Back contact solar cell

Abstract

The utility model provides a back contact solar cell. The back contact solar cell comprises a solar cell body, a first electrode and a second electrode, the polarities of the first electrode and the second electrode are opposite; the first electrode and the second electrode are arranged on the back surface of the solar cell body at intervals in an interdigital manner; the back face of the solar cell body comprises a first area and a second area which are arranged in parallel, and the first electrodes and the second electrodes are distributed in an axial symmetry mode along the boundary of the first area and the second area. The electrode grid line of the back contact solar cell is low in manufacturing difficulty and high in precision.

Description

Technical Field

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

[0002] The positive and negative electrode grid lines of a back-contact solar cell are both arranged on the back of the cell wafer. Due to the design without grid line electrodes on the front side of the cell wafer, there is no light shielding on the front side of the cell wafer, and the incident light can be utilized to the maximum extent. When preparing the positive and negative electrode grid lines of a traditional back-contact solar cell, they need to correspond to the doped regions with different polarities fabricated on the silicon substrate. In the industry, the back-contact cell mainly prepares the pattern of the doped region by means of laser etching. Through multiple laser etchings, a first doped region and a second doped region are respectively formed, and the two are separated by an isolation region. After the back passivation film is completed, the electrodes are prepared on the corresponding doped regions by means of printing or the like. During the preparation process, if the positive and negative electrode patterns are different, the laser processing patterns of the positive and negative electrode regions also correspond differently. Due to the error precision of the laser processing equipment itself, there will be a certain pattern precision deviation during the preparation of the two pole regions, which will eventually easily cause structural problems, increase the debugging cycle, and increase the manufacturing difficulty of the back-contact cell. Summary of the Utility Model

[0003] Based on this, the present application provides a back-contact solar cell with relatively low production difficulty and high precision of the electrode pattern structure.

[0004] The technical solution proposed by the present application is as follows:

[0005] The present application provides a back-contact solar cell, including a solar cell body, a first electrode, and a second electrode;

[0006] The first electrode and the second electrode have opposite polarities;

[0007] The first electrode and the second electrode are arranged in a finger-like and spaced manner on the back of the solar cell body;

[0008] The back of the solar cell body includes a first region and a second region arranged in parallel, and the first electrode and the second electrode are axially symmetrically distributed along the boundary line between the first region and the second region.

[0009] In any implementation manner, the first electrode includes a first sub-electrode and a second sub-electrode. A plurality of the first sub-electrodes are arranged in parallel and spaced along a first direction x in the first region, and a plurality of the second sub-electrodes are arranged in parallel and spaced along the first direction x in the second region;

[0010] The first sub-electrode and the second sub-electrode both include a main grid line and a fine grid line connected to each other. The main grid line extends along the second direction y, and the fine grid line extends along the first direction x. The main grid lines in the first sub-electrode and the main grid lines in the second sub-electrode are alternately arranged at intervals along the first direction x.

[0011] Wherein, both the first direction x and the second direction y are parallel to the back surface of the solar cell body and intersect.

[0012] In any embodiment, the second electrode includes a third sub-electrode and a fourth sub-electrode. A plurality of the third sub-electrodes are arranged side by side at intervals along the first direction x in the first region, and a plurality of the fourth sub-electrodes are arranged side by side at intervals along the first direction x in the second region.

[0013] The third sub-electrode and the fourth sub-electrode both include a main grid line and a fine grid line connected to each other. The main grid line extends along the second direction y, and the fine grid line extends along the first direction x. The main grid lines in the third sub-electrode and the main grid lines in the fourth sub-electrode are alternately arranged at intervals along the first direction x.

[0014] In any embodiment, the first sub-electrode, the second sub-electrode, the third sub-electrode, and the fourth sub-electrode all include pads.

[0015] The pad in the first sub-electrode is disposed on the first main grid line. The length of the first fine grid line passing through the range where the pad is located is shorter than the lengths of other first fine grid lines, so as to form a pad placement area for placing the pads in the third sub-electrode between adjacent first sub-electrodes or between the first sub-electrode and the edge of the first region.

