty.

[0101] See also Figure 7 In some embodiments, the width (length in the first direction) of the first edge connection line 40 is greater than the width (length in the second direction) of the portion of the remaining first grid lines 20 except the first bus grid line 22 located outside the second series area 14 (i.e., the portion of the remaining first grid lines 20 except the first bus grid line 22 except the first welding section 201).

[0102] Thus, since the first edge connection line 40 needs to bear the function of current converging and transmission, setting the width of the first edge connection line 40 to be wider can also reduce the transmission loss in the current converging process and improve the efficiency.

[0103] 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 current converging loss is caused during the current converging process.

[0104] Also, please read 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 portion of the second gate line 30 located outside the first series area 13 (the portion of the second gate line 30 except the second welding section 301).

[0105] Thus, since the first auxiliary connection line 61 plays the role of transmitting and converging current when cold soldering occurs, setting the width of the first auxiliary connection line 61 wider can also reduce transmission loss during the converging process and improve efficiency.

[0106] 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 .

[0107] See also Figure 3 and Figure 4 In some embodiments, the first edge connection line 40 is electrically connected to all the first gate lines 20 .

[0108] In this way, all currents collected by the isolated gate line segments of the first gate line 20 except those located between the first edge series connection region 131 and the first edge 121 can be integrated, thereby maximizing the efficiency of the back contact cell 100 .

[0109] 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 result in excessive efficiency loss and product defects.

[0110] In some embodiments, the first auxiliary connection line 61 connects 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.

[0111] 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 both sides of the first busbar line group 210 are provided with at least two second grid lines 30, it is preferred to provide the first auxiliary connection line 61 on both sides.

[0112] In addition, it should be noted that, in the present application, when there are multiple first busbar line groups 210, the first auxiliary connection line 61 may be provided only on one side or both sides of some of the first busbar line groups 210, while the first auxiliary connection line 61 may not be provided on both sides of the remaining first busbar line groups 210. In this case, it can also solve the problem of cold solder joints in some positions. In the present application, it is preferred that the first auxiliary connection line 61 is provided on both sides of each first busbar line group 210. Of course, if the first busbar line group 210 is located at the third edge 123, the first auxiliary connection line 61 only needs to be provided on one side of the first busbar line 22.

[0113] Of course, see Figure 3 and Figure 4 In some embodiments, there are multiple first busbar line groups 210, and the multiple first busbar line groups 210 are arranged at intervals in the second direction. In this way, the multiple first busbar line groups 210 can shorten the current convergence path, effectively reduce the convergence transmission loss, and improve efficiency.

[0114] In this case, first auxiliary connecting lines 61 are provided on both sides of the first bus bar group 210, and first auxiliary connecting lines 61 are provided between two adjacent first bus bar groups 210. The first auxiliary connecting line 61 located between two adjacent first bus bar groups 210 connects all second bus bar lines 30 located between two adjacent first bus bar groups 210.

[0115] In this way, the first auxiliary connection line 61 is connected to all the second busbars 30 between two adjacent first busbar groups 210 , which can substantially completely eliminate the influence of cold solder joints and improve the efficiency of the back contact battery 100 as much as possible.

[0116] Specifically, in such an embodiment, the number of the first busbar line groups 210 in the back contact battery 100 can be selected according to actual conditions such as the size of the battery cell and the loss during the transmission process, and is not limited here.

[0117] See also Figure 3 and Figure 4 In some embodiments, there are multiple first bus bar line groups 210, and the multiple first bus bar line groups 210 are spaced apart in the second direction. First auxiliary connection lines 61 are disposed on both sides of the first bus bar line groups 210, and the substrate 10 has a third edge 123 and a fourth edge 124 in the second direction; The plurality of first gate lines 20 further include a first edge bus gate line 203. Among the first gate lines 20 and the second gate lines 30, the first edge bus gate line 203 is the gate line closest to the third edge 123. The first edge bus gate line 203 is continuous at 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 The first gate lines 20 further include a second edge bus gate line 204 . Among the first gate lines 20 and the second gate lines 30 , the second edge bus gate line 204 is the gate line closest to the fourth edge 124 . The second edge bus gate line 204 is continuous at 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 .

[0118] In this way, the bus path can be further shortened and the bus transmission loss can be reduced by setting the first edge bus line 203 and the second edge bus line 204. It is not difficult to understand that since the first edge bus line 203 and the second edge bus 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 influence of cold solder joints caused by the insulating layer on the first edge bus line 203 and the second edge bus line 204 can also be basically reduced or even eliminated.

[0119] Of course, it is understandable that in some embodiments, the first edge bus bar line 203 and the second edge bus bar line 204 may not be provided.

[0120] In such a case, the first auxiliary connection line 61 located between the third edge 123 and the first bus bar line group 210 closest to the third edge 123 may connect all second bus bar lines 30 located between the third edge 123 and the first bus bar line group 210 closest to the third edge 123. And / or the first auxiliary connection line 61 located between the fourth edge 124 and the first bus bar line group 210 closest to the fourth edge 124 connects all second bus bar lines 30 located between the fourth edge 124 and the first bus bar line group 210 closest to the fourth edge 124.

[0121] Thus, through such a design, it is possible to avoid the occurrence of cold solder joints at the start and end solder joints of the solder strip at the upper and lower ends of the first edge serial connection area 131, thereby reducing performance.

[0122] See also Figure 7 and 8 As described above, the first gate line 20 may include a first welding segment 201 corresponding to the second series connection region 14 , and the second gate line 30 may include a second welding segment 301 corresponding to the first edge series connection region 131 .

[0123] In some embodiments, within the first edge series connection area 131, a first groove 15 is formed on the substrate 10, the first bus line 22 is partially 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 from the front side 11 to the back side 12), the height of the first insulating layer 51 is flush with the height of the second welding section 301, or the height of the first insulating layer 51 is less than the height of the second welding section 301, or the height of the first insulating layer 51 is greater than the height of the second welding section 301, and the height difference between the first insulating layer 51 and the second welding section 301 is less than or equal to 15um.

[0124] In this way, by forming the first groove 15 on the substrate 10 and setting the first insulating layer 51 in the groove, the height of the first insulating layer 51 can be made smaller than the height of the second welding section 301, or the first insulating layer 51 is flush with the second welding section 301, or the height of the first insulating layer 51 is greater than the second welding section 301 and the height difference between the two is less than or equal to 15um, thereby further reducing the risk of cold soldering caused by the first insulating layer 51.

[0125] In some embodiments, the first groove 15 may penetrate the back 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 line 22 located in the first groove 15 is in contact with the silicon substrate 101. In this way, after the substrate 10 is manufactured, the first groove 15 can be directly opened on the substrate 10 by etching (such as laser etching, etc.), without inserting an etching and grooving process in the process of preparing the substrate 10.

[0126] Specifically, in such a case, a complete substrate 10 may be provided first, and then a groove process may be performed directly at the position where the first insulating layer 51 is to be placed on the substrate 10 , and then the first gate line 20 and the second gate line 30 may be printed, and then the first insulating layer 51 may be disposed at the first groove 15 .

