Back contact cell, cell assembly and photovoltaic system

Abstract

The invention relates to the technical field of solar cells, and provides a back contact cell, a cell assembly and a photovoltaic system.In the back contact cell, a first bus electrode is arranged on the back face and close to the first edge, and the first bus electrode and a first bonding pad are spaced in the first direction; the first bus electrode is closer to the first edge than the first bonding pad, the first bus electrode comprises a plurality of first bus sections arranged in the second direction, each first bus section is connected with the plurality of first fine grids and is spaced from the second fine grids, and each first bus section comprises a first connecting part and a first gradual change part; the first connecting part is electrically connected with the first bonding pad, the first gradual change part is connected with the first connecting part and extends in the second direction, the width of the first gradual change part is gradually reduced in the direction away from the first connecting part, and the width of the first connecting part is larger than or equal to the maximum width of the first gradual change part. Therefore, the transmission loss and the usage amount of the slurry can be reduced while the edge subfissure risk is reduced.

Description

Technical Field

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

[0002] A back-contact battery is a type of battery in which all metal electrodes are located on the back of the silicon wafer, with no metal electrodes obstructing the front. It has higher short-circuit current and conversion efficiency.

[0003] In related technologies, the back of the back contact battery is provided with several main grids, and the main grids are provided with pads for welding. In order to achieve the current collection efficiency in the edge area, the main grids closest to the edge of the cell are usually placed at the edge. In this case, the welding of the solder ribbon to the pads on the outermost main grid can easily lead to stress concentration and cause microcracks in the cell. Summary of the Invention

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

[0005] This application is implemented as follows: the back contact battery in the embodiments of this application includes: A silicon substrate having opposing front and back sides, and having opposing first and second edges in a first direction; A plurality of first fine grids and a plurality of second fine grids are disposed on the back side, the plurality of first fine grids and the plurality of second fine grids being alternately arranged along a second direction and extending along a first direction, the second direction intersecting the first direction; A plurality of first pads are disposed on the back side and near the first edge, the plurality of first pads being spaced apart along the second direction, the first pads being connected to at least one first fine gate and spaced apart from the second fine gate; and A first bus electrode is disposed on the back side and near the first edge. The first bus electrode is spaced apart from the first pad in the first direction, and the first bus electrode is closer to the first edge than the first pad. The first bus electrode includes a plurality of first bus segments arranged along the second direction. Each first bus segment is connected to a plurality of first fine gates and spaced apart from the second fine gates. The first busbar includes a first connecting portion and a first gradient portion. The first connecting portion is electrically connected to the first pad. The first gradient portion is connected to the first connecting portion and extends along the second direction. In the direction away from the first connecting portion, the width of the first gradient portion gradually decreases. The width of the first connecting portion is greater than or equal to the maximum width of the first gradient portion.

[0006] In some embodiments, the width of the first connecting portion is 0.2mm-0.3mm.

[0007] In some embodiments, the maximum width of the first gradient portion is 0.2mm-0.3mm, and the minimum width of the first gradient portion is 0.05mm-0.07mm.

[0008] In some embodiments, the ratio of the maximum width of the first gradient portion to the minimum width of the first gradient portion is 2.5-6.

[0009] In some embodiments, the width of the first gradient portion decreases linearly in the direction away from the first connecting portion.

[0010] In some embodiments, the first gradient portion connects to 5-12 of the first fine gates located on the same side of the first pad and closest to the first pad.

[0011] In some embodiments, the number of first fine gates connected to all the first gradient portions is the same.

[0012] In some embodiments, in the second direction, both sides of the first connecting portion have the first gradient portion, and in two adjacent first confluence segments, the narrowest points of adjacent first gradient portions are connected to each other.

[0013] In some embodiments, the silicon substrate has opposing third and fourth edges in the second direction, and a first chamfer is formed at the intersection of the third edge and the first edge, with the first chamfer corresponding to a first fine gate; The first bus electrode further includes a first bent section, which is connected to a first gradient portion of the first bus section closest to the third edge. The first bent section is bent relative to the first bus section and connected to the first fine grid located at the first chamfer.

[0014] In some embodiments, the width of the first bent segment is smaller than the width of the first gradient portion.

[0015] In some embodiments, the back contact battery further includes: A second pad is disposed near the second edge, the second pad comprising a plurality of second pads spaced apart along the second direction, the second pad being connected to at least one second fine gate and spaced apart from the first fine gate; and A second bus electrode is disposed near the second edge, the second bus electrode is spaced apart from the second pad in the first direction, and the second bus electrode is closer to the second edge than the second pad; the second bus electrode includes a plurality of second bus segments arranged along the second direction, each second bus segment being connected to a plurality of second fine gates and spaced apart from the first fine gate; The second bus section includes a second connecting portion and a second gradient portion. The second connecting portion is electrically connected to the second pad. The second gradient portion is connected to the second connecting portion and extends along the second direction. In the direction away from the second connecting portion, the width of the second gradient portion gradually decreases. The width of the second connecting portion is greater than or equal to the maximum width of the second gradient portion.

[0016] In some embodiments, the width of the second connecting portion is 0.2mm-0.3mm.

[0017] In some embodiments, the maximum width of the second gradient portion is 0.2mm-0.3mm, and the minimum width of the second gradient portion is 0.05mm-0.07mm.

[0018] In some embodiments, the ratio of the maximum width of the second gradient portion to the minimum width of the second gradient portion is 2.5-6.

[0019] In some embodiments, the width of the second gradient portion decreases linearly in the direction away from the second connecting portion.

[0020] In some embodiments, the second gradient portion connects 5-12 of the second fine gates located on the same side of the second pad and closest to the second pad.

[0021] In some embodiments, the silicon substrate has opposing third and fourth edges in the second direction, and a second chamfer is formed at the intersection of the third edge and the second edge, with two second fine gates corresponding to the second chamfer. The second bus electrode further includes a second bent section, which is connected to a second tapered portion of the second bus section closest to the third edge. The second bent section is bent relative to the second bus section and connected to the second fine grid located at the second chamfer.

[0022] In some embodiments, the width of the second bending segment is smaller than the width of the second gradient portion.

[0023] This application also provides a battery assembly comprising a plurality of back contact batteries as described in any of the preceding claims.

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

[0025] In the back-contact battery, battery module, and photovoltaic system of this application embodiment, the first bus electrode is disposed on the back side and close to the first edge. The first bus electrode and the first pad are spaced apart in a first direction, and the first bus electrode is closer to the first edge than the first pad. The first bus electrode only serves to draw current to the first pad. Current drawing can be achieved simply by welding solder strips to the first pad. This can effectively reduce the risk of microcracks caused by stress concentration in the edge area during the welding process, thereby improving the module yield. In addition, by configuring the first bus section to include a first connecting portion and a first gradient portion, the width of the first gradient portion gradually decreases in the direction away from the first connecting portion, which can reduce the transmission loss of the first bus electrode during the current drawing process, thereby improving the efficiency of the back-contact battery and reducing the amount of paste used.

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

[0027] Figure 1 This is a schematic diagram of a photovoltaic system module provided in an embodiment of this application; Figure 2 This is a schematic diagram of a battery assembly provided in an embodiment of this application; Figure 3 This is a schematic diagram of the planar structure of the back contact battery provided in an embodiment of this application; Figure 4 yes Figure 3 A magnified schematic diagram of the back contact battery at point IV; Figure 5 yes Figure 4 A magnified schematic diagram of the back contact battery at point V; Figure 6 This is a schematic diagram of the structure of the first busbar of the back contact battery in an embodiment of this application; Figure 7 yes Figure 3 A schematic diagram of the cross-sectional structure of the back contact battery along line VII-VII. Figure 8 yes Figure 7 A magnified schematic diagram of the back contact battery at point VIII; Figure 9 This is a schematic diagram of the structure of the second busbar of the back contact battery in an embodiment of this application; Figure 10 yes Figure 3 A magnified schematic diagram of the back contact battery at point X; Figure 11 This is a schematic diagram of the structure of the first main grid segment and the third pad of the back contact battery in an embodiment of this application; Figure 12 This is a schematic diagram of the structure of the first main grid segment of the back contact battery in an embodiment of this application; Figure 13 This is a schematic diagram of the structure of the second main grid segment of the back contact battery in an embodiment of this application; Figure 14 This is a schematic diagram of the structure of the third main grid segment and the fourth pad of the back contact battery in an embodiment of this application; Figure 15 This is a schematic diagram of the structure of the third main grid segment of the back contact battery in an embodiment of this application; Figure 16 This is a schematic diagram of the fourth main grid segment of the back contact battery in an embodiment of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. It should be noted that the embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0029] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "several" means two or more, unless otherwise explicitly specified.

[0031] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0033] Please see Figure 1 and Figure 2 The photovoltaic system 1000 in this application embodiment may include the battery module 200 in this application embodiment, and the battery module 200 in this application embodiment may include a plurality of back contact cells 100 in this application embodiment. In the embodiments of this application, the plurality of back contact cells 100 in the battery module 200 may be connected in series to form a plurality of battery strings. The battery strings may be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output. For example, the connection between the individual cells may be achieved by welding solder strips, or the connection between the individual battery strings may be achieved by busbars. In some embodiments, the individual battery strings may form a cell array, and then be packaged together by a front plate, a front adhesive film, a rear adhesive film, and a back plate to form the battery module 200.

[0034] Please see Figures 3-6 The back contact battery 100 in this embodiment may include a silicon substrate 10, a plurality of first fine gates 20, a plurality of second fine gates 30, a plurality of first pads 40 and a first bus electrode 50.

[0035] The silicon substrate 10 has opposing front and back sides 11, and has opposing first edge 101 and second edge 102 in a first direction. The silicon substrate 10 has a third edge 103 and a fourth edge 104 in a second direction, which intersects with the first direction.

[0036] like Figure 3 As shown, both the first fine grid 20 and the second fine grid 30 are disposed on the back surface 11, and a plurality of first fine grids 20 and a plurality of second fine grids 30 are alternately arranged on the back surface 12 along the second direction and all extend along the first direction. In some embodiments, the first direction and the second direction may be the longitudinal direction and the transverse direction of the back contact battery 100, respectively, and the two are perpendicular to each other, for example, in Figure 3 In the example shown, the first direction can be the lateral direction of the back contact battery 100, and the second direction can be the longitudinal direction of the back contact battery 100.

[0037] like Figures 3-5 As shown, a first pad 40 is disposed on the back surface 11 and near the first edge 101. A plurality of first pads 40 are arranged at intervals along a second direction. The first pads 40 are connected to at least one first fine gate 20 and spaced apart from a second fine gate 30. That is, the first pads 40 are connected to the first fine gate 20, and the first pads 40 and the second fine gate 30 are insulated from each other. The first pads 40 are used for soldering with solder ribbon. In some embodiments, the plurality of first pads 40 may be arranged collinearly along the second direction.

[0038] The first bus electrode 50 is disposed on the back surface 11 and close to the first edge 101. The first bus electrode 50 is spaced apart from the first pad 40 in the first direction, and the first bus electrode 50 is closer to the first edge 101 than the first pad 40. That is, the distance between the first pad 40 and the first edge 101 is greater than the distance between the first bus electrode 50 and the first edge 101.

[0039] Please see Figure 4 and Figure 5 The first bus electrode 50 may include a plurality of first bus segments 51 arranged along the second direction. Each first bus segment 51 is connected to a plurality of first fine gates 20 and spaced apart from the second fine gates 30. That is, the first bus segment 51 is insulated from the second fine gates 30. Each first pad 40 is electrically connected to one first bus segment 51.

[0040] Among them, such as Figure 5 and Figure 6 As shown, the first bus section 51 may include a first connecting portion 511 and a first gradient portion 512. The first connecting portion 511 is electrically connected to the first pad 40. The first gradient portion 512 is connected to the first connecting portion 511 and extends along a second direction. In the direction away from the first connecting portion 511, the width of the first gradient portion 512 gradually decreases. The width L1 of the first connecting portion 511 is greater than or equal to the maximum width of the first gradient portion 512.

[0041] It is easy to understand that in the embodiments of this application, the first pad 40 is farther from the first edge 101 than the first bus electrode 50. The first bus electrode 50 is only used to collect current and transmit it to the solder strip through the first pad 40, and is not used to solder to the solder strip.

