Back contact cells, cell assemblies and photovoltaic systems

Abstract

The application relates to the technical field of solar cells, and provides a back contact cell, a cell assembly and a photovoltaic system. In the back contact cell, a first chamfer is formed at the intersection position of a first edge and a third edge; a plurality of first string connection regions include a first edge string connection region closest to the first edge, and there is no second string connection region between the first edge string connection region and the first edge; in the first fine grid and the second fine grid, the fine grid closest to the third edge is the first fine grid; in the plurality of first fine grids, the two first fine grids closest to the third edge correspond to the first chamfer; the two first fine grids corresponding to the first chamfer include the first edge fine grid closest to the third edge and the second edge fine grid adjacent to the first edge fine grid; and at least one of the first edge fine grid and the second edge fine grid does not extend to between the first edge string connection region and the first edge. In this way, the risk of hidden cracks at the first chamfer can be reduced.

Description

TECHNICAL FIELD

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

[0002] The back contact cell is a cell in which both P-type doped layer and N-type doped layer are arranged on the back surface of a silicon wafer, and the front surface is not shielded by metal electrodes, which has higher short-circuit current and conversion efficiency. The back surface of the back contact cell is provided with two kinds of fine grids of different polarities. At the position of the stringing area where the solder strip is arranged, the fine grids of the same polarity are connected with the solder strip, and the fine grids of the different polarity are disconnected at the solder strip.

[0003] In the related art, the corner of the back contact cell usually has a chamfer. During the lamination process, the chamfer is prone to hidden cracks. Therefore, how to reduce the risk of hidden cracks of the back contact cell has become a technical problem to be solved. SUMMARY

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

[0005] The present application is implemented in the following manner. The back contact cell of the present application comprises:

[0006] A substrate, the substrate has opposite first and second edges in a first direction, and opposite third and fourth edges in a second direction, the second direction intersects the first direction, and a first chamfer is formed at the intersection of the first edge and the third edge; the back surface of the substrate has a plurality of first stringing areas and a plurality of second stringing areas, the first stringing areas and the second stringing areas are arranged alternately in the first direction, and a plurality of the first stringing areas include a first edge stringing area closest to the first edge, and there is no second stringing area between the first edge stringing area and the first edge; and

[0007] A plurality of first fine grids and a plurality of second fine grids are arranged on the back surface of the substrate, the plurality of first fine grids and the plurality of second fine grids are arranged alternately along the second direction and extend along the first direction;

[0008] Among the first fine grids and the second fine grids, the fine grid closest to the third edge is the first fine grid, among a plurality of the first fine grids, the two first fine grids closest to the third edge correspond to the first chamfer, and the two first fine grids corresponding to the first chamfer include a first edge fine grid closest to the third edge and a second edge fine grid adjacent to the first edge fine grid;

[0009] At least one of the first edge fine grid and the second edge fine grid does not extend between the first edge stringing area and the first edge, and the rest of the first fine grids each have a portion between the first edge stringing area and the first edge.

[0010] In some embodiments, the first edge fine grid extends between the first edge stringing area and the first edge, and the second edge fine grid does not extend between the first edge stringing area and the first edge.

[0011] In some embodiments, a length of a line between an end of the first edge fine grid towards the first edge and any point on the first chamfer is greater than or equal to 0.4 mm and less than or equal to 1.5 mm; and / or

[0012] A length of a line between an end of the second fine grid towards the first edge and any point on the first chamfer is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

[0013] In some embodiments, the first fine grids include first collecting fine grids and at least one first busbar fine grid, the first collecting fine grids are discontinuous at the first edge stringing area and continuous at the second stringing area, the first busbar fine grid is continuous at both the first edge stringing area and the second stringing area, and the second fine grid is continuous at the first edge stringing area;

[0014] The back contact cell further includes:

[0015] A first edge busbar closer to the first edge than the first edge stringing area, the first edge busbar being electrically connected to at least part of the first collecting fine grid and to the first busbar fine grid; and

[0016] A first connecting grid line provided in the first edge stringing area, at least one side of the first busbar fine grid being provided with the first connecting grid line in the second direction, the first connecting grid line connecting at least two second fine grids on the same side of the first busbar fine grid;

[0017] In the first edge stringing area, the first edge fine grid is the first busbar fine grid, the first edge fine grid being continuous at the first edge stringing area and extending between the first edge stringing area and the first edge, and the second edge fine grid is the first collecting fine grid, the second edge fine grid being discontinuous at the first edge stringing area and not extending between the first edge stringing area and the first edge; or

[0018] The first edge fine grid and the second edge fine grid are the first collection fine grids, and the first edge fine grid and the second edge fine grid are discontinuous at the first edge stringing area and do not extend between the first edge stringing area and the first edge.

[0019] In some embodiments, the first edge fine grid is the first busbar fine grid, the first edge fine grid is continuous at the first edge stringing area and extends between the first edge stringing area and the first edge, the second edge fine grid is the first collection fine grid, the second edge fine grid is discontinuous at the first edge stringing area and does not extend between the first edge stringing area and the first edge,

[0020] Among them, except for the second edge fine grid, the rest of the first fine grid has a part between the first edge stringing area and the first edge, and the first edge busbar is electrically connected with all the first fine grid except the second edge fine grid.

[0021] In some embodiments, the first edge busbar is connected with the first edge fine grid, and the first edge busbar has a first bending section at the first chamfer, and the distance between the first bending section and the first chamfer is 0.2mm-0.6mm.

[0022] In some embodiments, the number of the first busbar fine grid is N, and N is a positive integer greater than 2;

[0023] Among them, the first connecting grid line is arranged between adjacent two first busbar fine grids, and the first connecting grid line between adjacent two first busbar fine grids connects at least part of the second fine grid between adjacent two first busbar fine grids.

[0024] In some embodiments, the first connecting grid line includes a first end connecting grid line closest to the third edge, a second end connecting grid line closest to the fourth edge, and a first intermediate connecting grid line between the first end connecting grid line and the second end connecting grid line.

[0025] The width of the first end connecting grid line is greater than the width of the first intermediate connecting grid line; and / or, the width of the second end connecting grid line is greater than the width of the first intermediate connecting grid line.

[0026] In some embodiments, the width of the first end connecting grid line is 1.3-1.8 times the width of the first intermediate connecting grid line; and / or

[0027] The width of the second end connecting grid line is 1.3-1.8 times the width of the first intermediate connecting grid line.

[0028] In some embodiments, the width of the first intermediate connection bus line is 0.5mm-0.7mm;

[0029] The width of the first end connection bus line is 0.8mm-1.2mm, and / or the width of the second end connection bus line is 0.8mm-1.2mm.

[0030] In some embodiments, the width of the first end connection bus line is greater than the width of the first edge bus bar; and / or

[0031] The width of the second end connection bus line is greater than the width of the first edge bus bar.

[0032] In some embodiments, the width of the first end connection bus line is 1.1-1.4 times the width of the first edge bus bar; and / or

[0033] The width of the second end connection bus line is 1.1-1.4 times the width of the first edge bus bar.

[0034] In some embodiments, the width of the first edge bus bar is 0.7mm-0.9mm;

[0035] The width of the first end connection bus line is 0.8mm-1.2mm, and / or the width of the second end connection bus line is 0.8mm-1.2mm.

[0036] In some embodiments, the width of the first end connection bus line and the width of the second end connection bus line are both greater than the width of the first edge bus bar, and the width of the first edge bus bar is greater than the width of the first intermediate connection bus line.

[0037] In some embodiments, the ratio of the width of the first end connection bus line, the width of the first edge bus bar, and the width of the first intermediate connection bus line is 1:0.8:0.6.

[0038] In some embodiments, the plurality of second string connection areas includes a second edge string connection area closest to the first edge, and the first bus bar fine grid includes a first bus bar section located between the second edge string connection area and the first edge;

[0039] The width of the first bus bar section is greater than the width of the portion of the remaining part of the first bus bar fine grid located outside the second string connection area; and / or

[0040] A first bus bar layer is arranged on the first bus bar section.

[0041] In some embodiments, the width of the first end connecting gate line and the width of the second end connecting gate line are both greater than the width of the first bus section and / or the first bus layer.

[0042] In some embodiments, the width of the first end connecting gate line and the width of the second end connecting gate line are both 1.1-1.4 times the width of the first bus section and / or the first bus layer.

[0043] In some embodiments, the second string connection area closest to the first edge is a second edge string connection area, the first fine gate is continuous at the second edge string connection area, and the second fine gate is discontinuous at the second edge string connection area.

[0044] The back contact cell further comprises a second connecting gate line, the second connecting gate line is arranged in the second edge string connection area, and the second connecting gate line connects the first bus fine gate and at least one first collection fine gate on one side of the first bus fine gate in the second direction.

[0045] In some embodiments, the length of the second connecting gate line is less than the length of the first connecting gate line.

[0046] In some embodiments, the ratio between the length of the second connecting gate line and the length of the first connecting gate line is 0.2-0.5.

[0047] In some embodiments, the length of the second connecting gate line is 2-3 mm, and the length of the first connecting gate line is 6-9 mm.

[0048] In some embodiments, the second connecting gate line includes a third end connecting gate line closest to the third edge, a fourth end connecting gate line closest to the fourth edge, and a second intermediate connecting gate line between the third end connecting gate line and the fourth end connecting gate line.

[0049] The width of the third end connecting gate line is greater than the width of the second intermediate connecting gate line; and / or, the width of the fourth end connecting gate line is greater than the width of the second intermediate connecting gate line.

[0050] In some embodiments, the width of the third end connecting gate line is 1.3-1.8 times the width of the second intermediate connecting gate line; and / or

[0051] The width of the fourth end connecting gate line is 1.3-1.8 times the width of the second intermediate connecting gate line.

[0052] In some embodiments, a second chamfer is formed at the intersection of the second edge and the third edge, a plurality of the second stringing regions include a third edge stringing region closest to the second edge, and there is no first stringing region between the third edge stringing region and the second edge.

[0053] The first edge fine grid and the second edge fine grid correspond to the second chamfer, and all the first fine grids extend to between the third edge stringing region and the second edge.

[0054] In some embodiments, the length of the line between the end of the second edge and any point on the second chamfer is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

[0055] In some embodiments, the second fine grid between the first edge fine grid and the second edge fine grid does not extend to between the third edge stringing region and the second edge.

[0056] In some embodiments, the second fine grid between the first edge fine grid and the second edge fine grid extends to between the third edge stringing region and the second edge, and the length of the line between the end of the second edge and any point on the second chamfer is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

[0057] In some embodiments, the plurality of second fine grids include a plurality of second collection fine grids and at least one second busbar fine grid, the second collection fine grids are discontinuous at the third edge stringing region and continuous at the first stringing region, the second busbar fine grid is continuous at the third edge stringing region and the first stringing region, and the first fine grid is continuous at the third edge stringing region.

[0058] The back contact cell further includes:

[0059] A second edge busbar closer to the second edge than the third edge stringing region, the second edge busbar being electrically connected to at least part of the second collection fine grid and electrically connected to the second busbar fine grid; and

[0060] A third connection grid line provided in the third edge stringing region, at least one side of the second busbar fine grid being provided with the third connection grid line in the second direction, the third connection grid line connecting at least two first fine grids on the same side of the second busbar fine grid.

[0061] In some embodiments, the number of second busbar fine grids is M, M being a positive integer greater than 2.

[0062] The third connection grid lines are arranged between the second bus fine grids, and the third connection grid lines between the second bus fine grids are connected to at least part of the first fine grids between the second bus fine grids.

[0063] In some embodiments, the third connection grid lines include a fifth end connection grid line closest to the third edge, a sixth end connection grid line closest to the fourth edge, and a third intermediate connection grid line between the fifth end connection grid line and the sixth end connection grid line.

[0064] The width of the fifth end connection grid line is greater than the width of the third intermediate connection grid line; and / or, the width of the sixth end connection grid line is greater than the width of the third intermediate connection grid line.

[0065] In some embodiments, the width of the fifth end connection grid line is 1.3-1.8 times the width of the third intermediate connection grid line; and / or

[0066] The width of the sixth end connection grid line is 1.3-1.8 times the width of the third intermediate connection grid line.

[0067] In some embodiments, the width of the fifth end connection grid line is greater than the width of the second edge bus line; and / or

[0068] The width of the sixth end connection grid line is greater than the width of the second edge bus line.

[0069] In some embodiments, the width of the fifth end connection grid line is 1.1-1.4 times the width of the second edge bus line; and / or

[0070] The width of the sixth end connection grid line is 1.1-1.4 times the width of the second edge bus line.

[0071] In some embodiments, the width of the fifth end connection grid line and the sixth end connection grid line are both greater than the width of the second edge bus line, and the width of the second edge bus line is greater than the width of the third intermediate connection grid line.

[0072] In some embodiments, the first stringing areas include a fourth edge stringing area closest to the second edge, the second fine grids are continuous at the fourth edge stringing area, and the first fine grids are discontinuous at the fourth edge stringing area.

[0073] The back contact cell further comprises a fourth connecting grid line, the fourth connecting grid line is arranged in the fourth edge series connection area, and the fourth connecting grid line connects at least one second collecting thin grid and at least one second collecting thin grid on one side of the second collecting thin grid in the second direction.

[0074] In some embodiments, the length of the fourth connecting grid line is less than the length of the third connecting grid line.

[0075] In some embodiments, the ratio between the length of the fourth connecting grid line and the length of the third connecting grid line is 0.2-0.5.

[0076] In some embodiments, the length of the fourth connecting grid line is 2mm-3mm, and the length of the third connecting grid line is 6mm-9mm.

[0077] The application further provides a battery assembly, which comprises a plurality of the back contact cells described in any one of the above.

[0078] The application further provides a photovoltaic system, which comprises the battery assembly described above.

[0079] In the back contact cell, the battery assembly and the photovoltaic system provided in the embodiments of the application, the first chamfer corresponds to only two first thin grids, which are the first edge thin grid and the second edge thin grid, and at least one of the first edge thin grid and the second edge thin grid does not extend to the first edge series connection area and the first edge, and the rest of the first thin grids all have a part between the first edge series connection area and the first edge, that is, at least one of the first edge thin grid and the second edge thin grid does not have a thin grid segment at the first chamfer and the first edge series connection area. In this way, at most only one first thin grid extends to the first edge series connection area and the first edge at the position corresponding to the first chamfer, that is, at most only one first thin grid has a thin grid segment between the first chamfer and the first edge series connection area, and at most only one first thin grid extends to the vicinity of the first chamfer from the end of the first thin grid towards the first edge, so that the stress at the first chamfer can be effectively avoided from being too concentrated, the risk of hidden cracking at the first chamfer can be reduced, and the reliability of the back contact cell can be improved.

[0080] Additional aspects and advantages of the application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0081] Figure 1 is a module schematic diagram of the photovoltaic system provided in the embodiments of the application.

[0082] Figure 2 is a module schematic diagram of the battery assembly provided in the embodiments of the application.

[0083] Figure 3 is a schematic diagram of a planar structure of a back contact battery provided by an embodiment of the present application;

[0084] Figure 4 is a schematic diagram of an enlarged structure of the back contact battery in at IV; Figure 3

[0085] Figure 5 is a schematic diagram of an enlarged structure of the back contact battery in at V; Figure 4

[0086] Figure 6 is a schematic diagram of a cross-sectional structure of the back contact battery in along line VI-VI; Figure 4

[0087] Figure 7 is a schematic diagram of a cross-sectional structure of the back contact battery in along line VII-VII; Figure 4

[0088] Figure 8 is a schematic diagram of an enlarged structure of the back contact battery in at VIII; Figure 4

[0089] Figure 9 is a schematic diagram of an enlarged structure of the back contact battery in at IX; Figure 3

[0090] Figure 10 is a schematic diagram of an enlarged structure of the back contact battery in at X; Figure 9

[0091] Figure 11 is another schematic diagram of an enlarged structure of the back contact battery in at X; Figure 9

[0092] Figure 12 is a schematic diagram of an enlarged structure of the back contact battery in at XII; Figure 9

[0093] Figure 13 is a schematic diagram of a first string connection area and a second string connection area of a back contact battery provided by an embodiment of the present application. DETAILED DESCRIPTION

[0094] ​​​​​​​​​In order to make the purposes, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. Examples of the embodiments are shown in the drawings, wherein identical or similar reference numerals denote identical or similar elements or elements having the same or similar functions throughout. It should be noted that the embodiments described below by referring to the drawings are merely exemplary for explaining the present application and should not be understood as limiting the present application. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present application and should not be used to limit the present application.

[0095] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "transverse", "longitudinal", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as limiting the present application.

[0096] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be understood as indicating or implying relative importance or implying a specific number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "several" is two or more, unless otherwise explicitly specified and limited.