[0127] Of course, in some other embodiments, a first recessed groove may be formed on the silicon substrate 101 at a position corresponding to the first edge series region 131 and the first bus line 22, and the first doping layer 102 and the back passivation film layer 104 may be recessed toward the side where the front side 11 is located at the first recessed groove to form a first groove 15 on the substrate 10.

[0128] Specifically, in such a case, during the manufacturing process, before preparing the first doping layer 102, a first recessed groove can be opened in the silicon substrate 101 at the position where the first doping layer 102 needs to be prepared and the first insulating layer 51 needs to be placed, and then the first doping 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 formed correspondingly on the substrate 10, and then the first gate line 20 and the second gate line 30 are printed, and then the first insulating layer 51 is set at the first groove 15.

[0129] See also Fig. 9 In some embodiments, at the first edge series connection area 131, a first auxiliary connection layer 80 may be provided on the second gate line 30, and the first auxiliary connection layer 80 is used for welding with the welding 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 15um.

[0130] In this way, by setting the first auxiliary connection layer 80 on the portion corresponding to the second gate line 30 and the first edge series area 131, the height of the first insulating layer 51 can be made smaller 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 first auxiliary connection layer 80 and the height difference between the two is less than or equal to 15um, thereby reducing the risk of cold soldering caused by the first insulating layer 51.

[0131] Specifically, in such an embodiment, the first auxiliary connection layer 80 can be stacked on the second welding section 301. The first auxiliary connection layer 80 can be a conductive material layer such as a solder paste layer, which is used for welding with the welding ribbon during the welding process, and is not specifically limited here.

[0132] See also Figure 4 and Fig.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 line 203 is connected to the first edge connection line 40 , the first edge connection line 40 has a first protrusion 41 protruding toward the third edge 123 .

[0133] See also Figure 4 and Fig.11 In some embodiments, at the junction where the second edge bus bar line 204 is connected to the first edge connection line 40 , the first edge connection line 40 has a second protrusion 42 protruding toward the fourth edge 124 .

[0134] In this way, the setting of the first protrusion 41 and the second protrusion 42 can provide redundancy for the first edge connecting line 40 at the corner of the back contact battery 100 located at the first edge 121, thereby avoiding inaccurate printing during the printing process, which causes the slurry to fail to form a complete filling at the corner, resulting in poor contact between the first edge connecting line 40 and the first edge bus bar line 203 and the second edge bus bar line 204.

[0135] Specifically, in such a case, in some embodiments, a bus layer may be provided on the portion of the first edge bus line 203 and the second edge bus line 204 located between the second edge series connection region 141 and the first edge 121 , which can reduce bus loss.

[0136] In addition, if Fig.10 and Fig.11 As shown, in some embodiments, in the back contact battery 100, chamfers are formed at the intersections of the first edge 121, the third edge 123 and the fourth edge 124, and the first grid line 20 is correspondingly arranged at the chamfers. Fig.10 and Fig.11 As shown, in order to achieve the connection between the first edge connection line 40 and the first gate line 20, the first edge connection line 40 has a bent portion at both chamfers. Of course, it can be understood that in some embodiments, if the back contact cell 100 does not have a chamfer, there is no need to set a bent portion.

[0137] See also Fig.10 and Fig.11 In some embodiments, at the junction of the first gate line 20 and the first edge connection line 40 , at least a portion of the first gate line 20 has a first gate line protrusion 202 protruding toward the first edge 121 compared to the first edge connection line 40 .

[0138] Thus, the first gate line protrusion 202 can ensure the stability of the electrical connection between the first gate line 20 and the first edge connection line 40, effectively avoiding the phenomenon that some first gate lines 20 cannot form stable contact with the first edge connection line 40 due to printing accuracy during the printing process.

[0139] See also Figure 3 and Figure 4In some embodiments, there are multiple first connection grid lines 32, the number of the first connection grid lines 32 is the same as the number of the first bus grid line groups 210 and they correspond one to one, the multiple first connection grid lines 32 are arranged at intervals along the second direction, and each first connection grid line 32 corresponds to one first bus grid line group 210. In the second edge series connection area 141, second auxiliary connection lines 62 are arranged on both sides of the first bus grid line group 210, and two first bus grid lines 22 in the first bus grid line group 210 are respectively connected to one second auxiliary connection line 62. In this way, the influence of the second insulating layer 52 on the two sides of the cold solder joint can be reduced.

[0140] See also Figure 3 and Figure 4 In such an embodiment, the second auxiliary connection line 62 located between two adjacent first bus gate line groups 210 connects all first gate lines 20 located between two adjacent first bus gate line groups 210. In this way, the cold solder joint effect caused by the second insulating layer 52 can be completely and substantially eliminated.

[0141] Of course, it is understandable that in some embodiments, a second auxiliary connection line 62 may be provided on one side of the first connection grid line 32, which may also reduce the effect of cold solder joints in some areas. Of course, in the present application, it is preferred that the second auxiliary connection line 62 is provided on both sides of the first connection grid line 32.

[0142] In addition, in some less preferred embodiments, when there are multiple first connecting grid lines 32, the second auxiliary connecting line 62 may be set on at least one of the first connecting grid lines 32, while the second auxiliary connecting line 62 may not be set on both sides of the remaining first connecting grid lines 32. This can also reduce the impact of cold soldering in some areas.

[0143] In some embodiments, the width (length in the first direction) of the second auxiliary connection line 62 is greater than the width (length in the second direction) of the remaining first busbar lines 20 except the first busbar lines 22 and located outside the second series connection region 14 (ie, the first welding section 201 ).

[0144] Thus, since the second auxiliary connection line 62 plays the role of transmitting and converging current when cold soldering occurs, setting the width of the second auxiliary connection line 62 wider can also reduce transmission loss during the converging process and improve efficiency.

[0145] Specifically, in such an embodiment, the width of the second auxiliary connection line 62 may be the same as the width of the first welding section 201 .

[0146] See also Figure 3 , Figure 4 and Figure 7In some embodiments, the first serial connection areas 13 further include a third edge serial connection area 132 that is most adjacent to the second edge serial connection area 141 . The third edge serial connection area 132 is located on a side of the second edge serial connection area 141 away from the first edge 121 .

[0147] The first connection gate lines 32 are continuous at the third edge series area 132 . A third auxiliary connection line 90 is disposed in the third edge series area 132 . In the second direction, the third auxiliary connection line 90 connects the first connection gate line 32 and at least one second gate line 30 located on both sides of the first connection gate line 32 .

[0148] Thus, by disposing the third auxiliary connection line 90 in the third edge series connection area 132 , it is possible to effectively avoid the phenomenon that the welding strip in the third edge series connection area 132 has a cold solder joint or poor contact at the first connection gate line 32 , resulting in the current transmitted from the first connection gate line 32 not being collected.

[0149] Specifically, Figure 4 and Figure 7 As shown, in such an embodiment, the number of third auxiliary connection lines 90 can be consistent with the number of first connection gate lines 32, and the two correspond one to one. The third auxiliary connection line 90 connects the first connection gate line 32 and also connects two second gate lines 30 adjacent to the first connection gate line 32.

