Solar cell, cell assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a solar cell piece, a cell assembly and a photovoltaic system, and the solar cell piece can comprise a cell substrate, a plurality of auxiliary grids, a plurality of main grids and a plurality of first bonding pads. The plurality of auxiliary grids are arranged on the battery substrate, the plurality of auxiliary grids are arranged at intervals along the first direction and extend along the second direction, and the second direction is crossed with the first direction. The plurality of main grids are also arranged on the battery substrate, the plurality of main grids are arranged in parallel at intervals along the second direction, and each main grid is connected with a plurality of auxiliary grids. A plurality of first bonding pads can be arranged on the main grid, and the first bonding pads are octagonal. Therefore, by adopting the arrangement of the bonding pad with the octagonal structure, the use of slurry can be reduced under the condition that the welding performance of the first bonding pad is not influenced, so that the cost is reduced.

Description

TECHNICAL FIELD

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

[0002] Solar cell power generation is a sustainable clean energy source, which can convert sunlight into electricity by using the photovoltaic effect of semiconductor p-n junction. In the related art, a main grid is usually arranged in a solar cell, and then a solder pad is arranged on the main grid to solder a solder strip to realize current bus output. However, printing the solder pad on the main grid requires a large amount of silver paste, which is high in cost. CONTENT

[0003] The present application provides a solar cell, a solar module and a photovoltaic system.

[0004] The present application is implemented in the following manner. The solar cell of the present application comprises:

[0005] a cell substrate; and

[0006] a plurality of sub-grids arranged on the cell substrate, the plurality of sub-grids being arranged in a first direction and extending in a second direction, the second direction intersecting the first direction;

[0007] a plurality of main grids arranged on the cell substrate, the plurality of main grids being arranged in parallel in the second direction, and each of the main grids being connected with a plurality of sub-grids; and

[0008] a plurality of first solder pads arranged on the main grids, the first solder pads being octagonal in shape.

[0009] Further, the first solder pads have a projection area of 1mm 2 -1.5mm 2 on the cell substrate.

[0010] Further, the first solder pads have a first straight side and a second straight side opposite to each other and parallel to each other in the first direction, the first straight side and the second straight side having a length of 0.4mm-0.6mm, and the first straight side and the second straight side having a spacing of 1mm-4mm.

[0011] The first solder pads have a third straight side and a fourth straight side opposite to each other in the second direction, the third straight side and the fourth straight side having a length of 0.5mm-0.8mm, and the third straight side and the fourth straight side having a spacing of 0.9mm-1.1mm.

[0012] Further, the first pad further comprises a first bevel connecting the first straight edge and the third straight edge, a second bevel connecting the first straight edge and the fourth straight edge, a third bevel connecting the second straight edge and the third straight edge, and a fourth bevel connecting the second straight edge and the fourth straight edge, wherein the length of the first bevel, the second bevel, the third bevel and the fourth bevel is 0.4mm-0.43mm.

[0013] Further, the length of the first straight edge and the second straight edge is equal, the length of the third straight edge and the fourth straight edge is equal, and the length of the first bevel, the second bevel, the third bevel and the fourth bevel is equal.

[0014] Further, the first pad further comprises a first bevel connecting the first straight edge and the third straight edge, a second bevel connecting the first straight edge and the fourth straight edge, a third bevel connecting the second straight edge and the third straight edge, and a fourth bevel connecting the second straight edge and the fourth straight edge, wherein the length of the first bevel, the second bevel, the third bevel and the fourth bevel is 0.4mm-0.43mm.

[0015] Further, the solar cell is a back contact solar cell, and the auxiliary bus bars and the main bus bars are arranged on the same surface of the cell substrate.

[0016] The auxiliary bus bars comprise a plurality of first auxiliary bus bars and a plurality of second auxiliary bus bars, and the first auxiliary bus bars and the second auxiliary bus bars are arranged alternately along the first direction.

[0017] The main bus bars comprise a plurality of first main bus bars and a plurality of second main bus bars, and the first main bus bars and the second main bus bars are arranged alternately along the second direction, the first main bus bars are electrically connected with the first auxiliary bus bars and are insulated from the second auxiliary bus bars, and the second main bus bars are electrically connected with the second auxiliary bus bars and are insulated from the first auxiliary bus bars.

[0018] The cell substrate has opposite first and second edges in the second direction, the first main bus bars comprise first edge main bus bars arranged close to the first edge and first intermediate main bus bars arranged between the first edge and the second edge, the first intermediate main bus bars are provided with the first pads, and the first edge main bus bars are not used for soldering.

[0019] The solar cell further comprises a second pad arranged on the cell substrate, the second pad is located on the side of the first edge main bus bars facing the second edge, and the second pad is connected with the first edge main bus bars through at least one first auxiliary bus bar.