[0097] In the present application, unless otherwise explicitly specified and limited, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above", and "over" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. "Below", "under", and "underneath" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0098] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements 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 repeatedly refer to numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and in itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0099] Please refer to Figure 1 and Figure 2 , the photovoltaic system 1000 in the embodiments of the present application can include the battery assembly 200 in the embodiments of the present application, the battery assembly 200 in the embodiments of the present application can include a plurality of back contact cells 100 in the embodiments of the present application. In the embodiments of the present application, the plurality of back contact cells 100 in the battery assembly 200 can be connected in series to form a plurality of cell strings, and each cell string can be connected in series, connected in parallel, or connected in series-parallel combination to realize the current output, for example, the connection between each cell can be realized by welding the welding strip, and the connection between each cell string can be realized by the bus bar. In some embodiments, each cell string can form a cell array, and then be packaged together by the front plate, the front adhesive film, the rear adhesive film and the back plate to form the battery assembly 200.

[0100] In the embodiments of the present application, please refer to Figures 3-7 , the back contact cell 100 in the embodiments of the present application can include a substrate 10, a plurality of first fine grids 20 and a plurality of second fine grids 30.

[0101] As shown in Figures 3-7 , the substrate 10 has opposite front surface 11 and back surface 12, the back surface 12 of the substrate 10 has opposite first edge 121 and second edge 122 in the first direction, the substrate 10 has third edge 123 and fourth edge 124 in the second direction, and the second direction intersects the first direction.

[0102] In some embodiments, the first direction and the second direction can be the longitudinal direction and the transverse direction of the back contact cell 100 respectively, and the two directions are perpendicular to each other, for example, in Figure 3 , the first direction can be the transverse direction of the back contact cell 100, and the second direction can be the longitudinal direction of the back contact cell 100. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, two diagonal directions of the back contact cell 100, which are not limited here.

[0103] Please refer to Figures 3-5 , the intersection position of the first edge 121 and the third edge 123 forms a first chamfer 125, and the back surface 12 has a plurality of first series connection areas 13 and a plurality of second series connection areas 14. The first series connection area 13 and the second series connection area 14 are respectively used to set the positive electrode welding strip and the negative electrode welding strip, that is to say, one of the first series connection area 13 and the second series connection area 14 is the positive electrode series connection area, and the other is the negative electrode series connection area.

[0104] As shown in Figure 3 and Figure 4As shown, in the first direction, the first stringing regions 13 and the second stringing regions 14 are arranged alternately, and the first stringing regions 13 include a first edge stringing region 131 closest to the first edge 121, and the first edge stringing region 131 is free of the second stringing regions 14 between the first edge stringing region 131 and the first edge 121. That is, as shown in FIG. 1, the first edge stringing region 131 is free of the second stringing regions 14 between the first edge stringing region 131 and the first edge 121. Figure 3 As shown, in the first stringing regions 13 and the second stringing regions 14, the stringing region closest to the first edge 121 is the first stringing region 13, and the first stringing region 13 is denoted as the first edge stringing region 131, and the first edge stringing region 131 is free of other stringing regions between the first edge stringing region 131 and the first edge 121.

[0105] As shown, the first stringing regions 13 and the second stringing regions 14 are arranged alternately in the second direction on the back surface 12 and extend in the first direction. Figure 3 As shown, the first stringing regions 13 and the second stringing regions 14 are arranged alternately in the second direction on the back surface 12 and extend in the first direction.

[0106] In some embodiments, all the first stringing regions 20 and all the second stringing regions 30 are arranged to cross the first stringing regions 13 and the second stringing regions 14, that is, the first stringing regions 13 and the second stringing regions 14 extend in the second direction to cross the first stringing regions 20 and the second stringing regions 30. In the first stringing regions 20 and the second stringing regions 30, the first stringing regions 20 are continuous at the second stringing regions 14, and the second stringing regions 30 are continuous at the first stringing regions 13.

[0107] As shown, Figure 5 In the first stringing regions 20 and the second stringing regions 30, the stringing region closest to the third edge 123 is the first stringing region 20, and in the first stringing regions 20, the two first stringing regions 20 closest to the third edge 123 correspond to the first chamfer 125, and the two first stringing regions 20 corresponding to the first chamfer 125 include a first edge stringing region 24 closest to the third edge 123 and a second edge stringing region 23 adjacent to the first edge stringing region 24.

[0108] In such embodiments, in all the first stringing regions 20, only the first edge stringing region 24 and the second edge stringing region 23 correspond to the first chamfer 125 (that is, the extension lines of the two cross the first chamfer 125), and in all the second stringing regions 30, only the second stringing region 30 between the first edge stringing region 24 and the second edge stringing region 23 corresponds to the first chamfer 125, that is, as shown in FIG. 1, the first chamfer 125 corresponds to only three stringing regions, including two first stringing regions 20 and one second stringing region 30. Figure 5 As shown, the first chamfer 125 corresponds to only three stringing regions, including two first stringing regions 20 and one second stringing region 30.

[0109] As shown, Figure 5As shown, at least one of the first edge fine grid 24 and the second edge fine grid 23 does not extend between the first edge stringer region 131 and the first edge 121, and the rest of the first fine grids 20 all have a portion between the first edge stringer region 131 and the first edge 121. That is, at least one of the first edge fine grid 24 and the second edge fine grid 23 is only located on one side of the first edge stringer region 131 towards the second edge 122, at least one of the two does not have a portion between the first edge stringer region 131 and the first edge 121, and at least one of the two does not have a fine grid segment between the first chamfer 125 and the first edge stringer region 131.

[0110] In the back contact cell 100, the cell assembly 200, and the photovoltaic system 1000 of the embodiments of the present application, only two first fine grids 20, i.e., the first edge fine grid 24 and the second edge fine grid 23, correspond to the first chamfer 125, at least one of the first edge fine grid 24 and the second edge fine grid 23 does not extend between the first edge stringer region 131 and the first edge 121, and the rest of the first fine grids 20 all have a portion between the first edge stringer region 131 and the first edge 121. That is, at least one of the first edge fine grid 24 and the second edge fine grid 23 does not have a fine grid segment between the first chamfer 125 and the first edge stringer region 131. In this way, at the position corresponding to the first chamfer 125, at most only one first fine grid 20 extends between the first edge stringer region 131 and the first edge 121, that is, at most only one first fine grid has a fine grid segment between the first chamfer 125 and the first edge stringer region 131, and at most only one first fine grid 20 extends to the vicinity of the first chamfer 125 from the end portion thereof towards the first edge 121. In this way, the stress at the first chamfer 125 can be effectively avoided from being too concentrated, the risk of hidden cracks at the first chamfer 125 can be reduced, and the reliability of the back contact cell 100 can be improved.

[0111] Please refer to Figures 3-4 In some embodiments, the first fine grids 20 can include first collection fine grids 21 and at least one first busbar fine grid 22, the first collection fine grids 21 are discontinuous at the first edge stringer region 131 and continuous at the second stringer region 14, the first busbar fine grid 22 is continuous at both the first edge stringer region 131 and the second stringer region 14, and the second fine grids 30 are continuous at the first edge stringer region 131.

[0112] That is, the first fine grid 20 includes at least two types of grid lines, one is the first collection fine grid 21, and the other is the first confluence fine grid 22. The first collection fine grid 21 is discontinuous at the first edge stringing area 131, and the first confluence fine grid 22 is continuous at the first edge stringing area 131. The second fine grid 30 is also continuous at the first edge stringing area 131. In the battery assembly 200, the solder strip in the first stringing area 13 (including the first edge stringing area 131) is used to be connected with the second fine grid 30 to realize the confluence output of the second fine grid 30, and the solder strip in the second stringing area 14 is used to be welded with the first fine grid 20 to realize the confluence output of the first fine grid 20.

[0113] As shown in Figure 3 , the back contact battery 100 can further include a first edge confluence line 40 and a first connection grid line 60.

[0114] The first edge confluence line 40 is closer to the first edge 121 than the first edge stringing area 131, and is electrically connected with at least part of the first collection fine grid 21 and the first confluence fine grid 22.

[0115] Specifically, in order to avoid the welding at the edge position of the first edge 121 causing the battery to have a hidden crack, the first edge confluence line 40 is not used for welding, but is used to collect the current of the part of the first collection fine grid 21 between the first edge stringing area 131 and the first edge 121, and then confluences to the same polarity solder strip in the second stringing area 14 (i.e. Figure 3 and Figure 4 the leftmost second stringing area 14 in the second stringing area 14) adjacent to the first edge stringing area 131 through the first confluence fine grid 22, so as to collect the current of the edge area of the fine grid segment of the first fine grid 20 at the first edge 121, and improve the efficiency of the back contact battery 100. If the first edge confluence line 40 and the first confluence fine grid 22 are not provided, the part of the first fine grid 20 between the first edge stringing area 131 and the first edge 121 will form an isolated fine grid segment, and the current of the part cannot be collected.

[0116] It is not difficult to understand that, in order to realize the insulation of the solder strip and the first confluence fine grid 22 at the first edge stringing area 131 to avoid electric leakage, a first insulation layer (not shown in the figure) can also be provided in the battery assembly 200. The first insulation layer can be provided on the first confluence fine grid 22 at the first edge stringing area 131, that is, the first insulation layer is provided on the part of the first confluence fine grid 22 corresponding to the first edge stringing area 131. The first insulation layer is used to insulate and separate the opposite polarity solder strip in the first edge stringing area 131 from the first confluence fine grid 22 to avoid short circuit.

[0117] The first connecting grid line 60 may be disposed within the first edge serialization area 131. In the second direction, at least one side of the first busbar fine grid 22 is provided with the first connecting grid line 60, and the first connecting grid line 60 connects at least two second fine grids 30 located on the same side of the first busbar fine grid 22.

[0118] Among them, such as Figure 4 , Figure 7 as well as Figure 8 As shown, in some embodiments, at least two second fine gates 30 connected to the first connecting gate line 60 may preferably include a second fine gate 30 adjacent to the first busbar fine gate 22 (i.e., Figure 3 and Figure 4 In some embodiments, the first connecting gate line 60 preferably connects to the second fine gate 30 closest to the first busbar 22, and the first connecting gate line 60 also connects to at least one of the remaining second fine gates 30 located on the same side as the second fine gate 30. That is, the first connecting gate line 60 preferably connects to at least one of the second fine gates 30 adjacent to the first busbar 22 and at least one of the remaining second fine gates 30 on the same side.

[0119] Thus, by setting the first edge bus line 40 and the first bus fine grid 22, the current collected by at least part of the isolated segment of the first fine grid 20 located between the first edge series region 131 and the first edge 121 can be channeled to the same polarity solder strip in the second series region 14 adjacent to the first edge series region 131. This can effectively avoid microcracks caused by soldering at the first edge 121 of the back contact battery 100 while ensuring the efficiency of the back contact battery 100.

[0120] Meanwhile, the first insulating layer provides insulation between the solder strip in the first edge series connection area 131 and the first busbar fine grid 22. With the first connecting grid line 60, even if a poor solder joint occurs between the second fine grid 30 near the first insulating layer and the solder strip due to the first insulating layer, the poorly soldered second fine grid 30 can still achieve current busbar output through the first connecting grid line 60, reducing the impact of the poor solder joint and thus ensuring the efficiency of the back contact battery 100.

[0121] As shown above, it is easy to understand that in this application, the first edge bus 40 is not used for welding; it is only used for current transmission and merging. The function of the first bus grid 22 is to collect and transmit current. Figure 3 and Figure 4 It can be seen that, in Figure 3 and Figure 4In the shown example, if the first edge busbar 40 and the first busbar fine grid 22 are not provided, the first fine grid 20 is disconnected at the first edge stringing area 131, and the current of the portion of the fine grid segment of the first fine grid 20 between the first edge stringing area 131 and the first edge 121 cannot be collected. Therefore, by providing the first edge busbar 40 and the first busbar fine grid 22, the current of at least part of the isolated fine grid segment of the first fine grid 20 in the edge area can be collected and transmitted to the solder strip provided in the adjacent second stringing area 14, thereby effectively avoiding the loss of efficiency.

[0122] However, due to the continuous provision of the first busbar fine grid 22 in the first edge stringing area 131, in order to avoid the short circuit caused by the contact between the solder strip on the first edge stringing area 131 and the first busbar fine grid 22, a first insulating layer (e.g. insulating glue) needs to be provided at the position corresponding to the first busbar fine grid 22 and the first edge stringing area 131, and the height of the first insulating layer is higher than the height of the second fine grid 30, that is, the protruding height of the first insulating layer is higher than the height of the second fine grid 30 in the thickness direction. In this case, the solder strip in the first edge stringing area 131 is prone to appear virtual soldering with the second fine grid 30 during the soldering process, which causes the current of part of the second fine grid 30 to be unable to be effectively collected (especially the second fine grid 30 adjacent to the first busbar fine grid 22, which is most likely to appear virtual soldering). Based on this, the present application connects at least two second fine grids 30 on the same side of the first busbar fine grid 22 by providing the first connecting grid line 60, and preferably selects the second fine grid 30 connected thereto to include the one adjacent to the first busbar fine grid 22. The part of the second fine grid 30 can be connected into a whole by the first connecting grid line 60, that is, even if one of the second fine grids 30 appears virtual soldering due to the presence of the first insulating layer, the output of the current can be realized through the first connecting grid line 60, thereby reducing or even completely eliminating the influence caused by virtual soldering.

[0123] Please refer to Figure 5 In some embodiments, the first edge fine grid 24 can be the first busbar fine grid 22, the first edge fine grid 24 is continuous at the first edge stringing area 131 and extends between the first edge stringing area 131 and the first edge 121, and the second edge fine grid 23 is the first collection fine grid 21, the second edge fine grid 23 is discontinuous at the first edge stringing area 131 and does not extend between the first edge stringing area 131 and the first edge 121. That is, in some embodiments, the first edge fine grid 24 extends between the first edge stringing area 131 and the first edge 121, the second edge fine grid 23 does not extend between the first edge stringing area 131 and the first edge 121, and the second edge fine grid 23 does not have a fine grid segment between the first edge stringing area 131 and the first edge 121 and the first chamfer 125.

[0124] Therefore, the first edge fine grid 24 is arranged to the first busbar fine grid 22, which can effectively avoid the existence of a larger area of carriers that cannot be collected near the first chamfer 125.

[0125] Of course, it can be understood that in some possible embodiments, the first edge fine grid 24 and the second edge fine grid 23 can also be the first collection fine grid 21, and the first edge fine grid 24 and the second edge fine grid 23 are both interrupted at the first edge stringing area 131 and do not extend between the first edge stringing area 131 and the first edge 121, that is, the first edge fine grid 24 and the second edge fine grid 23 do not have fine grid segments between the first edge stringing area 131 and the first edge 121 and the first chamfer 125. In such a case, although the carrier collection efficiency of a part of the area at the first chamfer 125 is low, such an arrangement can further reduce the risk of cracking at the first chamfer 125.

[0126] Further, in the embodiments of the present application, as shown in Figure 6 and Figure 7 The substrate 10 can 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, and the first doped layer 102 and the second doped layer 103 are arranged on the second surface 1012. The plurality of first doped layers 102 and the plurality of second doped layers 103 are arranged alternately along the second direction. The back passivation film layer 104 is at least laminated on the first doped layer 102 and the second doped layer 103. In some embodiments, the back passivation film layer 104 can cover the entire second surface 1012, that is, the first doped layer 102 and the second doped layer 103 and the region of the second surface 1012 without a doped layer are all laminated with the back passivation film layer 104.

[0127] Therefore, in the substrate 10, the surface on the side where the first surface 1011 is located is the front surface 11 of the substrate 10, and the side where the second surface 1012 is located is the back surface of the substrate 10. Of course, in some embodiments, a first passivation layer (not shown in the figure) can also be arranged between the first doped layer 102 and the silicon substrate 101, which can be, for example, a tunneling layer, an intrinsic amorphous silicon layer, etc. A second passivation layer (not shown in the figure) can also be arranged between the second doped layer 103 and the silicon substrate 101, which can be, for example, a tunneling layer, an intrinsic amorphous silicon layer, etc.

[0128] In the back contact cell 100, the first fine grid 20 corresponds to the first doped layer 102 one by one, the second fine grid 30 corresponds to the second doped layer 103 one by one, one of the first doped layer 102 and the second doped layer 103 can be a P-type doped layer, and the other can be an N-type doped layer. In some embodiments, the first fine grid 20 can fully penetrate the back passivation film layer 104 to form full contact with the first doped layer 102, or the first fine grid 20 can only partially penetrate the back passivation film layer 104 to form local metalization contact with the first doped layer 102, which is not limited here.

[0129] That is to say, in the embodiments of the present application, the first fine grid 20 is arranged corresponding to the first doped layer 102 and at least partially penetrates the back passivation film layer 104 to conductively contact the first doped layer 102, and the second fine grid 30 is arranged corresponding to the second doped layer 103 and at least partially penetrates the back passivation film layer 104 to conductively contact the second doped layer 103.

[0130] Please refer to Figure 5 In some embodiments, the first edge fine grid 24 extends between the first edge stringing area 131 and the first edge 121, and the second edge fine grid 23 does not extend between the first edge stringing area 131 and the first edge 121.

[0131] The length of the line between the end of the first edge fine grid 24 towards the first edge 121 and any point on the first chamfer 125 can be greater than or equal to 0.4mm and less than or equal to 1.5mm, such as 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm or other values between 0.4mm-1.5mm, which is not limited here.