[0150] In some embodiments, the width (length in the first direction) of the third auxiliary connection line 90 may be greater than the width (length in the second direction) of the portion of the second gate line 30 other than the first series connection region 13 (i.e., the portion other than the second welding section 301). In this way, setting the width of the third auxiliary connection line 90 wider can also reduce transmission loss during the convergence process and improve efficiency.

[0151] In some embodiments, the distance between the first edge series connection region 131 and the first edge 121 is greater than or equal to 2 mm and less than or equal to 20 mm.

[0152] In this way, it is possible to avoid the distance between the first edge series connection area 131 and the first edge 121 being too small, which causes the welding position to be too close to the first edge 121, thereby causing hidden cracks in the back contact battery 100, thereby reducing the risk of hidden cracks. It is also possible to avoid the distance between the first edge series connection area 131 and the first edge 121 being too large, which causes the length of the isolated gate line segment roughly located between the first edge series connection area 131 and the first edge 121 to be too long, thereby causing excessive loss in the transmission path process.

[0153] Specifically, in such an embodiment, the distance between the first edge series area 131 and the first edge 121 may 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-20mm, and is not limited here.

[0154] See also Figure 3 as well as Figure 12-Figure 15 In some embodiments, the plurality of second serial connection areas 14 further include a fourth edge serial connection area 142 closest to the second edge 122, and there is no first serial connection area 13 between the fourth edge serial connection area 142 and the second edge 122. In other words, Figure 3 and Fig.12 As shown, in the second serial connection area 14 and the first serial connection area 13 , the serial connection area closest to the second edge 122 is the second serial connection area 14 , and the second serial connection area 14 is represented as a fourth edge serial connection area 142 . There is no other serial connection area between the fourth edge serial connection area 142 and the second edge 122 .

[0155] The first series connection areas 13 further include a fifth edge series connection area 133 (ie, a fifth edge series connection area 133) adjacent to the fourth edge series connection area 142. Figure 3 and Fig.12 The first series connection area 13 closest to the second edge 122).

[0156] Among them, the plurality of 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 the plurality of second gate lines 30, the second bus gate lines 33 are continuous at the fourth edge series connection area 142 and the fifth edge series connection area 133, and at least part of the remaining second gate lines 30 are discontinuous at the fourth edge series connection area 142 and continuous at the fifth edge series connection area 133. For example, in some embodiments, among the second gate lines 30, except for the second bus gate lines 33, all the remaining second gate lines 30 (including the second connecting gate lines 23 mentioned above) are discontinuous at the fourth edge series connection area 142 and continuous at the fifth edge series connection area 133. For example, in some embodiments, among the second gate lines 30 , except for the second bus gate line 33 and the third edge bus gate line 303 described below, all other second gate lines 30 are interrupted at the fourth edge series connection area 142 and continuous at the fifth edge series connection area 133 .

[0157] like Figure 3 , Figure 4 as well as Fig.12As shown, in the embodiment of the present application, all first gate lines 20 are interrupted in all first series connection areas 13 except the first edge series connection area 131 and the fifth edge series connection area 133, and all first gate lines 20 are continuous in all second series connection areas 14. All second gate lines 30 are interrupted in all other second series connection areas 14 except the second edge series connection area 141 and the fourth edge series connection area 142, and all second gate lines 30 are continuous in all first series connection areas 13.

[0158] like Figure 3 and Fig.12 As shown, a plurality of first gate lines 20 include at least one second connecting gate line 23, and the second connecting gate line 23 is located between two second bus gate lines 33 in the second bus gate line group 310. Among the plurality of first gate lines 20, the second connecting gate line 23 is continuous at the fourth edge series connection area 142 and the fifth edge series connection area 133, and the remaining first gate lines 20 are continuous at the fourth edge series connection area 142 and interrupted at the fifth edge series connection area 133. The number of the second bus gate line group 310 corresponds to the number of the second connecting gate lines 23.

[0159] It should be noted that if Figure 3 , Figure 4 as well as Fig.12 As shown, in the illustrated embodiment, the first connecting gate line 32 and the second bus gate line 33 are different gate lines. It can be understood that in some embodiments, the first connecting gate line 32 and the second bus gate line 33 can also be the same gate line, that is, the first connecting gate line 32 is used as a second bus gate line 33, which is not specifically limited here.

[0160] In addition, in the illustrated embodiment, the second connecting gate line 23 and the first bus gate line 22 are different gate lines. It is understandable that in some embodiments, the second connecting gate line 23 and the first bus gate line 22 can also be the same gate line, that is, one first bus gate line 22 serves as one second connecting gate line 23.

[0161] The back contact cell 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 .

[0162] like Figure 3 and Fig.12As shown, the second edge connection line 110 is closer to the second edge 122 than the fourth edge series area 142, and the second edge connection line 110 is electrically connected to the second bus grid line 33, and the second edge connection line 110 is also electrically connected to at least part of the second grid lines 30 except the second bus grid line 33. Specifically, in order to avoid welding at the edge position of the second edge 122 and causing hidden cracks in the battery, the second edge connecting line 110 is not used for welding, but is used to collect the current of the isolated part formed by the second grid lines 30 except the second bus grid line 33 located between the fourth edge series area 142 and the second edge 122, and then converge to the same polarity welding strip in the fifth edge series area 133 adjacent to the fourth edge series area 142 through the second bus grid line 33, so as to collect the current of the isolated grid line segment of the edge area of ​​the second grid line 30 located at the second edge 122, thereby improving the efficiency of the back contact battery 100. If the second edge connecting line 110 and the second bus grid line 33 are not provided, the part of the second grid lines 30 except the second bus grid line 33 located between the fourth edge series area 142 and the second edge 122 will form an isolated grid line segment, and the current of this part cannot be collected.

[0163] like Figure 3 As shown, the third insulating layer 120 is arranged in the fourth edge series area 142 and is located on the second bus bar line 33, that is, the third insulating layer 120 is arranged on the portion corresponding to the second bus bar line 33 and the fourth edge series area 142. The third insulating layer 120 is arranged to insulate and separate the opposite polarity welding strip in the fourth edge series area 142 from the second bus bar line 33 to avoid short circuit.

[0164] The fourth insulating layer 1210 is arranged in the fifth edge series area 133 and is located on the second connecting gate line 23, that is, the fourth insulating layer 1210 is arranged on the portion corresponding to the second connecting gate line 23 and the fifth edge series area 133. The fourth insulating layer 1210 is arranged to insulate and separate the opposite polarity welding strip in the fifth edge series area 133 from the second connecting gate line 23 to avoid short circuit.

[0165] like Figure 3 and Fig.12 As shown, the fourth auxiliary connection line 130 is disposed in the fourth edge series connection area 142. In the second direction, at least one side of the second bus grid line 33 is provided with a fourth auxiliary connection line 130, and the fourth auxiliary connection line 130 connects at least two first grid lines 20 located on the same side of the second bus grid line group 310. Figure 4 and Fig.15As shown, in some embodiments, the 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 (ie Figure 3 and Fig.12 That is, in some embodiments, the fourth auxiliary connection line 130 is preferably connected to the first grid line 20 closest to the second bus grid line group 310, and the fourth auxiliary connection line 130 is also connected to at least one of the remaining first grid lines 20 on the same side as the first grid line 20. That is, the fourth auxiliary connection line 130 is preferably connected to at least the first grid line 20 adjacent to the second bus grid line group 310 and at least one of the remaining first grid lines 20 on the same side.