[0042] In the back contact battery 100, battery module 200 and photovoltaic system 1000 of the embodiments of this application, the first bus electrode 50 is disposed on the back side 11 and close to the first edge 101. The first bus electrode 50 and the first pad 40 are spaced apart in the first direction, and the first bus electrode 50 is closer to the first edge 101 than the first pad 40. The first bus electrode 50 only serves to draw current to the first pad 40. The current can be drawn by welding solder strips on the first pad 40. This can effectively reduce the risk of microcracks caused by stress concentration in the edge area during the welding process and improve the module yield.

[0043] Furthermore, by configuring the first busbar 51 to include a first connecting portion 511 and a first gradient portion 512, the width of the first gradient portion 512 gradually decreases in the direction away from the first connecting portion 511, which can reduce the transmission loss of the first busbar electrode 50 during the busbar transmission process, thereby improving the efficiency of the back contact battery 100, and at the same time reducing the amount of slurry used.

[0044] Specifically, in this application, a plurality of first doped layers (not shown), a plurality of second doped layers (not shown), and a back passivation film layer (not shown) may be provided on the back side 11 of the silicon substrate 10. The plurality of first doped layers and the plurality of second doped layers are alternately arranged along a second direction. The back passivation film layer is at least stacked on the first doped layers and the second doped layers. In some embodiments, the back passivation film layer may cover the entire second surface, that is, the first doped layers, the second doped layers, and the areas of the second surface where no doped layers are provided are all stacked with the back passivation film layer. A first passivation layer (not shown) may also be provided between the first doped layer and the silicon substrate. The first passivation layer may be, for example, a tunneling layer, an intrinsic amorphous silicon layer, or other film layer. A second passivation layer (not shown) may also be provided between the second doped layer and the silicon substrate. The second passivation layer may be, for example, a tunneling layer, an intrinsic amorphous silicon layer, or other film layer.

[0045] In the back contact battery 100, the first fine gate 20 corresponds one-to-one with the first doped layer, and the second fine gate 30 corresponds one-to-one with the second doped layer. One of the first and second doped layers can be a P-type doped layer, and the other can be an N-type doped layer. In some embodiments, the first fine gate 20 can completely penetrate the back passivation film layer to form a complete contact with the first doped layer, or the first fine gate 20 can only partially penetrate the back passivation film layer to form a localized metallized contact with the first doped layer. The specific method is not limited here.

[0046] That is to say, in the embodiments of this application, the first fine gate 20 is disposed corresponding to the first doped layer and at least partially penetrates the back passivation film layer and makes conductive contact with the first doped layer, and the second fine gate 30 is disposed corresponding to the second doped layer and at least partially penetrates the back passivation film layer and makes conductive contact with the second doped layer.

[0047] Please see Figure 3 In some embodiments, the back contact battery 100 may further include a plurality of first main gates 80 and a plurality of second main gates 90 disposed on the back side 11, wherein the plurality of first main gates 80 and the plurality of second main gates 90 are arranged alternately at intervals along a first direction and extend along a second direction.

[0048] The first main gate 80 is connected to a plurality of first fine gates 20, and the second fine gates 30 intersecting with the first main gate 80 are interrupted at the first main gate 80 to insulate and isolate them from the first main gate 80. The second main gate 90 is connected to a plurality of second fine gates 30, and the first fine gates 20 intersecting with the second main gate 90 are interrupted at the second main gate 90 to insulate and isolate them from the first fine gates 20.

[0049] like Figure 3 and Figure 4 As shown, in the first main gate 80 and the second main gate 90, the main gate closest to the first edge 101 can be the second main gate 90, and the main gate closest to the second edge 102 can be the first main gate 80.

[0050] It is not difficult to understand that, since the first fine gate 20 is discontinuous at the second main gate 90 closest to the first edge 101, therefore, as Figure 3 and Figure 4 As shown, the first fine gate 20 has an isolated fine gate segment between the second main gate 90, which is closest to the first edge 101, and the first edge 101.

[0051] In the embodiments of this application, the first bus electrode 50 is located at the position of the first edge 101. The first bus electrode 50 and the first edge 101 may not have a second fine gate 30. The first bus electrode 50 may be connected to the fine gate segment of the first fine gate 20 located between the second main gate 90 closest to the first edge 101 and the first edge 101, thereby converging the current on the isolated fine gate segment located in the edge region of the first fine gate 20 and transmitting it to the first pad 40, and then outputting it through the solder ribbon.

[0052] like Figure 4 As shown, in some embodiments, the first bus electrode 50 may be connected to all the first fine gates 20, thereby allowing current to be bused from the isolated fine gate segments of all the first fine gates 20 located between the second main gate 90 closest to the first edge 101 and the first edge 101 to the first pad 40.

[0053] Of course, the first bus electrode 50 can also be connected to all the first fine gates 20 except the first fine gate 20 connected to the first pad 40. The first fine gate 20 connected to the first pad 40 may not be directly connected to the first bus electrode 50. No specific restrictions are imposed here.

[0054] Please see Figure 5 In some embodiments, the first pad 40 can be connected to the first connection portion 511 through the first conductive structure 41, and the current collected on the first bus electrode 50 can be transmitted to the first pad 40 through the first conductive structure 41, and then output through the solder strip welded on the first pad 40.

[0055] In such an embodiment, the first conductive structure 41 may be a first fine gate 20 connected to the first pad 40, or it may be a first conductive connector disposed on the back surface 11 connecting the first pad 40 and the first bus section 51. Of course, the first conductive structure 41 may also include the first fine gate 20 connected to the first pad 40 and the first conductive connector disposed on the back surface 11.

[0056] For example, in some possible embodiments, the first conductive structure 41 may be the portion of the first fine gate 20 connected to the first pad 40 located between the first pad 40 and the first bus section 51. In such a case, the first bus electrode 50 may be connected to all the first fine gates 20. The current on the fine gate section of all the first fine gates 20 located at the first edge 101 can be transmitted through the first conductive structure 41 to the solder strip soldered to the first pad 40.

[0057] In this case, in order to reduce bus transmission loss, the width of the portion of the first fine gate 20 located between the first pad 40 and the first bus segment 51 can be set to be greater than the width of the rest of the first fine gate 20.

[0058] For example, in some possible implementations, the first conductive structure 41 may include, in addition to the portion of the first fine gate 20 connected to the first pad 40 located between the first pad 40 and the first bus section 51, first conductive connectors located on both sides of the first fine gate 20, with the two ends of the first conductive connectors connected to the first connection portions 511 of the first pad 40 and the first bus section 51, respectively. In such a case, the first bus electrode 50 may also be connected to all of the first fine gates 20.

[0059] Of course, it is easy to understand that in some possible embodiments, the first conductive structure 41 may only include the first conductive connector, while the first fine gate 20 connected to the first pad 40 may not extend between the first pad 40 and the first bus section 51, or the first fine gate 20 may not be connected to the first bus electrode 50.

[0060] like Figure 5 As shown, it is easy to understand that in this application, since the current collected by the first bus section 51 is transmitted to the first pad 40 at the first connection portion 511 of the first bus section 51, the current carried by the first connection portion 511 of the first bus section 51 is the largest, and the current carried by the portion of the first gradient portion 512 closer to the first connection portion 511 is also larger. Therefore, setting the width L1 of the first connection portion 511 in the first bus section 51 to be wider can reduce the transmission resistance at the bus junction and reduce transmission loss. On the other hand, setting the width of the first gradient portion 512 to gradually decrease in the direction away from the first connection portion 511 can effectively reduce the use of metal paste and reduce paste cost while effectively reducing bus losses.

[0061] Please see Figure 5 In some embodiments, a first chamfer 105 is formed at the intersection of the third edge 103 and the first edge 101. The first chamfer 105 corresponds to a first fine grid 20, that is, only the extension line of the first fine grid 20 intersects with the first chamfer 105.

[0062] like Figure 5 As shown, the first bus electrode 50 may further include a first bent section 52, which is connected to a first gradient portion 512 of the first bus section 51 closest to the third edge 103. The first bent section 52 is bent relative to the first bus section 51 and connected to a first fine gate 20 located at the first chamfer 105. In such a case, in some embodiments, all of the first fine gates 20 except those located at the first chamfer 105 may be connected to a plurality of first bus sections 51.

[0063] Thus, on the one hand, having only one first fine grid 20 at the first chamfer 105 can avoid the occurrence of microcracks at the first chamfer 105 due to an excessive number of first fine grids 20. On the other hand, by setting the first bending section 52, the current on the fine grid segment formed by the first fine grid 20 at the first chamfer 105 can be collected.

[0064] In some embodiments, the width of the first bending segment 52 is smaller than the minimum width of the first gradient portion 512. This effectively reduces the amount of slurry used.

[0065] Of course, it is understandable that when the back contact battery 100 does not have the first chamfer 105, the first bus electrode 50 may also not have the first bending segment 52.

[0066] In some embodiments, the first bus electrode 50 can be prepared by printing and sintering, in which case all the first bus sections 51 and the first bending sections 52 can be directly printed integrally.

[0067] In some embodiments, the number of first fine gates 20 connected to all first gradient portions 512 may be the same.

[0068] In this way, the current on each first gradient section 512 can be kept basically consistent, improving the uniformity of current transmission.

[0069] In some embodiments, the first gradient portion 512 connects 5-12 first fine gates 20 located on the same side of the first pad 40 and closest to the first pad 40, such as 5, 6, 7, 8, 9, 10, 11, or 12, and there is no specific limitation here.

[0070] Thus, by optimizing the number of first fine grids 20 connected to the first gradient section 512, it is possible to avoid excessive current transmission loss caused by an excessive number of first fine grids 20 connected to a single first gradient section 512. If it is necessary to reduce current transmission loss, the width needs to be increased, which would lead to excessively high paste costs for the first bus electrode 50. Simultaneously, this design also avoids the need for more first bus segments 51 and consequently more first pads 40 in the entire back contact battery 100 due to an insufficient number of first fine grids 20 connected to a single first gradient section 512, resulting in excessively high pad paste costs.

[0071] Please see Figure 5 and Figure 6 In some embodiments, the number of first gradient portions 512 in the first busbar 51 may be two. Specifically, in the second direction, both sides of the first connecting portion 511 have first gradient portions 512. In two adjacent first busbars 51, the narrowest points of adjacent first gradient portions 512 are connected to each other. That is, a portion of the first fine gate 20 between two adjacent first connecting portions 511 is connected to one first gradient portion 512, and another portion of the first fine gate 20 is connected to the other first gradient portion 512.

[0072] This configuration enables the connection between all the first fine grids 20 and the first bus electrode 50 between two adjacent first connection portions 511. In this way, even if there are unstable connections between some first connection portions 511 and the first conductive structure 41, current can still be transmitted through other first conductive structures, thereby improving the reliability of the back contact battery 100.

[0073] Please see Figure 6 Furthermore, in some embodiments, in the first merging section 51, two first gradient sections 512 may be symmetrically arranged on both sides of the first connecting section 511.

[0074] In this way, the current on the first gradient section 512 on both sides of the first connection section 511 can be kept basically consistent, thereby improving the uniformity of current transmission.

[0075] Of course, it is understandable that in some possible embodiments, the two first transition sections 512 in the first busbar 51 may also be asymmetrical, and no specific limitation is made here.

[0076] In some embodiments, two adjacent first gradient sections 512 in two adjacent first merging segments 51 may be symmetrical about the connection point of the two adjacent first gradient sections 512 in a second direction.

[0077] Thus, the structure of the two first transition portions 512 between two adjacent first connection portions 511 remains the same, and their transmission resistance is also basically consistent, thereby improving the uniformity of current transmission.

[0078] Specifically, in such an embodiment, two adjacent first gradient portions 512 can be symmetrical about the center line of the area between two adjacent first pads 40. That is, the center line between two adjacent first pads 40 can divide the area between two adjacent first pads 40 into two symmetrical upper and lower parts, and the two adjacent first gradient portions 512 are symmetrical about the center line.

[0079] Please see Figure 6 In some embodiments, the width L1 of the first connecting portion 511 may be 0.2mm-0.3mm.

[0080] Thus, by optimizing and controlling the width L1 of the first connecting part 511 within the specific range of 0.2mm-0.3mm, it is possible to avoid excessive current transmission loss due to an excessively small width L1 of the first connecting part 511, and also to avoid excessive slurry cost due to an excessively large width.

[0081] Specifically, in such an embodiment, the width L1 of the first connecting portion 511 may be, for example, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm or other values ​​between 0.2mm and 0.3mm, and no specific limitation is made here.