[0132] In some possible embodiments, the length of the line between the end of the second fine grid 30 located between the first edge fine grid 24 and the second edge fine grid 23 towards the first edge 121 and any point on the first chamfer 125 can also be greater than or equal to 0.4mm and less than or equal to 1.5mm, such as 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm or other values between 0.4mm-1.5mm, which is not limited here.

[0133] Therefore, by optimizing the distance between the end of the first edge fine grid 24 and the end of the second fine grid at the first chamfer 125 and the distance between the end of the first chamfer 125 and the end of the second fine grid, the distance is controlled within a specific range of 0.4mm-1.5mm, which can avoid the end of the first chamfer 125 being too close to the first chamfer 125 to cause the first chamfer 125 to easily crack, and can also avoid the end of the first chamfer 125 being too far from the first chamfer 125 to cause the area near the first chamfer 125 to be too large to affect the collection efficiency of the carriers. That is, such a setting can reduce the risk of cracking of the first chamfer 125 while avoiding the collection efficiency of the carriers being too low.

[0134] Please refer to Figure 3 In some embodiments, the back contact cell 100 can be a main grid-free back contact cell, in which, among the first fine grids 20, the first collection fine grid 21 is disconnected at the first stringing area 13 and continuous at the second stringing area 14, the first bus fine grid 22 is continuous at the first edge stringing area 131 and disconnected at the remaining first stringing areas 13, and continuous at the second stringing area 14.

[0135] As shown in Figure 3 , Figure 4 and Figure 8 In some embodiments, the first fine grid 20 (including the first collection fine grid 21 and the first bus fine grid 22) can include a first soldering section 201 corresponding to the second stringing area 14, that is, the first fine grid 20 is continuous at each second stringing area 14 and has a first soldering section 201 at the second stringing area 14 for soldering with a solder strip. The second fine grid 30 (including the second collection fine grid 31 and the second bus fine grid 32 below) can include a second soldering section 301 corresponding to the first stringing area 13 (including the first edge stringing area 131), that is, the second fine grid 30 is continuous at each first stringing area 13 and has a second soldering section 301 at the first stringing area 13 for soldering with a solder strip.

[0136] In some embodiments, in the first collection fine grid 21, the width (i.e., the length in the second direction) of the first soldering section 201 can be greater than the width of the remaining part. In this way, the contact area of the first collection fine grid 21 with the solder strip can be increased, and the stability of soldering can be improved.

[0137] In some embodiments, the first soldering section 201 can be a double-layer structure. Specifically, in some embodiments, the first fine grid 20 can include a first collection layer penetrating through the back passivation film layer 104 and a first soldering layer stacked on the first collection layer and not penetrating through the back passivation film layer 104.

[0138] In some embodiments, the first collection layer may be continuous at the second serial connection area 14 and discontinuous at the first serial connection area 13, and the first welding layer may be disposed at the second serial connection area 14 and located on the first collection layer. In such a case, in the first fine grid 20, the portion corresponding to the first welding layer is the first welding segment 201.

[0139] Of course, in some other embodiments, the first welding segment 201 may be a single-layer structure. In this case, the first collecting layer is interrupted at both the second series connection area 14 and the first series connection area 13. The first welding layer is disposed at the second series connection area 14 and electrically connected to the two ends of the first collecting layer formed at the second series connection area 14. It is easy to understand that in these cases, the portion corresponding to the first welding layer is the first welding segment 201.

[0140] In some embodiments, the width of the first welding layer can be set to be greater than the width of the first collecting layer, where the width refers to the length of both in the second direction. This increases the welding area during welding and improves the reliability of the welding process.

[0141] In some embodiments, the second welding segment 301 may also be a double-layer structure. Specifically, in some embodiments, the second fine gate 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 but does not penetrate the back passivation film layer 104.

[0142] In some embodiments, the second collection layer may be continuous at the first serial connection area 13 and discontinuous at the second serial connection area 14, and the second welding layer may be disposed at the first serial connection area 13 and located on the second collection layer. In such a case, in the second fine grid 30, the portion corresponding to the second welding layer is the second welding segment 301.

[0143] Of course, in other embodiments, the second collecting layer may also be interrupted at both the first series connection area 13 and the second series connection area 14, and the second welding layer is disposed at the first series connection area 13 and electrically connected to the two ends of the second collecting layer formed at the first series connection area 13. It is easy to understand that in these cases, the portion corresponding to the second welding layer is the second welding segment 301.

[0144] In some embodiments, the width of the second welding layer may also be set to be greater than the width of the second collecting layer, where the width refers to the length of both in the second direction.

[0145] like Figure 3 and Figure 4 As shown in the embodiments of this application, in order to minimize the impact of poor soldering, when the first busbar fine gate 22 has a second fine gate 30 on both sides, it is preferable to simultaneously provide a first connecting gate line 60 on both sides of the first busbar fine gate 22.

[0146] In some embodiments, the width (i.e., the length in the second direction) of the first busbar fine grid 22 can be greater than the width (i.e., the length in the second direction) of the portion of the first collection fine grid 21 located outside the second stringing region 14 (i.e., the portion of the first collection fine grid 21 other than the first soldered section 201).

[0147] Thus, since the first busbar fine grid 22 needs to undertake the busbar transmission function, setting the width of the first busbar fine grid 22 to be wider can reduce transmission loss during busbar and improve efficiency.

[0148] In addition, as shown in Figure 3 , Figure 4 and Figure 8 , in embodiments of the present application, in the first busbar fine grid 22, it is continuous only at the first edge stringing region 131, but is disconnected at other first stringing regions 13, and at the same time, the first busbar fine grid 22 is continuous at the second stringing region 14 and has the first soldered section 201 at the second stringing region 14, and only the section closest to the first edge 121 of the first busbar fine grid 22 undertakes the busbar function. Therefore, in some embodiments, in order to save paste and reduce costs, only this part of the grid section can be set to be wider.

[0149] In such a case, please refer to Figure 3 , Figure 4 and Figure 8 , the second stringing region 14 can include the second edge stringing region 141 closest to the first edge 121. The first busbar fine grid 22 can include the first busbar section 221 located between the second edge stringing region 141 and the first edge 121. In some embodiments, the width (i.e., the length in the second direction) of the first busbar section 221 can be greater than the width of the portion of the first busbar fine grid 22 other than the first busbar section 221 (i.e., the portion other than the first soldered section 201) located outside the second stringing region 14.

[0150] Thus, only setting the width of the first busbar section 221 to be wider can reduce the use of paste while reducing busbar transmission loss, thereby reducing costs.

[0151] Specifically, as mentioned above, in such embodiments, the first busbar fine grid 22 is continuous at the second edge stringing region 141 and has the first solder section 201 at the second edge stringing region 141, the first busbar section 221 can converge the current to the solder tape arranged at the second edge stringing region 141, and only arranging part of the first busbar section 221 wider can reduce the use of paste. In such cases, the first busbar section 221 can be in contact with the first doped layer 102 at least partially through the back passivation film layer 104, or not through the back passivation film layer 104, which is not limited here. In such embodiments, the width of the first busbar section 221 can be the same as the width of the first solder section 201.

[0152] Referring to Figure 8 In some possible embodiments, the first busbar layer 70 can be arranged on the first busbar section 221. In this way, by arranging the first busbar layer 70 on the first busbar section 221, the cross-sectional area of the first busbar section 221 is increased, which can also reduce transmission loss, and at the same time, the first busbar layer 70 can be made of paste with lower cost than the first busbar section 221, which can reduce costs. It is not difficult to understand that in such cases, the width of the first busbar section 221 can be the same as the width of the part of the first busbar fine grid 22 other than the first solder section 201, and the first busbar section 221 can be in contact with the first doped layer 102 at least partially through the back passivation film layer 104, or not through the back passivation film layer 104, which is not limited here.

[0153] Specifically, in such embodiments, the first busbar layer 70 can be made of non-burn-through paste, the first busbar layer 70 does not contact the first doped layer 102 through the back passivation film layer 104, and the paste cost of the first busbar layer 70 is lower than that of the first busbar section 221. It can be understood that since the first busbar layer 70 is arranged on the first busbar section 221, the first busbar section 221 can also not need to be widened, which can also achieve the purpose of reducing transmission loss.

[0154] Further, in some embodiments, the width (length in the second direction) of the first busbar layer 70 can be greater than the width (length in the second direction) of the part of the first collection fine grid 21 other than the first solder 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.

[0155] Specifically, in such embodiments, the width of the first busbar layer 70 can be the same as the width of the first welding section 201. In this context, the width of the first welding section 201 refers to the length of the first welding section 201 in the second direction. As described above, when the width of the first welding layer is greater than the width of the first collecting layer, the width of the first welding section 201 is the width of the first welding layer (i.e., the length in the second direction). Similar descriptions will be made below, and reference can be made to this treatment.

[0156] In this way, it can be ensured that there is no large transmission loss during the busbar process. At the same time, during printing, the first busbar layer 70 can be printed at the same time as the first welding layer at the first welding section 201. When printing is performed using the same screen, there is no need to open screen slots of different sizes on the screen, thereby saving manufacturing procedures and reducing manufacturing difficulty.

[0157] According to the above description, in the embodiments of the present application, in order to reduce the busbar loss, the first busbar section 221 can be directly thickened (i.e., the first busbar section 221 is thickened) to achieve this, or the first busbar layer 70 can be provided at the position (i.e., the first busbar layer 70 is provided on the first busbar section 221) to achieve this. When the first busbar section 221 and the first busbar layer 70 are both present, the width of the first busbar section 221 can be less than the width of the first busbar layer 70.

[0158] Please refer to Figure 8 In some embodiments, the width (length in the first direction) of the first edge busbar line 40 can be greater than the width (length in the second direction) of the part of the first collecting fine grid 21 located outside the second series connection area 14 (i.e., the part of the first collecting fine grid 21 other than the first welding section 201).

[0159] In this way, since the first edge busbar line 40 needs to bear the busbar transmission function, the width of the first edge busbar line 40 is set to be wider, which can also reduce the transmission loss during the busbar process and improve efficiency.

[0160] Specifically, in such embodiments, the width of the first edge busbar line 40 can be the same as the width of the first welding section 201. In this way, it can be ensured that there is no large busbar loss during the busbar process, and at the same time, during printing, only screen slots of the same size need to be opened on the screen to print the three at the same time, which can effectively save manufacturing procedures and reduce manufacturing difficulty.

[0161] In addition, please continue to refer to Figure 8In some embodiments, the width (length in the first direction) of the first connection grid line 60 is greater than the width (length in the second direction) of the portion of the first collection fine grid 21 located outside the second stringing region 14 (i.e. the portion of the first collection fine grid 21 other than the first soldering section 201).

[0162] Thus, since the first connection grid line 60 functions to transmit and converge the current when a virtual soldering occurs, setting the width of the first connection grid line 60 to be wider can also reduce the transmission loss in the convergence process and improve the efficiency.

[0163] Please refer to Figures 3-5 In some embodiments, the first edge fine grid 24 is the first convergence fine grid 22, the first edge fine grid 24 is continuous at the first edge stringing region 131 and extends between the first edge stringing region 131 and the first edge 121, the second edge fine grid 23 is the first collection fine grid 21, the second edge fine grid 23 is discontinuous at the first edge stringing region 131 and does not extend between the first edge stringing region 131 and the first edge 121,

[0164] In some embodiments, the first edge fine grid 24 is the first convergence fine grid 22, the first edge fine grid 24 is continuous at the first edge stringing region 131 and extends between the first edge stringing region 131 and the first edge 121, the second edge fine grid 23 is the first collection fine grid 21, the second edge fine grid 23 is discontinuous at the first edge stringing region 131 and does not extend between the first edge stringing region 131 and the first edge 121,

[0165] Thus, among all the first collection fine grids 21, the second edge fine grid 23 does not have an isolated fine grid section between the first edge stringing region 131 and the first edge 121, and the remaining first collection fine grids 21 have isolated fine grid sections between the first edge stringing region 131 and the first edge 121, and the first edge convergence line can converge the current collected by the isolated fine grid sections of the first collection fine grids 21 between the first edge stringing region 131 and the first edge 121 among all the first fine grids 20 other than the first edge fine grid 24, thereby maximizing the efficiency of the back contact battery 100.

[0166] Of course, in some embodiments, the first edge convergence line 40 can also be electrically connected to only part of the first collection fine grids 21, and in such a case, the number of first collection fine grids 21 not electrically connected to the first edge convergence line 40 is less than or equal to 4. Thus, even if some of the first collection fine grids 21 are not connected to the first edge convergence line 40, the number is small and does not cause excessive loss of efficiency to cause product defects.

[0167] Please refer to Figure 5In some embodiments, the first edge busbar 40 is connected with the first edge fine grid 24, and the first edge busbar 40 has a first bending section 41 at the first chamfer 125. The distance between the first bending section 41 and the first chamfer 125 can be 0.2mm-0.6mm, for example, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, or other values between 0.2mm and 0.6mm, which is not limited in particular herein.

[0168] In this way, by optimizing the distance between the first bending section 41 and the first chamfer 125, the risk of hidden cracks caused by the existence of the first bending section 41 can be effectively reduced.

[0169] In some embodiments, the first connection grid line 60 can be connected with 2-20 second fine grids 30. In this way, by setting the number of second fine grids 30 connected with the first connection grid line 60 within this reasonable range, the influence of false welding can be reduced as much as possible or even eliminated.

[0170] In the embodiments of the present application, the number of the first busbar fine grid 22 can be one. In this case, the first connection grid line 60 can be arranged on one side of the first busbar fine grid 22, or the first connection grid line 60 can be arranged on both sides of the first busbar fine grid 22, which is not limited in particular herein. When the second fine grid 30 is arranged on both sides of the first busbar fine grid 22, it is preferred that the first connection grid line 60 is arranged on both sides.

[0171] In addition, it should be noted that in the present application, when the number of the first busbar fine grid 22 is more than one, the first connection grid line 60 can be arranged on one side or both sides of only part of the first busbar fine grid 22, and the first connection grid line 60 can not be arranged on both sides of the remaining first busbar fine grid 22. In this case, it can also solve the problem of false welding in part of the position. In the present application, it is preferred that the first connection grid line 60 is arranged on both sides of each first busbar fine grid 22. Of course, if the first busbar fine grid 22 is located at the third edge 123, the first connection grid line 60 only needs to be arranged on one side of the first busbar fine grid 22.

[0172] Of course, please refer to Figure 3 and Figure 4 In some embodiments, the number of the first busbar fine grid 22 can be N, N being a positive integer greater than 2. In this way, arranging multiple first busbar fine grids 22 can shorten the current busbar path, effectively reduce the busbar transmission loss, and improve the efficiency.

[0173] In such a case, the number of the first connecting bus lines 60 is multiple, and the multiple first connecting bus lines 60 are arranged at intervals along the second direction. The first connecting bus line 60 can be arranged between any two adjacent first bus bars 22. The first connecting bus line 60 arranged between the two adjacent first bus bars 22 connects at least part of the second bus bars 30 arranged between the two adjacent first bus bars 22.

[0174] As shown in FIG. 1, Figure 3 and Figure 4 In some embodiments, the first connecting bus line 60 arranged between the two adjacent first bus bars 22 can connect all the second bus bars 30 arranged between the two adjacent first bus bars 22.

[0175] In this way, connecting the first connecting bus line 60 to all the second bus bars 30 arranged between the two adjacent first bus bars 22 can substantially eliminate the influence of the virtual soldering and improve the efficiency of the back contact battery 100 as much as possible.

[0176] Specifically, in such embodiments, the number of the first bus bars 22 in the back contact battery 100 can be selected according to the size of the battery piece and the actual situation such as the loss in the transmission process, which is not limited herein.

[0177] Further, as shown in FIG. 1, Figure 3 and Figure 4 In such embodiments, the first connecting bus lines 60 can include a first end connecting bus line 61 closest to the third edge 123, a second end connecting bus line 62 closest to the fourth edge 124, and a first intermediate connecting bus line 63 arranged between the first end connecting bus line 61 and the second end connecting bus line 62. The width of the first end connecting bus line 61 is greater than the width of the first intermediate connecting bus line 63.

[0178] In this way, on the one hand, the width of the first end connecting bus line 61 is set to be relatively wide, and the width of the first intermediate connecting bus line 63 is set to be relatively narrow, which can improve the current collection capability of the edge area of the back contact battery 100, reduce the transmission loss of the edge area, and improve the efficiency. On the other hand, when the first end connecting bus line 61 needs to be contacted or soldered with the solder strip, setting the width of the first end connecting bus line 61 to be relatively wide can improve the soldering area or contact area of the solder strip in the first edge stringing area 131, ensure the stability of the contact between the end of the solder strip and the first end connecting bus line 61, and effectively avoid the end of the solder strip from deviating to cause it to fail to form stable and reliable contact with the first end connecting bus line 61. Moreover, setting the width of the first intermediate connecting bus line 63 to be slightly narrow can also save the use of paste.

[0179] In some embodiments, the width of the second end connecting grid line 62 can also be greater than the width of the first middle connecting grid line 63.