[0166] The fifth auxiliary connection line 1310 is disposed in the fifth edge series connection area 133. In the second direction, at least one side of the second bus grid line group 310 is provided with the fifth auxiliary connection line 1310, and the fifth auxiliary connection line 1310 connects the second bus grid line 33 located on one side of the second connection grid line 23 and at least one second grid line 30 adjacent to the second bus grid line 33. That is to say, in some embodiments, the fifth auxiliary connection line 1310 is connected to the second bus grid line 33 located on one side of the second connection grid line 23 and at least one second grid line 30 adjacent to the second bus grid line 33.

[0167] In this way, by setting the second edge connecting line 110 and the second busbar line group 310, the current collected by at least part of the isolated section of the second busbar line 30 located between the fourth edge series area 142 and the second edge 122 can be converged to the welding strip of the same polarity in the fifth edge series area 133 adjacent to the fourth edge series area 142, which can effectively avoid hidden cracks caused by 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 welding strip in the fourth edge series area 142 and the second bus grid line 33. Through the setting of the fourth auxiliary connecting line 130, even if a cold solder joint occurs between the first grid line 20 and the welding strip near the third insulating layer 120 due to the setting of the third insulating layer 120, due to the existence of the fourth auxiliary connecting line 130, the first grid line 20 with a cold solder joint can also realize current bus output through the fourth auxiliary connecting line 130, thereby reducing or even eliminating the cold solder joint influence caused by the third insulating layer 120, thereby ensuring the efficiency of the back contact battery 100.

[0168] The second bus grid line group 310 is configured to include two adjacent second bus grid lines 33, and the third insulating layers 120 on the two second bus grid lines 33 are adjacent, which can reduce the radiation area of ​​the cold solder joint caused by the first insulating layer 51, and further reduce the risk of cold solder joint. The design of the second connecting grid line 23 being continuous in the fifth edge series area 133 can avoid the second connecting grid line 23 from having a cold solder joint and causing its current to be unable to be collected. The design of the fourth insulating layer 1210 can insulate the second connecting grid line 23. Through the design of the fifth auxiliary connecting line 1310, even if a cold solder joint occurs between the first grid line 20 and the welding strip near the fourth insulating layer 1210 due to the setting of the fourth insulating layer 1210, due to the existence of the fifth auxiliary connecting line 1310, the first grid line 20 with a cold solder joint can also realize the current bus output through the fifth auxiliary connecting line 1310, reducing or even eliminating the influence of the cold solder joint caused by the fourth insulating layer 1210, thereby ensuring the efficiency of the back contact battery 100.

[0169] That is to say, the present application can reduce or even eliminate the effects of cold solder joints caused by the third insulating layer 120 and the fourth insulating layer 1210 by specially designing the electrode structure on the back side of the back-contact battery 100 near the second edge 122, thereby improving the electrical performance of the back-contact battery 100 and ensuring the efficiency of the back-contact battery 100.

[0170] As shown above, it is not difficult to understand that in the present application, the second edge connection line 110 is not used for welding, but is only used for current transmission and collection, and the function of the second busbar line 33 is to collect and transmit. Figure 3 and Fig.12 It is known that in Figure 3 and Fig.12 In the example shown, if the second edge connection line 110 and the second bus grid line 33 are not provided, part of the second grid line 30 is disconnected at the fourth edge series connection area 142, and the current of part of the grid line segments of the disconnected second grid line 30 located between the fourth edge series connection area 142 and the second edge 122 cannot be collected. Therefore, by providing the second edge connection line 110 and the second bus grid line 33, the current of at least part of the isolated grid line segments of the second grid line 30 located in the edge area can be transferred to the welding strip provided in the adjacent fourth edge series connection area 142, thereby effectively avoiding efficiency loss.

[0171] Since the second bus grid line 33 is continuously arranged in the fourth edge series connection area 142, in order to prevent the welding strip on the fourth edge series connection area 142 from contacting with the second bus grid line 33 and causing a short circuit, a third insulating layer 120 (such as insulating glue) needs to be arranged at the position corresponding to the second bus grid line 33 and the fourth edge series connection area 142, and the height of the third insulating layer 120 is higher than the height 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 this case, the welding strip in the fourth edge series connection area 142 is prone to have a cold solder joint with the first grid line 20 during the welding process, resulting in the current on part of the first grid line 20 being unable to flow. The fourth auxiliary connection line 130 is used to connect at least two first gate lines 20 on the same side of the second bus grid line 33, and the first gate line 20 connected thereto preferably includes the one adjacent to the second bus grid line 33. The fourth auxiliary connection line 130 can be used to connect some of the first gate lines 20 into a whole at the fourth edge series connection area 142. Even if one of the first gate lines 20 has a cold solder joint due to the presence of the third insulating layer 120, the fourth auxiliary connection line 130 can be used to output current, thereby reducing or even completely eliminating the impact of the cold solder joint.

[0172] In addition, since the second connection gate line 23 is located between the two third insulating layers 120, the risk of cold soldering is the greatest. If the second connection gate line 23 is interrupted at the fifth edge series connection area 133, an isolated segment is likely to occur, resulting in the inability to collect the current of that portion. Therefore, the second connection gate line 23 is set to be continuous at the fifth edge series connection area 133, which can avoid the problem of an isolated segment resulting in the inability to collect part of the current.

[0173] Since the second connecting gate line 23 is continuous at the fourth edge series connection area 142 and the fifth edge series connection area 133, in order to avoid the welding strip on the fifth edge series connection area 133 from contacting the second connecting gate 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 second connecting gate line 23 and the fifth edge series connection area 133, and the height of the fourth insulating layer 1210 is higher than the height of the second gate line 30, that is, in the thickness direction, the protruding height of the fourth insulating layer 1210 is higher than the height of the second gate line 30. In this case, the welding strip in the fifth edge series connection area 133 is prone to have a virtual solder joint with the second gate line 30 during the welding process, resulting in that the current on part of the second gate line 30 cannot be effectively collected, especially with the second connecting The second gate line 30 (i.e., the second bus gate line 33) adjacent to the connecting gate line 23 is most likely to have a cold solder joint. Based on this, the present application sets a fifth auxiliary connecting line 1310 to connect the second bus gate line 33 on one side of the second connecting gate line 23 and at least one second gate line 30 adjacent to the second bus gate line 33. The second bus gate line 33 can be connected to the remaining at least one second gate line 30 as a whole at the fifth edge series connection area 133 through the fifth auxiliary connecting line 1310. Even if one of the first gate lines 20 has a cold solder joint due to the presence of the fourth insulating layer 1210, the current can be output through the fifth auxiliary connecting line 1310, thereby reducing or even completely eliminating the cold solder joint effect caused by the fourth insulating layer 1210.