[0082] Please see Figure 6 In some embodiments, the minimum width L2 of the first gradient portion 512 is 0.05mm-0.07mm.

[0083] In this way, by optimizing and controlling the minimum width L2 of the first gradient part 512 within the specific range of 0.05mm-0.07mm, it is possible to avoid the minimum width L2 of the first gradient part 512 being too small, which would prevent the minimum part from forming a stable connection with the first fine grid 20. It is also possible to avoid the minimum width being too wide, which would increase the cost of the slurry.

[0084] Specifically, in such an embodiment, the minimum width L2 of the first gradient portion 512 may be, for example, 0.05mm, 0.052mm, 0.054mm, 0.056mm, 0.058mm, 0.06mm, 0.062mm, 0.064mm, 0.066mm, 0.068mm, 0.07mm, or other values ​​between 0.05mm and 0.07mm, without any specific limitation here.

[0085] Please see Figure 6 In some embodiments, the width of the first connecting portion 511 can remain substantially constant in the second direction. In such cases, the maximum width of the first gradient portion 512 can be the same as the width L1 of the first connecting portion 511. That is, the maximum width of the first gradient portion 512 can be 0.2mm-0.3mm, for example, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, or other values ​​between 0.2mm and 0.3mm. No specific limitation is imposed here.

[0086] Of course, in some possible embodiments, the width L1 of the first connecting portion 511 may also gradually narrow from the middle to both sides, that is, it is wider in the middle and narrower at both ends. In such a case, the maximum width of the first gradient portion 512 may be the same as the minimum width of the first connecting portion 511, and there is no specific limitation here.

[0087] Please see Figure 6 In some embodiments, the maximum width of the first gradient portion 512 (i.e. Figure 6 The ratio of the width L1 of the first connecting portion 511 to the minimum width L2 of the first gradient portion 512 (i.e., the ratio of L1 to L2) shown can be 2.5-6, for example, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, or other values ​​in the range of 2.5-6. For example, when the maximum width of the first gradient portion 512 is 0.2mm, the minimum width L2 of the first gradient portion 512 can be 0.033mm-0.08mm; when the maximum width of the first gradient portion 512 is 0.24mm, the minimum width L2 of the first gradient portion 512 can be 0.04mm-0.096mm.

[0088] Specifically, after careful research and demonstration by the inventors of this application, it was discovered that such a specific design can balance the relationship between the flow transmission loss and the slurry cost, and can reduce the slurry cost as much as possible while ensuring that the flow transmission loss is not too large.

[0089] In some embodiments, in the first busbar 51, the width of the first gradient portion 512 may decrease linearly in the direction away from the first connecting portion 511.

[0090] Thus, by setting the width of the first gradient section 512 to decrease linearly, it is easier to manufacture, the manufacturing process is simplified, and the grid pattern is also simpler.

[0091] Please see Figure 3 as well as Figures 7-9 In some embodiments, the back contact battery 100 may further include a second pad 60 and a second bus electrode 70.

[0092] Second pads 60 are disposed on the back surface 11 and near the second edge 102. A plurality of second pads 60 are arranged at intervals along the second direction. Each second pad 60 is connected to at least one second fine gate 30 and spaced apart from the first fine gate 20. That is, the second pads 60 are connected to the second fine gate 30 and are insulated from the first fine gate 20. The second pads 60 are used for soldering with solder ribbon. In some embodiments, the plurality of second pads 60 may be arranged collinearly along the second direction.

[0093] like Figure 7 and Figure 8 As shown, the second bus electrode 70 is disposed on the back surface 11 and close to the second edge 102. The second bus electrode 70 and the second pad 60 are spaced apart in the first direction, and the second bus electrode 70 is closer to the second edge 102 than the second pad 60. That is, the distance between the second pad 60 and the second edge 102 is greater than the distance between the second bus electrode 70 and the second edge 102.

[0094] like Figures 7-9 As shown, the second bus electrode 70 may include a plurality of second bus segments 71 arranged along a second direction. Each second bus segment 71 is connected to a plurality of second fine gates 30 and spaced apart from the first fine gate 20, that is, the second bus segment 71 is insulated from the first fine gate 20. Each second pad 60 is electrically connected to one second bus segment 71.

[0095] Among them, such as Figure 8 and Figure 9As shown, the second bus section 71 may include a second connecting portion 711 and a second gradient portion 712. The second connecting portion 711 is electrically connected to the second pad 60. The second gradient portion 712 is connected to the second connecting portion 711 and extends along a second direction. In the direction away from the second connecting portion 711, the width of the second gradient portion 712 gradually decreases. The width L3 of the second connecting portion 711 is greater than or equal to the maximum width of the second gradient portion 712.

[0096] It is easy to understand that in the embodiments of this application, the second pad 60 is farther from the second edge 102 than the second bus electrode 70. The second bus electrode 70 is only used to collect current and transmit it to the solder strip through the second pad 60, and is not used to solder to the solder strip.

[0097] Thus, the second bus electrode 70 is disposed on the back side 11 and close to the second edge 102. The second bus electrode 70 and the second pad 60 are spaced apart in the first direction, and the second bus electrode 70 is closer to the second edge 102 than the second pad 60. The second bus electrode 70 only serves to draw current to the second pad 60. The current can be drawn by welding solder strips on the second pad 60. This can effectively reduce the risk of microcracks caused by stress concentration in the edge area during the welding process and improve the component yield.

[0098] Furthermore, by configuring the second bus section 71 to include a second connecting portion 711 and a second gradient portion 712, the width of the second gradient portion 712 is smaller than the width L3 of the second connecting portion 711. In the direction away from the second connecting portion 711, the width of the second gradient portion 712 gradually decreases, which can reduce the transmission loss of the second bus electrode 70 during the bus transmission process, thereby improving the efficiency of the back contact battery 100, and at the same time reducing the amount of slurry used.

[0099] It is easy to understand that, since the second fine gate 30 is discontinuous at the first main gate 80 closest to the second edge 102, the second fine gate 30 has an isolated fine gate segment between the first main gate 80 closest to the second edge 102 and the second edge 102.

[0100] In such an embodiment, the second bus electrode 70 is located at the position of the second edge 102. The second bus electrode 70 and the second edge 102 may not have a first fine gate 20. The second bus electrode 70 can be connected to the fine gate segment of the second fine gate 30 located between the first main gate 80 closest to the second edge 102 and the second edge 102, thereby converging the current on the isolated fine gate segment located in the edge region of the second fine gate 30 and transmitting it to the second pad 60, and then outputting it through the solder ribbon.

[0101] like Figure 7As shown, in some embodiments, the second bus electrode 70 may be connected to all the second fine gates 30, thereby allowing current to be bused from the isolated fine gate segments of all the second fine gates 30 located between the first main gate 80 and the second edge 102 closest to the second edge 102 to the second pad 60.

[0102] Of course, the second bus electrode 70 can also be connected to all the second fine gates 30 except the second fine gate 30 connected to the second pad 60. The second fine gate 30 connected to the second pad 60 may not be directly connected to the second bus electrode 70. No specific restrictions are imposed here.

[0103] Please see Figure 8 In some embodiments, the second pad 60 can be connected to the second connection portion 711 through the second conductive structure 61, and the current collected on the second bus electrode 70 can be transmitted to the second pad 60 through the second conductive structure 61, and then output through the solder strip welded on the second pad 60.

[0104] In such an embodiment, the second conductive structure 61 may be a second fine gate 30 connected to the second pad 60, or it may be a second conductive connector disposed on the back surface 11 and connected to the second pad 60 and the second bus section 71. Of course, the second conductive structure 61 may also include the second fine gate 30 connected to the second pad 60 and the second conductive connector disposed on the back surface 11.

[0105] For example, in some possible embodiments, the second conductive structure 61 may be the portion of the second fine gate 30 connected to the second pad 60 located between the second pad 60 and the second bus section 71. In such a case, the second bus electrode 70 may be connected to all the second fine gates 30. Current on the fine gate segments of all the second fine gates 30 located at the second edge 102 can be transmitted through the second conductive structure 61 to the solder strip soldered to the second pad 60.

[0106] In this case, in order to reduce bus transmission loss, the width of the portion of the second fine gate 30 located between the second pad 60 and the second bus segment 71 can be set to be greater than the width of the rest of the second fine gate 30.

[0107] For example, in some possible implementations, the second conductive structure 61, in addition to including the portion of the second fine gate 30 connected to the second pad 60 located between the second pad 60 and the second bus section 71, may also include second conductive connectors located on both sides of the second fine gate 30, with the two ends of the second conductive connectors respectively connected to the second connection portion 711 of the second pad 60 and the second bus section 71. In such a case, the second bus electrode 70 may also be connected to all of the second fine gates 30.

[0108] Of course, it is easy to understand that in some possible embodiments, the second conductive structure 61 may only include the second conductive connector, while the second fine gate 30 connected to the second pad 60 may not extend between the second pad 60 and the second bus section 71, or the second fine gate 30 may not be connected to the second bus electrode 70.

[0109] like Figure 8 As shown, it is easy to understand that in this application, since the current collected by the second bus section 71 is transmitted to the second pad 60 at the second connection portion 711 of the second bus section 71, the current carried by the second connection portion 711 of the second bus section 71 is the largest, and the current carried by the portion of the second gradient portion 712 closer to the second connection portion 711 is also larger. Therefore, by setting the width L3 of the second connection portion 711 in the second bus section 71 to be wider, the transmission resistance at the bus junction can be reduced, and the transmission loss can be reduced. By setting the width of the second gradient portion 712 to gradually decrease in the direction away from the second connection portion 711, the use of metal paste can be reduced while effectively reducing the bus loss, thereby reducing paste cost.

[0110] Please see Figure 8 In some embodiments, a second chamfer 106 is formed at the intersection of the third edge 103 and the second edge 102, and the second chamfer 106 corresponds to two second fine grids 30. For example... Figure 5 and Figure 8 As shown, in the first fine grid 20 and the second fine grid 30, the fine grid closest to the third edge 103 is the second fine grid 30, and the first chamfer 105 and the second chamfer 106 each correspond to two second fine grids 30 and one first fine grid.

[0111] The second bus electrode 70 also includes a second bent section 72, which is connected to the second gradient portion 712 of the second bus section 71 closest to the third edge 103. The second bent section 72 is bent relative to the second bus section 71 and connected to the second fine gate 30 located at the second chamfer 106. In some embodiments, all the second fine gates 30 except those located at the second chamfer 106 may be connected to a plurality of second bus sections 71.

[0112] Thus, on the one hand, having only one first fine grid 20 and two second fine grids 30 at the second chamfer 106 can avoid the second chamfer 106 being prone to microcracks due to an excessive number of second fine grids 30. On the other hand, by setting the second bending section 72, the current on the fine grid section formed by the second fine grids 30 at the second chamfer 106 can be collected.

[0113] In some embodiments, the width of the second bend 572 is smaller than the minimum width of the second gradient portion 712. This effectively reduces the amount of slurry used.

[0114] Of course, it is understandable that if the back contact battery 100 does not have the second chamfer 106, the second bus electrode 70 may also not have the second bending segment 72.

[0115] In some embodiments, the second bus electrode 70 can be fabricated by printing and sintering, in which case all the second bus segments 71 and the second bending segments 72 can be directly printed integrally.

[0116] In some embodiments, the number of second fine gates 30 connected to all second gradient portions 712 may be the same.

[0117] In this way, the current on each second gradient section 712 can be kept basically consistent, improving the uniformity of current transmission.

[0118] In some embodiments, the second gradient portion 712 connects 5-12 second fine gates 30 located on the same side of the second pad 60 and closest to the second pad 60, for example, 5, 6, 7, 8, 9, 10, 11, or 12, and there is no specific limitation here.

[0119] Thus, by optimizing the number of second fine grids 30 connected to the second gradient section 712, it is possible to avoid excessive current transmission loss caused by an excessive number of second fine grids 30 connected to a single second gradient section 712. If a reduction in current transmission loss is required, the width needs to be increased, which would lead to excessively high paste costs for the second bus electrode 70. Simultaneously, this design also avoids the need for more second bus segments 71 in the entire back contact battery 100 due to a smaller number of second fine grids 30 connected to a single second gradient section 712, which would necessitate more second pads 60 and thus excessively high pad paste costs.