[0020] Further, the second pad is connected with the first edge main bus bars through one first auxiliary bus bar, and the first auxiliary bus bar connecting the second pad and the first edge main bus bars is located at the center of the second pad.

[0021] Further, the solar cell further comprises a first bus structure, which is disposed on the cell substrate and does not form ohmic contact with the cell substrate, and the first bus structure connects the second pad and the first edge main grid.

[0022] Further, the second pad is connected to the first edge main grid through one of the first auxiliary grids, and the first bus structure comprises a first bus line and a second bus line, and the first bus line and the second bus line are respectively located on two sides of the first auxiliary grid connecting the second pad and the first edge main grid, and the first bus line and the second bus line are symmetrical.

[0023] Further, the width of the first bus line and the second bus line is 0.04mm-0.08mm.

[0024] Further, the second auxiliary grid corresponding to the second pad is disconnected at the second pad to form a first discontinuous region, and a first connecting electrode is connected to the second pad, and the first connecting electrode passes through the first discontinuous region to connect the first auxiliary grid adjacent to the second pad.

[0025] Further, the first auxiliary grid connected to the first connecting electrode has a second discontinuous region between the first connecting electrode and the first edge main grid, and the solar cell further comprises a second connecting electrode, which is disposed at the second discontinuous region, one end of the second connecting electrode is connected to the second auxiliary grid disconnected at the second pad, and the other end of the second connecting electrode is connected to the second auxiliary grid adjacent to the second pad.

[0026] Further, the width of the first connecting electrode in the second direction is greater than the width of the first auxiliary grid and the second auxiliary grid in the first direction.

[0027] Further, the second main grids comprise a second edge main grid disposed close to the second edge and a second intermediate main grid located between the second edge and the first edge, and the first pad is disposed on the second intermediate main grid, and the second edge main grid is not used for soldering.

[0028] The solar cell further comprises a third pad disposed on the cell substrate, and the third pad is located on one side of the second edge main grid facing the first edge, and the third pad is connected to the second edge main grid through at least one of the second auxiliary grids.

[0029] Further, the third pad is connected to the second edge main grid through one of the second auxiliary grids, and the second auxiliary grid connecting the third pad and the second edge main grid is located at the center position of the third pad.

[0030] Further, the solar cell further comprises a second busbar structure, the second busbar structure is arranged on the cell substrate, and the second busbar structure connects the third pad and the second edge main busbar.

[0031] Further, the third pad is connected with the second edge main busbar through a second sub-busbar, the second busbar structure comprises a third busbar line and a fourth busbar line, the third busbar line and the fourth busbar line are respectively arranged on two sides of the second sub-busbar connecting the third pad and the second edge main busbar, and the third busbar line and the fourth busbar line are symmetrical.

[0032] Further, the width of the third busbar line and the fourth busbar line is 0.04mm-0.08mm.

[0033] Further, the first sub-busbar corresponding to the third pad is disconnected at the third pad to form a third discontinuous region, a third connecting electrode is connected on the third pad, and the third connecting electrode passes through the third discontinuous region to connect the second sub-busbar adjacent to the third pad.

[0034] Further, the second sub-busbar connected with the third connecting electrode has a fourth discontinuous region between the third connecting electrode and the second edge main busbar, the solar cell further comprises a fourth connecting electrode, the fourth connecting electrode is arranged at the fourth discontinuous region, one end of the fourth connecting electrode is connected to the first sub-busbar disconnected at the third pad, and the other end of the fourth connecting electrode is connected to the first sub-busbar adjacent to the third pad.

[0035] Further, the width of the third connecting electrode in the second direction is greater than the width of the first sub-busbar and the second sub-busbar in the first direction.

[0036] The application further provides a battery assembly comprising a plurality of the solar cell pieces.

[0037] The application further provides a photovoltaic system comprising the battery assembly.

[0038] In the solar cell, the battery assembly and the photovoltaic system, a plurality of first pads are arranged on the main busbar, and the shape of the first pad is an octagonal structure. In this way, by adopting the octagonal structure of the pad, the use of paste can be reduced without affecting the welding performance of the first pad, thereby reducing the cost. That is to say, compared with the traditional square and rectangular design, by the octagonal design, the use of paste in four corners can be reduced while meeting the welding performance requirements.

[0039] 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

[0040] Figure 1 This is a schematic diagram of the photovoltaic system provided in the embodiments of this application.

[0041] Figure 2 This is a schematic diagram of the structure of the solar cell provided in the embodiments of this application.

[0042] Figure 3 yes Figure 2 Enlarged schematic diagram at point III;

[0043] Figure 4 This is another structural schematic diagram of the solar cell provided in the embodiments of this application.

