Electrode structure of back contact battery, back contact battery and assembly and system thereof

Abstract

The utility model relates to the technical field of solar cells, and discloses an electrode structure of a back contact cell, the back contact cell, an assembly and a system thereof, and the electrode structure comprises a first grid line which is used for collecting a first polarity area; the second grid line is used for collecting a second polarity region; the first main grid is connected with the first grid line and comprises a first edge main grid which is arranged on one side, close to the first edge, of the back contact battery; the second main grid is connected with the second grid line; the second main grid comprises a second edge main grid which is arranged on one side, close to the second edge, of the back contact battery; the first grid line comprises a first extending grid line connected with the end part of the first main grid, and the first extending grid line extends to a preset position of the first edge and / or the second edge along the first direction to form a first grid line protruding part. By adopting the solar cell, the technical problem of improving the carrier collection efficiency and the conversion efficiency of the solar cell can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cells, in particular to an electrode structure of a back-contact cell, a back-contact cell, and a component and system thereof. Background Art

[0002] A back-contact solar cell is a cell in which both the emitter and base contact electrodes are placed on the back side of the cell (non-light-receiving side). The light-receiving side of the cell is not blocked by any metal electrodes, which effectively increases the short-circuit current of the cell. At the same time, the back side can allow for wider metal grid lines to reduce the series resistance and thus increase the fill factor. This type of cell with no obstruction on the front side not only has a high conversion efficiency, but also looks more beautiful. At the same time, components with full back electrodes are easier to assemble.

[0003] The back-contact cell forms alternating P-type doped regions and N-type doped regions on the backlit surface, with the metal electrode correspondingly covering the backlit surface. The current transmission of carriers inside the cell is mainly lateral transmission. Since the back-contact cell has no metal electrode blocking the light-receiving surface, it can avoid shading losses and improve the conversion efficiency to a certain extent. However, due to the long lateral transmission distance, the lateral transmission of most carriers will cause significant series resistance loss, resulting in limited improvement in conversion efficiency. In addition, the back-contact cell has very few openings in the area corresponding to the main grid, resulting in little carrier collection and low efficiency.

[0004] For back-contact solar cells, electrode pattern design is the core technology of the battery. How to improve the efficiency of carrier collection and the conversion efficiency of solar cells by improving the electrode pattern has become a technical problem that needs to be urgently solved by technical personnel in this field. Utility Model Content

[0005] The utility model provides an electrode structure of a back-contact battery, a back-contact battery and its components and system, which can solve the technical problem of improving the carrier collection efficiency and the conversion efficiency of solar cells.

[0006] In order to solve the above technical problems, on the one hand, the present invention provides an electrode structure of a back-contact battery, the electrode structure comprising:

[0007] a first grid line for collecting a first polarity region;

[0008] a second grid line for collecting a second polarity region;

[0009] a first busbar connected to the first busbar, the first busbar comprising a first edge busbar disposed on a side of the back contact cell close to the first edge;

[0010] a second busbar connected to the second busbar, the second busbar comprising a second edge busbar disposed on a side of the back contact cell close to the second edge;

[0011] The first gate line includes a first extended gate line connected to an end of the first main gate, and the first extended gate line extends along a first direction to a predetermined position of the first edge and / or the second edge to form a first gate line protrusion.

[0012] Optionally, the second main grid includes a second edge main grid and other second main grids arranged on the side of the back contact battery close to the second edge, the length of the second edge main grid along the second direction is less than or equal to the length of the other second main grids, and the first extended grid line extends along the first direction to a preset position of the second edge to form a first grid line protrusion.

[0013] Optionally, the first gate line protrusion protrudes from the second edge bus bar, or is flush with the second edge bus bar.

[0014] Optionally, the length of the first gate line protrusion is d1, the distance between the first gate line protrusion and the second edge is d2, and d1:d2=(2-5):(1-2).

[0015] Optionally, a length d1 of the first gate line protrusion is 300-2000 μm.

[0016] Optionally, the second gate line includes a second extended gate line connected to an end of the second main gate, and the second extended gate line extends along the first direction to a preset position of the first edge and / or the second edge to form a second gate line protrusion.

[0017] Optionally, the first main grid includes a first edge main grid and other first main grids arranged on the side of the back contact battery close to the first edge, the length of the first edge main grid along the second direction is less than or equal to the length of the other first main grids, and the second extended grid line extends along the first direction to a preset position of the first edge to form a second grid line protrusion.

[0018] Optionally, the second gate line protrusion protrudes from the first edge bus bar, or is flush with the first edge bus bar.