[0120] Please see Figure 8 and Figure 9 In some embodiments, the number of second gradient portions 712 in the second busbar 71 may be two. Specifically, in the second direction, the second connecting portion 711 has second gradient portions 712 on both sides. In two adjacent second busbars 71, the narrowest points of adjacent second gradient portions 712 are connected to each other. That is, a portion of the second fine gate 30 between two adjacent second connecting portions 711 is connected to one second gradient portion 712, and another portion of the second fine gate 30 is connected to the other second gradient portion 712.

[0121] This configuration enables the connection between all the second fine grids 30 and the second bus electrode 70 between two adjacent second connection portions 711. In this way, even if there are unstable connections between some second connection portions 711 and the second conductive structure 61, current can still be transmitted through other first conductive structures, thereby improving the reliability of the back contact battery 100.

[0122] Please see Figure 9 Furthermore, in some embodiments, in the second bus section 71, two second transition sections 712 may be symmetrically arranged on both sides of the second connecting section 711.

[0123] In this way, the current on the second gradient portions 712 on both sides of the second connection portion 711 can be kept basically consistent, thereby improving the uniformity of current transmission.

[0124] Of course, it is understandable that in some possible embodiments, the two second transition sections 712 in the second busbar 71 may also be asymmetrical, and no specific limitation is made here.

[0125] In some embodiments, two adjacent second gradient sections 712 in two adjacent second busbar sections 71 may be symmetrical about the connection point of the two adjacent second gradient sections 712 in a second direction.

[0126] Thus, the structure of the two second transition portions 712 between two adjacent second connection portions 711 remains the same, and their transmission resistance is also basically consistent, thereby improving the uniformity of current transmission.

[0127] Specifically, in such an embodiment, two adjacent second gradient portions 712 can be symmetrical about the center line of the area between two adjacent second pads 60. That is, the center line between two adjacent second pads 60 can divide the area between two adjacent second pads 60 into two symmetrical upper and lower parts, and the two adjacent second gradient portions 712 are symmetrical about the center line.

[0128] Please see Figure 9 In some embodiments, the width L3 of the second connecting portion 711 may be 0.2mm-0.3mm.

[0129] Thus, by optimizing and controlling the width L3 of the second connecting part 711 within the specific range of 0.2mm-0.3mm, it is possible to avoid excessive current transmission loss due to an excessively small width L3 of the second connecting part 711, and also to avoid excessive slurry cost due to an excessively large width.

[0130] Specifically, in such an embodiment, the width L3 of the second connecting portion 711 may be, for example, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, or other values ​​between 0.2mm and 0.3mm, and is not limited here.

[0131] Please see Figure 9 In some embodiments, the minimum width L4 of the second gradient portion 712 is 0.05mm-0.07mm.

[0132] In this way, by optimizing and controlling the minimum width L4 of the second gradient section 712 within the specific range of 0.05mm-0.07mm, it is possible to avoid the minimum width L4 of the second gradient section 712 being too small, which would prevent the minimum part from forming a stable connection with the second fine grid 30. It is also possible to avoid the minimum width being too wide, which would increase the cost of the slurry.

[0133] Specifically, in such an embodiment, the minimum width L4 of the second gradient portion 712 may be, for example, 0.05mm, 0.052mm, 0.054mm, 0.056mm, 0.058mm, 0.06mm, 0.062mm, 0.064mm, 0.066mm, 0.068mm, 0.07mm, or other values ​​between 0.05mm and 0.07mm, and is not limited here.

[0134] In some embodiments, the width of the second connecting portion 711 can remain substantially constant in the second direction. In such cases, the maximum width of the second gradient portion 712 can be the same as the width L3 of the second connecting portion 711. That is to say, the maximum width of the second gradient portion 712 can be 0.2mm-0.3mm, for example, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, or other values ​​between 0.2mm and 0.3mm, and no specific limitation is made herein.

[0135] Of course, in some possible embodiments, the width L3 of the second connecting portion 711 may also gradually narrow from the middle to both sides, that is, it is wider in the middle and narrower at both ends. In such a case, the maximum width of the second gradient portion 712 may be the same as the minimum width of the second connecting portion 711, and there is no specific limitation here.

[0136] Please see Figure 9 In some embodiments, the maximum width of the second gradient portion 712 (i.e. Figure 9The ratio of the width L3 of the second connecting portion 711 to the minimum width L4 of the second gradient portion 712 (i.e., the ratio of L3 to L4) shown can be 2.5-6, for example, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, or other values ​​in the range of 2.5-6. For example, when the maximum width of the second gradient portion 712 is 0.2mm, the minimum width L4 of the second gradient portion 712 can be 0.033mm-0.08mm; when the maximum width of the second gradient portion 712 is 0.24mm, the minimum width L4 of the second gradient portion 712 can be 0.04mm-0.096mm.

[0137] Specifically, after careful research and demonstration by the inventors of this application, it was discovered that such a specific design can balance the relationship between the flow transmission loss and the slurry cost, and can reduce the slurry cost as much as possible while ensuring that the flow transmission loss is not too large.

[0138] In some embodiments, in the second bus section 71, the width of the second gradient section 712 may decrease linearly in the direction away from the second connection section 711.

[0139] Thus, by setting the width of the second gradient portion 712 to decrease linearly, it is easier to manufacture, the manufacturing process is simplified, and the electrode pattern is also simpler.

[0140] Please see Figure 3 , Figure 8 as well as Figure 10 In some embodiments, the first main gate 80 may include a first edge main gate 81 that is closest to the second edge 102. The first edge main gate 81 is the main gate that is closest to the second edge 102 among the first main gate 80 and the second main gate 90. The other first main gates 80, except for the first edge main gate 81, have second main gates 90 on both sides.

[0141] Please refer to the following: Figure 8 and Figure 10 The second main gate 90 may include a second edge main gate 91 adjacent to the first edge main gate 81, and the spacing between the second edge main gate 91 and the second edge 102 is greater than the spacing between two adjacent second main gates 90.

[0142] Please refer to the following: Figure 3 , Figure 8 as well as Figure 10In some embodiments, the first fine gate 20 connected to the first main gate 80 may include a first gate line segment 21 located between two adjacent second main gates 90 and a second gate line segment 22 located between the second edge main gate 91 and the second edge 102. The length of the second gate line segment 22 is greater than the length of the first gate line segment 21. The first gate line segment 21 is connected to the first main gate 80 between two adjacent second main gates 90, and the second gate line segment 22 is connected to the first edge main gate 81.

[0143] Among them, such as Figure 10 As shown, the first gate segment 21 is continuous at the first main gate 80 between two adjacent second main gates 90. Figure 8 As shown, the second gate segment 22 is interrupted at the first edge main gate 81. In some embodiments, the second gate segment 22 includes a first portion 221 and a second portion 222 spaced apart from each other, both the first portion 221 and the second portion 222 being connected to the first edge main gate 81.

[0144] In this way, by setting the longer second grid line segment 22 to be interrupted at the first edge main grid 81 and dividing it into two shorter parts, the printing accuracy can be improved during printing. This effectively prevents a large offset from occurring during the printing process, which would cause it to come into contact with the fine grid of opposite polarity and cause a short circuit, thereby improving the yield of the back contact battery 100.

[0145] Please refer to the following: Figure 3 , Figure 8 as well as Figure 10 In some embodiments, a plurality of third pads 110 may be provided at the location of the first main gate 80. The plurality of third pads 110 are arranged at intervals along the second direction and connected to the first main gate 80. The third pads 110 are connected to at least one first fine gate 20. The plurality of third pads 110 may be arranged collinearly along the second direction.

[0146] A plurality of fourth pads 120 may be provided at the location of the second main gate 90. The plurality of fourth pads 120 are arranged at intervals along the second direction and connected to the second main gate 90. The fourth pads 120 are connected to at least one second fine gate 30. The plurality of fourth pads 120 may be arranged collinearly along the second direction.

[0147] The first edge main gate 81 includes a plurality of first main gate segments 801 arranged along the second direction. In the second direction, each first main gate segment 801 is connected to a plurality of first fine gates 20, and the first main gate segment 801 is connected to the third pad 110.

[0148] Please see Figure 8 and Figure 11In some embodiments, the first main gate segment 801 has a first cutout area 8013 such that the first main gate segment 801 includes a first gate line portion 8011 and a second gate line portion 8012 spaced apart along a first direction. That is, the first main gate segment 801 includes a first gate line portion 8011 and a second gate line portion 8012 spaced apart, and the first gate line portion 8011 and the second gate line portion 8012 are separated by the first cutout area 8013.

[0149] like Figure 8 As shown, the second gate line segment 22 is interrupted at the first cutout area 8013. The first part 221 of the second gate line segment 22 is connected to the first gate line portion 8011, and the second part 222 of the second gate line segment 22 is connected to the second gate line portion 8012.

[0150] Thus, by setting the first hollow area 8013 and breaking the second grid line segment 22 at the first hollow area 8013, the amount of main grid slurry used can be reduced, thereby reducing slurry costs.

[0151] Specifically, such as Figure 10 As shown, the first gate segment 21 is continuous at the first main gate 80 between two adjacent second main gates 90, that is, the first gate segment 21 is continuous at the second main gate segment 802. Figure 8 As shown, the second gate line segment 22 is interrupted at the first cutout area 8013 and includes a first part 221 and a second part 222 that are spaced apart from each other. The first part 221 is connected to the first gate line portion 8011, and the second part 222 is connected to the second gate line portion 8012.

[0152] In some embodiments, the first portion 221 may be located between the first gate line portion 8011 and the second edge main gate 91 and connected to the first gate line portion 8011, and the second portion 222 may be located between the second gate line portion 8012 and the second edge 102 and connected to the second gate line portion 8012. Of course, in some embodiments, at least a portion of the first portion 221 may protrude from the first gate line portion 8011 and extend into the first hollow area 8013, and at least a portion of the second portion 222 may protrude from the second gate line portion 8012 and extend into the first hollow area 8013; the specific details are not limited here.

[0153] Please see Figure 11 In some embodiments, the widths of the first gate line portion 8011 and the second gate line portion 8012 gradually decrease in the direction away from the third pad 110, while the width of the first cutout area 8013 gradually increases. This configuration can effectively reduce bus transmission losses while lowering paste costs.

[0154] It is easy to understand that since the current collected by the first gate line portion 8011 and the second gate line portion 8012 ultimately needs to be output at the location of the third pad 110, the portion of the first gate line portion 8011 and the second gate line portion 8012 closer to the third pad 110 carries a larger current. Therefore, setting the width of the first gate line portion 8011 and the second gate line portion 8012 closer to the third pad 110 to be wider can reduce the current transmission loss. On the other hand, setting the width of the first gate line portion 8011 and the second gate line portion 8012 to gradually decrease in the direction away from the third pad 110 can effectively reduce the use of metal paste while reducing current transmission loss, thereby reducing paste cost.

[0155] Please see Figure 11 and Figure 12 In some embodiments, the first main gate segment 801 may further include a third connecting portion 8014 located at the ends of the first gate line portion 8011 and the second gate line portion 8012 facing the third pad 110. The third connecting portion 8014 is connected to the third pad 110. The first gate line portion 8011 and the second gate line portion 8012 are respectively connected to both sides of the third connecting portion 8014. The width L6 of the third connecting portion 8014 is greater than or equal to the sum of the maximum width L5 of the first gate line portion 8011 and the maximum width L7 of the second gate line portion 8012, that is, L5 > L5 + L7.

[0156] This configuration allows the current collected by the first gate line portion 8011 and the second gate line portion 8012 to be transmitted to the third connection portion 8014 and then to the third pad 110. The wider L6 of the third connection portion 8014 reduces current transmission losses. Furthermore, the third connection portion 8014 improves the connection stability between the first main gate segment 801 and the third pad 110.

[0157] In some embodiments, the ratio between the maximum width L5 of the first gate line portion 8011 and the width L6 of the third connecting portion 8014 can be 0.3-0.4, such as 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, or other values ​​between 0.3 and 0.4. The ratio between the maximum width L7 of the second gate line portion 8012 and the width L6 of the third connecting portion 8014 can also be 0.3-0.4, such as 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, or other values ​​between 0.3 and 0.4.

[0158] Thus, through such optimized design, the third connection part 8014 can carry the current collected by the first grid line part 8011 and the second grid line part 8012 while effectively controlling the bus transmission loss, and at the same time, effectively controlling the slurry cost.