[0044] Figure 5 yes Figure 4 A magnified view of a portion of the solar cell in the image;

[0045] Figure 6 yes Figure 4 Another enlarged view of a portion of the solar cell.

[0046] Explanation of key component symbols:

[0047] Photovoltaic system 1000, battery module 200, solar cell 100, battery substrate 10, sub-busbar 20, first sub-busbar 21, second sub-busbar 22, main busbar 30, first main busbar 31, second main busbar 32, first edge main busbar 311, second edge main busbar 321, first pad 40, second pad 50, first busbar structure 60, first busbar line 61, second busbar line 62, first connecting electrode 70, second connecting electrode 80, first discontinuity region 221, second discontinuity region 211, third discontinuity region 212, fourth discontinuity region 222, third pad 90, second busbar structure 110, first busbar line 111, second busbar line 112, third connecting electrode 120, fourth connecting electrode 130. Detailed Implementation

[0048] 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 the 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.

[0049] In the description of the present application, it needs to be understood that the terms "upper", "lower", "left", "right", "transverse", "longitudinal", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0050] In addition, the terms "first", "second", are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features referred to. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "several" is two or more, unless otherwise explicitly specified and limited.

[0051] In the present application, unless otherwise explicitly specified and limited, "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "above" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. "Below", "below" and "below" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0052] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0053] Please refer to Figure 1 The photovoltaic system 1000 in the embodiment of the present application can include the battery assembly 200 in the embodiment of the present application, the battery assembly 200 in the embodiment of the present application can include a plurality of solar cell pieces 100 in the embodiment of the present application, a plurality of solar cell pieces 100 can be connected in series to form a plurality of cell strings, and each cell string can form a battery assembly 200 by series connection, parallel connection or series-parallel connection.

[0054] Please refer to Figure 2 The solar cell 100 in the embodiments of the present application can include a cell substrate 10, a plurality of sub-grids 20, a plurality of main grids 30, and a plurality of first pads 40. The plurality of sub-grids 20 are arranged on the cell substrate 10, and the plurality of sub-grids 20 are arranged in a first direction and extend in a second direction, the second direction being perpendicular to the first direction. The plurality of main grids 30 are also arranged on the cell substrate 10, and the plurality of main grids 30 are arranged in parallel in the second direction, and each of the plurality of main grids 30 is connected with the plurality of sub-grids 20. The plurality of first pads 40 can be arranged on the main grid 30, and the shape of the first pad 40 is octagonal.

[0055] Specifically, as shown in Figure 2 The first direction can be the longitudinal direction in the figure, and the second direction can be the transverse direction in the figure, and the two directions are perpendicular to each other, which is described in this paper. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, two diagonal directions of the cell, which are not limited in detail.

[0056] It can be understood that in the traditional technical solution, the pads on the main grid are usually rectangular, square, etc., which has a large area, consumes more paste, and has a high cost. In the solar cell 100, the cell assembly 200, and the photovoltaic system of the embodiments of the present application, a plurality of first pads 40 are arranged on the main grid 30, and the shape of the first pad 40 is octagonal structure. In this way, by using the octagonal structure of the pad, the use of the paste can be reduced without affecting the welding performance of the first pad 40, thereby reducing the cost. That is, compared with the traditional square and rectangular design, by using the octagonal design, the use of the paste in the four corners can be reduced while meeting the welding performance requirements.

[0057] Specifically, in the embodiments of the present application, the cell substrate 10 can be understood as including a silicon wafer and structures such as a doping layer and a passivation layer arranged on the silicon wafer, that is, a pre-prepared cell without electrode preparation. It can be understood that the sub-grid 20 forms an ohmic contact with the doping layer in the cell substrate 10 to collect carriers, and the main grid 30 is used to converge the current in the sub-grid 20. In some examples, the main grid 30 can form an ohmic contact with the doping layer or not, which is not limited in detail.

[0058] In addition, in the embodiments of the present application, the solar cell 100 can be a PERC cell, a Topcon cell, an HJT solar cell, or the like, and can also be a back contact cell. When the solar cell 100 is a bifacial cell, the front surface and the back surface of the cell substrate 10 can be provided with the sub-grid 20 and the main grid 30, the polarity of the sub-grids 20 on the same surface is the same, and the polarity of the main grids 30 is also the same, and the polarity of the sub-grids 20 on different surfaces is different.

[0059] When the solar cell 100 is a back contact solar cell 100, the sub-grids 20 are all arranged on the back surface of the cell substrate 10, and the two doped layers in the cell substrate 10 are also located on the back surface of the silicon wafer. In this case, the sub-grids 20 include two sub-grids 20 with different polarities, and the main grids 30 also include two main grids 30 with different polarities, and the specific structure is described below.