[0174] like Figure 3 and Fig.12 As shown, in the embodiment of the present application, in order to reduce the influence of cold soldering as much as possible, when at least two first grid lines 20 are provided on both sides of the second bus grid line group 310, it is preferred that fourth auxiliary connecting lines 130 are provided on both sides of the second bus grid line group 310. Of course, if the second bus grid line group 310 is located at the edge of the second direction, the fourth auxiliary connecting line 130 may be provided on one side of the second bus grid line group 310. In some embodiments, the width of the second bus grid line 33 (i.e., the length in the second direction) may be greater than the width (i.e., the length in the second direction) of the remaining second grid lines 30 except the second bus grid line 33 and located outside the first series connection area 13 (i.e., the portion except the second welding section 301).

[0175] Thus, since the second busbar line 33 needs to bear the function of current transmission, setting the width of the second busbar line 33 wider can reduce the transmission loss in the current transmission process and improve efficiency. The second welding section 301 is used for welding, and setting the second welding section 301 wider can improve the reliability and stability of welding. The width of the second busbar line 33 can be the same as the width of the second welding section 301.

[0176] In addition, if Figure 3 , Fig.12 as well as Fig.15 As shown, in some embodiments, in the second bus grid line 33, it is continuous only at the fourth edge series area 142, and is disconnected at other second series areas 14. Of course, in some embodiments, as described above, when the second bus grid line 33 and the first connecting grid line 32 are the same grid line, the second bus grid line 33 is continuous at the second edge series area 141.

[0177] The second bus grid line 33 is continuous at the fourth edge series connection area 142, and only a section of the second bus grid line 33 closest to the second edge 122 (i.e., the section between the fifth edge series connection area 133 and the second edge 122) bears the bus function. Therefore, in some embodiments, in order to save slurry and reduce costs, only this part of the grid line segment can be set to be wider.

[0178] In such cases, see Figure 3 , Fig.12 and Fig.15 , the second bus grid line 33 may include a second bus segment 331 located between the fifth edge series connection area 133 and the second edge 122. In some embodiments, the width (i.e., the length in the second direction) of the second bus segment 331 may be greater than the width of the remaining portion of the second bus grid line 33 located outside the first series connection area 13 (i.e., the portion other than the second welding segment 301 of the portion other than the second bus segment 331).

[0179] In this way, only by setting the width of the second conduit segment 331 to be wider, the use of slurry can be reduced while reducing the conduit transmission loss, thereby reducing costs.

[0180] Specifically, as described above, in such an embodiment, the second bus segment 331 can converge the current to the soldering strip disposed at the fifth edge series connection area 133, and only a portion of the second bus segment 331 is disposed wider to reduce the use of the slurry. In this case, the second bus segment 331 penetrates the back passivation film layer 104 and contacts the first doping layer 102.

[0181] See also Fig.15 In other embodiments, a second bus layer 140 may be provided on the second bus segment 331. Thus, by providing the second bus layer 140 on the second bus segment 331, it is equivalent to increasing the cross-sectional area of ​​the second bus segment 331, which can also reduce transmission loss. At the same time, the second bus layer 140 can be made of a slurry with a lower cost than that of the second bus segment 331, which can reduce costs.

[0182] Specifically, in such an embodiment, the second busbar line 33 may be an ordinary busbar line, and except for being wider at the second welding section 301, the widths of the remaining positions may be the same. The second busbar layer 140 is provided on the second busbar section 331, which is equivalent to increasing the cross-sectional area of ​​the second busbar section 331. In other words, since the second busbar layer 140 is provided on the second busbar section 331, it is also unnecessary to widen the second busbar section 331, which can also achieve the purpose of reducing transmission loss. Of course, in some embodiments, the second busbar section 331 may also be widened, which is not specifically limited here.

[0183] The second bus layer 140 may be made of a non-burn-through slurry. The second bus layer 140 does not penetrate the back passivation film layer 104 and contacts the first doping layer 102. The slurry cost of the second bus layer 140 is lower than the slurry cost of the second bus segment 331. For example, when both the second bus layer 140 and the second bus segment 331 are silver paste layers, the silver content in the second bus layer 140 may be lower than the silver content in the second bus segment 331. For another example, the second bus segment 331 may be a silver paste layer, and the second bus layer 140 may be a copper layer, a silver-clad copper layer or other lower-cost metal layer.

[0184] Furthermore, in such an embodiment, the width (length in the second direction) of the second bus layer 140 may be greater than the width (length in the second direction) of the portion of the second bus line 30 other than the second bus line 33 that is located outside the first series connection area 13 (i.e., the portion other than the second welding section 301). In this way, by increasing the width of the second bus layer 140, the transmission capacity can be further improved and the transmission loss can be reduced.

[0185] 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). Similar descriptions appear below, which can be understood by referring to them.

[0186] In this way, it can be ensured that no large transmission loss will be caused during the convergence process. At the same time, during the printing process, the second convergence layer 140 can be printed simultaneously with the first welding layer at the second welding section 301. When the same screen is used for printing, there is no need to open screen slots of different sizes on the screen, which saves manufacturing processes and reduces manufacturing difficulty.

[0187] See also Fig.15In some embodiments, the width (length in the first direction) of the second edge connection line 110 is greater than the width (length in the second direction) of the portion of the second grid lines 30 other than the second bus grid line 33 located outside the first series area 13 (i.e., the portion of the second grid lines 30 other than the second bus grid line 33 other than the second welding section 301).

[0188] Thus, since the second edge connection line 110 needs to bear the function of current converging and transmission, setting the width of the second edge connection line 110 to be wider can also reduce the transmission loss in the current converging process and improve the efficiency.

[0189] Specifically, in such an embodiment, the width of the second edge connection line 110 may be the same as the width of the second welding section 301. In this way, it can be ensured that no large current converging loss is caused during the current converging process.

[0190] Also, please read Fig.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 portion of the first gate line 20 located outside the second series area 14 (the portion of the first gate line 20 except the first welding section 201).

[0191] Thus, since the fourth auxiliary connection line 130 plays the role of transmitting and converging current when cold soldering occurs, setting the width of the fourth auxiliary connection line 130 wider can also reduce transmission loss during the converging process and improve efficiency.

[0192] In some embodiments, the width of the fourth auxiliary connection line 130 may be the same as the width of the second edge connection line 110 , and the widths of both may also be the same as the widths of the second welding section 301 and the first welding section 201 .

[0193] See also Figure 3 and Fig.12 In some embodiments, the second edge connection line 110 is electrically connected to all the second gate lines 30 .

[0194] In this way, all currents collected by the isolated gate line segments of the second gate line 30 except those located between the fourth edge series connection region 142 and the second edge 122 can be integrated, thereby maximizing the efficiency of the back contact battery 100 .

[0195] Of course, in some embodiments, the second edge connection line 110 may be electrically connected to only some of the remaining second gate lines 30 except the second bus gate line 33. In this case, the number of the second gate lines 30 that are not electrically connected to the second edge connection line 110 is less than or equal to 4. In this way, 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 result in excessive efficiency loss and product defects.