[0159] like Figure 11 and Figure 12 As shown, in some embodiments, the third pad 110 may have a first protrusion 111 on the side facing the first main gate segment 801, and the first protrusion 111 may be connected to the first connecting portion 511. In this way, it is convenient to connect the first main gate segment 801 and the third pad 110.

[0160] Of course, in some embodiments, the side of the third pad 110 facing the first main gate segment 801 may not have the first protrusion 111.

[0161] In addition, in some possible embodiments, the first main gate segment 801 may not have the third connecting portion 8014, but may only include the first gate line portion 8011 and the second gate line portion 8012 that are directly connected to the third pad 110, and no specific limitation is made here.

[0162] In some embodiments, in the second direction, the overall width of the first main gate segment 801 remains constant, that is, the distance between the side of the first main gate segment 801 facing the first edge 101 and the side of the first main gate segment 801 facing the second edge 102 remains constant. Figure 8 and Figure 11 As shown, the first gate line portion 8011 is a straight line parallel to the second direction on the side facing the first edge 101, and the second gate line portion 8012 is a straight line parallel to the second direction on the side facing the second edge 102. In this case, by designing the width of the first cutout area 8013 in a gradient manner, the width of the first gate line portion 8011 and the second gate line portion 8012 gradually decreases in the direction away from the third pad 110, without the need to design the graphics of the first gate line portion 8011 and the second gate line portion 8012 separately, thus simplifying the screen printing process.

[0163] Please see Figure 11 and Figure 12 In some embodiments, the first gate line portion 8011 and the second gate line portion 8012 may be symmetrical about the center line of the third pad 110 in a first direction. In this way, it is not necessary to design the first gate line portion 8011 and the second gate line portion 8012 as two different structures, which can simplify the pattern of the printing screen and reduce the difficulty of the process.

[0164] Of course, in some embodiments, the length of the second portion 222 of the second gate line segment 22 may be greater than the length of the first portion 221 of the second gate line segment 22, and at the same position of the first gate line portion 8011 and the second gate line portion 8012, the width of the second gate line portion 8012 is greater than the width of the first gate line portion 8011. It should be noted that "the same position" refers to the intersection of the same first fine gate 20 and its extension with the first gate line portion 8011 and the second gate line portion 8012.

[0165] Thus, since the second part 222 is longer and has a larger current, while the first part 221 is shorter and has a smaller current, setting the width of the second gate line 8012 to be larger at the same location can reduce the bus transmission loss.

[0166] Please see Figure 12 In some embodiments, the maximum width L5 of the first gate line portion 8011 can be 0.1mm-0.14mm, and the minimum width L8 of the first gate line portion 8011 can be 0.03mm-0.05mm.

[0167] Thus, by optimizing the maximum and minimum widths of the first grid line portion 8011, it is possible to avoid the minimum width of the first grid line portion 8011 being too small, which would prevent the minimum portion from forming a stable connection with the first fine grid 20, and also to avoid the minimum width being too wide, which would lead to excessively high slurry costs. Simultaneously, it also avoids the maximum width of the first grid line portion 8011 being too small, which would lead to excessive current loss, and also avoids the maximum width of the first grid line portion 8011 being too large, which would lead to excessively high slurry costs.

[0168] Specifically, in such an embodiment, the maximum width L5 of the first gate line portion 8011 can be, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, or other values ​​between 0.1mm and 0.14mm. The minimum width L8 of the first gate line portion 8011 can be, for example, 0.03mm, 0.032mm, 0.034mm, 0.036mm, 0.038mm, 0.04mm, 0.042mm, 0.044mm, 0.046mm, 0.048mm, 0.05mm, or other values ​​between 0.03mm and 0.05mm, and is not specifically limited here.

[0169] In some embodiments, the ratio between the maximum width L5 of the first gate line portion 8011 and the minimum width L8 of the first gate line portion 8011 can be 1.5-5, such as 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or other values ​​between 1.5-5, and no specific limitation is made here.

[0170] Specifically, after careful research and demonstration by the inventors of this application, it was discovered that such a specific design can balance the relationship between the flow transmission loss and the slurry cost, and can reduce the slurry cost as much as possible while ensuring that the flow transmission loss is not too large.

[0171] In some embodiments, the width of the first gate line portion 8011 decreases linearly in the direction away from the third pad 110.

[0172] Thus, by setting the width of the first gate line portion 8011 to decrease linearly, it is easier to fabricate, the fabrication process is simplified, and the electrode pattern is also simpler.

[0173] In some embodiments, the maximum width L7 of the second gate line portion 8012 may be 0.1mm-0.14mm, and the minimum width L9 of the second gate line portion 8012 may be 0.03mm-0.05mm.

[0174] Thus, by optimizing the specific width of the second grid line portion 8012, it is possible to avoid the minimum width L9 of the second grid line portion 8012 being too small, which would prevent this minimum portion from forming a stable connection with the first fine grid 20. It is also possible to avoid the maximum width being too wide, which would lead to excessively high slurry costs. Simultaneously, it also avoids the maximum width of the second grid line portion 8012 being too small, which would lead to excessive current loss, and the maximum width of the second grid line portion 8012 being too large, which would lead to excessively high slurry costs.

[0175] Specifically, in such an embodiment, the maximum width L7 of the second gate line portion 8012 can be, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, or other values ​​between 0.1mm and 0.14mm. The minimum width L9 of the second gate line portion 8012 can be, for example, 0.03mm, 0.032mm, 0.034mm, 0.036mm, 0.038mm, 0.04mm, 0.042mm, 0.044mm, 0.046mm, 0.048mm, 0.05mm, or other values ​​between 0.03mm and 0.05mm, and is not specifically limited here.

[0176] In some embodiments, the ratio between the maximum width L7 of the second gate line portion 8012 and the minimum width L9 of the second gate line portion 8012 can be 1.5-5, such as 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or other values ​​between 1.5-5, and no specific limitation is made here.

[0177] Specifically, after careful research and demonstration by the inventors of this application, it was discovered that such a specific design can balance the relationship between the flow transmission loss and the slurry cost, and can reduce the slurry cost as much as possible while ensuring that the flow transmission loss is not too large.

[0178] In some embodiments, the width of the second gate line portion 8012 decreases linearly in the direction away from the third pad 110.

[0179] Thus, by setting the width of the second gate line portion 8012 to decrease linearly, it is easier to manufacture, the manufacturing process is simplified, and the electrode pattern is also simpler.

[0180] Please see Figure 11 and Figure 12 In some embodiments, the first grid line portion 8011 has a first overlapping protrusion 8015 on the side facing the first portion 221, the first portion 221 is connected to the first overlapping protrusion 8015, and each first portion 221 corresponds to one first overlapping protrusion 8015. The second grid line portion 8012 has a second overlapping protrusion 8016 on the side facing the second portion 222, the second portion 222 is connected to the second overlapping protrusion 8016, and each second portion 222 corresponds to one second overlapping protrusion 8016.

[0181] Thus, by providing the first overlapping protrusion 8015 and the second overlapping protrusion 8016, the connection stability between the first part 221 and the second part 222 and the first main gate segment 801 can be improved, and the width of the first gate line part 8011 and the second gate line part 8012 is too narrow, which would prevent them from forming a stable connection with the first part 221 and the second part 222.

[0182] Specifically, it is easy to understand that since the first main grid segment 801 has a first hollow area 8013 and the second grid line segment 22 is interrupted at the first hollow area 8013, the contact area between the first part 221 and the first grid line portion 8011 and the contact area between the second part 222 and the second grid line portion 8012 are both small. If the overall width of the first grid line portion 8011 and the second grid line portion 8012 is widened, the cost of the slurry will increase significantly. Therefore, in this embodiment, by setting the first overlapping protrusion 8015 and the second overlapping protrusion 8016, the contact area between the first part 221 and the second part 222 and the first main grid segment 801 can be increased, thereby improving the stability of the connection.

[0183] Please see Figure 12 In some embodiments, the length L10 of the second overlapping protrusion 8016 in the first direction can be 0.02mm-0.04mm, and the length L11 of the second overlapping protrusion 8016 in the second direction can be 0.1mm-0.16mm.

[0184] Thus, by specifically setting the dimensions of the second overlapping protrusion 8016, the connection stability between the first portion 221 and the first main gate segment 801 can be ensured while controlling the slurry cost. Simultaneously, it can also prevent the second overlapping protrusion 8016 from being too long in the second direction, which could easily lead to a short circuit with the fine gate of opposite polarity.

[0185] Specifically, in such an embodiment, the length L10 of the second overlapping protrusion 8016 in the first direction can be, for example, 0.02mm, 0.022mm, 0.024mm, 0.023mm, 0.028mm, 0.03mm, 0.032mm, 0.034mm, 0.033mm, 0.038mm, 0.04mm, or other values ​​between 0.02mm and 0.04mm, without limitation herein. The length L11 of the second overlapping protrusion 8016 in the second direction can be, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, or other values ​​between 0.1mm and 0.16mm, without limitation herein.

[0186] In some embodiments, the length of the first overlapping protrusion 8015 in the first direction may be 0.02mm-0.04mm, and the length of the first overlapping protrusion 8015 in the second direction may be 0.1mm-0.16mm.

[0187] Thus, by specifically designing the dimensions of the first overlapping protrusion 8015, the connection stability between the first part 221 and the first main gate segment 801 can be ensured while controlling the slurry cost. Simultaneously, it can also prevent the first overlapping protrusion 8015 from being too long in the second direction, which could easily lead to a short circuit with the fine gate of opposite polarity.

[0188] Specifically, in such an embodiment, the length of the first overlapping protrusion 8015 in the first direction may be, for example, 0.02mm, 0.022mm, 0.024mm, 0.023mm, 0.028mm, 0.03mm, 0.032mm, 0.034mm, 0.033mm, 0.038mm, 0.04mm, or other values ​​between 0.02mm and 0.04mm, without limitation herein. The length of the first overlapping protrusion 8015 in the second direction may be, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, or other values ​​between 0.1mm and 0.16mm, without limitation herein.

[0189] In some embodiments, the first gate line portion 8011 may connect 5-12 first fine gates 20 located on the same side of the third pad 110 and closest to the third pad 110, for example 5, 6, 7, 8, 9, 10, 11, or 12, and no specific limitation is made here.

[0190] Thus, by optimizing the number of first fine grids 20 connected to the first grid line portion 8011, it is possible to avoid excessive current transmission loss caused by an excessive number of first fine grids 20 connected to a single first grid line portion 8011. If it is necessary to reduce the current transmission loss, the width needs to be widened, which would result in excessively high paste cost for the first grid line portion 8011. At the same time, it is also possible to avoid the need for more first grid line portions 8011 to be set in the entire back contact battery 100 due to a small number of first fine grids 20 connected to a single first grid line portion 8011, which would lead to excessively high solder pad paste cost.

[0191] Similarly, the second gate line portion 8012 can also connect to 5-12 first fine gates 20 located on the same side of the third pad 110 and closest to the third pad 110, such as 5, 6, 7, 8, 9, 10, 11, or 12, without any specific restrictions here.

[0192] Please see Figure 12 In some embodiments, the width L6 of the third connecting portion 8014 may be 0.32mm-0.36mm.

[0193] In this way, the excessive loss of current transmission caused by an excessively small width L6 of the third connecting part 8014 can be avoided, as can the excessively large width of the part leading to excessively high slurry costs.

[0194] Specifically, in such an embodiment, the width L6 of the third connecting portion 8014 may be, for example, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm or other values ​​between 0.32mm and 0.36mm, and no specific limitation is made here.

[0195] Please see Figure 8 , Figure 10 as well as Figure 13 In some embodiments, the first main gate 80, other than the first edge main gate 81, may include a plurality of second main gate segments 802 arranged along the second direction. The second main gate segments 802 are connected to the third pad 110. The second main gate segments 802 do not have a cutout area. The first fine gate 20 is continuous at the second main gate segment 802 (i.e., the first gate line segment 21 is continuous at the second main gate segment 802). In the direction away from the third pad 110, the width of the second main gate segment 802 gradually decreases.

[0196] Thus, by setting the width of the second main grid segment 802 to gradually decrease in the direction away from the third pad 110, the amount of paste used can be reduced while decreasing the current transmission loss. Simultaneously, setting the first grid segment 21 to be continuous at the second main grid segment 802 can improve the connection stability between the first grid segment 21 and the second main grid segment 802. Furthermore, since the first grid segment 21 is relatively short, it can be formed directly in a single printing operation, simplifying the pattern of the printing screen.