[0016] In any embodiment, the pad in the second sub-electrode is disposed on the first main grid line. The length of the first fine grid line passing through the range where the pad is located is shorter than the lengths of other first fine grid lines, so as to form a pad placement area for placing the pads in the fourth sub-electrode between adjacent second sub-electrodes.

[0017] In any embodiment, the pad in the third sub-electrode is disposed on the second main grid line. The length of the second fine grid line passing through the range where the pad is located is shorter than the lengths of other second fine grid lines, so as to form a pad placement area for placing the pads in the first sub-electrode between adjacent third sub-electrodes.

[0018] In any embodiment, the pad in the fourth sub-electrode is disposed on the second main grid line; the length of the second fine grid line passing through the range where the pad is located is shorter than the lengths of other second fine grid lines, so as to form a pad placement area for placing the pad in the second sub-electrode between adjacent fourth sub-electrodes or between the fourth sub-electrode and the edge of the second region.

[0019] In any embodiment, along the first direction x, a first fine grid line is provided on one side of the first main grid line in the second sub-electrode located at the edge of the second region, and the first fine grid line extends from the first main grid line towards the adjacent second sub-electrode; first fine grid lines are provided on both sides of the first main grid lines in the remaining second sub-electrodes and the first sub-electrode.

[0020] In any embodiment, along the first direction x, a second fine grid line is provided on one side of the second main grid line in the third sub-electrode located at the edge of the first region, and the second fine grid line extends from the second main grid line towards the adjacent third sub-electrode; second fine grid lines are provided on both sides of the second main grid lines in the remaining third sub-electrodes and the fourth sub-electrode.

[0021] In any embodiment, the number of the first sub-electrodes is one less than the number of the second sub-electrodes; and / or

[0022] The number of the fourth sub-electrodes is one less than the number of the third sub-electrodes.

[0023] Compared with the prior art, the present application has at least the following beneficial effects:

[0024] By dividing the back surface of the solar cell body into a first region and a second region arranged in parallel, and making the first electrode and the second electrode be axially symmetrically distributed along the boundary line between the first region and the second region; compared with the conventional back-contact solar cell that needs to use two sets of grid patterns to separately prepare the first electrode and the second electrode, the electrode pattern of the back-contact solar cell in the present application is beneficial to reducing the pattern error caused by laser processing, is more convenient for adjusting the grid pattern, makes the manufacturing difficulty of the electrode grid line smaller and the precision higher, and reduces the risk of structural problems in the battery. Description of the Drawings

[0025] To better describe and illustrate the embodiments or examples provided in the present application, one or more drawings can be referred to. The additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, and the currently understood best mode of these applications. And in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0026] Figure 1Schematic diagram of the distribution of the first electrode and the second electrode in the back-contact solar cell according to an embodiment of the present application;

[0027] Figure 2 Schematic diagram of the first region and the second region in the back-contact solar cell according to an embodiment of the present application;

[0028] Figure 3 Schematic diagram of the distribution of the first electrode in the back-contact solar cell according to an embodiment of the present application;

[0029] Figure 4 Schematic diagram of the distribution of the second electrode in the back-contact solar cell according to an embodiment of the present application.

[0030] Explanation of reference numerals:

[0031] 10. Back-contact solar cell; 11. Solar cell body; 12. First electrode; 13. Second electrode; 14. Pad; 15. Pad placement area; 111. First region; 112. Second region; 121. First sub-electrode; 122. Second sub-electrode; 123. First main grid line; 124. First fine grid line; 131. Third sub-electrode; 132. Fourth sub-electrode; 133. Second main grid line; 134. Second fine grid line. Detailed implementation manners

[0032] To make the above objects, features, and advantages of the present application more obvious and understandable, the following provides a detailed description of the specific implementation manners of the present application. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0033] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0034] In this application, unless otherwise clearly defined or limited, terms such as "installation", "connection", "linkage", "fixation", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0036] Please refer to Figure 1 and Figure 2 , some embodiments of this application provide a back-contact solar cell 10, which includes a solar cell body 11, a first electrode 12, and a second electrode 13; wherein, the polarities of the first electrode 12 and the second electrode 13 are opposite, that is, one of the first electrode 12 and the second electrode 13 is the positive electrode and the other is the negative electrode; the first electrode 12 and the second electrode 13 are arranged in an interdigitated manner at intervals on the back of the solar cell body 11; the back of the solar cell body 11 includes a first region 111 and a second region 112 arranged in parallel, and the first electrode 12 and the second electrode 13 are axially symmetrically distributed along the boundary line (such as Figure 2 shown as L in

[0037] in) between the first region 111 and the second region 112.