[0196] In some embodiments, the fourth auxiliary connection line 130 connects 2-20 first gate lines 20. Thus, by setting the number of first gate lines 20 connected to the fourth auxiliary connection line 130 within this reasonable range, the influence of cold solder joints can be reduced as much as possible or even eliminated.

[0197] In the embodiment of the present application, the number of the second bus grid line group 310 may be single. In this case, the fourth auxiliary connection line 130 may be provided only on one side of the second bus grid line group 310, or the fourth auxiliary connection line 130 may be provided on both sides of the second bus grid line group 310, and the specific details are not limited here. When both sides of the second bus grid line group 310 are provided with at least two first grid lines 20, the fourth auxiliary connection line 130 is preferably provided on both sides.

[0198] In addition, it should be noted that, in the present application, when there are multiple second busbar line groups 310, the fourth auxiliary connection line 130 may be provided only on one side or both sides of some of the second busbar line groups 310, while the fourth auxiliary connection line 130 may not be provided on both sides of the remaining second busbar line groups 310. In this case, it can also solve the problem of cold solder joints in some positions. In the present application, it is preferred that the fourth auxiliary connection line 130 is provided on both sides of each second busbar line group 310. Of course, if the second busbar line group 310 is located at the third edge 123, the fourth auxiliary connection line 130 only needs to be provided on one side of the second busbar line 33.

[0199] Of course, see Figure 3 and Fig.12 In some embodiments, there are multiple second busbar line groups 310, and the multiple second busbar line groups 310 are arranged at intervals in the second direction. In this way, the multiple second busbar line groups 310 can shorten the current bus path, effectively reduce the bus transmission loss, and improve efficiency.

[0200] In this case, fourth auxiliary connection lines 130 are provided on both sides of the second bus bar line group 310, and fourth auxiliary connection lines 130 are provided between two adjacent second bus bar line groups 310. The fourth auxiliary connection line 130 located between two adjacent second bus bar line groups 310 connects all first gate lines 20 located between two adjacent second bus bar line groups 310.

[0201] In this way, the fourth auxiliary connection line 130 is connected to all the first busbars 20 between two adjacent second busbar groups 310 , which can substantially completely eliminate the influence of cold solder joints and improve the efficiency of the back contact battery 100 as much as possible.

[0202] 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 actual conditions such as the size of the battery cell and the loss during the transmission process, and is not limited here.

[0203] See also Figure 3 and Fig.12 In some embodiments, there are multiple second bus bar line groups 310, and the multiple second bus bar line groups 310 are spaced apart in the second direction. Fourth auxiliary connection lines 130 are disposed on both sides of the second bus bar line groups 310, and the substrate 10 has a third edge 123 and a fourth edge 124 in the second direction; The plurality of second gate lines 30 further include a third edge bus gate line 303, the third edge bus gate line 303 is located between the third edge 123 and the second bus gate line group 310 closest to the third edge 123, the third edge bus gate line 303 is continuous at the fourth edge series connection area 142 and the fifth edge series connection area 133 and is electrically connected to the second edge connection line 110; and / or The plurality of second gate lines 30 further include a fourth edge bus gate line 304 , which is located between the fourth edge 124 and the second bus gate line group 310 closest to the fourth edge 124 , and is continuous at the fourth edge series connection area 142 and the fifth edge series connection area 133 and is electrically connected to the second edge connection line 110 .

[0204] In this way, by disposing the third edge bus gate line 303 and the fourth edge bus gate line 304 , the bus path can be further shortened and the bus transmission loss can be reduced.

[0205] Specifically, it is not difficult to understand that since the third edge bus line 303 and the fourth edge bus line 304 are continuous at the fourth edge series connection area 142, an insulating layer also needs to be disposed thereon. Figure 3 and Fig.12As shown, in the fourth edge series connection area 142, an auxiliary connection line may also be provided between the third edge bus grid line 303 and the third edge 123, and the auxiliary connection line may connect all the first grid lines 20 between the third edge bus grid line 303 and the third edge 123. Similarly, in the fourth edge series connection area 142, an auxiliary connection line may also be provided between the fourth edge bus grid line 304 and the fourth edge 124, and the auxiliary connection line may connect all the first grid lines 20 between the fourth edge bus grid line 304 and the fourth edge 124. In this way, through such a design, the influence of the cold solder joint caused by the insulating layer on the third edge bus grid line 303 and the fourth edge bus grid line 304 can also be basically reduced or even eliminated.

[0206] Of course, it is understandable that in some embodiments, the third edge bus bar line 303 and the fourth edge bus bar line 304 may not be provided.

[0207] In such a case, the fourth auxiliary connection line 130 located between the third edge 123 and the second bus bar line group 310 closest to the third edge 123 may connect all first bus bars 20 located between the third edge 123 and the second bus bar line group 310 closest to the third edge 123. And / or the fourth auxiliary connection line 130 located between the fourth edge 124 and the second bus bar line group 310 closest to the fourth edge 124 connects all first bus bars 20 located between the fourth edge 124 and the second bus bar line group 310 closest to the fourth edge 124.

[0208] Thus, through such a design, it is possible to avoid the occurrence of cold solder joints at the start and end solder joints of the solder strip at the upper and lower ends of the fourth edge serial connection area 142, thereby preventing the performance from being degraded.

[0209] See also Fig.15 and 16 As described above, the second gate line 30 may include a second welding segment 301 corresponding to the first series connection region 13 , and the first gate line 20 may include a first welding segment 201 corresponding to the fourth edge series connection region 142 .

[0210] In some embodiments, in the fourth edge series connection area 142, a second groove 16 is formed on the substrate 10, the second bus line 33 is partially located in the second groove 16, and the third insulating layer 120 is at least partially disposed in the second groove 16. In the thickness direction of the back-contact battery 100 (that is, the direction from the front side 11 to the back side 12), the height of the third insulating layer 120 is flush with the height of the first welding 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.

[0211] In this way, by forming a second groove 16 on the substrate 10 and setting the third insulating layer 120 in the groove, the height of the third insulating layer 120 can be made smaller than the height of the first welding section 201, or the third insulating layer 120 is flush with the first welding section 201, or the height of the third insulating layer 120 is greater than the first welding section 201 and the height difference between the two is less than or equal to 15um, thereby further reducing the risk of cold soldering caused by the third insulating layer 120.

[0212] In some embodiments, the second groove 16 may penetrate 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 portion of the second busbar 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 opened on the substrate 10 by etching (such as laser etching, etc.), without inserting an etching and grooving process in the process of preparing the substrate 10.

[0213] Specifically, in such a case, a complete substrate 10 may be provided first, and then a groove process may be directly performed on the substrate 10 at the position where the third insulating layer 120 is to be placed, and then the second gate line 30 and the first gate line 20 may be printed, and then the third insulating layer 120 may be arranged at the second groove 16 .

[0214] Of course, in some other embodiments, a second recessed groove may be formed on the silicon substrate 101 at a position corresponding to the fourth edge series region 142 and the second bus line 33, and the second doping layer 103 and the back passivation film layer 104 may be recessed toward the side where the front side 11 is located at the second recessed groove to form a second groove 16 on the substrate 10.