[0019] Optionally, the length of the second gate line protrusion is d3, the distance between the second gate line protrusion and the first edge is d4, and d3:d4=(2-5):(1-2).

[0020] Optionally, a length d3 of the second gate line protrusion is 300-2000 μm.

[0021] Optionally, the first main gate is provided with a first Pad point, and the number of the second extended gate lines is less than the number of the first Pad points; the second main gate is provided with a second Pad point, and the number of the first extended gate lines is less than the number of the second Pad points.

[0022] Optionally, the first main gate is a segmented main gate, wherein the first main gate includes several first segmented main gates, and the first gate line includes several first extended gate lines connected to the ends of the first segmented main gates, each of the first extended gate lines passes through all the first segmented main gates arranged along the first direction, and extends along the first direction to a preset position of the second edge to form a first gate line protrusion.

[0023] Optionally, the first segmented main gate and the first gate line are connected as one through a first extended gate line.

[0024] Optionally, the second main gate includes several second segmented main gates, and the second gate lines include several second extended gate lines connected to the ends of the second segmented main gates, each of the second extended gate lines passes through all the second segmented main gates arranged along the first direction, and extends along the first direction to a preset position of the first edge to form a second gate line protrusion.

[0025] Optionally, the second segmented main gate and the second gate line are connected as one through a second extended gate line.

[0026] Optionally, a third Pad point is provided on the first segmented main gate, and the number of the second extended gate lines is less than the number of the third Pad point; a fourth Pad point is provided on the second segmented main gate, and the number of the first extended gate lines is less than the number of the fourth Pad point.

[0027] Optionally, the first extended gate lines are heterodyne gate lines with opposite polarity to the silicon wafer, the second extended gate lines are homodyne gate lines with the same polarity as the silicon wafer, and the number of the first extended gate lines is greater than the number of the second extended gate lines.

[0028] Optionally, the first extended gate lines are heterogeneous gate lines with opposite polarity to the silicon wafer, and the number is N1; the second extended gate lines are homogeneous gate lines with the same polarity as the silicon wafer, and the number is N2, where N1-N2=(1-2).

[0029] Optionally, when the back contact cell is N-type silicon, the first polarity region is a P-type doped region, and the first extended gate line is a P-type gate line; the second polarity region is an N-type doped region, and the second extended gate line is an N-type gate line;

[0030] When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the first extended gate line is an N-type gate line; the second polarity region is a P-type doped region, and the second extended gate line is a P-type gate line.

[0031] Optionally, when the back contact cell is N-type silicon, the first polarity region is a P-type doped region, and the total length of all P-type gate lines is greater than the total length of all N-type gate lines;

[0032] When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the total length of all N-type gate lines is greater than the total length of all P-type gate lines.

[0033] Optionally, when the back contact cell is N-type silicon, the first polarity region is a P-type doped region, and the ratio a of the total length of all P-type gate lines to the total length of all N-type gate lines is 1<a≤1.2;

[0034] When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the ratio b of the total length of all N-type gate lines to the total length of all P-type gate lines is 1<b≤1.2.

[0035] Optionally, the first extended gate line includes a first edge extended gate line and a first middle extended gate line, the first middle extended gate line is arranged between the fourth Pad points, and the first edge extended gate line is arranged on the side of the back contact battery close to the third edge and / or fourth edge.

[0036] Optionally, the second extended gate line includes a second middle extended gate line, and the second middle extended gate line is provided between the third Pad points.

[0037] On the other hand, an embodiment of the present invention further provides a back-contact battery, which includes the above-mentioned electrode structure, and the electrode structure is arranged on the backlight surface of the back-contact battery.

[0038] Optionally, the back contact battery includes a first polarity region and a second polarity region, the first polarity region includes a first polarity extension region, the first polarity extension region extends along a first direction to form a first polarity protrusion, and the first extension gate line is electrically connected to the first polarity region.

[0039] Optionally, the first polarity extension region runs through the back side of the back contact cell, the first extended gate line runs through the first segmented main grid, and the first extended gate line is fully connected to the first polarity extension region.

[0040] Optionally, the second polarity region includes a second polarity extension region, the second polarity extension region extends along the first direction to form a second polarity protrusion, and the second extended gate line is electrically connected to the second polarity region.

[0041] Optionally, the second polarity extension region runs through the back side of the back contact cell, the second extended gate line runs through the second segmented main grid, and the second extended gate line is fully connected to the second polarity extension region.

[0042] Optionally, the first polarity extension region and / or the second polarity extension region is provided with a first opening.

[0043] Optionally, the width of the first opening is 150-450 nm.