[0060] In some embodiments, the area of the first solder pad 40 in the orthographic projection on the cell substrate 10 (i.e., the orthographic projection in the thickness direction) can be 1mm 2 -4mm 2 .

[0061] In this way, by arranging the first solder pad 40 in an octagonal structure and reasonably setting the area of the first solder pad 40, the reliability of soldering can be ensured while reducing the use of paste.

[0062] Specifically, in such embodiments, the area of the first solder pad 40 in the orthographic projection on the cell substrate 10 can be, for example, any value between 1mm 2 , 1.1mm 2 , 1.15mm 2 , 1.2mm 2 , 1.25mm 2 , 1.3mm 2 , 1.35mm 2 , 1.4mm 2 , 1.45mm 2 , 1.5mm 2 , 2mm 2 , 2.5mm 2 , 3mm 2 , 3.5mm 2 , 3.5mm 2 or 1mm 2 -4mm 2 , and the specific value is not limited herein.

[0063] Please refer to Figure 3In some embodiments, the first pad 40 has opposite and parallel first and second straight edges 41 and 42 in the first direction, the lengths of the first and second straight edges 41 and 42 are 0.4-0.6 mm, and the distance between the first and second straight edges 41 and 42 is 1-1.3 mm.

[0064] The first pad 40 has opposite third and fourth straight edges 43 and 44 in the second direction, the lengths of the third and fourth straight edges 43 and 44 are 0.5-0.8 mm, and the distance between the third and fourth straight edges 43 and 44 is 0.9-1.1 mm.

[0065] In this way, the lengths of the four straight edges of the octagon are reasonably designed, so that when welding, the solder strip can have sufficient contact length with the first pad 40 in the first direction, and also have sufficient contact length with the pad in the second direction, thereby ensuring the welding quality.

[0066] Further, in some embodiments, the first pad 40 further includes a first oblique edge 45 connecting the first and third straight edges 41 and 43, a second oblique edge 46 connecting the first and fourth straight edges 41 and 44, a third oblique edge 47 connecting the second and third straight edges 42 and 43, and a fourth oblique edge 48 connecting the second and fourth straight edges 42 and 44, and the lengths of the first, second, third and fourth oblique edges 45, 46, 47 and 48 are 0.4-0.43 mm.

[0067] In this way, by reasonably designing the sizes of the four straight edges and the four oblique edges, the octagonal pad can be in a relatively regular form, and the area of the first pad 40 can be ensured not to be too small or too large.

[0068] In such embodiments, preferably, the lengths of the first and second straight edges 41 and 42 are equal, the lengths of the third and fourth straight edges 43 and 44 are equal, and the lengths of the first, second, third and fourth oblique edges 45, 46, 47 and 48 are equal.

[0069] In addition, in some embodiments, the plurality of first pads 40 can include a plurality of test pads, and the test pads have a larger area in the orthographic projection on the battery substrate 10 than the rest of the first pads 40.

[0070] In this way, the area of part of the first pads 40 can be set to be larger, so that when the solar cell 100 is tested for electrical performance (such as PL testing, etc.), the pads have a large enough area to contact the test probe, thereby improving the stability and reliability of the electrical performance test.

[0071] Specifically, in the embodiments of the present application, the area of the test pad is preferably 3 mm2 - 4mm 2 The area of the remaining first pads 40 is preferably 1mm 2 - 1.5mm 2 .

[0072] Referring to Figure 4 In some embodiments, the solar cell 100 is a back contact solar cell 100, and the bus bars 20 and the main grids 30 are arranged on the same side of the cell substrate 10, i.e., all the bus bars 20 and the main grids 30 are arranged on the back of the cell.

[0073] Referring to Figure 3 In this case, the bus bars 20 include a plurality of first bus bars 21 and a plurality of second bus bars 22, and the plurality of first bus bars 21 and the plurality of second bus bars 22 are arranged alternately and spaced apart in the first direction; one of them is a positive bus bar, and the other is a negative bus bar.

[0074] The main grid 30 includes a plurality of first main grids 31 and a plurality of second main grids 32, and the plurality of first main grids 31 and the plurality of second main grids 32 are arranged alternately and spaced apart in the second direction, the first main grid 31 is electrically connected to the first bus bar 21 and insulated from the second bus bar 22, and the second main grid 32 is electrically connected to the second bus bar 22 and insulated from the first bus bar 21. As Figure 4 As shown, in order to achieve insulation between the first main grid 31 and the second bus bar 22, and insulation between the second main grid 32 and the first bus bar 21, the first bus bar 21 can be arranged to be disconnected at the position intersecting the second main grid 32, and the second bus bar 22 can be arranged to be disconnected at the position intersecting the first main grid 31.