[0197] Please see Figure 13 In some embodiments, the maximum width L12 of the second main gate segment 802 can be 0.32mm-0.36mm, and the minimum width L13 of the second main gate segment 802 can be 0.06mm-0.1mm.

[0198] Thus, by optimizing the design of the maximum width L12 of the second main grid segment 802, it is possible to avoid excessive current transmission loss due to an excessively small maximum width L12 of the second main grid segment 802, and also to avoid excessive slurry cost due to an excessively large maximum width.

[0199] Furthermore, by optimizing the minimum width of the second main grid segment 802, it is possible to avoid the minimum width L13 of the second main grid segment 802 being too small, which would prevent this minimum part from forming a stable connection with the first fine grid 20. It is also possible to avoid the minimum width of the second main grid segment 802 being too wide, which would increase the slurry cost. In other words, this specific design can balance the relationship between current transmission loss and slurry cost while ensuring a stable connection between the second main grid segment 802 and the first fine grid 20.

[0200] Specifically, in such an embodiment, the maximum width L12 of the second main gate segment 802 can be, for example, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, or other values ​​between 0.32mm and 0.36mm, without any specific limitation. The minimum width L13 of the second main gate segment 802 can be, for example, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, or other values ​​between 0.06mm and 0.1mm, without any specific limitation.

[0201] In some embodiments, the ratio between the maximum width L12 of the second main gate segment 802 and the minimum width L13 of the second main gate segment 802 can be 1.5-5, such as 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or other values ​​between 1.5-5, and no specific limitation is made here.

[0202] Specifically, after careful research and demonstration by the inventors of this application, it was discovered that such a specific design can balance the relationship between the flow transmission loss and the slurry cost, and can reduce the slurry cost as much as possible while ensuring that the flow transmission loss is not too large.

[0203] In some embodiments, the width of the second main gate segment 802 decreases linearly in the direction away from the third pad 110.

[0204] Thus, by setting the width of the second main gate segment 802 to decrease linearly, it is easier to fabricate, the fabrication process is simplified, and the electrode pattern is also simpler.

[0205] In some embodiments, the minimum width L8 of the first gate line portion 8011 and the minimum width L9 of the second gate line portion 8012 are both smaller than the minimum width L13 of the second main gate segment 802.

[0206] Thus, the minimum width of the second main gate segment 802 is set to be relatively large, which allows the first fine gate 20 located at the minimum width position to form a relatively stable connection with the second main gate 802.

[0207] In some embodiments, the length of the first portion 221 is less than the width of the first gate line segment 21, and the length of the second portion 222 is also less than the length of the first gate line segment 21. At the same location, the width of the second main gate segment 802 is greater than the width of the first gate line portion 8011 and the second gate line portion 8012. "At the same location" refers to the intersection of the same first fine gate 20 and its extension with the first gate line portion 8011, the second gate line portion 8012, and the second main gate segment 802.

[0208] Thus, by setting the width of the first grid line portion 8011 and the second grid line portion 8012 to be smaller, the slurry cost can be reduced, and by setting the width of the second main grid section 802 to be larger, the bus transmission loss can be reduced.

[0209] Specifically, the second gate segment 22 is interrupted at the first main gate segment 801. The first gate segment 8011 only needs to collect the current on the first part 221 on one side, and the second gate segment 8012 only needs to collect the current on the second part 222 on one side. The current collected by both is relatively small. However, the second main gate segment 802 needs to collect the current of the entire first gate segment 21, and the current collected is relatively large. Therefore, setting the length of the second main gate segment 802 to be wider can reduce the current transmission loss, while setting the width of the first gate segment 8011 and the second gate segment 8012 to be smaller can save slurry and reduce costs.

[0210] In some embodiments, the ratio between the maximum width L5 of the first gate line portion 8011 and the maximum width L12 of the second main gate segment 802 can be 0.3-0.4, such as 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, or other values ​​between 0.3 and 0.4. In some embodiments, the ratio between the maximum width L7 of the second gate line portion 8012 and the maximum width L12 of the second main gate segment 802 can also be 0.3-0.4, such as 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, or other values ​​between 0.3 and 0.4.

[0211] In some embodiments, the ratio between the minimum width L8 of the first gate line portion 8011 and the minimum width L13 of the second main gate segment 802 may be 0.3-0.6, such as 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, or other values ​​between 0.3 and 0.6, without specific limitations. In some embodiments, the ratio between the minimum width L9 of the second gate line portion 8012 and the minimum width L13 of the second main gate segment 802 may also be 0.3-0.6, such as 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, or other values ​​between 0.3 and 0.6, without specific limitations.

[0212] In this way, through such optimized design, the relationship between busbar transmission loss and slurry cost can be balanced, thereby effectively controlling slurry cost while reducing busbar transmission loss.

[0213] Please see Figure 13 In some possible embodiments, the third pad 110 may also have a first protrusion 111 on the side facing the second main gate segment 802, and the first protrusion 111 may be connected to the second main gate segment 802. In this way, it is convenient to connect the second main gate segment 802 and the third pad 110.

[0214] Of course, in some embodiments, the third pad 110 may not have the first protrusion 111 on the side facing the second main gate segment 802.

[0215] In some embodiments, the width of the second main gate segment 802 decreases linearly in the direction away from the third pad 110.

[0216] Thus, by setting the width of the second main gate segment 802 to decrease linearly, it is easier to fabricate, the fabrication process is simplified, and the electrode pattern is also simpler.

[0217] Please see Figures 3-5 as well as Figure 10In some embodiments, the second main gate 90 may include a third edge main gate 92 that is closest to the first edge 101. The third edge main gate 92 is the main gate that is closest to the first edge 101 among the second main gate 90 and the first main gate 80. The other second main gates 90, except for the third edge main gate 92, have a first main gate 80 on both sides.

[0218] Please refer to the following: Figure 5 and Figure 10 The first main gate 80 may include a fourth edge main gate 82 adjacent to the third edge main gate 92, and the distance between the fourth edge main gate 82 and the first edge 101 is greater than the distance between two adjacent first main gates 80.

[0219] Please refer to the following: Figure 3 , Figure 5 as well as Figure 10 In some embodiments, the second fine gate 30 connected to the second main gate 90 may include a third gate segment 31 located between two adjacent first main gates 80 and a fourth gate segment 32 located between the fourth edge main gate 82 and the first edge 101. The length of the fourth gate segment 32 is greater than the length of the third gate segment 31. The third gate segment 31 is connected to the second main gate 90 between two adjacent first main gates 80, and the fourth gate segment 32 is connected to the third edge main gate 92.

[0220] Among them, such as Figure 10 As shown, the third gate segment 31 is continuous at the second main gate 90 between two adjacent first main gates 80. Figure 5 As shown, the fourth gate segment 32 is interrupted at the third edge main gate 92 so that the fourth gate segment 32 includes a third portion 321 and a fourth portion 322 spaced apart from each other, both of which are connected to the third edge main gate 92.

[0221] Thus, by setting the longer fourth grid segment 32 to be discontinuous at the third edge main grid 92 and dividing it into two shorter parts, the printing accuracy can be improved during printing. This effectively prevents large offsets from occurring during the printing process, which could lead to contact with the fine grid of opposite polarity and cause a short circuit, thereby improving the reliability of the back contact battery 100.

[0222] Please refer to the following: Figure 3 , Figure 5 as well as Figure 10 In some embodiments, the third edge main gate 92 includes a plurality of third main gate segments 901 arranged along a second direction. In the second direction, each third main gate segment 901 is connected to a plurality of second fine gates 30, and the third main gate segment 901 is connected to the fourth pad 120.

[0223] Please see Figure 5 and Figure 14In some embodiments, the third main gate segment 901 has a second cutout area 9013 such that the third main gate segment 901 includes a third gate line portion 9011 and a fourth gate line portion 9012 spaced apart along a first direction. That is, the third main gate segment 901 includes a third gate line portion 9011 and a fourth gate line portion 9012 spaced apart, and the third gate line portion 9011 and the fourth gate line portion 9012 are separated by the second cutout area 9013.

[0224] like Figure 5 As shown, the fourth gate line segment 32 is interrupted at the second cutout area 9013, the third part 321 of the fourth gate line segment 32 is connected to the third gate line portion 9011, and the fourth part 322 of the fourth gate line segment 32 is connected to the fourth gate line portion 9012.

[0225] Thus, by setting the second cutout area 9013 and disconnecting the fourth grid line segment 32 at the second cutout area 9013, the amount of main grid slurry used can be reduced, thereby reducing slurry costs.

[0226] Specifically, such as Figure 10 As shown, the third gate segment 31 is continuous at the second main gate 90 between two adjacent first main gates 80, that is, the third gate segment 31 is continuous at the fourth main gate segment 902. Figure 5 As shown, the fourth gate line segment 32 is interrupted at the second cutout area 9013 so that the fourth gate line segment 32 includes a third part 321 and a fourth part 322 that are spaced apart from each other. The third part 321 is connected to the third gate line portion 9011, and the fourth part 322 is connected to the fourth gate line portion 9012.

[0227] In some embodiments, the third portion 321 may be located between the third gate line portion 9011 and the fourth edge main gate 82 and connected to the third gate line portion 9011, and the fourth portion 322 may be located between the fourth gate line portion 9012 and the first edge 101 and connected to the fourth gate line portion 9012. Of course, in some embodiments, at least a portion of the third portion 321 may protrude from the third gate line portion 9011 and extend into the second cutout area 9013, and at least a portion of the fourth portion 322 may protrude from the fourth gate line portion 9012 and extend into the second cutout area 9013; the specific details are not limited here.

[0228] Please see Figure 14 In some embodiments, the widths of the third gate line portion 9011 and the fourth gate line portion 9012 gradually decrease in the direction away from the fourth pad 120, while the width of the second cutout area 9013 gradually increases. This configuration can effectively reduce bus transmission losses while lowering paste costs.

[0229] It is easy to understand that since the current collected by the third gate line portion 9011 and the fourth gate line portion 9012 ultimately needs to be output at the location of the fourth pad 120, the portion of the third gate line portion 9011 and the fourth gate line portion 9012 closer to the fourth pad 120 carries a larger current. Therefore, setting the width of the third gate line portion 9011 and the fourth gate line portion 9012 closer to the fourth pad 120 to be wider can reduce the current transmission loss. On the other hand, setting the width of the third gate line portion 9011 and the fourth gate line portion 9012 to gradually decrease in the direction away from the fourth pad 120 can effectively reduce the use of metal paste while reducing current loss, thereby reducing paste cost.

[0230] Please see Figure 14 and Figure 15 In some embodiments, the third main gate segment 901 may further include a fourth connecting portion 9014 located at the ends of the third gate line portion 9011 and the fourth gate line portion 9012 facing the fourth pad 120. The fourth connecting portion 9014 is connected to the fourth pad 120. The third gate line portion 9011 and the fourth gate line portion 9012 are respectively connected to both sides of the fourth connecting portion 9014. The width L15 of the fourth connecting portion 9014 is greater than or equal to the sum of the maximum width L14 of the third gate line portion 9011 and the maximum width L16 of the fourth gate line portion 9012, that is, L14 > L14 + L16.

[0231] This configuration allows the current collected by the third gate line section 9011 and the fourth gate line section 9012 to be transmitted to the fourth connection section 9014 and then to the fourth pad 120. The wider L15 of the fourth connection section 9014 reduces current transmission losses. Furthermore, the fourth connection section 9014 improves the connection stability between the third main gate section 901 and the fourth pad 120.

[0232] In some embodiments, the ratio between the maximum width L14 of the third gate line portion 9011 and the width L15 of the fourth connecting portion 9014 can be 0.3-0.4, such as 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, or other values ​​between 0.3 and 0.4. The ratio between the maximum width L16 of the fourth gate line portion 9012 and the width L15 of the fourth connecting portion 9014 can also be 0.3-0.4, such as 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, or other values ​​between 0.3 and 0.4.

[0233] Thus, through such optimized design, the fourth connection 9014 can carry the current collected by the third grid line 9011 and the fourth grid line 9012 while effectively controlling the bus transmission loss, and at the same time, effectively controlling the slurry cost.

[0234] like Figure 14 and Figure 15 As shown, in some embodiments, the fourth pad 120 may have a second protrusion 121 on the side facing the third main gate segment 901, and the second protrusion 121 may be connected to the first connecting portion 511. In this way, it is convenient to connect the third main gate segment 901 and the fourth pad 120.