[0038] Specifically, the width of the isolation region between the first doping region and the second doping region on the back surface of the back-contact solar cell is usually only a few tens of micrometers. Its width is relatively narrow, and the accuracy requirements for laser processing are relatively high. At present, the processing accuracy of laser equipment is generally about 15μm - 20μm. The error of laser processing will seriously affect the width of the interval region between the first doping region and the second doping region. This requires that the accuracy control of the grid line pattern itself be quite strict during the manufacturing process of the cell. However, the laser marking accuracy is limited by the size of the light spot itself. Without considering overlap, the error of laser etching is the size of the light spot, and its actual length will deviate from the design to a certain extent.

[0039] Since the first doping region and the second doping region of the back-contact solar cell are prepared step by step, when designing the grid line pattern, it is necessary to design the sizes of the two sets of grid line patterns according to complementarity so that the first doping region and the second doping region can be spaced apart. If there is a deviation during the laser processing of the two patterns, it will lead to structural failure, resulting in risks such as leakage, hot spots, and even a decrease in conversion efficiency. In addition, for the scheme of using two sets of grid line patterns, when adjusting one set of laser processing patterns, the other set of processing patterns also needs to be adjusted accordingly. Otherwise, it will cause local structural problems in the cell, and then lead to batch structural problems and defects in the cell. Therefore, different electrode patterns will increase the difficulty of laser preparation of the doping region structure on the back surface of the back-contact solar cell, resulting in problems such as poor pattern accuracy, complex processing work, and battery structure defects.

[0040] In response to this, for the above-mentioned back-contact solar cell 10 of the present application, the back surface of the solar cell body 11 is divided into a first region 111 and a second region 112 arranged in parallel, and the first electrode 12 and the second electrode 13 are axially symmetrically distributed along the boundary line between the first region 111 and the second region 112; when preparing the structure of the above-mentioned back-contact solar cell 10, after preparing the first electrode 12 corresponding to the first doping region, only need to flip the grid line pattern 180° along the boundary line between the first region 111 and the second region 112, and then use this grid line pattern to prepare the second electrode 13 corresponding to the second doping region. Only one set of processing patterns is needed during the entire preparation process of the processing pattern.

[0041] Thus, compared with the traditional method that requires two sets of grid patterns to separately fabricate the back-contact solar cell 10, when fabricating the electrodes of the back-contact solar cell 10 of the present application, the precision of laser processing twice for fabricating the electrodes is consistent, avoiding the matching problems generated during the laser processing due to the differences in the grid patterns, and reducing the risks such as inefficiency, leakage, and hot spots brought by the grid pattern errors and difference points. When fabricating the electrodes of the back-contact solar cell 10 of the present application, the grid pattern matching is simpler, the adjustment of the grid pattern is more convenient, and the manufacturing difficulty of the electrode grid lines is smaller, which is beneficial to improving the manufacturing precision and reducing the risk of structural problems in the battery.

[0042] It can be understood that "the first electrode 12 and the second electrode 13 are axially symmetrically distributed along the dividing line between the first region 111 and the second region 112" means that when the entire first electrode 12 is flipped 180° along the above-mentioned dividing line, it overlaps with the second electrode 13, and when the entire second electrode 13 is flipped 180° along the above-mentioned dividing line, it overlaps with the first electrode 12. That is, the first electrode 12 and the second electrode 13 are mirror-symmetric with respect to a plane perpendicular to the back surface of the solar cell body 11 and passing through the above-mentioned dividing line, being mirror images of each other. The back-contact solar cell 10 includes a front surface and a back surface. Among them, the front surface usually serves as the light-receiving surface of the battery, and the back surface usually serves as the backlight surface of the battery.