[0075] Referring to Figure 4 and Figure 5 As shown, the cell substrate 10 has opposite first and second edges 111 and 112 in the second direction, and the plurality of first main grids 31 include a first edge main grid 311 arranged close to the first edge 111 and a first intermediate main grid 312 located between the first and second edges 111 and 112, the first intermediate main grid 312 is provided with a first pad 40, and the first edge main grid 311 is not used for welding.

[0076] The solar cell 100 further includes a second pad 50 arranged on the cell substrate 10, the second pad 50 is located on the side of the first edge main grid 311 facing the second edge 112, and the second pad 50 is connected to the first edge main grid 311 by at least one first bus bar 21. The second pad 50 can have the same structure as the first pad 40, which will not be described here.

[0077] Thus, the second solder pad 50 is not disposed on the first edge main busbar 311, and the first edge main busbar 311 can not be soldered, but only serves as a role of a busbar to transmit the current collected by the sub-busbar in the edge region to the position of the second solder pad 50, and then is led out through the solder tape soldered on the second solder pad 50, the position of the second solder pad 50 being far away from the first edge 111, the soldering on the edge of the battery piece can be avoided, and thus the stress concentration caused by the soldering process can be avoided to cause the battery piece to be cracked.

[0078] Referring to Figure 5 In some embodiments, the second solder pad 50 is connected to the first edge main busbar 311 through a first sub-busbar 21, and the first sub-busbar 21 connecting the second solder pad 50 and the first edge main busbar 311 is located at the central position of the second solder pad 50.

[0079] Thus, the sub-busbars 20 on both sides of the second solder pad 50 can be substantially uniformly distributed, and the current collection capability can be improved.

[0080] Specifically, the central position means that the second solder pad 50 is symmetrical about the central position in the first direction, that is, the second solder pad 50 is symmetrical about the first sub-busbar 21 connecting the solder pad.

[0081] Referring to Figure 5 In some embodiments, the solar cell piece 100 further comprises a first busbar structure 60 disposed on the cell substrate 10 and not forming an ohmic contact with the cell substrate 10, and the first busbar structure 60 connects the second solder pad 50 and the first edge main busbar 311. For example, the first busbar structure 60 can be obtained by screen printing, for example, the first busbar structure 60 is printed at the same time as the main busbar is printed.

[0082] Thus, by setting the first busbar structure 60 and the first sub-busbar 21 together to transmit the current on the first edge main busbar 311, the busbar effect of the first edge main busbar 311 can be improved, and the overcurrent phenomenon caused by only using the first sub-busbar 21 for busbar can be avoided, and the busbar efficiency can be improved.

[0083] Further, as Figure 5 shown, in some embodiments, the second solder pad 50 is connected to the first edge main busbar 311 through a first sub-busbar 21, the first busbar structure 60 comprises a first busbar line 61 and a second busbar line 62, the first busbar line 61 and the second busbar line 62 are respectively located on both sides of the first sub-busbar 21 connecting the second solder pad 50 and the first edge main busbar 311, and the first busbar line 61 and the second busbar line 62 are symmetrical.

[0084] Thus, by arranging one busbar on each side of the second pad 50, the busbar structure can be formed without directly thickening the position of the sub-grid, but by the busbars arranged at intervals, the busbar efficiency can be improved while reducing the use of paste. At the same time, the two busbars are arranged symmetrically, so that the first sub-grid 21 is connected at the center of the second pad 50, and the sub-grids near the second pad 50 can be evenly distributed.

[0085] In some embodiments, the width of the first busbar 61 and the second busbar 62 can be 0.04mm-0.08mm. Thus, by reasonably setting the width of the two, the use of paste can be reduced while ensuring the busbar efficiency.

[0086] Specifically, in such embodiments, the width of the first busbar 61 and the second busbar 62 can be, for example, 0.04mm, 0.045mm, 0.05mm, 0.055mm, 0.06mm, 0.065mm, 0.07mm, 0.075mm, 0.08mm or any value between 0.04mm-0.08mm, which is not particularly limited herein.

[0087] Please refer to Figure 5 The second sub-grid 22 corresponding to the second pad 50 (i.e., the second sub-grid 22 interfering with the second pad 50 in the second direction) is disconnected at the second pad 50 to form a first discontinuous region 221, and the first connecting electrode 70 is connected to the first sub-grid 21 adjacent to the second pad 50 through the first discontinuous region 221.