[0180] In some embodiments, the width of the first end connecting grid line 61 can be 1.3-1.8 times the width of the first middle connecting grid line 63.

[0181] In this way, by optimizing the width ratio of the two, the current collection capability of the edge area can be improved while effectively controlling the paste cost of the entire first connecting grid line 60 in layout, thereby improving the stability of contact with the solder strip while ensuring current collection efficiency and controlling the loss of the bus bar.

[0182] Specifically, in such embodiments, the width of the first end connecting grid line 61 may, for example, be 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, or other values between 1.3-1.8 times the width of the first middle connecting grid line 63, without being limited specifically.

[0183] In some embodiments, the width of the first middle connecting grid line 63 can be 0.5-0.7 mm, for example, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, or other values between 0.5-0.7 mm. The width of the first end connecting grid line 61 can be 0.8-1.2 mm, for example, 0.8 mm, 0.85 mm, 0.9 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, or other values between 0.8-1.2 mm.

[0184] In this way, by optimizing the specific width of the first middle connecting grid line 63 and the first end connecting grid line 61, the bus bar transmission performance can be ensured, the bus bar transmission loss can be reduced, the paste cost can be effectively controlled, and the stability of the contact between the end of the solder strip and the first end connecting grid line 61 can be ensured.

[0185] In some possible embodiments, the width of the first middle connecting grid line 63 can be 0.6 mm, and the width of the first end connecting grid line 61 can be 1 mm.

[0186] In some embodiments, the width of the second end connecting grid line 62 can also be 1.3-1.8 times the width of the first middle connecting grid line 63.

[0187] In this way, by optimizing the width ratio of the two, the current collection capability of the edge area can be improved while effectively controlling the paste cost of the entire first connecting grid line in layout, thereby improving the stability of contact with the solder strip while ensuring current collection efficiency and controlling the loss of the bus bar.

[0188] Specifically, in such embodiments, the width of the second end connecting grid line 62 may, for example, be 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, or other values between 1.3-1.8 times the width of the first intermediate connecting grid line 63, specifically without limitation.

[0189] In some embodiments, the width of the first intermediate connecting grid line 63 may, for example, be 0.5mm-0.7mm, such as 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, or other values between 0.5mm-0.7mm. The width of the second end connecting grid line 62 may, for example, be 0.8mm-1.2mm, such as 0.8mm, 0.85mm, 0.9mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, or other values between 0.8mm-1.2mm.

[0190] In this way, by specifically optimizing the width of the first intermediate connecting grid line 63 and the second end connecting grid line 62, the cost of the paste can be effectively controlled while ensuring the performance of the busbar transmission and reducing the loss of the busbar transmission, and the stability of the contact between the end of the solder strip and the second end connecting grid line 62 can also be ensured.

[0191] In some possible embodiments, the width of the first intermediate connecting grid line 63 may, for example, be 0.6mm, and the width of the second end connecting grid line 62 may, for example, be 1mm.

[0192] In embodiments of the present application, the width of the first end connecting grid line 61 and the second end connecting grid line 62 may, for example, be the same or different, specifically without limitation.

[0193] In some embodiments, the width of the first end connecting grid line 61 may, for example, be greater than the width of the first edge busbar line 40, and / or the width of the second end connecting grid line 62 may, for example, be greater than the width of the first edge busbar line 40.

[0194] In this way, by setting the width of the first edge busbar line to be narrower than the first end connecting grid line 61 and the second end connecting grid line 62, the busbar cost can be reduced while achieving the busbar of the isolated fine grid segments of the first fine grid 20 in the edge region.

[0195] In some embodiments, the width of the first end connecting grid line 61 and the second end connecting grid line 62 may, for example, both be greater than the width of the first edge busbar line 40, and the width of the first edge busbar line 40 may, for example, be greater than the width of the first intermediate connecting grid line 63.

[0196] Therefore, by setting the width of the first edge busbar 40 to be larger than the width of the first intermediate connecting grid line 63, the current collection efficiency of the edge region can be improved and the current transmission loss of the first edge busbar 40 can be reduced. By setting the width of the first end connecting grid line 61 and the second end connecting grid line 62 to be larger, the stability of the contact between the end of the solder strip and the first end connecting grid line 61 and the second end connecting grid line 62 can be ensured while the current collection efficiency of the edge region is improved and the current transmission loss is reduced.

[0197] Specifically, it is also not difficult to understand that the first edge busbar 40 needs to collect the current of all the isolated fine grid segments of the first fine grid 20 located between the first edge 121 and the first edge stringing region 131, and the first intermediate connecting grid line 63 only needs to collect the current of part of the second fine grid 30. In this case, in order to reduce the current transmission loss of the first edge busbar 40, the width of the first edge busbar 40 can be set to be relatively wide. As for the first end connecting grid line 61 and the second end connecting grid line 62, they are set to be wider in order to improve the current collection efficiency of the edge region, avoid the reduction of the current collection efficiency caused by the defects of the edge region, and ensure the stability of the contact between the end of the solder strip and the connecting grid line.

[0198] In some embodiments, the width of the first end connecting grid line 61 can be 1.1-1.4 times, for example, 1.1 times, 1.15 times, 1.2 times, 1.25 times, 1.3 times, 1.35 times, 1.4 times, or other values between 1.1 and 1.4 times, of the width of the first edge busbar 40; and / or, the width of the second end connecting grid line 62 can be 1.1-1.4 times, for example, 1.1 times, 1.15 times, 1.2 times, 1.25 times, 1.3 times, 1.35 times, 1.4 times, or other values between 1.1 and 1.4 times, of the width of the first edge busbar 40.

[0199] Therefore, by setting the width ratio in this way, the current collection capacity of the edge region can be improved and the current transmission loss of the first edge busbar 40 can be reduced while the cost of the paste is effectively controlled.

[0200] In some embodiments, the width of the first edge busbar 40 can be 0.7-0.9 mm, for example, 0.7 mm, 0.72 mm, 0.74 mm, 0.76 mm, 0.78 mm, 0.8 mm, 0.82 mm, 0.84 mm, 0.86 mm, 0.88 mm, 0.9 mm, or other values between 0.7 mm and 0.9 mm. The width of the first end connecting grid line 61 and the second end connecting grid line 62 can be as described above, which will not be repeated here.

[0201] Therefore, by setting the width of the first edge busbar 40 within this reasonable range, the transmission performance of the first edge busbar can be ensured while effectively controlling the paste cost.

[0202] In some embodiments, the width of the first edge busbar 40 can be 0.8 mm.

[0203] In some embodiments, the ratio of the width of the first end connecting grid line 61, the width of the first edge busbar 40, and the width of the first intermediate connecting grid line 63 is 1:0.8:0.6, i.e., when the width of the first end connecting grid line 61 is 1 mm, the width of the first edge busbar 40 is 0.8 mm, and the width of the first intermediate connecting grid line 63 is 0.6 mm.

[0204] Therefore, by optimizing the width ratio of the three, the current collection capability of the entire edge region, the busbar transmission performance, and the contact stability of the solder ribbon can be optimized, thereby improving the overall performance of the back contact battery.

[0205] In some embodiments, the width of the first end connecting grid line 61 and the width of the second end connecting grid line 62 can both be greater than the width of the first busbar section 221 and / or the first busbar layer 70. The specific description of the first busbar section 221 and the first busbar layer 70 is described above and is not repeated here.

[0206] Further, in such a case, the width of the first end connecting grid line 61 and the width of the second end connecting grid line 62 are both 1.1 times to 1.4 times the width of the first busbar section 221 and / or the first busbar layer 70.

[0207] Therefore, by specifically designing the width of the first end connecting grid line 61, the second end connecting grid line 62, and the first busbar layer 70, the busbar transmission performance of the first busbar layer 70 and the contact stability of the solder ribbon can be optimized.

[0208] Specifically, in such embodiments, the width of the first end connecting grid line 61 and the second end connecting grid line 62 can be as described above, and the width of the first busbar section 221 and / or the first busbar layer 70 can be 0.7 mm to 0.9 mm, for example, 0.7 mm, 0.72 mm, 0.74 mm, 0.76 mm, 0.78 mm, 0.8 mm, 0.82 mm, 0.84 mm, 0.86 mm, 0.88 mm, 0.9 mm, or other values between 0.7 mm and 0.9 mm. Of course, it can be understood that when the first busbar section 221 and the first busbar layer 70 are both present, the width of the first busbar section 221 can be set to be smaller than the width of the first busbar layer 70.

[0209] In some possible embodiments, in order to improve the uniformity of the transmission of the first edge busbar 40 and the first busbar section 221 and / or the first busbar layer 70, the width of the first edge busbar 40 can be the same as the width of the first busbar section 221 and / or the first busbar layer 70, for example, the width of both can be 0.8 mm.

[0210] Please refer to Figure 3 , Figure 4 and Figure 8 In some embodiments, if the second string-connection regions 14 include a second edge string-connection region 141 closest to the first edge 121 (i.e., the second string-connection region 14 adjacent to the first edge string-connection region 131), the first fine grid 20 is continuous at the second edge string-connection region 141, and the second fine grid 30 is discontinuous at the second edge string-connection region 141.

[0211] In such a case, the back contact battery 100 can further include a second connection grid line 90, which is arranged in the second edge string-connection region 141 and connects the first busbar fine grid 22 and at least one first collection fine grid 21 located on one side of the first busbar fine grid 22 in the second direction.

[0212] In this way, by arranging the second connection grid line 90 in the second edge string-connection region 141, the phenomenon that the solder strip in the second edge string-connection region 141 cannot collect the current transmitted from the first busbar fine grid 22 due to virtual welding or poor contact at the first busbar fine grid 22 can be effectively avoided.

[0213] Specifically, as shown in Figure 4 and Figure 8 In such embodiments, the number of second connection grid lines 90 can be consistent with the number of first busbar fine grids 22, and one-to-one correspondence exists between them. When the first busbar fine grid 22 is located in the middle position (i.e., the first busbar fine grid 22 has first collection fine grids 21 on both sides), the second connection grid line 90 connects the first busbar fine grid 22 and also connects two first collection fine grids 21 adjacent to the first busbar fine grid 22 (i.e., the first collection fine grids 21 located on both sides of the first busbar fine grid 22 and adjacent thereto).

[0214] When the grid line closest to the third edge 123 is the first busbar fine grid 22, the first busbar fine grid 22 has only one side with a first collection fine grid 21. In such a case, the second connection grid line 90 connected to the first busbar fine grid 22 located at the third edge 123 at least connects the first collection fine grid 21 adjacent to the first busbar fine grid 22, and the number of first collection fine grids 21 connected by the second connection grid line 90 is 1-6.

[0215] Similarly, when the grid line closest to the fourth edge 124 is the first busbar 22, the first busbar 22 has a first collection grid 21 on only one side. In this case, the second connecting grid line 90 connected to the first busbar 22 located at the fourth edge 124 connects at least the first collection grid 21 adjacent to the first busbar 22. The number of first collection grids 21 connected by the second connecting grid line 90 is 1-6.

[0216] In some embodiments, the width (length in the first direction) of the second connecting gate line 90 may be greater than the width (length in the second direction) of the portion of the first collecting fine gate 21 located outside the second serial connection area 14 (i.e., the portion of the first collecting fine gate 21 excluding the first solder section 201). Thus, since the second connecting gate line 90 functions to transmit and combine current when a poor solder joint occurs at the first bus fine gate 22, setting the width of the second connecting gate line 90 wider can also reduce transmission losses during the current combining process and improve efficiency.

[0217] like Figure 4 As shown, in some embodiments, the length of the second connecting gate line 90 (length in the second direction) may be less than the length of the first connecting gate line 60 (length in the second direction).

[0218] Thus, setting the second connecting grid line 90 shorter can save on slurry costs.

[0219] Specifically, since the first busbar 22 does not require an insulating layer to achieve insulation at the second edge connection area 141, even if a cold solder joint may occur at the first busbar 22, the affected area is small. In this case, by setting a shorter second connecting grid line 90, the occurrence of cold solder joints can be effectively avoided, thus preventing some of the first collecting grids 21 adjacent to the first busbar 22 from being unable to be welded to the solder strip, thereby achieving the purpose of saving slurry costs.

[0220] In such an embodiment, the ratio between the length of the second connecting gate line 90 and the length of the first connecting gate line 60 can be 0.2-0.5, such as 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 or other values ​​between 0.2 and 0.5, and no specific limitation is made here.

[0221] In this way, by optimizing the ratio between the two, the risk of poor soldering of the solder strip in the first edge connection area 131 and the second edge connection area 141 can be reduced while controlling the cost of the slurry as much as possible.

[0222] In some embodiments, the length of the second connecting busbar 90 can be 2mm-3mm, such as 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, or other values between 2mm-3mm. The length of the first connecting busbar 60 can be 6mm-9mm, such as 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, or other values between 2mm-3mm, without limitation here.

[0223] In this way, by specifically designing the length of the two, the risk of virtual soldering of the solder strip at the first edge stringing area 131 and the second edge stringing area 141 can be reduced while the cost of the paste is controlled as much as possible.

[0224] Further, please refer to Figure 4 In such embodiments, the plurality of second connecting busbars 90 can include a third end connecting busbar 91 closest to the third edge 123, a fourth end connecting busbar 92 closest to the fourth edge 124, and a second intermediate connecting busbar 93 between the third end connecting busbar 91 and the fourth end connecting busbar 92. The width of the third end connecting busbar 91 is greater than the width of the second intermediate connecting busbar 93.

[0225] In this way, on the one hand, by setting the width of the third end connecting busbar 91 to be wider and the width of the second intermediate connecting busbar 93 to be narrower, the current collection capability of the edge area of the back contact battery 100 can be improved, the transmission loss of the edge area can be reduced, and the efficiency can be improved. On the other hand, when the third end connecting busbar 91 needs to be in contact or soldered with the solder strip, setting the width of the third end connecting busbar 91 to be wider can increase the soldering area or contact area of the third end connecting busbar 91 with the solder strip in the first edge stringing area 131, ensuring the stability of the contact between the end of the solder strip and the third end connecting busbar 91, effectively avoiding the end of the solder strip from shifting and causing it to fail to form stable and reliable contact with the third end connecting busbar 91. Moreover, setting the width of the second intermediate connecting busbar 93 to be slightly narrower can also save the use of paste.

[0226] In some embodiments, the width of the fourth end connecting busbar 92 can also be greater than the width of the second intermediate connecting busbar 93.

[0227] Specifically, as Figure 4As shown, in such embodiments, in the first fine grids 20 and the second fine grids 30, the fine grids closest to the third edge 123 and the fourth edge 124 are both the first fine grids 20 and both the first bus fine grids 22, the first end connecting grid line 91 is connected with the first bus fine grid 22 closest to the third edge 123, and the second end connecting grid line 92 is connected with the first bus fine grid 22 closest to the fourth edge 123.

[0228] In some embodiments, the width of the third end connecting grid line 91 can be 1.3-1.8 times the width of the second intermediate connecting grid line 93.

[0229] In this way, by optimizing the width ratio of the two, the current collection capability of the edge area can be improved while effectively controlling the paste cost of the entire second connecting grid line 90 in layout, thereby improving the stability of contact with the solder strip while ensuring current collection efficiency and controlling bus loss.

[0230] Specifically, in such embodiments, the width of the third end connecting grid line 91 can be, for example, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, or other values between 1.3-1.8 times the width of the second intermediate connecting grid line 93, without limitation in particular.

[0231] In some embodiments, the width of the second intermediate connecting grid line 93 can be 0.5-0.7 mm, for example, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, or other values between 0.5-0.7 mm. The width of the third end connecting grid line 91 can be 0.8-1.2 mm, for example, 0.8 mm, 0.85 mm, 0.9 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, or other values between 0.8-1.2 mm.

[0232] In this way, by optimizing the specific width of the second intermediate connecting grid line 93 and the third end connecting grid line 91, the bus transmission performance can be ensured, the bus transmission loss can be reduced, the paste cost can be effectively controlled, and the stability of the contact between the end of the solder strip and the third end connecting grid line 91 can be ensured.

[0233] In some possible embodiments, the width of the second intermediate connecting grid line 93 can be 0.6 mm, and the width of the third end connecting grid line 91 can be 1 mm.

[0234] In some embodiments, in some embodiments, the width of the fourth end connecting grid line 92 can also be 1.3-1.8 times the width of the second intermediate connecting grid line 93.

[0235] Therefore, by optimizing the width ratio of the two, the current collection capability of the edge area can be improved, and the paste cost of the entire second connection grid line 90 during layout can be effectively controlled, thereby improving the stability of contact with the solder ribbon while ensuring current collection efficiency and controlling the loss of the busbar.

[0236] Specifically, in such embodiments, the width of the fourth end connection grid line 92 may, for example, be 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, or other values between 1.3 and 1.8 times the width of the second intermediate connection grid line 93, specifically without limitation.

[0237] In some embodiments, the width of the second intermediate connection grid line 93 may, for example, be 0.5 mm to 0.7 mm, such as 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, or other values between 0.5 mm and 0.7 mm. The width of the fourth end connection grid line 92 may, for example, be 0.8 mm to 1.2 mm, such as 0.8 mm, 0.85 mm, 0.9 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, or other values between 0.8 mm and 1.2 mm.