[0043] Please refer to Figure 2 , in some embodiments, the first region 111 and the second region 112 are respectively the left half and the right half of the back surface of the solar cell body 11; the dividing line L between the first region 111 and the second region 112 is the vertical central axis of the back surface of the solar cell body 11.

[0044] Please refer to Figure 3 , in some embodiments, the first electrode 12 includes a first sub-electrode 121 and a second sub-electrode 122; a plurality of first sub-electrodes 121 are arranged in parallel at intervals along the first direction x within the first region 111, and a plurality of second sub-electrodes 122 are arranged in parallel at intervals along the first direction x within the second region 112; both the first sub-electrode 121 and the second sub-electrode 122 include a first main grid line 123 and a first fine grid line 124 that are connected to each other; the first main grid line 123 extends along the second direction y, and the first fine grid line 124 extends along the first direction x; the first main grid lines 123 in the first sub-electrodes 121 and the first main grid lines 123 in the second sub-electrodes 122 are alternately arranged at intervals along the first direction x; wherein, both the first direction x and the second direction y are parallel to the back surface of the solar cell body 11 and intersect.

[0045] Please refer to Figure 4, in some embodiments, the second electrode 13 includes a third sub - electrode 131 and a fourth sub - electrode 132. A plurality of third sub - electrodes 131 are arranged in parallel and spaced apart along the first direction x within the first region 111, and a plurality of fourth sub - electrodes 132 are arranged in parallel and spaced apart along the first direction x within the second region 112. Both the third sub - electrode 131 and the fourth sub - electrode 132 include a second main grid line 133 and a second fine grid line 134 that are connected to each other. The second main grid line 133 extends along the second direction y, and the second fine grid line 134 extends along the first direction x. The second main grid lines 133 in the third sub - electrodes 131 and the second main grid lines 133 in the fourth sub - electrodes 132 are arranged alternately and spaced apart along the first direction x.

[0046] In some embodiments, the widths of the first fine grid line 124 and the second fine grid line 134 are 0.01 mm to 0.05 mm. The multiple fine grid lines in each sub - electrode are arranged at equal intervals, and the distance between two adjacent fine grid lines is 0.5 mm to 1 mm. The distance between the two closest fine grid lines within the first region 111 and within the second region 112 is 0.5 mm to 2 mm. The lengths of the first fine grid line 124 and the second fine grid line 134 can be adjusted according to the size of the back surface of the solar cell body 11 and the number of corresponding main grid lines. Generally, the lengths of the first fine grid line 124 and the second fine grid line 134 are between 5 mm and 30 mm.

[0047] In some embodiments, the specific lengths of the first main grid line 123 and the second main grid line 133 can be determined according to the size of the back surface of the solar cell body 11. Generally, the lengths of the first main grid line 123 and the second main grid line 133 are 0.4 to 0.6 times the length of the solar cell body 11 along the second direction y, and the main grid line length values are generally between 60 mm and 120 mm. The widths of the first main grid line 123 and the second main grid line 133 can be determined according to the size of the back surface of the solar cell body 11 and the number of main grid lines. The width of the main grid line is generally between 0.02 mm and 0.2 mm.

[0048] Please refer to Figure 1 , Figure 3 and Figure 4 , in some embodiments, the first sub - electrode 121, the second sub - electrode 122, the third sub - electrode 131, and the fourth sub - electrode 132 all include pads 14. The pads 14 are mainly provided for soldering the bus bars to collect and output the current to the bus bars. In some specific examples, a plurality of pads 14 are usually arranged at intervals on each main grid line, and the number thereof can be 3 to 10; the distance between adjacent pads 14 on the same main grid line can be 5 mm to 20 mm. The length of the pad 14 along the first direction x can be 1 mm to 3 mm, and the length along the second direction y can be 1 mm to 3 mm.

[0049] Please refer toFigure 3 In some embodiments, the pad 14 in the first sub-electrode 121 is disposed on the first main gate line 123; the length of the first fine gate line 124 passing through the range where the pad 14 is located in the first sub-electrode 121 is shorter than the lengths of the other first fine gate lines 124, so as to form a pad placement area 15 for placing the pad 14 in the third sub-electrode 131 between adjacent first sub-electrodes 121 or between the first sub-electrode 121 and the edge of the first region 111. In this way, a placement space is reserved for setting the pad 14 in the third sub-electrode 131, the contact between the first fine gate line 124 and the pad 14 in the third sub-electrode 131 is avoided, and at the same time, the lengths of the first fine gate lines 124 outside the range where the pad 14 is located are made as long as possible.