[0088] In some embodiments, the first sub-grid 21 connected to the first connecting electrode 70 has a second discontinuous region 211 between the first connecting electrode 70 and the first edge main grid 311, and the solar cell piece 100 further comprises a second connecting electrode 80, which is arranged at the second discontinuous region 211, one end of the second connecting electrode 80 being connected to the second sub-grid 22 disconnected at the second pad 50, and the other end being connected to the second sub-grid 22 adjacent to the second pad 50.

[0089] Thus, by arranging the first discontinuous region 221, the second discontinuous region 211, the first connecting electrode 70 and the second connecting electrode 80, the second sub-grid 22 disconnected at the second pad 50 and unable to be directly connected to the second main grid 32 can be connected to the adjacent second sub-grid 22 through the second connecting electrode 80, thereby realizing busbar connection, and the design of the first connecting electrode 70 can enable the part of the first sub-grid 21 forming the second discontinuous region 211 to realize busbar connection through the first connecting electrode 70, thereby ensuring the collection efficiency.

[0090] Further, in some embodiments, the first connecting electrode 70 has a width in the second direction that is greater than the width of the first and second sub- grids 21 and 22 in the first direction. In this way, the difficulty of the manufacturing process for the sub- grid 20 and the first connecting electrode 70 can be reduced, and the manufacturing efficiency can be improved.

[0091] Referring to Figure 4 and Figure 6 In some embodiments, the plurality of second main grids 32 include a second edge main grid 321 disposed near the second edge 112 and a second intermediate main grid 322 located between the second edge 112 and the first edge 111, the second intermediate main grid 322 being provided with the first pad 40, and the second edge main grid 321 not being used for soldering.

[0092] The solar cell 100 further includes a third pad 90 disposed on the cell substrate 10, the third pad 90 being located on a side of the second edge main grid 321 facing the first edge 111, and the third pad 90 being connected to the second edge main grid 321 by at least one of the second sub- grids 22. The third pad 90 can have the same structure as the first pad 40, and thus will not be described here.

[0093] In this way, the third pad 90 is not disposed on the second edge main grid 321, and the second edge main grid 321 can not be soldered, but only serves as a busbar to transmit the current collected by the sub- grids in the edge region to the position of the third pad 90, and then be led out by the solder ribbon soldered on the third pad 90. The position of the third pad 90 is far from the second edge 112, which can avoid soldering on the edge of the cell, and thus avoid the stress being too concentrated during soldering, which can cause the cell to crack.

[0094] Referring to Figure 6 In some embodiments, the third pad 90 is connected to the second edge main grid 321 by one second sub- grid 22, and the second sub- grid 22 connecting the third pad 90 and the second edge main grid 321 is located at the center position of the third pad 90.

[0095] In this way, the sub- grids 20 on both sides of the third pad 90 can be substantially uniformly distributed, and the current collection capability can be improved.

[0096] Specifically, the center position means that the third pad 90 is symmetrical about the center position in the first direction, that is, the third pad 90 is symmetrical about the second sub- grid 22 connecting the pad.

[0097] Referring to Figure 6In some embodiments, the solar cell 100 further comprises a second busbar structure 110 disposed on the cell substrate 10 and not forming ohmic contact with the cell substrate 10, the second busbar structure 110 connecting the third pad 90 and the second edge main busbar 321. In an exemplary embodiment, the second busbar structure 110 can be obtained by screen printing, for example, printing the second busbar structure 110 at the same time of printing the main busbar.

[0098] In this way, by disposing the second busbar structure 110 together with the second sub-busbar 22 to conduct the current on the second edge main busbar 321, the busbar effect of the second edge main busbar 321 can be improved, and the overcurrent phenomenon caused by only using the second sub-busbar 22 to conduct can be avoided, and the busbar efficiency can also be improved.

[0099] Further, as shown in Figure 6 In some embodiments, the third pad 90 is connected to the second edge main busbar 321 through a second sub-busbar 22, the second busbar structure 110 comprises a third busbar line 111 and a fourth busbar line 112, the third busbar line 111 and the fourth busbar line 112 are respectively located on both sides of the second sub-busbar 22 connecting the third pad 90 and the second edge main busbar 321, and the third busbar line 111 and the fourth busbar line 112 are symmetrical.

[0100] In this way, by disposing a busbar line on both sides of the third pad 90, it is not necessary to directly thicken the position of the sub-busbar 20 to form a busbar structure, but to achieve by the busbar lines arranged at intervals, which can improve the busbar efficiency while reducing the use of paste. At the same time, the symmetrical arrangement of the two busbar lines can make the second sub-busbar 22 connected at the center position of the third pad 90, so that the sub-busbars near the third pad 90 can be evenly distributed.

[0101] In some embodiments, the width of the third busbar line 111 and the fourth busbar line 112 can be 0.04mm-0.08mm. In this way, by reasonably setting the width of the two, the use of paste can be reduced while ensuring the busbar efficiency.