[0238] Therefore, by optimizing the specific width of the second intermediate connection grid line 93 and the fourth end connection grid line 92, the paste cost can be effectively controlled while ensuring the transmission performance of the busbar and reducing the transmission loss of the busbar, and the stability of the contact between the end of the solder ribbon and the fourth end connection grid line 92 can be ensured.

[0239] In some possible embodiments, the width of the second intermediate connection grid line 93 may, for example, be 0.6 mm, and the width of the fourth end connection grid line 92 may, for example, be 1 mm.

[0240] In embodiments of the present application, the widths of the third end connection grid line 91 and the fourth end connection grid line 92 may, for example, be the same or different, specifically without limitation.

[0241] In some embodiments, the distance between the first edge stringing area 131 and the first edge 121 is greater than or equal to 2 mm and less than or equal to 8 mm.

[0242] Therefore, the distance between the first edge stringing area 131 and the first edge 121 can be prevented from being too small, which can cause the welding position to be too close to the first edge 121, thereby causing the back contact battery 100 to have hidden cracks and reducing the risk of hidden cracks. The distance between the first edge stringing area 131 and the first edge 121 can also be prevented from being too large, which can cause the length of the isolated fine grid segment between the first edge stringing area 131 and the first edge 121 to be too long, thereby causing excessive loss during the transmission process.

[0243] Specifically, in such embodiments, the distance between the first edge stringing region 131 and the first edge 121 can be, for example, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, or any value between 2 mm and 8 mm, without being particularly limited here.

[0244] In some embodiments, the distance between the first edge stringing region 131 and the first edge 121 is smaller than the distance between the first edge stringing region 131 and the second edge stringing region 141.

[0245] In this way, on the one hand, the distance between the first edge stringing region 131 and the first edge 121 is set to be small, so as to avoid the distance being too large and causing excessive transmission loss, and on the other hand, the first edge stringing region 131 and the second edge stringing region 141 are set to be far apart, so as to avoid the stringing regions being too close and causing a risk of electric leakage.

[0246] Please refer to Figure 3 and Figure 9 In some embodiments, the second stringing regions 14 can include a third edge stringing region 142 closest to the second edge 122, and the third edge stringing region 142 has no first stringing region 13 between it and the second edge 122, that is, as shown in Figure 3 and Figure 9 In the first stringing region 13 and the second stringing region 14, the stringing region closest to the second edge 122 is the second stringing region 14, and the second stringing region 14 is denoted as the third edge stringing region 142, and the third edge stringing region 142 has no other stringing region between it and the second edge 122.

[0247] The second fine grids 30 include second collection fine grids 31 and at least one second confluence fine grid 32, the second collection fine grids 31 are discontinuous at the third edge stringing region 142 and continuous at the first stringing region 13, and the second confluence fine grid 32 is continuous at the third edge stringing region 142, and the first fine grid 20 is continuous at the second edge stringing region 141.

[0248] That is, the second fine grid 30 includes at least two types of grid lines, one is the second collection fine grid 31, and the other is the second confluence fine grid 32, the second collection fine grid 31 is discontinuous at the third edge stringing region 142, and the second confluence fine grid 32 is continuous at the third edge stringing region 142, and the first fine grid 20 is also continuous at the third edge stringing region 142.

[0249] The back contact battery 100 also includes a second edge bus 110 and a third connecting grid line 130. The second edge bus 110 is closer to the second edge 122 than the third edge series region 142. The second edge bus 110 is electrically connected to at least a portion of the second collecting grid 31 and to the second bus grid 32. Specifically, to avoid microcracks in the battery caused by welding at the edge of the second edge 122, the second edge bus 110 is not used for welding. It is used to collect the current in the second collecting grid 31 located between the third edge series region 142 and the second edge 122, and then the current is fed through the second bus grid 32 to the first series region 14 adjacent to the third edge series region 142 (i.e., Figure 3 and Figure 9 On the same polarity solder strip in the first series area 14) on the rightmost side, the current of the fine grid segment in the edge region of the second fine grid 30 located at the second edge 122 is collected, thereby improving the efficiency of the back contact battery 100. If the second edge bus line 110 and the second bus fine grid 32 are not provided, the part of the second fine grid 30 located between the third edge series area 142 and the second edge 122 will form an isolated fine grid segment, and the current in this part cannot be collected.

[0250] It is easy to understand that, in order to achieve insulation between the solder strip and the second busbar 32 at the third edge series connection area 142 to avoid leakage, a second insulating layer (not shown) may also be provided in the battery assembly 200. The second insulating layer may be provided in the third edge series connection area 142 and located on the second busbar 32. That is, a second insulating layer is provided on the portion of the second busbar 32 corresponding to the third edge series connection area 142. The purpose of the second insulating layer is to insulate and separate the opposite polarity solder strip in the third edge series connection area 142 from the second busbar 32 to avoid short circuit.

[0251] The third connecting gate line 130 may be disposed within the third edge concatenation region 142. In the second direction, at least one side of the second busbar fine gate 32 is provided with the third connecting gate line 130, and the third connecting gate line 130 connects at least two first fine gates 20 located on the same side of the second busbar fine gate 32. In some embodiments, preferably, the at least two first fine gates 20 connected to the third connecting gate line 130 include the first fine gate 20 adjacent to the second busbar fine gate 32 (i.e., Figure 3 and Figure 9The third connecting grid line 130 is preferably connected to the first grid 20 closest to the second edge busbar 32 (i.e. the first grid 20 closest to the second edge busbar 32 of the first edge string 10). That is, in some embodiments, the third connecting grid line 130 is preferably connected to the first grid 20 closest to the second edge busbar 32, and the third connecting grid line 130 is also connected to at least one of the remaining first grids 20 on the same side of the second edge busbar 32. That is, the third connecting grid line 130 is preferably connected to at least the first grid 20 adjacent to the second edge busbar 32 and at least one of the remaining first grids 20 on the same side.

[0252] Thus, by providing the second edge busbar 110 and the second edge busbar 32, the current collected by the isolated section of the first grid 20 between the third edge string 142 and the second edge 122 can be transferred to the solder ribbon of the same polarity in the adjacent first string 13, thereby effectively avoiding the hidden cracks caused by soldering on the second edge 122 of the back contact battery 100 while ensuring the efficiency of the back contact battery 100. At the same time, by providing the third connecting grid line 130, even if the first grid 20 near the second insulating layer and the solder ribbon are not welded due to the provision of the second insulating layer, the first grid 20 with virtual welding can also be connected to the third connecting grid line 130 to achieve current transfer, thereby reducing the impact of virtual welding and ensuring the efficiency of the back contact battery 100.

[0253] As shown above, it is not difficult to understand that in the present application, the second edge busbar 110 is not used for soldering, and only for current transmission and collection, and the function of the second edge busbar 32 is collection and transmission. By Figure 3 and Figure 9 It can be seen that in the example shown in Figure 3 and Figure 9 If the second edge busbar 110 and the second edge busbar 32 are not provided, the second grid 30 is disconnected at the third edge string 142, and the current of the section of the second grid 30 between the third edge string 142 and the second edge 122 cannot be collected. Therefore, by providing the second edge busbar 110 and the second edge busbar 32, the current of at least part of the isolated grid section of the second grid 30 in the edge region can be transferred to the solder ribbon provided in the adjacent first string 13, thereby effectively avoiding the loss of efficiency.

[0254] In this case, the solder tape in the third edge stringing area 142 is prone to appear virtual soldering with the first fine grid 20 during the soldering process, which causes the current on part of the first fine grid 20 (especially the first fine grid 20 adjacent to the second bus fine grid 32, which is most likely to appear virtual soldering) to be unable to be effectively collected. Based on this, the present application connects at least two first fine grids 20 on the same side of the second bus fine grid 32 through the third connection grid line 130, and preferably selects the first fine grid 20 connected thereto to include the first fine grid 20 adjacent to the second bus fine grid 32. Part of the first fine grid 20 can be connected into a whole through the third connection grid line 130, that is, even if one of the first fine grids 20 appears virtual soldering due to the presence of the second insulating layer, it can also output current through the third connection grid line 130, thereby reducing or even completely eliminating the influence of virtual soldering.

[0255] Referring to Figure 9 and Figure 10 In some embodiments, a second chamfer 126 is formed at the intersection position of the second edge 122 and the third edge 123, the first edge fine grid 24 and the second edge fine grid 23 correspond to the second chamfer 126, and all the first fine grids 20 extend between the third edge stringing area 142 and the second edge 122.

[0256] Therefore, since the stringing area closest to the second edge 122 is the second stringing area 14, the first fine grid 20 does not need to be interrupted at this area, and thus the setting can improve the collection efficiency of carriers in the area near the second chamfer 126.

[0257] Specifically, in such embodiments, the first chamfer 125 and the second chamfer 126 can be substantially aligned in the second direction, and in the first fine grid 20 and the second fine grid 30, only the first edge fine grid 24, the second edge fine grid 23, and the second fine grid 30 between the first edge fine grid 24 and the second edge fine grid 23 correspond to the first chamfer 125 and the second chamfer 126, and the remaining first fine grid 20 and second fine grid 30 are located in the area outside the position of the first chamfer 125 and the second chamfer 126.

[0258] Referring to Figure 10In some embodiments, further, in such embodiments, the length of the line between the end of the first edge fine grid 24 and the second edge 122 and any point on the second chamfer 126 can be greater than or equal to 0.4 mm and less than or equal to 1.5 mm, such as 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, or other values between 0.4 mm and 1.5 mm, without limitation as to specific values herein.

[0259] In this way, by optimizing the distance between the first edge fine grid 24 and the second edge fine grid 23 and the second chamfer 126, and controlling the distance within a specific range of 0.4 mm to 1.5 mm, the end of the first edge fine grid 24 and the second edge fine grid 23 can be prevented from being too close to the second chamfer 126, which can cause the second chamfer 126 to be prone to hidden cracks, and the end of the first edge fine grid 24 and the second edge fine grid 23 can be prevented from being too far from the second chamfer 126, which can cause the area near the second chamfer 126 to be too large to be collected, thereby affecting the collection efficiency of the carriers. That is, such a configuration can reduce the risk of hidden cracks at the second chamfer 126 while avoiding too low a collection efficiency of the carriers.

[0260] Referring to Figure 10 In some possible embodiments, the second fine grid 30 between the first edge fine grid 24 and the second edge fine grid 23 can also extend between the third edge stringing area 142 and the second edge 122.

[0261] In this case, the second edge busbar 110 can be electrically connected to all the second fine grids 30. In this way, the carriers in the area of the second chamfer 126 can be collected as much as possible.

[0262] Further, in this case, the length of the line between the end of the second fine grid 30 and the second edge 122 and any point on the second chamfer 126 can be greater than or equal to 0.4 mm and less than or equal to 1.5 mm, such as 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, or other values between 0.4 mm and 1.5 mm, without limitation as to specific values herein.

[0263] In this way, the collection efficiency of the carriers at the second chamfer 126 can be improved while further reducing the risk of hidden cracks at the second chamfer 126.

[0264] As Figure 10As shown, in such embodiments, the second edge busbar 110 connects the second fine grid 30 between the first edge fine grid 24 and the second edge fine grid 23, and the second edge busbar 110 has a second bending section 1101 at the second chamfer 126, and the distance between the second bending section 1101 and the second chamfer 126 can be 0.2mm-0.6mm, for example, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, or other values between 0.2mm-0.6mm, which is not limited in particular herein.

[0265] In this way, by optimizing the distance between the second bending section 1101 and the second chamfer 126, the risk of hidden cracks caused by the existence of the second chamfer 126 can be effectively reduced.

[0266] Of course, please refer to Figure 11 In some possible embodiments, the second fine grid 30 between the first edge fine grid 24 and the second edge fine grid 23 can also not extend to between the third edge stringing area 142 and the second edge 122.

[0267] In this way, the risk of hidden cracks caused by the second fine grid 30 between the first edge fine grid 24 and the second edge fine grid 23 to the second chamfer 126 can be completely and substantially eliminated, and in such cases, the second edge busbar 110 can not need to be provided with the second bending section 1101, and the risk of virtual welding caused by the second edge busbar 110 can be reduced.

[0268] Please refer to Figure 3 , Figure 9 and Figure 10 In some embodiments, the second edge busbar 110 is electrically connected with all the second fine grids 30. In this way, the current collected by the isolated fine grid section of all the second fine grids 30 between the third edge stringing area 142 and the second edge 122 can be bused, and the efficiency of the back contact battery 100 can be maximized.

[0269] Of course, in some embodiments, the second edge busbar 110 can also be electrically connected with part of the second fine grids 30, and in such cases, the number of second collection fine grids 31 not electrically connected with the second edge busbar 110 is less than or equal to 4. In this way, even if part of the second collection fine grids 31 are not connected with the second edge busbar 110, the number is small, and it will not cause too much loss of efficiency and lead to product defects.

[0270] Furthermore, in some embodiments, if the second fine gate 30 located between the first edge fine gate 24 and the second edge fine gate 23 does not extend between the third edge connecting region 142 and the second edge 122, the second edge bus line 110 may be connected to all second fine gates 30 except for the second fine gate 30.

[0271] Please see Figure 3 and Figure 9 In some embodiments, among a plurality of second fine grids 30, the second collecting fine grid 31 is interrupted at the second serial connection region 14 and continuous at the first serial connection region 13, and the second bus fine grid 32 is continuous at the third edge serial connection region 142 and interrupted at the remaining second serial connection regions 14, and continuous at the first serial connection region 13.

[0272] like Figure 3 and Figure 9 As shown in the embodiments of this application, in order to minimize the impact of poor soldering, when the second busbar fine gate 32 has a first fine gate 20 on both sides, it is preferable to simultaneously provide a third connecting gate line 130 on both sides of the second busbar fine gate 32.

[0273] In some embodiments, the second fine grid 30 has a second welding section 301, the structure of which has been described above and will not be repeated here. In some embodiments, in the second collecting fine grid 31, the width (i.e., the length in the second direction) of the second welding section 301 may be greater than the width of the remaining portion. In this way, the contact area between the second collecting fine grid 31 and the welding strip can be increased, thereby improving the stability of the welding.

[0274] In some embodiments, the width of the second busbar 32 (i.e., its length in the second direction) may be greater than the width (i.e., its length in the second direction) of the portion of the second collection bar 31 located outside the first serial area 13 (i.e., the portion of the second collection bar 31 excluding the second welding section 301).

[0275] Therefore, since the second bus fine gate 32 needs to undertake the function of bus transmission, setting the width of the second bus fine gate 32 to be wider can reduce transmission loss during the bus process and improve efficiency.

[0276] Furthermore, in the embodiments of this application, the second busbar 32 is continuous only at the third edge connection region 142, and disconnected at the other second connection regions 14. Simultaneously, the second busbar 32 is continuous at the first connection region 13 and has a second welded section 301 at the first connection region 13. Only the section of the second busbar 32 closest to the first edge 121 performs the busbar function. Therefore, in some embodiments, to save slurry and reduce costs, only this portion of the busbar segment can be made wider.

[0277] In such a case, please refer toFigure 3 、 Figure 9 and Figure 12 In some possible embodiments, the first plurality of serially connected regions 13 can include a fourth edge serially connected region 132 closest to the first edge 121. The second busbar 32 can include a second busbar section 321 located between the fourth edge serially connected region 132 and the first edge 121, the width (i.e. the length in the second direction) of the second busbar section 321 being greater than the width of the portions of the second busbar 32 other than the second busbar section 321 and the second solder section 301 (i.e. the portions of the second busbar 32 other than the second busbar section 321 and the second solder section 301).

[0278] In this way, by only making the width of the second busbar section 321 wider, the use of paste can be reduced while reducing the busbar transmission loss, thereby reducing the cost.

[0279] In particular, as mentioned above, in such embodiments, the second busbar 32 is continuous at the fourth edge serially connected region 132 and has the second solder section 301 at the fourth edge serially connected region 132, the second busbar section 321 can bus the current to the solder ribbon provided at the fourth edge serially connected region 132, and only making the portion of the second busbar section 321 wider can reduce the use of paste. In such cases, the second busbar section 321 can at least partially penetrate the back passivation film layer 104 to contact the second doped layer 103, or can not penetrate the back passivation film layer 104, which is not limited here in particular. In such embodiments, the width of the second busbar section 321 can be the same as the width of the second solder section 301.

[0280] Referring to Figure 12 In some possible embodiments, the second busbar layer 140 can be provided on the second busbar section 321. In this way, by providing the second busbar layer 140 on the second busbar section 321, the cross-sectional area of the second busbar section 321 is equivalent to being increased, which can also reduce the transmission loss, and at the same time, the second busbar layer 140 can be made of paste that is less costly than the second busbar section 321, thereby reducing the cost. It is not difficult to understand that in such cases, the width of the second busbar section 321 can be the same as the width of the portion of the second busbar 32 other than the second solder section 301, and the second busbar section 321 can at least partially penetrate the back passivation film layer 104 to contact the second doped layer 104, or can not penetrate the back passivation film layer 104, which is not limited here in particular.