[0215] Specifically, in such a case, during the manufacturing process, before preparing the first doping layer 102, a second recessed groove can be opened in the silicon substrate 101 at the position 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 to form the substrate 10. Since the second recessed groove is opened on the silicon substrate 101, the above-mentioned second groove 16 can be formed correspondingly on the substrate 10, and then the second gate line 30 and the first gate line 20 are printed, and then the third insulating layer 120 is set at the second groove 16.

[0216] See also Fig.17In some embodiments, at the fourth edge series connection area 142, a second auxiliary connection layer 150 may be provided on the first gate line 20, and the second auxiliary connection layer 150 is used for welding with the welding 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 15um.

[0217] In this way, by setting the second auxiliary connection layer 150 on the portion corresponding to the first gate line 20 and the fourth edge series area 142, the height of the third insulating layer 120 can be made smaller than the height of the second auxiliary connection layer 150, or the third insulating layer 120 is flush with the second auxiliary connection layer 150, or the height of the third insulating layer 120 is greater than the second auxiliary connection layer 150 and the height difference between the two is less than or equal to 15um, thereby reducing the risk of cold soldering caused by the third insulating layer 120.

[0218] Specifically, in such an embodiment, the second auxiliary connection layer 150 can be stacked on the first welding section 201. The second auxiliary connection layer 150 can be a conductive material layer such as a solder paste layer, which is used for welding with the welding ribbon during the welding process, and is not specifically limited here.

[0219] See also Fig.12 , Fig.18 and Fig.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, and the intermediate bus section 113, the first edge bus section 111, and the second edge bus section 112 all extend along the second direction. Fig.12 As shown, the three can be arranged in parallel and spaced apart along the first direction. The middle bus section 113 is closer to the second edge 122 than the first edge bus section 111 and the second edge bus section 112 .

[0220] The first edge bus section 111 is disposed near the third edge 123, the second edge bus section 112 is disposed near the fourth edge 124, and the second edge connection line 110 further includes a first connection section 114 and a second connection section 115, both of which extend along the first direction. The first connection section 114 connects the middle bus section 113 and the first edge bus section 111, and the second connection section 115 connects the middle bus section 113 and the second edge bus section 112; The first edge bus section 111 connects the two second grid lines 30 closest to the third edge 123. At the junction of the first edge bus section 111 and the first connecting section 114, the first edge bus section 111 has a third convex portion 1101 protruding toward the fourth edge 124, and the first connecting section 114 has a fourth convex portion 1102 protruding toward the first edge 121. At the junction of the middle bus section 113 and the first connecting section 114, the middle bus section 113 has a fifth convex portion 1103 protruding toward the third edge 123, and the first connecting section 114 has a sixth convex portion 1104 protruding toward the second edge 122; and / or The second edge bus section 112 connects the two second grid lines 30 closest to the fourth edge 124. At the junction of the second edge bus section 112 and the second connecting section 115, the second edge bus section 112 has a seventh protrusion 1105 protruding toward the third edge 123, and the second connecting section 115 has an eighth protrusion 1106 protruding toward the first edge 121. At the junction of the middle bus section 113 and the second connecting section 115, the middle bus section 113 has a ninth protrusion 1107 protruding toward the fourth edge 124, and the second connecting section 115 has a tenth protrusion 1108 protruding toward the second edge 122.

[0221] Thus, when the connection between the second edge 122 and the third edge 123 and the fourth edge 124 has a chamfer, the second edge connection line 110 is set to a structure of 3 vertical segments + 2 horizontal segments, so that the chamfer can be avoided and the printing difficulty can be reduced. At the same time, corresponding convex parts are set at the junction of each confluence segment, and redundancy can be set at the corner of the second edge 122 to avoid poor contact between each confluence segment due to inaccurate printing during the printing process, which causes the slurry to fail to form a complete filling at the corner.

[0222] Of course, it is understood that in some embodiments, when a chamfer is formed at the intersection of the second edge 122, the third edge 123, and the fourth edge 124, the second edge connection line 110 can also be arranged in the same manner as the first edge connection line 40 (for example, there is a bend), and the specifics are not limited here. Of course, it is understood that in some embodiments, if the back contact battery 100 does not have a chamfer, it is sufficient to set a second edge connection line 110 that extends vertically and continuously along the second direction.

[0223] See also Fig.18 and Fig.19 In some embodiments, at the junction of the second gate line 30 and the second edge connection line 110 , at least a portion of the second gate line 30 has a second gate line protrusion 302 protruding toward the second edge 122 compared to the second edge connection line 110 .

[0224] Thus, the second gate line protrusion 302 can ensure the stability of the electrical connection between the second gate line 30 and the second edge connection line 110, effectively avoiding the phenomenon that some second gate lines 30 cannot form stable contact with the second edge connection line 110 due to printing accuracy during the printing process.

[0225] See also Figure 3 and Fig.12 In some embodiments, there are multiple second connection grid lines 23, the number of the second connection grid lines 23 is the same as that of the second bus grid line group 310 and they correspond one to one, the multiple second connection grid lines 23 are arranged at intervals along the second direction, and each second connection grid line 23 corresponds to one second bus grid line group 310. In the fifth edge series connection area 133, both sides of the second bus grid line group 310 are provided with fifth auxiliary connection lines 1310, and two second bus grid lines 33 in the second bus grid line group 310 are respectively connected to one fifth auxiliary connection line 1310. In this way, the effect of the fourth insulating layer 1210 on the two sides of the cold solder joint can be reduced.

[0226] See also Figure 3 and Fig.12 In such an embodiment, the fifth auxiliary connection line 1310 located between two adjacent second bus gate line groups 310 connects all second gate lines 30 located between two adjacent second bus gate line groups 310. In this way, the cold solder joint effect caused by the fourth insulating layer 1210 can be completely and substantially eliminated.

[0227] Of course, it is understandable that in some embodiments, a fifth auxiliary connection line 1310 may be further provided on one side of the second connection grid line 23, which may also reduce the effect of cold solder joints in some areas. Of course, in the present application, the fifth auxiliary connection line 1310 is preferably provided on both sides of the second connection grid line 23.

[0228] In addition, in some less preferred embodiments, when there are multiple second connection grid lines 23, the fifth auxiliary connection line 1310 may be set on at least one of the second connection grid lines 23, while the fifth auxiliary connection line 1310 may not be set on both sides of the remaining second connection grid lines 23. This can also reduce the impact of cold soldering in some areas.

[0229] In some embodiments, the width (length in the first direction) of the fifth auxiliary connection line 1310 is greater than the width (length in the second direction) of the portion (ie, the second welding section 301 ) of the second busbar lines 30 other than the second busbar lines 33 outside the first series connection region 13 .

[0230] Thus, since the fifth auxiliary connection line 1310 plays the role of transmitting and converging current when cold soldering occurs, setting the width of the fifth auxiliary connection line 1310 wider can also reduce transmission loss during the converging process and improve efficiency.

[0231] Specifically, in such an embodiment, the width of the fifth auxiliary connection line 1310 may be the same as the width of the second welding section 301 .