[0102] Specifically, in such embodiments, the width of the third busbar line 111 and the fourth busbar line 112 can be, for example, 0.04mm, 0.045mm, 0.05mm, 0.055mm, 0.06mm, 0.065mm, 0.07mm, 0.075mm, 0.08mm or any value between 0.04mm-0.08mm, which is not specifically limited herein.

[0103] Please refer to Figure 5 and Figure 6The first sub-grid 21 corresponding to the third pad 90 is broken at the third pad 90 to form a third discontinuous region 212, and the third connecting electrode 120 is connected to the third pad 90 and passes through the third discontinuous region 212 to connect the second sub-grid 22 adjacent to the third pad 90.

[0104] The second sub-grid 22 connected to the third connecting electrode 120 has a fourth discontinuous region 222 between the third connecting electrode 120 and the second edge main grid 321, and the solar cell sheet 100 further comprises a fourth connecting electrode 130 arranged at the fourth discontinuous region 222, one end of the fourth connecting electrode 130 being connected to the first sub-grid 21 broken at the third pad 90, and the other end of the fourth connecting electrode 130 being connected to the first sub-grid 21 adjacent to the third pad 90.

[0105] In this way, by arranging the third discontinuous region 212, the fourth discontinuous region 222, the third connecting electrode 120 and the fourth connecting electrode 130, the first sub-grid 21 broken at the third pad 90 and unable to be directly connected to the second main grid 32 can be connected to the adjacent first sub-grid 21 through the fourth connecting electrode 130, so as to realize current collection, and the design of the third connecting electrode 120 can make the part of the second sub-grid 22 with the fourth discontinuous region 222 unable to be directly connected to the second edge main grid 321 to realize current collection through the third connecting electrode 120, thereby ensuring the collection efficiency.

[0106] Further, in some embodiments, the third connecting electrode 120 has a width in the second direction greater than the width of the second sub-grid 22 and the first sub-grid 21 in the first direction. In this way, the difficulty of the manufacturing process for manufacturing the sub-grid 20 and the third connecting electrode 120 can be reduced, and the manufacturing efficiency can be improved.

[0107] In the description of the present specification, the description referring to the terms “some embodiments”, “illustrative embodiments”, “examples”, “specific examples”, or “some examples” and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiments or examples. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0108] In addition, the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A solar cell, characterized in that, include: Battery substrate; and A plurality of sub-gates are disposed on the battery substrate, the plurality of sub-gates being spaced apart along a first direction and extending along a second direction, the second direction intersecting the first direction; A plurality of main grids are disposed on the battery substrate, the main grids being arranged parallel to each other at intervals along a second direction, and each main grid is connected to a plurality of sub-grids; and A plurality of first pads are provided on the main gate, and the first pads are octagonal in shape.

2. The solar cell according to claim 1, characterized in that, The first pad has a projected area of ​​1 mm² on the battery substrate. 2 -4mm 2 .

3. The solar cell according to claim 1, characterized in that, The first pad has a first straight edge and a second straight edge that are opposite to and parallel to each other in the first direction. The lengths of the first straight edge and the second straight edge are 0.4mm-0.6mm, and the distance between the first straight edge and the second straight edge is 1mm-1.3mm. The first pad has a third straight edge and a fourth straight edge opposite each other in the second direction. The length of the third straight edge and the fourth straight edge is 0.5mm-0.8mm, and the distance between the third straight edge and the fourth straight edge is 0.9mm-1.1mm.

4. The solar cell according to claim 3, characterized in that, The first pad further includes a first inclined side connecting the first straight edge and the third straight edge, a second inclined side connecting the first straight edge and the fourth straight edge, a third inclined side connecting the second straight edge and the third straight edge, and a fourth inclined side connecting the second straight edge and the fourth straight edge, wherein the lengths of the first inclined side, the second inclined side, the third inclined side and the fourth inclined side are 0.4mm-0.43mm.

5. The solar cell according to claim 4, characterized in that, The lengths of the first straight edge and the second straight edge are equal, the lengths of the third straight edge and the fourth straight edge are equal, and the lengths of the first hypotenuse, the second hypotenuse, the third hypotenuse, and the fourth hypotenuse are equal.

6. The solar cell according to claim 1, characterized in that, The plurality of first pads includes a plurality of test pads, wherein the orthographic projection area of ​​the test pads on the battery substrate is greater than the orthographic projection area of ​​the remaining first pads on the battery substrate.