[0281] Specifically, in such embodiments, the second busbar layer 140 can be made of a non-punch-through paste, the second busbar layer 140 does not contact the first doped layer 102 through the back passivation film layer 104, and the paste cost of the second busbar layer 140 is lower than that of the second busbar segment 321. It can be understood that, since the second busbar layer 140 is arranged on the second busbar segment 321, the second busbar segment 321 can also be free of the widening treatment, and can also achieve the purpose of reducing the transmission loss.

[0282] Further, in some embodiments, the width (length in the second direction) of the second busbar layer 140 can be greater than the width (length in the second direction) of the part of the second collection fine grid 31 located outside the first series connection region 13 (i.e., the part of the second collection fine grid 31 other than the second solder segment 301). In this way, by increasing the width of the second busbar layer 140, the transmission capacity can be further improved, and the transmission loss can be reduced.

[0283] Specifically, in such embodiments, the width of the second busbar layer 140 can be the same as the width of the second solder segment 301. In this regard, the width of the second solder segment 301 refers to the length of the second solder segment 301 in the second direction. As described above, when the width of the second solder layer is greater than the width of the second collection layer, the width of the second solder segment 301 is the width (i.e., the length in the second direction) of the second solder layer. For similar descriptions below, please refer to this processing solution. In this regard, the width of the second solder segment 301 can be the same as the width of the first solder segment 201.

[0284] In this way, it can be ensured that the transmission loss will not be caused during the busbar process. At the same time, in the printing process, the second busbar layer 140 can be printed at the same time as the first solder layer. When the same screen is used for printing, there is no need to open screen slots of different sizes on the screen, which saves the manufacturing process and reduces the manufacturing difficulty.

[0285] According to the above description, in the embodiments of the present application, in order to reduce the busbar loss, the second busbar segment 321 can be directly thickened at some positions (i.e., the second busbar segment 321 is thickened), or the second busbar layer 140 can be arranged at some positions (i.e., the second busbar layer 140 is arranged on the second busbar segment 321). When the second busbar segment 321 and the second busbar layer 140 are both present, the width of the second busbar segment 321 can be less than the width of the second busbar layer 140.

[0286] Please refer to Figure 12In some embodiments, the width (length in the first direction) of the second edge busbar 110 can be greater than the width (length in the second direction) of the portion of the second collection fine grid 31 located outside the first series connection area 13 (i.e. the portion of the second collection fine grid 31 other than the second soldering section 301).

[0287] In this way, since the second edge busbar 110 needs to bear the busbar transmission function, setting the width of the second edge busbar 110 to be wider can also reduce the transmission loss in the busbar process and improve efficiency.

[0288] Specifically, in such embodiments, the width of the second edge busbar 110 can be the same as the width of the second soldering section 301. In this way, it can be ensured that there will be no large busbar loss in the busbar process, and at the same time, when printing, only the same size of screen slots need to be opened on the screen to print the three at the same time, which can effectively save the manufacturing process and reduce the manufacturing difficulty.

[0289] In some embodiments, the width (length in the first direction) of the third connection grid line 130 is greater than the width (length in the second direction) of the portion of the second collection fine grid 31 located outside the first series connection area 13 (i.e. the portion of the second collection fine grid 31 other than the second soldering section 301).

[0290] In this way, since the third connection grid line 130 plays a role in transmitting and busbaring the current when virtual soldering occurs, setting the width of the third connection grid line 130 to be wider can also reduce the transmission loss in the busbar process and improve efficiency.

[0291] In some embodiments, the third connection grid line 130 connects 2-20 first fine grids 20. In this way, setting the number of first fine grids 20 connected to the third connection grid line 130 within this reasonable range can reduce or even eliminate the impact of virtual soldering as much as possible.

[0292] In the embodiments of the present application, the number of second busbar fine grids 32 can be single. In this case, it can be that only one side of the second busbar fine grid 32 is provided with the third connection grid line 130, or both sides of the second busbar fine grid 32 are provided with the third connection grid line 130, which is not limited specifically herein. When the second busbar fine grid 32 has first fine grids 20 on both sides, it is preferred that the third connection grid line 130 is provided on both sides.

[0293] In addition, it should be noted that, in the present application, when the number of the second bus fine grids 32 is multiple, the third connection grid lines 130 can be arranged on one side or both sides of only some of the second bus fine grids 32, and the third connection grid lines 130 can not be arranged on both sides of the remaining second bus fine grids 32. In this case, the problem of false welding in some positions can also be solved. In the present application, it is preferred that the third connection grid lines 130 are arranged on both sides of each of the second bus fine grids 32.

[0294] Of course, please refer to Figure 3 and Figure 9 In some embodiments, the number of the second bus fine grids 32 can also be M, M being a positive integer greater than 2. In this way, arranging multiple second bus fine grids 32 can shorten the current bus path, effectively reduce the bus transmission loss, and improve the efficiency.

[0295] In this case, the third connection grid lines 130 are arranged between the adjacent two second bus fine grids 32, and the third connection grid lines 130 located between the adjacent two second bus fine grids 32 connect at least part of the first fine grids 20 located between the adjacent two second bus fine grids 32.

[0296] As shown in Figure 3 and Figure 9 In some embodiments, the third connection grid lines 130 located between the adjacent two second bus fine grids 32 can connect all the first fine grids 20 located between the adjacent two second bus fine grids 32.

[0297] In this way, connecting the third connection grid lines 130 to all the first fine grids 20 between the adjacent two second bus fine grids 32 can basically completely eliminate the influence of false welding and improve the efficiency of the back contact battery 100 as much as possible.

[0298] Specifically, in such embodiments, the number of the second bus fine grids 32 in the back contact battery 100 can be selected according to the size of the battery piece and the actual situation of the transmission process, and is not limited herein.

[0299] Further, please refer to Figure 9 In some embodiments, the plurality of third connection grid lines 130 can include a fifth end connection grid line 1301 closest to the third edge 123, a sixth end connection grid line 1302 closest to the fourth edge 124, and a third intermediate connection grid line 1303 located between the fifth end connection grid line 1301 and the sixth end connection grid line 1302. The width of the fifth end connection grid line 1301 is greater than the width of the third intermediate connection grid line 1303.

[0300] In this way, on the one hand, the width of the fifth end connecting busbar 1301 is set to be wider and the width of the third middle connecting busbar 1303 is set to be narrower, which can improve the current collection capability of the edge area of the back contact battery 100, reduce the transmission loss of the edge area, and improve the efficiency. On the other hand, when the fifth end connecting busbar 1301 needs to be contacted or welded with the solder strip, the width of the fifth end connecting busbar 1301 is set to be wider, which can improve the welding area or contact area of the solder strip in the third edge string connection area 142, ensure the stability of the contact between the end of the solder strip and the fifth end connecting busbar 1301, and effectively avoid the end of the solder strip from deviating to cause the end of the solder strip to fail to form stable and reliable contact with the fifth end connecting busbar 1301. In addition, the width of the third middle connecting busbar 1303 is set to be slightly narrower, which can also save the use of paste.

[0301] In some embodiments, the width of the sixth end connecting busbar 1302 can also be greater than the width of the third middle connecting busbar 1303.

[0302] In some embodiments, the width of the fifth end connecting busbar 1301 can be 1.3-1.8 times the width of the third middle connecting busbar 1303.

[0303] In this way, by optimizing the width ratio of the two, the current collection capability of the edge area can be improved while effectively controlling the paste cost of the entire third connecting busbar 130 during layout, thereby improving the stability of contact with the solder strip while ensuring current collection efficiency and controlling the confluence loss.

[0304] Specifically, in such embodiments, the width of the fifth end connecting busbar 1301 can be, for example, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, or other values between 1.3-1.8 times the width of the third middle connecting busbar 1303, and the specific value is not limited.

[0305] In some embodiments, the width of the third middle connecting busbar 1303 can be 0.5-0.7 mm, for example, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, or other values between 0.5-0.7 mm. The width of the fifth end connecting busbar 1301 can be 0.8-1.2 mm, for example, 0.8 mm, 0.85 mm, 0.9 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, or other values between 0.8-1.2 mm.

[0306] Thus, by performing such an optimization design on the specific width of the third intermediate connecting busbar 1303 and the fifth end connecting busbar 1301, the current collecting capability of the edge area can be improved while the paste cost of the entire third connecting busbar 130 is effectively controlled during layout, so as to improve the stability of contact with the solder strip while ensuring the current collecting efficiency and controlling the current collecting loss.

[0307] In some possible embodiments, the width of the third intermediate connecting busbar 1303 can be 0.6 mm, and the width of the fifth end connecting busbar 1301 can be 1 mm.

[0308] In some embodiments, in some embodiments, the width of the sixth end connecting busbar 1302 can also be 1.3-1.8 times the width of the third intermediate connecting busbar 1303.

[0309] Thus, by performing such an optimization design on the width ratio of the two, the current collecting capability of the edge area can be improved while the paste cost of the entire third connecting busbar 130 is effectively controlled during layout, so as to improve the stability of contact with the solder strip while ensuring the current collecting efficiency and controlling the current collecting loss.

[0310] Specifically, in such embodiments, the width of the sixth end connecting busbar 1302 can be, for example, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, or other values between 1.3-1.8 times the width of the third intermediate connecting busbar 1303, without being limited specifically.

[0311] In some embodiments, the width of the third intermediate connecting busbar 1303 can be 0.5-0.7 mm, for example, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, or other values between 0.5-0.7 mm. The width of the sixth end connecting busbar 1302 can be 0.8-1.2 mm, for example, 0.8 mm, 0.85 mm, 0.9 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, or other values between 0.8-1.2 mm.

[0312] Thus, by performing such an optimization design on the specific width of the third intermediate connecting busbar 1303 and the sixth end connecting busbar 1302, the current collecting capability of the edge area can be improved while the paste cost of the entire third connecting busbar 130 is effectively controlled during layout, so as to improve the stability of contact with the solder strip while ensuring the current collecting efficiency and controlling the current collecting loss.

[0313] In some possible embodiments, the width of the third intermediate connecting busbar 1303 can be 0.6 mm, and the width of the sixth end connecting busbar 1302 can be 1 mm.

[0314] In the embodiments of the present application, the fifth end connecting busbar 1301 and the sixth end connecting busbar 1302 can have the same width or different width, which is not limited here.

[0315] In some embodiments, the width of the fifth end connecting busbar 1301 can be greater than the width of the second edge busbar 110, and / or the width of the sixth end connecting busbar 1302 can be greater than the width of the second edge busbar 110.

[0316] In this way, by setting the width of the second edge busbar 110 to be smaller than the width of the fifth end connecting busbar 1301 and the sixth end connecting busbar 1302, the paste cost can be reduced while achieving the busbar connection of the isolated fine busbar segments of the second fine busbar 30 in the edge area.

[0317] In some embodiments, the width of the fifth end connecting busbar 1301 and the sixth end connecting busbar 1302 can be greater than the width of the second edge busbar 110, and the width of the second edge busbar 110 can be greater than the width of the third intermediate connecting busbar 1303.

[0318] In this way, by setting the width of the second edge busbar 110 to be greater than the width of the third intermediate connecting busbar 1303, the busbar transmission loss of the second edge busbar 110 can be reduced, and by setting the width of the fifth end connecting busbar 1301 and the sixth end connecting busbar 1302 to be greater, the current collection efficiency of the edge area can be improved, the busbar transmission loss can be reduced, and the stability of the contact between the end of the solder strip and the fifth end connecting busbar 1301 and the sixth end connecting busbar 1302 can be ensured.

[0319] Specifically, it is also not difficult to understand that the second edge busbar 110 needs to busbar connect all the isolated fine busbar segments of the second fine busbar 30 located between the second edge 122 and the third edge string area 142, and the third intermediate connecting busbar 1303 only needs to busbar connect part of the first fine busbar 20, in such a case, in order to reduce the busbar transmission loss of the second edge busbar 110, the width of the second edge busbar 110 can be set to be wider. As for the fifth end connecting busbar 1301 and the sixth end connecting busbar 1302 being set to be wider, it is to improve the current collection efficiency of the edge area, avoid the decrease of the collection efficiency due to the more defects in the edge area, and ensure the stability of the contact between the end of the solder strip and the connecting busbar.

[0320] In some embodiments, the width of the fifth end connecting grid line 1301 is 1.1-1.4 times, such as 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4 or other values between 1.1-1.4 times of the width of the second edge bus bar 110; and / or, the width of the sixth end connecting grid line 1302 is 1.1-1.4 times, such as 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4 or other values between 1.1-1.4 times of the width of the second edge bus bar 110.

[0321] In this way, by such specific design of the width ratio, the current collection capability of the edge region can be improved and the bus bar transmission loss of the second edge bus bar 110 can be reduced, while the paste cost can be effectively controlled.

[0322] In some embodiments, the width of the second edge bus bar can be 0.7-0.9 mm, such as 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9 mm or other values between 0.7-0.9 mm. The widths of the fifth end connecting grid line 1301 and the sixth end connecting grid line 1302 can be as described above, which is not repeated here.

[0323] In this way, by setting the width of the second edge bus bar 110 within this reasonable range, the transmission performance of the second edge bus bar can be ensured, while the paste cost can be effectively controlled.

[0324] In some embodiments, the width of the second edge bus bar 110 can be 0.8 mm.

[0325] In some embodiments, the ratio of the width of the fifth end connecting grid line 1301, the width of the second edge bus bar 110 and the width of the third intermediate connecting grid line 1303 is 1:0.8:0.6, i.e., when the width of the fifth end connecting grid line 1301 is 1 mm, the width of the fifth end connecting grid line 1301 is 0.8 mm and the width of the third intermediate connecting grid line 1303 is 0.6 mm.

[0326] In this way, by such optimized design of the width ratio of the three, the current collection capability, bus bar transmission performance and contact stability of the solder ribbon of the entire edge region can be optimized, thereby improving the overall performance of the back contact battery.

[0327] In some embodiments, the width of the fifth end connecting gate line 1301 and the width of the sixth end connecting gate line 1302 can both be greater than the width of the second bus section 321 and / or the second bus layer 140. The specific description of the second bus section 321 and the second bus layer 140 is referred to the above, and is not repeated here.

[0328] Further, in such a case, the width of the fifth end connecting gate line 1301 and the width of the sixth end connecting gate line 1302 can both be 1.1 times to 1.4 times of the width of the second bus section 321 and / or the second bus layer 140.

[0329] In this way, by specifically designing the width of the fifth end connecting gate line 1301, the sixth end connecting gate line 1302 and the second bus layer, the bus transmission performance of the second bus layer 140 and the contact stability of the solder strip can be optimized.

[0330] Specifically, in such embodiments, the width of the fifth end connecting gate line 1301 and the sixth end connecting gate line 1302 can be as described above, and the width of the second bus section 321 and / or the second bus layer 140 can be 0.7 mm to 0.9 mm, for example, 0.7 mm, 0.72 mm, 0.74 mm, 0.76 mm, 0.78 mm, 0.8 mm, 0.82 mm, 0.84 mm, 0.86 mm, 0.88 mm, 0.9 mm or other values between 0.7 mm and 0.9 mm. Of course, it can be understood that when the second bus section 321 and the second bus layer 140 are both present, the width of the second bus section 321 can be set to be smaller than the width of the second bus layer 140.

[0331] In some possible embodiments, in order to improve the uniformity of the transmission of the second edge bus line 110 and the second bus section 321 and / or the second bus layer 140, the width of the second edge bus line 110 can be the same as the width of the second bus section 321 and / or the second bus layer 140, for example, both of which can be 0.8 mm.

[0332] Please refer to Figure 3 , Figure 9 and Figure 12 In some embodiments, the plurality of first string connection regions 13 can further include a fourth edge string connection region 132 closest to the second edge 122 (i.e., the first string connection region 13 adjacent to the third edge string connection region 142), the second fine gate 30 is continuous at the fourth edge string connection region 132, and the first fine gate 20 is discontinuous at the fourth edge string connection region 132.

[0333] In such a case, the back contact cell 100 can further include a fourth connecting grid line 150, which is arranged in the fourth edge serial connection area 132 and connects the second busbar fine grid 32 and at least one second collection fine grid 31 located on one side of the second busbar fine grid 32 in the second direction.

[0334] In this way, by arranging the fourth connecting grid line 150 in the fourth edge serial connection area 132, the phenomenon that the current transmitted from the second busbar fine grid 32 cannot be collected due to the occurrence of virtual welding or poor contact of the solder strip at the second busbar fine grid 32 in the fourth edge serial connection area 132 can be effectively avoided.

[0335] Specifically, as shown in Figure 9 and Figure 12 In such an embodiment, the number of the fourth connecting grid line 150 can be consistent with the number of the second busbar fine grid 32, and one-to-one correspondence, when the second busbar fine grid 32 is located in the middle position (i.e., the second busbar fine grid 32 has the second collection fine grid 31 on both sides), the fourth connecting grid line connects the second busbar fine grid 32 and the two second collection fine grids 31 adjacent to the second busbar fine grid 32 (i.e., the second collection fine grids 31 located on both sides of the second busbar fine grid 32 and adjacent to it).