[0232] See also Figure 3 , Fig.12 and Fig.15 In some embodiments, the plurality of second serial connection regions 14 further include a sixth edge serial connection region 143 that is most adjacent to the fifth edge serial connection region 133 , and the sixth edge serial connection region 143 is located on a side of the fifth edge serial connection region 133 away from the second edge 122 .

[0233] The second connection gate lines 23 are continuous at the sixth edge series area 143 . A sixth auxiliary connection line 160 is disposed in the sixth edge series area 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 .

[0234] Thus, by disposing the sixth auxiliary connection line 160 in the sixth edge series connection area 143, it is possible to effectively avoid the phenomenon that the welding strip in the sixth edge series connection area 143 has a cold solder joint or poor contact at the second connection gate line 23, resulting in the current transmitted from the second connection gate line 23 not being collected.

[0235] Specifically, Fig.12 and Fig.15 As shown, in such an embodiment, the number of the sixth auxiliary connection lines 160 can be consistent with the number of the second connection gate lines 23, and the two correspond one to one. The sixth auxiliary connection line 160 connects the second connection gate lines 23 and also connects two first gate lines 20 adjacent to the second connection gate lines 23.

[0236] In some embodiments, the width (length in the first direction) of the sixth auxiliary connection line 160 may be greater than the width (length in the second direction) of the portion of the first gate line 20 other than the second series connection region 14 (i.e., the portion other than the first welding section 201). In this way, setting the width of the sixth auxiliary connection line 160 wider can also reduce transmission loss during the convergence process and improve efficiency.

[0237] 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.

[0238] In this way, it is possible to avoid the distance between the fourth edge series connection area 142 and the second edge 122 being too small, which causes the welding position to be too close to the second edge 122, thereby causing hidden cracks in the back contact battery 100, thereby reducing the risk of hidden cracks. It is also possible to avoid the distance between the fourth edge series connection area 142 and the second edge 122 being too large, which causes the length of the isolated gate line segment roughly located between the fourth edge series connection area 142 and the second edge 122 to be too long, thereby causing excessive loss during the transmission path.

[0239] Specifically, in such an embodiment, the distance between the fourth edge series area 142 and the second edge 122 may 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-20mm, and is not limited here.

[0240] In the above embodiment, the fourth edge series connection area 142 has opposite polarity to the first edge series connection area 131, the fifth edge series connection area 133 has opposite polarity to the second edge series connection area 141, and the sixth edge series connection area 143 has opposite polarity to the third edge series connection area 132. The click structures of the two edges of the back contact cell 100 in the first direction are different and asymmetric.

[0241] It can be understood that, in some possible embodiments, the polarity of the fourth edge series connection area 142 and the first edge series connection area 131 may also be the same, the polarity of the fifth edge series connection area 133 and the second edge series connection area 141 may also be the same, and the polarity of the sixth edge series connection area 143 and the third edge series connection area 132 may also be the same. In this case, the structures of the two edges of the back contact battery 100 in the first direction are the same and symmetrical. That is to say, in this case, in the back contact battery 100, the three series connection areas closest to the second edge 122 are symmetrical to the first edge series connection area 131, the second edge series connection area 141 and the third edge series connection area 132. Edge connection lines, auxiliary connection lines and other structures are also provided on one side of the second edge 122, which are completely symmetrical with one side of the first edge 121. In order to avoid redundancy, its specific structure is not described here.

[0242] See also Figure 3In some embodiments, the substrate 10 has a third edge 123 and a fourth edge 124 in the second direction, and a seventh auxiliary connecting line 170 and an eighth auxiliary connecting line 180 may be provided in the first series connection area 13 other than the first edge series connection area 131 and the fifth edge series connection area 133. The seventh auxiliary connecting line 170 connects the N second gate lines 30 closest to the third edge 123, and the eighth auxiliary connecting line 180 connects the M second gate lines 30 closest to the fourth edge 124, wherein N and M are both greater than or equal to 2 and less than or equal to 8.

[0243] In some embodiments, a ninth auxiliary connection line 190 and a tenth auxiliary connection line 1100 may be provided in the second series connection area 14 other than the second edge series connection area 141 and the fourth edge series connection area 142, the ninth auxiliary connection line 190 connecting the P first gate lines closest to the third edge, and the tenth auxiliary connection line 1100 connecting the Q first gate lines closest to the fourth edge, wherein P and Q are both greater than or equal to 2 and less than or equal to 8.

[0244] In this way, the seventh auxiliary connection line 170 and the eighth auxiliary connection line 180 are respectively arranged at the head and tail ends of the welding strip of the first series connection area 13 in the middle area, which can effectively avoid the problem that the welding strip on the first series connection area 13 has a cold solder joint at the start solder joint and the end solder joint, resulting in the current of some gate lines cannot be collected. Similarly, by respectively arranging the ninth auxiliary connection line 190 and the tenth auxiliary connection line 1100 at the positions of the second series connection area 14 in the middle area close to the third edge 123 and the fourth edge 124, that is, the ninth auxiliary connection line 190 and the tenth auxiliary connection line 1100 are respectively arranged at the head and tail ends of the welding strip in the second series connection area 14, which can effectively avoid the problem that the welding strip on the second series connection area 14 has a cold solder joint at some positions of the start solder joint and the end solder joint, resulting in the current of some gate lines cannot be collected.

[0245] See also Figure 3In some embodiments, in the first series connection area 13, the X first gate lines 20 closest to the third edge 123 are discontinuous at the first series connection area 13, and the Y first gate lines 20 closest to the fourth edge 124 are discontinuous at the first series connection area 13, and the width of the discontinuous area formed by the X first gate lines 20 closest to the third edge 123 gradually increases in the direction toward the third edge 123, and the width of the discontinuous area formed by the Y first gate lines 20 closest to the fourth edge 124 gradually increases in the direction toward the fourth edge 124, wherein X and Y are both greater than or equal to 2. That is to say, in such an embodiment, in the first series connection area 13, among the at least two second gate lines 30 closest to the third edge 123, the second welding section 301 on the second gate line 30 closer to the third edge 123 is wider in the second direction. Among the at least two second gate lines 30 closest to the fourth edge 124 , the second welding segments 301 on the second gate lines 30 closer to the fourth edge 124 are wider in the second direction.

[0246] In the second series connection area 14, the W second gate lines 30 closest to the third edge 123 are discontinuous in the second series connection area 14, and the Z second gate lines 30 closest to the fourth edge 124 are discontinuous in the second series connection area 14, and the width of the discontinuous area formed by the W second gate lines 30 closest to the third edge 123 gradually increases in the direction toward the third edge 123, and the width of the discontinuous area formed by the Z second gate lines 30 closest to the fourth edge 124 gradually increases in the direction toward the fourth edge 124, wherein W and Z are both greater than or equal to 2. That is to say, in such an embodiment, in the second series connection area 14, among the at least two first gate lines 20 closest to the third edge 123, the first welding section 201 on the first gate line 20 closer to the third edge 123 has a wider length in the second direction. Among the at least two first gate lines 20 closest to the fourth edge 124 , the first welding segments 201 on the first gate lines 20 closer to the fourth edge 124 are wider in the second direction.

[0247] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0248] In addition, the above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in 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 area. A third auxiliary connection line is provided in the third edge series 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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