7. The solar cell according to claim 1, characterized in that, The solar cell is a back-contact solar cell, and the sub-grid and the main grid are both disposed on the same side of the cell substrate; The sub-gate includes a plurality of first sub-gates and a plurality of second sub-gates, which are arranged alternately and at intervals along the first direction. The main gate includes a plurality of first main gates and a plurality of second main gates, the plurality of first main gates and the plurality of second main gates are arranged alternately along the second direction, the first main gates are electrically connected to the first sub-gates and insulated from the second sub-gates, and the second main gates are electrically connected to the second sub-gates and insulated from the first sub-gates; The battery substrate has a first edge and a second edge opposite to each other in the second direction. The plurality of first main gates include a first edge main gate disposed near the first edge and a first intermediate main gate located between the first edge and the second edge. The first intermediate main gate is provided with the first pad. The first edge main gate is not used for soldering. The solar cell further includes a second pad disposed on the cell substrate. The second pad is located on the side of the first edge main grid facing the second edge, and the second pad is connected to the first edge main grid through at least one of the first sub-grids.

8. The solar cell according to claim 7, characterized in that, The second pad is connected to the first edge main gate through a first sub-gate, and the first sub-gate connecting the second pad and the first edge main gate is located at the center of the second pad.

9. The solar cell according to claim 7, characterized in that, The solar cell further includes a first busbar structure, which is disposed on the cell substrate and does not form an ohmic contact with the cell substrate. The first busbar structure connects the second pad and the first edge main grid.

10. The solar cell according to claim 9, characterized in that, The second pad is connected to the first edge main gate through a first sub-gate. The first bus structure includes a first bus line and a second bus line. The first bus line and the second bus line are located on both sides of the first sub-gate connecting the second pad and the first edge main gate, and the first bus line and the second bus line are symmetrical.

11. The solar cell according to claim 10, characterized in that, The widths of the first busbar and the second busbar are 0.04mm-0.08mm.

12. The solar cell according to claim 7, characterized in that, The second sub-gate corresponding to the second pad is disconnected at the second pad to form a first discontinuity region. A first connection electrode is connected on the second pad. The first connection electrode passes through the first discontinuity region and connects to the first sub-gate adjacent to the second pad. The first sub-gate connected to the first connecting electrode has a second discontinuity region between the first connecting electrode and the first edge main gate. The solar cell also includes a second connecting electrode, which is disposed at the second discontinuity region. One end of the second connecting electrode is connected to the second sub-gate that is disconnected at the second pad, and the other end is connected to the second sub-gate adjacent to the second pad.

13. The solar cell according to claim 12, characterized in that, The width of the first connecting electrode in the second direction is greater than the width of the first sub-gate and the second sub-gate in the first direction.

14. The solar cell according to claim 7, characterized in that, The second main gate includes a second edge main gate disposed near the second edge and a second intermediate main gate located between the second edge and the first edge. The first pad is disposed on the second intermediate main gate, and the second edge main gate is not used for soldering. The solar cell further includes a third pad disposed on the cell substrate. The third pad is located on the side of the second edge main grid facing the first edge, and the third pad is connected to the second edge main grid through at least one second sub-grid.

15. The solar cell according to claim 14, characterized in that, The third pad is connected to the second edge main gate via a second sub-gate, and the second sub-gate connecting the third pad and the second edge main gate is located at the center of the third pad.

16. The solar cell according to claim 14, characterized in that, The solar cell also includes a second busbar structure disposed on the cell substrate, the second busbar structure connecting the third pad and the second edge main grid.

17. The solar cell according to claim 16, characterized in that, The third pad is connected to the second edge main gate through a second sub-gate. The second bus structure includes a third bus line and a fourth bus line. The third bus line and the fourth bus line are located on both sides of the second sub-gate connecting the third pad and the second edge main gate, and the third bus line and the fourth bus line are symmetrical.

18. The solar cell according to claim 17, characterized in that, The widths of the third and fourth busbars are 0.04mm-0.08mm.

19. The solar cell according to claim 14, characterized in that, The first sub-gate corresponding to the third pad is disconnected at the third pad to form a third discontinuity region. A third connection electrode is connected to the third pad. The third connection electrode passes through the third discontinuity region and connects to the second sub-gate adjacent to the third pad. The second sub-gate connected to the third connecting electrode has a fourth discontinuity region between the third connecting electrode and the second edge main gate. The solar cell also includes a fourth connecting electrode, which is disposed at the fourth discontinuity region. One end of the fourth connecting electrode is connected to the first sub-gate that is disconnected at the third pad, and the other end is connected to the first sub-gate adjacent to the third pad.

20. The solar cell according to claim 19, characterized in that, The width of the third connecting electrode in the second direction is greater than the width of the first sub-gate and the second sub-gate in the first direction.

21. A battery assembly, characterized in that, Includes the solar cell as described in any one of claims 1-20.

22. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 21.

Images