[0050] Please refer to Figure 3 In some embodiments, the pad 14 in the second sub-electrode 122 is disposed on the first main gate line 123; the length of the first fine gate line 124 passing through the range where the pad 14 is located in the second sub-electrode 122 is shorter than the lengths of the other first fine gate lines 124, so as to form a pad placement area 15 for placing the pad 14 in the fourth sub-electrode 132 between adjacent second sub-electrodes 122. In this way, a placement space is reserved for setting the pad 14 in the fourth sub-electrode 132, the contact between the first fine gate line 124 and the pad 14 in the fourth sub-electrode 132 is avoided, and at the same time, the lengths of the first fine gate lines 124 outside the range where the pad 14 is located are made as long as possible.

[0051] Please refer to Figure 4 In some embodiments, the pad 14 in the third sub-electrode 131 is disposed on the second main gate line 133; the length of the second fine gate line 134 passing through the range where the pad 14 is located in the third sub-electrode 131 is shorter than the lengths of the other second fine gate lines 134, so as to form a pad placement area 15 for placing the pad 14 in the first sub-electrode 121 between adjacent third sub-electrodes 131. In this way, a placement space is reserved for setting the pad 14 in the first sub-electrode 121, the contact between the second fine gate line 134 and the pad 14 in the first sub-electrode 121 is avoided, and at the same time, the lengths of the second fine gate lines 134 outside the range where the pad 14 is located are made as long as possible.

[0052] Please refer to Figure 4, in some embodiments, the pad 14 in the fourth sub - electrode 132 is disposed on the second main grid line 133; the length of the second fine grid line 134 passing through the range where the pad 14 is located in the fourth sub - electrode 132 is shorter than the lengths of the other second fine grid lines 134, so as to form a pad placement area 15 for placing the pad 14 in the second sub - electrode 122 between adjacent fourth sub - electrodes 132 or between the fourth sub - electrode 132 and the edge of the second region 112. In this way, a placement space is reserved for setting the pad 14 in the second sub - electrode 122, avoiding contact between the second fine grid line 134 and the pad 14 in the second sub - electrode 122, and at the same time making the lengths of the second fine grid lines 134 outside the range where the pad 14 is located as long as possible.

[0053] Please refer to Figure 3 , in some embodiments, along the first direction x, the first fine grid line 124 is provided only on one side of the first main grid line 123 in the second sub - electrode 122 located at the edge of the second region 112, and the first fine grid line 124 extends from the first main grid line 123 towards the adjacent second sub - electrode 122; the first fine grid lines 124 are provided on both sides of the first main grid line 123 in the remaining second sub - electrodes 122 and the first sub - electrode 121. The number of the second sub - electrodes 122 is one more than the number of the first sub - electrodes 121. With such a setting, the patterns of the first electrode 12 and the second electrode 13 can be better complementary.

[0054] Please refer to Figure 4 , in some embodiments, along the first direction x, the second fine grid line 134 is provided only on one side of the second main grid line 133 in the third sub - electrode 131 located at the edge of the first region 111, and the second fine grid line 134 extends from the second main grid line 133 towards the adjacent third sub - electrode 131; the second fine grid lines 134 are provided on both sides of the second main grid line 133 in the remaining third sub - electrodes 131 and the fourth sub - electrodes 132. The number of the third sub - electrodes 131 is one more than the number of the fourth sub - electrodes 132. With such a setting, the patterns of the first electrode 12 and the second electrode 13 can be better complementary.

[0055] The technical features of the above - described embodiments can be combined arbitrarily. For the sake of brevity in description, not all possible combinations of the technical features in the above - described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0056] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims, and the specification and the drawings can be used to explain the content of the claims.