[0336] In some embodiments, the width (length in the first direction) of the fourth connecting grid line 150 is greater than the width (length in the second direction) of the part of the second collection fine grid 31 located outside the first serial connection area 13 (i.e., the part of the second collection fine grid 31 other than the second soldering section 301). In this way, since the fourth connecting grid line 150 plays a role in transmitting and collecting current when virtual welding occurs at the second busbar fine grid 32, setting the width of the fourth connecting grid line 150 wider can also reduce the transmission loss in the collection process and improve efficiency.

[0337] As shown in Figure 9 In some embodiments, the length (length in the second direction) of the fourth connecting grid line 150 can be less than the length (length in the second direction) of the third connecting grid line 130.

[0338] In this way, setting the fourth connecting grid line 150 shorter can save the cost of paste.

[0339] Specifically, since the second busbar fine grid 32 does not need to be provided with an insulating layer to achieve insulation at the fourth edge serial connection area 132, even if virtual welding is likely to occur at the second busbar fine grid 32, the range affected by virtual welding is smaller, and in such a case, only by arranging a shorter fourth connecting grid line 150 can effectively avoid the occurrence of virtual welding to cause some second collection fine grids 31 adjacent to the second busbar fine grid 32 to be unable to be welded with the solder strip, thereby achieving the purpose of saving the cost of paste.

[0340] In such embodiments, the ratio between the length of the fourth connecting busbar 150 and the length of the third connecting busbar 130 can be 0.2-0.5, such as 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 or other values between 0.2-0.5, without limitation here.

[0341] In this way, by optimizing the ratio between the two, the cost of the paste can be controlled as much as possible while reducing the risk of virtual soldering of the solder strip in the third edge stringing area 142 and the fourth edge stringing area 132.

[0342] In some embodiments, the length of the fourth connecting busbar 150 can be 2mm-3mm, such as 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm or other values between 2mm-3mm. The length of the third connecting busbar 90 can be 6mm-9mm, such as 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm or other values between 2mm-3mm, without limitation here.

[0343] In this way, by optimizing the ratio between the two, the cost of the paste can be controlled as much as possible while reducing the risk of virtual soldering of the solder strip in the third edge stringing area 142 and the fourth edge stringing area 132.

[0344] Please refer to Figure 9 In some embodiments, among the plurality of second busbar fine grids 32, the second busbar fine grid 32 closest to the third edge 123 has a certain distance from the third edge 123, and among the plurality of fourth connecting busbars 150 in the fourth edge stringing area 132, the fourth connecting busbar 150 closest to the third edge 123 is provided with a fifth connecting busbar 50 between the third edge 123, the second fine grid 30 between the fourth connecting busbar 150 closest to the third edge 123 and the third edge 123, and the fifth connecting busbar 50 can be spaced apart from the fourth connecting busbar 150 in the second direction or the fifth connecting busbar 50 is directly connected to the fourth connecting busbar 150, without limitation here.

[0345] In this way, by providing the fifth connecting busbar 50, the part of the second collecting fine grid 31 closest to the third edge 123 can be connected together, thereby realizing the collection of the current of the second collecting fine grid 31 in the edge area and avoiding poor welding of the solder strip in the edge area, which leads to a decrease in the collection efficiency of the edge area.

[0346] Please continue to refer to Figure 9In some possible embodiments, in the second busbar fine grids 32 closest to the fourth edge 124, the second busbar fine grid 32 closest to the fourth edge 124 is spaced apart from the fourth edge 124, and in the fourth connection grid lines 150 closest to the fourth edge 124 in the fourth edge stringing area 132, the sixth connection grid line 120 is arranged between the fourth connection grid line 150 closest to the fourth edge 124 and the second fine grid 30 between the fourth connection grid line 150 closest to the fourth edge 124 and the fourth edge 124. The sixth connection grid line 120 can be spaced apart from the fourth connection grid line 150 in the second direction, or the sixth connection grid line 120 can be directly connected to the fourth connection grid line 150, which is not limited herein.

[0347] In this way, by arranging the sixth connection grid line 120, the second collection fine grids 31 closest to the fourth edge 124 can be connected together, so that the current of the second collection fine grids 31 in the edge area can be collected, and the poor welding of the solder strip in the edge area can be avoided to reduce the collection efficiency of the edge area.

[0348] Please refer to Figure 9 In some embodiments, the width of the fifth connection grid line 50 is greater than the width of the fourth connection grid line 150.

[0349] In this way, on the one hand, by setting the width of the fifth connection grid line 50 to be relatively wide or relatively narrow, the current collection capability of the edge area of the back contact battery 100 can be improved, the transmission loss of the edge area can be reduced, and the efficiency can be improved. On the other hand, when the fifth connection grid line 50 needs to be in contact with or welded to the solder strip, the width of the fifth connection grid line 50 is set to be relatively wide, so that the welding area or the contact area of the fifth connection grid line 50 and the solder strip can be increased, the stability of the contact between the end of the solder strip and the fifth connection grid line 50 can be ensured, and the end of the solder strip can be effectively prevented from deviating to cause the end of the solder strip to fail to form stable and reliable contact with the fifth connection grid line 50. In addition, the width of the fourth connection grid line 150 is set to be slightly narrower, so that the use of the paste can be saved.

[0350] In some embodiments, the width of the sixth connection grid line 120 is greater than the width of the fourth connection grid line 150.

[0351] In some embodiments, the width of the fifth connection grid line 50 can be 1.3-1.8 times the width of the fourth connection grid line 150.

[0352] In this way, by optimizing the width ratio of the two, the current collection capability of the edge area can be improved while the paste cost can be effectively controlled, so that the stability of the contact with the solder strip can be improved while the current collection efficiency and the busbar loss are ensured.

[0353] Specifically, in such embodiments, the width of the fifth connecting busbar 50 can be, for example, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, or other values between 1.3-1.8 times the width of the fourth connecting busbar 150, without limitation in particular.

[0354] In some embodiments, the width of the fourth connecting busbar 150 can be 0.5-0.7mm, for example 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, or other values between 0.5-0.7mm. The width of the fifth connecting busbar 50 can be 0.8-1.2mm, for example 0.8mm, 0.85mm, 0.9mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, or other values between 0.8-1.2mm.

[0355] In this way, by specifically optimizing the width of the fourth connecting busbar 150 and the fifth connecting busbar 50, the cost of the paste can be effectively controlled while ensuring the performance of the busbar and reducing the loss of the busbar, and the stability of the contact between the end of the solder strip and the fifth connecting busbar 50 can also be ensured.

[0356] In some possible embodiments, the width of the fourth connecting busbar 150 can be 0.6mm, and the width of the fifth connecting busbar 50 can be 1mm.

[0357] In some embodiments, in some embodiments, the width of the sixth connecting busbar 120 can also be 1.3-1.8 times the width of the fourth connecting busbar 150.

[0358] In this way, by optimizing the width ratio of the two, the current collection capacity of the edge area can be improved while the cost of the paste is effectively controlled, so that the current collection efficiency and the contact stability with the solder strip are improved while the busbar loss is controlled.

[0359] Specifically, in such embodiments, the width of the sixth connecting busbar 120 can be, for example, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, or other values between 1.3-1.8 times the width of the fourth connecting busbar 150, without limitation in particular.

[0360] In some embodiments, the fourth connecting busbar 150 can have a width of 0.5mm-0.7mm, such as 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, or any other value between 0.5mm and 0.7mm. The sixth connecting busbar 120 can have a width of 0.8mm-1.2mm, such as 0.8mm, 0.85mm, 0.9mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, or any other value between 0.8mm and 1.2mm.

[0361] In this way, by specifically optimizing the width of the fourth connecting busbar 150 and the sixth connecting busbar 120, the cost of the paste can be effectively controlled while ensuring the performance of the busbar and reducing the loss of the busbar, and the stability of the contact between the end of the solder strip and the sixth connecting busbar 120 can also be ensured.

[0362] In some possible embodiments, the fourth connecting busbar 150 can have a width of 0.6mm, and the sixth connecting busbar 120 can have a width of 1mm.

[0363] In embodiments of the present application, the width of the fifth connecting busbar 50 and the sixth connecting busbar 120 can be the same or different, which is not limited specifically herein.

[0364] In some embodiments, the distance between the third edge stringing area 142 and the second edge 122 can be greater than or equal to 2mm and less than or equal to 8mm.

[0365] In this way, the distance between the third edge stringing area 142 and the second edge 122 can be prevented from being too small, so that the welding position is too close to the second edge 122, which can cause the back contact battery 100 to have a hidden crack and reduce the risk of hidden cracks. The distance between the third edge stringing area 142 and the second edge 122 can also be prevented from being too large, so that the length of the isolated thin busbar segment located between the third edge stringing area 142 and the second edge 122 is too long, which can cause a large loss during the transmission process.

[0366] Specifically, in such embodiments, the distance between the third edge stringing area 142 and the second edge 122 can be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, or any value between 2mm and 8mm, which is not limited specifically herein.

[0367] In some embodiments, the distance between the third edge stringing area 142 and the second edge 122 can be less than the distance between the third edge stringing area 142 and the fourth edge stringing area 132.

[0368] In this way, on the one hand, the distance between the third edge stringing area 142 and the second edge 122 is set to be small, so as to avoid the distance being too large and causing the transmission loss to be too large, and on the other hand, the third edge stringing area 142 and the fourth edge stringing area 132 can avoid the stringing areas being too dense and causing the risk of electric leakage to be large.

[0369] In the above embodiment, the polarity of the third edge stringing area 142 and the first edge stringing area 131 is opposite, and the structures of the two edges of the back contact battery 100 in the first direction are different and asymmetric. It can be understood that in some possible embodiments, the polarity of the third edge stringing area 142 and the first edge stringing area 131 can also be the same, and in such a case, the structures of the two edges of the back contact battery 100 in the first direction are the same and symmetric, that is, in such a case, in the back contact battery 100, the two stringing areas closest to the second edge 122 are symmetric with the first edge stringing area 131 and the second edge stringing area 141, and structures such as bus lines, connection grid lines, etc. are also provided at the side of the second edge 122, which are completely symmetric with the side of the first edge 121. In order to avoid redundancy, the specific structures are not described here.

[0370] Please refer to Figure 3 In some embodiments, the substrate 10 has a third edge 123 and a fourth edge 124 in the second direction, and in the plurality of first stringing areas 13, the seventh connection grid line 160 and the eighth connection grid line 170 are arranged in the remaining first stringing areas 13 except the first edge stringing area 131 and the fourth edge stringing area 132, the seventh connection grid line 160 connects A roots of the second fine grid lines 30 closest to the third edge 123, and the eighth connection grid line 170 connects B roots of the second fine grid lines 30 closest to the fourth edge 124, where A and B are both greater than or equal to 2 and less than or equal to 8.

[0371] In some embodiments, the widths of the seventh connection grid line 160 and the eighth connection grid line 170 can be substantially the same as the widths of the first end connection grid line 61 and the second end connection grid line 62.

[0372] In some embodiments, in the plurality of second stringing areas 14, the ninth connection grid line 180 and the tenth connection grid line 190 are arranged in the remaining second stringing areas 14 except the second edge stringing area 141 and the third edge stringing area 142, the ninth connection grid line 180 connects P roots of the first fine grid lines closest to the third edge 123, and the tenth connection grid line 190 connects Q roots of the first fine grid lines closest to the fourth edge 124, where P and Q are both greater than or equal to 2 and less than or equal to 8.

[0373] In some embodiments, the width of the ninth connection gate line 180 and the tenth connection gate line 190 can be substantially the same as the width of the fifth end connection gate line 1301 and the sixth end connection gate line 1302.

[0374] In this way, by arranging the seventh connection gate line 160 and the eighth connection gate line 170 at the positions close to the third edge 123 and the fourth edge 124 of the remaining first connection areas 13 except the first edge connection area 131 and the fourth edge connection area 132, i.e., arranging the seventh connection gate line 160 and the eighth connection gate line 170 at the head and tail ends of the solder strip in the first connection area 13, the problem that the current of part of the gate lines cannot be collected due to the virtual welding of the solder strip at the start and end welding points on the first connection area 13 can be effectively avoided. Similarly, by arranging the ninth connection gate line 180 and the tenth connection gate line 190 at the positions close to the third edge 123 and the fourth edge 124 of the remaining second connection areas 14 except the second edge connection area 141 and the third edge connection area 142, i.e., arranging the ninth connection gate line 180 and the tenth connection gate line 190 at the head and tail ends of the solder strip in the second connection area 14, the problem that the current of part of the gate lines cannot be collected due to the virtual welding of the solder strip at part of the start and end welding points on the second connection area 14 can be effectively avoided.

[0375] Please refer to Figure 4 , Figure 9 and Figure 13 In some embodiments, the first connection area 13 can include a first end region 1304 close to the third edge 123, a second end region 1305 close to the fourth edge 124, and a first intermediate region 1306 between the first end region 1304 and the second end region 1305.

[0376] The width (i.e., the length in the first direction) of the first end region 1304 and the second end region 1305 is greater than the width of the first intermediate region 1306, the width (i.e., the length in the first direction) of the first end region 1304 gradually increases in the direction towards the third edge 123, and the width of the second end region 1305 gradually increases in the direction towards the fourth edge 124.

[0377] In this way, by arranging the width of the two end regions of the first connection area 13 to gradually increase towards the edges, the problem that the solder strip is easily offset in the two end regions during the welding process and thus contacts the gate lines of the opposite polarity can be effectively avoided, and the reliability and stability of the welding can be ensured.

[0378] Specifically, in such a case, the width of the discontinuous region formed by the first fine grids 20 corresponding to the first end region 1304 gradually increases in the direction towards the third edge 123, and the width of the discontinuous region formed by the first fine grids 20 corresponding to the second end region 1305 gradually increases in the direction towards the fourth edge 124.

[0379] Further, in such an embodiment, the first end region 1304 corresponds to 2-4 first fine grids 20 and 2-4 second fine grids 30; and the second end region 1305 corresponds to 2-4 first fine grids 20 and 2-4 second fine grids 30.

[0380] In this way, the excessive length of the first end region 1304 and the second end region 1305 in the first direction can be avoided, and the excessive number of the first fine grids 20 in the discontinuous region caused by the excessive length can be avoided, so as to avoid the reduction of the collection efficiency.

[0381] In some embodiments, the left and right sides of the first stringing region 13 are symmetrical in the first direction. The left and right sides of the second stringing region 14 are symmetrical in the first direction.

[0382] In this way, the various connection grid lines described above can be arranged in the center of the stringing region, so as to facilitate the stable contact between the solder strip and the first connection grid line.

[0383] Please refer to Figure 13 In some embodiments, the included angle a1 between the boundary line of the first end region 1304 in the first direction and the first direction is less than or equal to 85° and greater than or equal to 60°, i.e. 60°≤a1≤85°, and the size of a1 may, for example, be 60°, 62°, 64°, 66°, 68°, 70°, 72°, 74°, 76°, 78°, 80°, 82°, 84°, 85°, or other values between 60°-80°.

[0384] Specifically, as Figure 9 shown, the "boundary line of the first end region 1304 in the first direction" refers to the line between the end points formed by the discontinuity of the first fine grids 20 corresponding to the first end region 1304 in the first end region 1304.

[0385] In this way, the discontinuous region of the first fine grids 20 in the first end region 1304 can be effectively avoided.

[0386] Please refer to Figure 13In some embodiments, the included angle a2 between the boundary line of the second end region 1305 and the second direction is less than or equal to 85° and greater than or equal to 60°, i.e. 60°≤a2≤85°, and the magnitude of a2 may, for example, be 60°, 62°, 64°, 66°, 68°, 70°, 72°, 74°, 76°, 78°, 80°, 82°, 84°, 85°, or other values between 60° and 80°.

[0387] Specifically, as shown in Figure 9 The "boundary line of the second end region 1305 in the first direction" refers to the line between the end points formed by the discontinuity of the first fine grid 20 corresponding to the second end region 1305.

[0388] In this way, the discontinuity area of the first fine grid 20 in the second end region 1305 can be effectively avoided from being too large.

[0389] Please refer to Figure 13 In some embodiments, the second stringing area 14 can include a third end region 1401 near the third edge 123, a fourth end region 1402 near the fourth edge 124, and a second intermediate region 1403 between the third end region 1401 and the fourth end region 1402.

[0390] The width (i.e. the length in the first direction) of the third end region 1401 and the fourth end region 1402 is greater than the width of the second intermediate region 1403, and the width (i.e. the length in the first direction) of the third end region 1401 gradually increases in the direction towards the third edge 123, and the width of the fourth end region 1402 gradually increases in the direction towards the fourth edge 124.

[0391] In this way, by setting the width of the upper and lower end regions of the second stringing area 14 to gradually increase towards the edges, it can effectively avoid the two ends of the solder strip from being easily offset during the soldering process to cause contact with the grid lines of the opposite polarity, ensuring the reliability and stability of the soldering.

[0392] Specifically, in such a case, the width of the discontinuity area formed by the second fine grid 30 corresponding to the third end region 1401 gradually increases in the direction towards the third edge 123, and the width of the discontinuity area formed by the second fine grid 30 corresponding to the fourth end region 1402 gradually increases in the direction towards the fourth edge 124.