[0235] Of course, in some embodiments, the side of the fourth pad 120 facing the third main gate segment 901 may not have the second protrusion 121.

[0236] In addition, in some possible embodiments, the third main gate segment 901 may not have the fourth connection portion 9014, but may only include the third gate line portion 9011 and the fourth gate line portion 9012 directly connected to the fourth pad 120, and no specific limitation is made here.

[0237] In some embodiments, in the second direction, the overall width of the third main gate segment 901 remains constant, that is, the distance between the side of the third main gate segment 901 facing the second edge 102 and the side of the third main gate segment 901 facing the first edge 101 remains constant. Figure 5 and Figure 14 As shown, the third gate line portion 9011 is a straight line parallel to the second direction on the side facing the second edge 102, and the fourth gate line portion 9012 is a straight line parallel to the second direction on the side facing the first edge 101. In this case, by designing a gradient in the width of the second cutout area 9013, the widths of the third gate line portion 9011 and the fourth gate line portion 9012 gradually decrease in the direction away from the fourth pad 120, without the need to design the graphics of the third gate line portion 9011 and the fourth gate line portion 9012 separately, thus simplifying the screen printing process.

[0238] Please see Figure 14 and Figure 15 In some embodiments, the third gate line portion 9011 and the fourth gate line portion 9012 may be symmetrical about the center line of the fourth pad 120 in the first direction. In this way, it is not necessary to design the third gate line portion 9011 and the fourth gate line portion 9012 as two different structures, which can simplify the pattern of the printing screen and reduce the difficulty of the process.

[0239] Of course, in some embodiments, the length of the fourth portion 322 of the fourth gate line segment 32 may be greater than the length of the third portion 321 of the fourth gate line segment 32, and at the same position of the third gate line portion 9011 and the fourth gate line portion 9012, the width of the fourth gate line portion 9012 is greater than the width of the third gate line portion 9011. It should be noted that "the same position" refers to the intersection of the same second fine gate 30 and its extension with the third gate line portion 9011 and the fourth gate line portion 9012.

[0240] Thus, since the fourth part 322 is longer and has a larger current, while the third part 321 is shorter and has a smaller current, setting the width of the fourth gate line 9012 to be larger at the same location can reduce bus transmission loss.

[0241] Please see Figure 15 In some embodiments, the maximum width L14 of the third gate line portion 9011 can be 0.1mm-0.14mm, and the minimum width L17 of the third gate line portion 9011 can be 0.03mm-0.05mm.

[0242] Thus, by optimizing the maximum and minimum widths of the third grid line portion 9011, it is possible to avoid the minimum width of the third grid line portion 9011 being too small, which would prevent this minimum portion from forming a stable connection with the second fine grid 30, and also to avoid its minimum width being too wide, which would lead to excessively high slurry costs. Simultaneously, it also avoids the maximum width of the third grid line portion 9011 being too small, which would lead to excessive current loss, and also avoids the maximum width of the third grid line portion 9011 being too large, which would lead to excessively high slurry costs.

[0243] Specifically, in such an embodiment, the maximum width L14 of the third gate line portion 9011 can be, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, or other values ​​between 0.1mm and 0.14mm. The minimum width L17 of the third gate line portion 9011 can be, for example, 0.03mm, 0.032mm, 0.034mm, 0.036mm, 0.038mm, 0.04mm, 0.042mm, 0.044mm, 0.046mm, 0.048mm, 0.05mm, or other values ​​between 0.03mm and 0.05mm, and is not specifically limited herein.

[0244] In some embodiments, the ratio between the maximum width L14 of the third gate line portion 9011 and the minimum width L17 of the third gate line portion 9011 can be 1.5-5, such as 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or other values ​​between 1.5-5, and no specific limitation is made here.

[0245] Specifically, after careful research and demonstration by the inventors of this application, it was discovered that such a specific design can balance the relationship between the flow transmission loss and the slurry cost, and can reduce the slurry cost as much as possible while ensuring that the flow transmission loss is not too large.

[0246] In some embodiments, the width of the third gate line portion 9011 decreases linearly in the direction away from the fourth pad 120.

[0247] Thus, by setting the width of the third gate line 9011 to decrease linearly, it is easier to manufacture, the manufacturing process is simplified, and the electrode pattern is also simpler.

[0248] In some embodiments, the maximum width L16 of the fourth gate line portion 9012 may be 0.1mm-0.14mm, and the minimum width L18 of the fourth gate line portion 9012 may be 0.03mm-0.05mm.

[0249] Thus, by optimizing the specific width of the fourth grid line portion 9012, it is possible to avoid the minimum width L18 of the fourth grid line portion 9012 being too small, which would prevent this minimum portion from forming a stable connection with the second fine grid 30. It is also possible to avoid the maximum width being too wide, which would lead to excessively high slurry costs. Simultaneously, it also avoids the maximum width of the fourth grid line portion 9012 being too small, which would lead to excessive current loss, and the maximum width of the fourth grid line portion 9012 being too large, which would lead to excessively high slurry costs.

[0250] Specifically, in such an embodiment, the maximum width L16 of the fourth gate line portion 9012 can be, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, or other values ​​between 0.1mm and 0.14mm. The minimum width L18 of the fourth gate line portion 9012 can be, for example, 0.03mm, 0.032mm, 0.034mm, 0.036mm, 0.038mm, 0.04mm, 0.042mm, 0.044mm, 0.046mm, 0.048mm, 0.05mm, or other values ​​between 0.03mm and 0.05mm, and is not specifically limited herein.

[0251] In some embodiments, the ratio between the maximum width L16 of the fourth gate line portion 9012 and the minimum width L18 of the fourth gate line portion 9012 may be 1.5-5, such as 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or other values ​​between 1.5-5, and no specific limitation is made here.

[0252] Specifically, after careful research and demonstration by the inventors of this application, it was discovered that such a specific design can balance the relationship between the flow transmission loss and the slurry cost, and can reduce the slurry cost as much as possible while ensuring that the flow transmission loss is not too large.

[0253] In some embodiments, the width of the fourth gate line portion 9012 decreases linearly in the direction away from the fourth pad 120.

[0254] Thus, by setting the width of the fourth gate line 9012 to decrease linearly, it is easier to manufacture, the manufacturing process is simplified, and the electrode pattern is also simpler.

[0255] Please see Figure 14 and Figure 15 In some embodiments, the third gate line portion 9011 has a third overlapping protrusion 9015 on the side facing the third portion 321, the third portion 321 is connected to the third overlapping protrusion 9015, and each third portion 321 corresponds to one third overlapping protrusion 9015. The fourth gate line portion 9012 has a fourth overlapping protrusion 9016 on the side facing the fourth portion 322, the fourth portion 322 is connected to the fourth overlapping protrusion 9016, and each fourth portion 322 corresponds to one fourth overlapping protrusion 9016.

[0256] Thus, by providing the third overlapping protrusion 9015 and the fourth overlapping protrusion 9016, the connection stability between the third part 321 and the fourth part 322 and the third main gate segment 901 can be improved, and the width of the third gate line part 9011 and the fourth gate line part 9012 is too narrow, which would prevent them from forming a stable connection with the third part 321 and the fourth part 322.

[0257] Specifically, it is easy to understand that since the third main grid segment 901 has a second hollow area 9013, and the fourth grid line segment 32 is interrupted at the second hollow area 9013, the contact area between the third part 321 and the third grid line portion 9011 and the contact area between the fourth part 322 and the fourth grid line portion 9012 are both small. If the overall width of the third grid line portion 9011 and the fourth grid line portion 9012 is widened, the cost of the slurry will increase significantly. Therefore, in this embodiment, by providing the third overlapping protrusion 9015 and the fourth overlapping protrusion 9016, the contact area between the third part 321 and the fourth part 322 and the third main grid segment 901 can be increased, thereby improving the stability of the connection.

[0258] Please see Figure 15 In some embodiments, the length L19 of the fourth overlapping protrusion 9016 in the first direction can be 0.02mm-0.04mm, and the length L20 of the fourth overlapping protrusion 9016 in the second direction can be 0.1mm-0.16mm.

[0259] Thus, by specifically setting the dimensions of the fourth overlapping protrusion 9016, the connection stability between the third part 321 and the third main grid segment 901 can be ensured while controlling the slurry cost. Simultaneously, it can also prevent the fourth overlapping protrusion 9016 from being too long in the second direction, which could easily lead to a short circuit with the fine grid of opposite polarity.

[0260] Specifically, in such an embodiment, the length L19 of the fourth overlapping protrusion 9016 in the first direction can be, for example, 0.02mm, 0.022mm, 0.024mm, 0.023mm, 0.028mm, 0.03mm, 0.032mm, 0.034mm, 0.033mm, 0.038mm, 0.04mm, or other values ​​between 0.02mm and 0.04mm, without limitation herein. The length L20 of the fourth overlapping protrusion 9016 in the second direction can be, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, or other values ​​between 0.1mm and 0.16mm, without limitation herein.

[0261] In some embodiments, the length of the third overlapping protrusion 9015 in the first direction may be 0.02mm-0.04mm, and the length of the third overlapping protrusion 9015 in the second direction may be 0.1mm-0.16mm.

[0262] Thus, by specifically designing the dimensions of the third overlapping protrusion 9015, the connection stability between the third part 321 and the third main gate segment 901 can be ensured while controlling the paste cost. Simultaneously, it can also prevent the third overlapping protrusion 9015 from being too long in the second direction, which could easily lead to a short circuit with the fine gate of opposite polarity.

[0263] Specifically, in such an embodiment, the length of the third overlapping protrusion 9015 in the first direction can be, for example, 0.02mm, 0.022mm, 0.024mm, 0.023mm, 0.028mm, 0.03mm, 0.032mm, 0.034mm, 0.033mm, 0.038mm, 0.04mm, or other values ​​between 0.02mm and 0.04mm, without limitation herein. The length of the third overlapping protrusion 9015 in the second direction can be, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, or other values ​​between 0.1mm and 0.16mm, without limitation herein.

[0264] In some embodiments, the third gate line portion 9011 may connect 5-12 second fine gates 30 located on the same side of the fourth pad 120 and closest to the fourth pad 120, for example 5, 6, 7, 8, 9, 10, 11, or 12, and there is no specific limitation here.

[0265] Thus, by optimizing the number of second fine grids 30 connected to the third grid line 9011, it is possible to avoid excessive current transmission loss caused by an excessive number of second fine grids 30 connected to a single third grid line 9011. If it is necessary to reduce the current transmission loss, the width needs to be increased, which would lead to excessively high paste cost for the third grid line 9011. At the same time, it is also possible to avoid the need to set more third grid lines 9011 in the entire back contact battery 100 due to a small number of second fine grids 30 connected to a single third grid line 9011, which would lead to excessively high solder pad paste cost.

[0266] Similarly, the fourth gate line 9012 can also connect to 5-12 second fine gates 30 located on the same side of the fourth pad 120 and closest to the fourth pad 120, such as 5, 6, 7, 8, 9, 10, 11, or 12, without any specific restrictions here.

[0267] Please see Figure 15 In some embodiments, the width L15 of the fourth connecting portion 9014 may be 0.32mm-0.36mm.

[0268] In this way, the width L15 of the fourth connecting part 9014 can be avoided from being too small, which would result in excessive current transmission loss, and the width can also be avoided from being too large, which would result in excessive slurry cost.

[0269] Specifically, in such an embodiment, the width L15 of the fourth connecting portion 9014 may be, for example, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm or other values ​​between 0.32mm and 0.36mm, and no specific limitation is made here.

[0270] Please see Figure 5 , Figure 10 as well as Figure 16 In some embodiments, the second main gate 90, other than the third edge main gate 92, may include a plurality of fourth main gate segments 902 arranged along the second direction. The fourth main gate segments 902 are connected to the fourth pad 120. The fourth main gate segments 902 do not have a cutout area. The second fine gate 30 is continuous at the fourth main gate segment 902 (i.e., the third gate line segment 31 is continuous at the fourth main gate segment 902). In the direction away from the fourth pad 120, the width of the fourth main gate segment 902 gradually decreases.

[0271] Thus, by setting the width of the fourth main grid segment 902 to gradually decrease in the direction away from the fourth pad 120, the amount of paste used can be reduced while decreasing the bus transmission loss. Simultaneously, setting the third grid segment 31 to be continuous at the fourth main grid segment 902 can improve the connection stability between the third grid segment 31 and the fourth main grid segment 902. Furthermore, since the third grid segment 31 is relatively short, it can be formed directly in a single printing operation, simplifying the pattern of the printing screen.