Claims

1. A back contact solar cell, characterized in that: It includes a solar cell body, a first electrode and a second electrode; The first electrode and the second electrode have opposite polarities; The first electrode and the second electrode are arranged at intervals on the back side of the solar cell body in an interdigitated shape; The back side of the solar cell body includes a first region and a second region arranged in parallel, and the first electrode and the second electrode are distributed in an axisymmetric manner along a boundary line between the first region and the second region.

2. The back contact solar cell according to claim 1, characterized in that: The first electrode includes a first sub-electrode and a second sub-electrode, a plurality of the first sub-electrodes are arranged in parallel and spaced relation along a first direction x in the first region, and a plurality of the second sub-electrodes are arranged in parallel and spaced relation along the first direction x in the second region; The first sub-electrode and the second sub-electrode each include a first main grid line and a first fine grid line connected to each other, the first main grid line extends along the second direction y, and the first fine grid line extends along the first direction x; the first main grid lines in the first sub-electrode and the first main grid lines in the second sub-electrode are alternately arranged along the first direction x; The first direction x and the second direction y are both parallel to the back side of the solar cell body and intersect with each other.

3. The back contact solar cell according to claim 2, characterized in that: The second electrode includes a third sub-electrode and a fourth sub-electrode, a plurality of the third sub-electrodes are arranged in parallel and spaced relation along the first direction x in the first region, and a plurality of the fourth sub-electrodes are arranged in parallel and spaced relation along the first direction x in the second region; The third sub-electrode and the fourth sub-electrode each include a second main grid line and a second fine grid line connected to each other, the second main grid line extends along the second direction y, and the second fine grid line extends along the first direction x; the second main grid line in the third sub-electrode and the second main grid line in the fourth sub-electrode are alternately arranged along the first direction x.

4. The back contact solar cell according to claim 3, characterized in that: The first sub-electrode, the second sub-electrode, the third sub-electrode and the fourth sub-electrode each include a pad; The pad in the first sub-electrode is arranged on the first main gate line; the length of the first fine gate line passing through the range where the pad is located is shorter than the length of other first fine gate lines, so as to form a pad placement area for placing the pad in the third sub-electrode between adjacent first sub-electrodes or between the first sub-electrode and the edge of the first region.

5. The back contact solar cell according to claim 4, characterized in that: The pad in the second sub-electrode is arranged on the first main gate line; the length of the first fine gate line passing through the range where the pad is located is shorter than the length of other first fine gate lines, so as to form a pad placement area for placing the pad in the fourth sub-electrode between adjacent second sub-electrodes.

6. The back contact solar cell according to claim 4, characterized in that: The pad in the third sub-electrode is arranged on the second main gate line; the length of the second fine gate line passing through the range where the pad is located is shorter than the length of other second fine gate lines, so as to form a pad placement area for placing the pad in the first sub-electrode between adjacent third sub-electrodes.

7. The back contact solar cell according to claim 4, characterized in that: The pad in the fourth sub-electrode is arranged on the second main gate line; the length of the second fine gate line passing through the range where the pad is located is shorter than the length of other second fine gate lines, so as to form a pad placement area for placing the pad in the second sub-electrode between adjacent fourth sub-electrodes or between the fourth sub-electrode and the edge of the second region.

8. The back-contact solar cell according to any one of claims 2 to 7, characterized in that: Along the first direction x, a first fine gate line is provided on one side of the first main gate line in the second sub-electrode located at the edge of the second area, and the first fine gate line extends from the first main gate line toward the adjacent second sub-electrode; first fine gate lines are provided on both sides of the first main gate lines in the remaining second sub-electrodes and the first sub-electrode.

9. The back-contact solar cell according to any one of claims 3 to 7, characterized in that: Along the first direction x, a second fine gate line is provided on one side of the second main gate line in the third sub-electrode located at the edge of the first area, and the second fine gate line extends from the second main gate line toward the adjacent third sub-electrode; second fine gate lines are provided on both sides of the second main gate lines in the remaining third sub-electrodes and the fourth sub-electrodes.

10. The back-contact solar cell according to any one of claims 3 to 7, characterized in that: The number of the first sub-electrodes is one less than the number of the second sub-electrodes; and / or The number of the fourth sub-electrodes is one less than the number of the third sub-electrodes.

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