[0393] Further, in such embodiments, the third end region 1401 corresponds to 2-4 first fine grids 20 and 2-4 second fine grids 30, and the fourth end region 1402 corresponds to 2-4 first fine grids 20 and 2-4 second fine grids 30.

[0394] In this way, the length of the third end region 1401 and the fourth end region 1402 in the first direction can be effectively controlled, and the number of the second fine grids 30 in the second end region 1305 can be effectively controlled.

[0395] As shown in FIG. 13, the third end region 1401 and the fourth end region 1402 are located in the second end region 1305. Figure 13 In some embodiments, an included angle a3 between the boundary line of the third end region 1401 in the first direction and the first direction is less than or equal to 85° and greater than or equal to 60°, i.e., 60°≤a3≤85°. For example, the included angle a3 can be 60°, 62°, 64°, 66°, 68°, 70°, 72°, 74°, 76°, 78°, 80°, 82°, 84°, 85°, or other values between 60° and 80°.

[0396] Specifically, as shown in FIG. 14, the "boundary line of the third end region 1401 in the first direction" refers to a line between the end points formed by the discontinuity of the second fine grids 30 corresponding to the third end region 1401 in the third end region 1401. Figure 4

[0397] In this way, the discontinuity of the second fine grids 30 in the third end region 1401 can be effectively avoided.

[0398] As shown in FIG. 13, the third end region 1401 and the fourth end region 1402 are located in the second end region 1305. Figure 13 In some embodiments, an included angle a4 between the boundary line of the fourth end region 1402 in the first direction and the first direction is less than or equal to 85° and greater than or equal to 60°, i.e., 60°≤a4≤85°. For example, the included angle a4 can be 60°, 62°, 64°, 66°, 68°, 70°, 72°, 74°, 76°, 78°, 80°, 82°, 84°, 85°, or other values between 60° and 80°.

[0399] Specifically, as shown in FIG. 15, the "boundary line of the fourth end region 1402 in the first direction" refers to a line between the end points formed by the discontinuity of the second fine grids 30 corresponding to the fourth end region 1402 in the fourth end region 1402. Figure 4

[0400] In this way, the discontinuity of the second fine grids 30 in the fourth end region 1402 can be effectively avoided.

[0401] As shown in FIG. 13, the third end region 1401 and the fourth end region 1402 are located in the second end region 1305. Figure 13 In some embodiments, the length of the first end region 1304 in the second direction is less than the length of the third end region 1401 in the second direction. The length of the second end region 1305 in the second direction is less than the length of the fourth end region 1402 in the second direction.

[0402] ​​As described above, the first fine grid 20 includes the first soldering section 201 corresponding to the second stringing area 14, and the second fine grid 30 includes the second soldering section 301 corresponding to the first stringing area 13.

[0403] In some embodiments, the length (i.e. the length in the first direction) of the first soldering section 201 can be 0.4mm-0.8mm, for example 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm or other values between 0.4mm-0.8mm, without limitation in particular.

[0404] The length (i.e. the length in the first direction) of the second soldering section 301 can also be 0.4mm-0.8mm, for example 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm or other values between 0.4mm-0.8mm, without limitation in particular.

[0405] In this way, by optimizing the length of the first soldering section 201 and the second soldering section 202 and setting their length in the range of 0.4mm-0.8mm, the soldering area of the soldering section and the stringing area can be ensured while saving the paste cost as much as possible, that is, such setting can effectively save the paste cost while ensuring the stability of the soldering.

[0406] In some embodiments, the length (i.e. the length in the first direction) of the second soldering section 301 located in the first end area 1304 is the same, and the length of the second soldering section 301 located in the second end area 1305 is also the same.

[0407] In this way, the second soldering section 301 in the first end area 1304 and the second end area 1305 does not need to be lengthened, and the use of paste can be saved.

[0408] In addition, in some embodiments, the length of the first soldering section 201 located in the third end area 1401 is the same, and the length of the first soldering section 201 located in the fourth end area 1402 is also the same.

[0409] In this way, the first soldering section 201 in the third end area 1401 and the fourth end area 1402 does not need to be lengthened, and the use of paste can be saved.

[0410] In the description of the specification, reference to "some embodiments", "certain embodiments", "exemplary embodiments", "specific embodiments", or "some examples" etc., indicate that the particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The appearing of the above-mentioned phrases in various places in the specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0411] Moreover, the above-mentioned preferred embodiments are only some of the preferred embodiments of the present application, and are not used to limit the present application, and any modification, equivalent replacement, and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A back contact cell, characterized by, The back contact battery comprises: a substrate, the substrate has opposite first and second edges in a first direction, and has opposite third and fourth edges in a second direction intersecting the first direction, a first chamfer is formed at the intersection of the first and third edges; the back surface of the substrate has a plurality of first and second stringing areas, the first and second stringing areas are arranged alternately in the first direction, a plurality of the first stringing areas include a first edge stringing area closest to the first edge, and there is no second stringing area between the first edge stringing area and the first edge; and a plurality of first and second fine grids arranged on the back surface of the substrate, the first and second fine grids are arranged alternately along the second direction and extend along the first direction; of the first and second fine grids, the fine grid closest to the third edge is the first fine grid, of the plurality of first fine grids, the two first fine grids closest to the third edge correspond to the first chamfer, the two first fine grids corresponding to the first chamfer include a first edge fine grid closest to the third edge and a second edge fine grid adjacent to the first edge fine grid; wherein at least one of the first edge fine grid and the second edge fine grid does not extend between the first edge stringing area and the first edge, and the remaining first fine grids all have a portion between the first edge stringing area and the first edge.

2. The back contact cell of claim 1, wherein, The first edge fine grid extends between the first edge stringing area and the first edge, and the second edge fine grid does not extend between the first edge stringing area and the first edge.

3. The back contact cell of claim 2, wherein, The length of the line segment between the end of the first edge fine grid towards the first edge and any point on the first chamfer is greater than or equal to 0.4 mm and less than or equal to 1.5 mm; and / or The length of the line segment between the end of the second fine grid between the first edge fine grid and the second edge fine grid towards the first edge and any point on the first chamfer is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

4. The back contact cell of claim 1, wherein, The plurality of first fine grids include a plurality of first collection fine grids and at least one first convergence fine grid, the first collection fine grids are discontinuous at the first edge stringing area and continuous at the second stringing area, the first convergence fine grid is continuous at both the first edge stringing area and the second stringing area, and the second fine grids are continuous at the first edge stringing area; The back contact battery further comprises: a first edge convergence line, the first edge convergence line is closer to the first edge than the first edge stringing area, the first edge convergence line is electrically connected to at least part of the first collection fine grids and the first convergence fine grid; and a first connection grid line arranged in the first edge stringing area, at least one side of the first convergence fine grid is provided with the first connection grid line in the second direction, and the first connection grid line connects at least two second fine grids on the same side of the first convergence fine grid. The first edge fine grid is the first bus fine grid, the first edge fine grid is continuous at the first edge stringing area and extends between the first edge stringing area and the first edge, and the second edge fine grid is the first collection fine grid, the second edge fine grid is discontinuous at the first edge stringing area and does not extend between the first edge stringing area and the first edge. The first edge fine grid and the second edge fine grid are both the first collection fine grid, and the first edge fine grid and the second edge fine grid are both discontinuous at the first edge stringing area and do not extend between the first edge stringing area and the first edge.

5. The back contact cell of claim 4, wherein, The first edge fine grid is the first bus fine grid, the first edge fine grid is continuous at the first edge stringing area and extends between the first edge stringing area and the first edge, and the second edge fine grid is the first collection fine grid, the second edge fine grid is discontinuous at the first edge stringing area and does not extend between the first edge stringing area and the first edge, Wherein, the first edge fine grid is the first bus fine grid, the first edge fine grid is continuous at the first edge stringing area and extends between the first edge stringing area and the first edge, and the second edge fine grid is the first collection fine grid, the second edge fine grid is discontinuous at the first edge stringing area and does not extend between the first edge stringing area and the first edge, 6. The back contact cell of claim 5, wherein, The first edge bus line is connected with the first edge fine grid, and the first edge bus line has a first bending section at the first chamfer, and the distance between the first bending section and the first chamfer is 0.2mm-0.6mm.

7. The back contact cell of claim 5, wherein, The number of the first bus fine grids is N, and N is a positive integer greater than 2. Wherein, the first connecting grid line is arranged between adjacent two first bus fine grids, and the first connecting grid line between adjacent two first bus fine grids connects at least part of the second fine grid between adjacent two first bus fine grids.

8. The back contact cell of claim 7, wherein, The first connecting grid line includes a first end connecting grid line closest to the third edge, a second end connecting grid line closest to the fourth edge, and a first intermediate connecting grid line between the first end connecting grid line and the second end connecting grid line. The width of the first end connecting grid line is greater than the width of the first intermediate connecting grid line; and / or, the width of the second end connecting grid line is greater than the width of the first intermediate connecting grid line.

9. The back contact cell of claim 8, wherein, The width of the first end connecting grid line is 1.3-1.8 times the width of the first intermediate connecting grid line; and / or The width of the second end connecting grid line is 1.3-1.8 times the width of the first intermediate connecting grid line.

10. The back contact cell of claim 8, wherein, The width of the first intermediate connecting grid line is 0.5mm-0.7mm; The width of the first end connecting grid line is 0.8mm-1.2mm, and / or, the width of the second end connecting grid line is 0.8mm-1.2mm.

11. The back contact cell of claim 8, wherein, The width of the first end connecting grid line is greater than the width of the first edge bus line; and / or The width of the second end connecting grid line is greater than the width of the first edge bus line.

12. The back contact cell of claim 11, wherein, The width of the first end connecting gate line is 1.1-1.4 times the width of the first edge bus bar; and / or The width of the second end connecting gate line is 1.1-1.4 times the width of the first edge bus bar.

13. The back contact cell according to claim 11 or 12, characterized in that, The width of the first edge bus bar is 0.7-0.9 mm; The width of the first end connecting gate line is 0.8-1.2 mm, and / or the width of the second end connecting gate line is 0.8-1.2 mm.

14. The back contact cell of claim 8, wherein, The width of the first end connecting gate line and the width of the second end connecting gate line are both greater than the width of the first edge bus bar, and the width of the first edge bus bar is greater than the width of the first intermediate connecting gate line.

15. The back contact cell of claim 14, wherein, The ratio of the width of the first end connecting gate line, the width of the first edge bus bar and the width of the first intermediate connecting gate line is 1:0.8:0.

6.

16. The back contact cell of claim 8, wherein, The second stringer area closest to the first edge is included in the plurality of second stringer areas, and the first bus fine gate includes a first bus section located between the second edge stringer area and the first edge; The width of the first bus section is greater than the width of the remaining part of the first bus fine gate located outside the second stringer area; and / or The first bus section is provided with a first bus layer.

17. The back contact cell of claim 16, wherein, The width of the first end connecting gate line and the width of the second end connecting gate line are both greater than the width of the first bus section and / or the first bus layer.

18. The back contact cell of claim 16, wherein, The width of the first end connecting gate line and the width of the second end connecting gate line are both 1.1-1.4 times the width of the first bus section and / or the first bus layer.

19. The back contact cell of claim 4, wherein, The second stringer area closest to the first edge is included in the plurality of second stringer areas, and the first fine gate is continuous at the second edge stringer area, and the second fine gate is discontinuous at the second edge stringer area; The back contact cell further includes a second connecting gate line, and the second connecting gate line is arranged in the second edge stringer area and connects the first bus fine gate and at least one first collection fine gate located on one side of the first bus fine gate in the second direction.

20. The back contact cell of claim 19, wherein, The length of the second connecting gate line is less than the length of the first connecting gate line.

21. The back contact cell of claim 20, wherein, The ratio between the length of the second connecting gate line and the length of the first connecting gate line is 0.2-0.

5.

22. The back contact cell of claim 20, wherein, The length of the second connecting gate line is 2-3 mm, and the length of the first connecting gate line is 6-9 mm.

23. The back contact cell of claim 19, wherein, The plurality of second connecting gate lines include a third end connecting gate line closest to the third edge, a fourth end connecting gate line closest to the fourth edge, and a second intermediate connecting gate line located between the third end connecting gate line and the fourth end connecting gate line; The width of the third end connecting gate line is greater than the width of the second intermediate connecting gate line; and / or the width of the fourth end connecting gate line is greater than the width of the second intermediate connecting gate line.

24. The back contact cell of claim 23, wherein, The width of the third end connecting gate line is 1.3-1.8 times the width of the second intermediate connecting gate line; and / or The width of the fourth end connecting gate line is 1.3-1.8 times the width of the second intermediate connecting gate line. The fourth end connecting gate line has a width of 1.3-1.8 times of the width of the second middle connecting gate line.

25. The back contact cell of claim 1 wherein, A second chamfer is formed at the intersection of the second edge and the third edge, a plurality of the second string connection regions include a third edge string connection region closest to the second edge, and the third edge string connection region has no first string connection region between the second edge; The first edge fine gate and the second edge fine gate correspond to the second chamfer, and all the first fine gates extend to between the third edge string connection region and the second edge.

26. The back contact cell of claim 25, wherein, The length of the line between the end of the first edge fine gate and the second edge fine gate and any point on the second chamfer is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

27. The back contact cell of claim 25, wherein, The second fine gate between the first edge fine gate and the second edge fine gate does not extend to between the third edge string connection region and the second edge.

28. The back contact cell of claim 25, wherein, The second fine gate between the first edge fine gate and the second edge fine gate extends to between the third edge string connection region and the second edge, and the length of the line between the end of the second edge fine gate and any point on the second chamfer is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

29. The back contact cell of claim 1 wherein, The plurality of second fine gates include a plurality of second collection fine gates and at least one second bus fine gate, the second collection fine gates are discontinuous at the third edge string connection region and continuous at the first string connection region, the second bus fine gate is continuous at the third edge string connection region and the first string connection region, and the first fine gate is continuous at the third edge string connection region; The back contact battery further comprises: A second edge bus line closer to the second edge than the third edge string connection region, the second edge bus line being electrically connected to at least part of the second collection fine gate and the second bus fine gate; and A third connecting gate line arranged in the third edge string connection region, at least one side of the second bus fine gate being provided with the third connecting gate line in the second direction, and the third connecting gate line connecting at least two first fine gates on the same side of the second bus fine gate.

30. The back contact cell of claim 29, wherein, The number of the second bus fine gates is M, M being a positive integer greater than 2; The third connecting gate line is arranged between adjacent two second bus fine gates, and the third connecting gate line between the adjacent two second bus fine gates connects at least part of the first fine gates between the adjacent two second bus fine gates.

31. The back contact cell of claim 30, wherein, The plurality of third connecting gate lines include a fifth end connecting gate line closest to the third edge, a sixth end connecting gate line closest to the fourth edge, and a third middle connecting gate line between the fifth end connecting gate line and the sixth end connecting gate line. The width of the fifth end connecting gate line is greater than the width of the third middle connecting gate line; and / or, the width of the sixth end connecting gate line is greater than the width of the third middle connecting gate line.

32. The back contact cell of claim 31, wherein, The width of the fifth end connecting gate line is 1.3-1.8 times the width of the third middle connecting gate line; and / or The width of the sixth end connecting gate line is 1.3-1.8 times the width of the third middle connecting gate line.

33. The back contact cell of claim 31, wherein, The width of the fifth end connecting gate line is greater than the width of the second edge bus bar; and / or The width of the sixth end connecting gate line is greater than the width of the second edge bus bar.

34. The back contact cell of claim 31, wherein, The width of the fifth end connecting gate line is 1.1-1.4 times the width of the second edge bus bar; and / or The width of the sixth end connecting gate line is 1.1-1.4 times the width of the second edge bus bar.

35. The back contact cell of claim 31, wherein, The width of the fifth end connecting gate line and the width of the sixth end connecting gate line are both greater than the width of the second edge bus bar, and the width of the second edge bus bar is greater than the width of the third middle connecting gate line.

36. The back contact cell of claim 29, wherein, The first string area includes a fourth edge string area closest to the second edge, the second fine gate line is continuous at the fourth edge string area, and the first fine gate line is discontinuous at the fourth edge string area. The back contact cell further includes a fourth connecting gate line, the fourth connecting gate line is arranged in the fourth edge string area, and in the second direction, the fourth connecting gate line connects at least one second bus fine gate line and at least one second collection fine gate line located on one side of the second bus fine gate line.

37. The back contact cell of claim 36, wherein, The length of the fourth connecting gate line is less than the length of the third connecting gate line.

38. The back contact cell of claim 37, wherein, The ratio between the length of the fourth connecting gate line and the length of the third connecting gate line is 0.2-0.

5.

39. The back contact cell of claim 37, wherein, The length of the fourth connecting gate line is 2-3 mm, and the length of the third connecting gate line is 6-9 mm.

40. A battery assembly comprising: The battery assembly includes a plurality of back contact cells according to any one of claims 1-39.

41. A photovoltaic system characterized by, The battery assembly includes the battery assembly according to claim 40.

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