[0272] Please see Figure 16 In some embodiments, the maximum width L21 of the fourth main gate segment 902 can be 0.32mm-0.36mm, and the minimum width L22 of the fourth main gate segment 902 can be 0.06mm-0.1mm.

[0273] Thus, by optimizing the design of the maximum width L21 of the fourth main grid segment 902, it is possible to avoid excessive current transmission loss due to an excessively small maximum width L21, and also to avoid excessive slurry cost due to an excessively large maximum width.

[0274] Furthermore, by optimizing the minimum width of the fourth main grid segment 902, it is possible to avoid the minimum width L22 of the fourth main grid segment 902 being too small, which would prevent this minimum part from forming a stable connection with the second fine grid 30. It is also possible to avoid the minimum width of the fourth main grid segment 902 being too wide, which would increase the slurry cost. In other words, this specific design can balance the relationship between current transmission loss and slurry cost while ensuring a stable connection between the fourth main grid segment 902 and the second fine grid 30.

[0275] Specifically, in such an embodiment, the maximum width L21 of the fourth main gate segment 902 can be, for example, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, or other values ​​between 0.32mm and 0.36mm, without any specific limitation. The minimum width L22 of the fourth main gate segment 902 can be, for example, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, or other values ​​between 0.06mm and 0.1mm, without any specific limitation.

[0276] In some embodiments, the ratio between the maximum width L21 of the fourth main gate segment 902 and the minimum width L22 of the fourth main gate segment 902 can be 1.5-5, such as 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or other values ​​between 1.5-5, and no specific limitation is made here.

[0277] Specifically, after careful research and demonstration by the inventors of this application, it was discovered that such a specific design can balance the relationship between the flow transmission loss and the slurry cost, and can reduce the slurry cost as much as possible while ensuring that the flow transmission loss is not too large.

[0278] In some embodiments, the width of the fourth main gate segment 902 decreases linearly in the direction away from the fourth pad 120.

[0279] Thus, by setting the width of the fourth main gate segment 902 to decrease linearly, it is easier to fabricate, the fabrication process is simplified, and the electrode pattern is also simpler.

[0280] In some embodiments, the minimum width L17 of the third gate line portion 9011 and the minimum width L18 of the fourth gate line portion 9012 are both smaller than the minimum width L22 of the fourth main gate segment 902.

[0281] Thus, the minimum width of the fourth main gate segment 902 is set relatively large, which allows the second fine gate 30 located at the minimum width position to form a relatively stable connection with the second main gate 802.

[0282] In some embodiments, the length of the third portion 321 is less than the width of the third gate line segment 31, and the length of the fourth portion 322 is also less than the length of the third gate line segment 31. At the same location, the width of the fourth main gate segment 902 is greater than the widths of the third gate line portion 9011 and the fourth gate line portion 9012. "At the same location" refers to the intersection of the same second fine gate 30 and its extension with the third gate line portion 9011, the fourth gate line portion 9012, and the fourth main gate segment 902.

[0283] Thus, by setting the width of the third grid line section 9011 and the fourth grid line section 9012 to be smaller, the slurry cost can be reduced, and by setting the width of the fourth main grid section 902 to be larger, the bus transmission loss can be reduced.

[0284] Specifically, the fourth gate segment 32 is interrupted at the third main gate segment 901. The third gate segment 9011 only needs to collect the current on one side of the third portion 321, and the fourth gate segment 9012 only needs to collect the current on one side of the fourth portion 322. The current collected by both is relatively small. However, the fourth main gate segment 902 needs to collect the current of the entire third gate segment 31, and the current collected is relatively large. Therefore, setting the length of the fourth main gate segment 902 to be wider can reduce the current transmission loss, while setting the width of the third gate segment 9011 and the fourth gate segment 9012 to be smaller can save slurry and reduce costs.

[0285] In some embodiments, the ratio between the maximum width L14 of the third gate line portion 9011 and the maximum width L21 of the fourth main gate segment 902 may be 0.3-0.4, such as 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, or other values ​​between 0.3 and 0.4. In some embodiments, the ratio between the maximum width L16 of the fourth gate line portion 9012 and the maximum width L21 of the fourth main gate segment 902 may also be 0.3-0.4, such as 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, or other values ​​between 0.3 and 0.4.

[0286] In some embodiments, the ratio between the minimum width L17 of the third gate line portion 9011 and the minimum width L22 of the fourth main gate segment 902 may be 0.3-0.6, such as 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, or other values ​​between 0.3 and 0.6, without specific limitations. In some embodiments, the ratio between the minimum width L18 of the fourth gate line portion 9012 and the minimum width L22 of the fourth main gate segment 902 may also be 0.3-0.6, such as 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, or other values ​​between 0.3 and 0.6, without specific limitations.

[0287] In this way, through such optimized design, the relationship between busbar transmission loss and slurry cost can be balanced, thereby effectively controlling slurry cost while reducing busbar transmission loss.

[0288] Please see Figure 16 In some possible embodiments, the fourth pad 120 may also have a second protrusion 121 on the side facing the fourth main gate segment 902, and the second protrusion 121 may be connected to the fourth main gate segment 902. In this way, it is convenient to connect the fourth main gate segment 902 and the fourth pad 120.

[0289] Of course, in some embodiments, the fourth pad 120 may not have the second protrusion 121 on the side facing the fourth main gate segment 902.

[0290] In some embodiments, the width of the fourth main gate segment 902 decreases linearly in the direction away from the fourth pad 120.

[0291] Thus, by setting the width of the fourth main gate segment 902 to decrease linearly, it is easier to fabricate, the fabrication process is simplified, and the electrode pattern is also simpler.

[0292] It should be noted that in some possible embodiments, in a single first main gate 80, adjacent main gate segments (including the first main gate segment 801 and the second main gate segment 802) can be connected to each other to form a continuous first main gate 80. In this case, the first main gate 80 is a continuous structure, and the second fine gates 30 are all broken at the first main gate 80. Of course, in some embodiments, in the first main gate 80, a portion of the main gate segments can be connected to each other, with at least two main gate segments spaced apart, or all the main gate segments can be spaced apart. In this case, there is a second fine gate 30 between the two spaced main gate segments. The second fine gate 30 located at the interval can extend continuously and uninterruptedly along the first direction, or the second fine gate 30 located at the interval can be divided into multiple fine gate segments to improve printing accuracy. Adjacent fine gate segments can be made conductive by setting other conductive elements. That is to say, in the embodiments of this application, the first main gate 80 can be a continuous structure or a discontinuous structure.

[0293] Similarly, in some possible embodiments, adjacent main gate segments (including the third main gate segment 901 and the fourth main gate segment 902) in the second main gate 90 can be connected to each other to form a continuous second main gate 90. In this case, the second main gate 90 is a continuous structure, and the second fine gates 30 are all broken at the second main gate 90. Of course, in some embodiments, in the second main gate 90, a portion of the main gate segments can be connected to each other, with at least two main gate segments spaced apart, or all the main gate segments can be spaced apart. In this case, there is a second fine gate 30 between the two spaced main gate segments. The second fine gate 30 located at the interval can extend continuously and uninterruptedly along the first direction, or the second fine gate 30 located at the interval can be divided into multiple fine gate segments to improve printing accuracy. Adjacent fine gate segments can be made conductive by setting other conductive elements. That is to say, in the embodiments of this application, the second main gate 90 can be a continuous structure or a discontinuous structure.

[0294] In the description of this specification, the references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0295] Furthermore, the above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A back contact cell, characterized in that, include: A silicon substrate having opposing front and back sides, and having opposing first and second edges in a first direction; A plurality of first fine grids and a plurality of second fine grids are disposed on the back side, the plurality of first fine grids and the plurality of second fine grids being alternately arranged along a second direction and extending along a first direction, the second direction intersecting the first direction; A plurality of first pads are provided on the back side and near the first edge, the plurality of first pads are arranged at intervals along the second direction, and the first pads are connected to at least one first fine gate and spaced apart from the second fine gate; and A first bus electrode is disposed on the back side and near the first edge. The first bus electrode is spaced apart from the first pad in the first direction, and the first bus electrode is closer to the first edge than the first pad. The first bus electrode includes a plurality of first bus segments arranged along the second direction. Each first bus segment is connected to a plurality of first fine gates and spaced apart from the second fine gates. The first busbar includes a first connecting portion and a first gradient portion. The first connecting portion is electrically connected to the first pad. The first gradient portion is connected to the first connecting portion and extends along the second direction. In the direction away from the first connecting portion, the width of the first gradient portion gradually decreases. The width of the first connecting portion is greater than or equal to the maximum width of the first gradient portion.

2. The back contact cell of claim 1, wherein, The width of the first connecting part is 0.2mm-0.3mm.

3. The back contact cell of claim 2, wherein, The maximum width of the first gradient section is 0.2mm-0.3mm, and the minimum width of the first gradient section is 0.05mm-0.07mm.

4. The back contact cell of claim 3, wherein, The ratio of the maximum width of the first gradient portion to the minimum width of the first gradient portion is 2.5-6.

5. The back contact cell of claim 1, wherein, In the direction away from the first connecting portion, the width of the first gradient portion decreases linearly.

6. The back contact cell of claim 1, wherein, The first gradient section connects to 5-12 of the first fine gates located on the same side of the first pad and closest to the first pad.

7. The back contact cell of claim 1, wherein, The number of first fine grids connected to all the first gradient sections is the same.

8. The back contact cell of claim 1, wherein, In the second direction, both sides of the first connecting portion have the first gradient portion, and in two adjacent first confluence segments, the narrowest points of the adjacent first gradient portions are connected to each other.

9. The back contact cell of claim 1, wherein, The silicon substrate has a third edge and a fourth edge opposite to each other in the second direction, and a first chamfer is formed at the intersection of the third edge and the first edge, and the first chamfer corresponds to a first fine gate; The first bus electrode further includes a first bent section, which is connected to a first gradient portion of the first bus section closest to the third edge. The first bent section is bent relative to the first bus section and connected to the first fine grid located at the first chamfer.

10. The back contact cell of claim 9, wherein, The width of the first bend is smaller than the width of the first gradient section.

11. The back contact cell of claim 1, wherein, The back contact battery also includes: A second pad is disposed near the second edge, the second pad comprising a plurality of second pads spaced apart along the second direction, the second pad being connected to at least one second fine gate and spaced apart from the first fine gate; and A second bus electrode is disposed near the second edge, the second bus electrode is spaced apart from the second pad in the first direction, and the second bus electrode is closer to the second edge than the second pad; the second bus electrode includes a plurality of second bus segments arranged along the second direction, each second bus segment being connected to a plurality of second fine gates and spaced apart from the first fine gate; The second bus section includes a second connecting portion and a second gradient portion. The second connecting portion is electrically connected to the second pad. The second gradient portion is connected to the second connecting portion and extends along the second direction. In the direction away from the second connecting portion, the width of the second gradient portion gradually decreases. The width of the second connecting portion is greater than or equal to the maximum width of the second gradient portion.

12. The back contact cell of claim 11, wherein, The width of the second connecting part is 0.2mm-0.3mm.

13. The back contact cell of claim 11, wherein, The maximum width of the second gradient section is 0.2mm-0.3mm, and the minimum width of the second gradient section is 0.05mm-0.07mm.

14. The back contact cell of claim 13, wherein, The ratio of the maximum width of the second gradient section to the minimum width of the second gradient section is 2.5-6.

15. The back contact cell of claim 11, wherein, In the direction away from the second connecting portion, the width of the second gradient portion decreases linearly.

16. The back contact cell of claim 11, wherein, The second gradient section connects to 5-12 second fine gates located on the same side of the second pad and closest to the second pad.

17. The back contact battery according to claim 11, characterized in that, The silicon substrate has opposing third and fourth edges in the second direction, and a second chamfer is formed at the intersection of the third edge and the second edge, with two second fine gates corresponding to the second chamfer. The second bus electrode further includes a second bent section, which is connected to a second tapered portion of the second bus section closest to the third edge. The second bent section is bent relative to the second bus section and connected to the second fine grid located at the second chamfer.

18. The back contact battery according to claim 17, characterized in that, The width of the second bend is smaller than the width of the second gradient section.

19. A battery assembly, characterized in that, Includes the back contact battery as described in any one of claims 1-18.

20. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 19.

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