[0044] On the other hand, the present invention also provides a back-contact battery assembly, which includes the above-mentioned back-contact battery.

[0045] On the other hand, the present invention also provides a back-contact battery system, which includes the above-mentioned back-contact battery assembly.

[0046] The implementation of the present invention has the following beneficial effects:

[0047] The present invention includes a first grid line for collecting a first polarity region, a second grid line for collecting a second polarity region, a first main grid and a second main grid, wherein the first main grid includes a first edge main grid arranged on a side of the back contact battery close to the first edge, and the second main grid includes a second edge main grid arranged on a side of the back contact battery close to the second edge. The first grid line includes a first extended grid line connected to the end of the first main grid, and the first extended grid line extends along the first direction to a preset position of the first edge and / or the second edge to form a first grid line protrusion. The present invention extends the auxiliary grid to the GAP area of ​​the edge, and utilizes the grid line protrusion formed by the extension of the first extended grid line to effectively increase the current collection capacity of the area, improve the carrier collection efficiency, effectively reduce the efficiency loss of the edge area of ​​the first edge and / or the second edge, and improve the efficiency of the battery cell.

[0048] Furthermore, the first busbar is a segmented busbar, comprising a plurality of first segmented busbars, and the first gate lines comprise first extended gate lines connected to the ends of the first segmented busbars. Each of the first extended gate lines penetrates all first segmented busbars arranged along the first direction and extends along the first direction to a predetermined position at the second edge, thereby forming a first gate line protrusion. In this case, after each first extended gate line penetrates all first segmented busbars arranged along the first direction, the first segmented busbars and the first gate lines are integrally connected via the first extended gate lines, thereby providing multiple current collection paths and improving the reliability of current collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the first embodiment of the electrode structure of the back contact battery of the present invention;

[0050] Figure 2 yes Figure 1 An enlarged view of section A is shown;

[0051] Figure 3 yes Figure 1 An enlarged view of portion B is shown;

[0052] Figure 4This is a schematic diagram of a second embodiment of the electrode structure of a back-contact battery of the present invention;

[0053] Figure 5 yes Figure 4 An enlarged view of section A is shown;

[0054] Figure 6 yes Figure 4 An enlarged view of portion B is shown;

[0055] Figure 7 This is a schematic diagram of a third embodiment of the electrode structure of a back-contact battery of the present invention;

[0056] Figure 8 yes Figure 7 An enlarged view of section A is shown;

[0057] Figure 9 yes Figure 7 An enlarged view of section B is shown. DETAILED DESCRIPTION

[0058] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention will be further described in detail below with reference to the accompanying drawings. It is hereby stated that any directional terms such as "up," "down," "left," "right," "front," "back," "inside," and "outside" that appear or will appear in this document are based solely on the accompanying drawings and are not intended to limit the present invention.

[0059] The utility model provides an electrode structure for a back-contact battery, the electrode structure comprising a first grid line for collecting a first polarity region, a second grid line for collecting a second polarity region, a first busbar connected to the first grid line, and a second busbar connected to the second grid line. The first busbar comprises a first edge busbar disposed on a side of the back-contact battery close to a first edge; the second busbar comprises a second edge busbar disposed on a side of the back-contact battery close to a second edge; the first grid line comprises a first extended grid line connected to an end of the first busbar, the first extended grid line extending along a first direction to a predetermined position of the first edge and / or the second edge to form a first grid line protrusion.

[0060] The utility model extends the auxiliary grid to the GAP area of ​​the edge, and utilizes the grid line protrusion formed by extending the first extended grid line to effectively increase the current collection capacity of the area, improve the carrier collection efficiency, effectively reduce the efficiency loss of the edge area of ​​the first edge and / or the second edge, and improve the efficiency of the battery cell.

[0061] Example 1

[0062] refer to Figure 1 、 Figure 2 and Figure 3, this embodiment provides an electrode structure of a back-contact battery, including:

[0063] A first grid line 10 for collecting a first polarity region;

[0064] A second grid line 20 for collecting a second polarity region;

[0065] a first busbar 30 connected to the first busbar 10 , the first busbar 30 including a first edge busbar 31 disposed on a side of the back contact cell close to the first edge;

[0066] a second busbar 40 connected to the second busbar 20 , the second busbar 40 including a second edge busbar 41 disposed on a side of the back contact cell close to the second edge;

[0067] The first gate line 10 includes a first extended gate line 11 connected to an end of the first main gate 30 . The first extended gate line 11 extends along a first direction to a predetermined position of the first edge and / or the second edge to form a first gate line protrusion 12 .

[0068] In this embodiment, the second busbar 40 includes a second edge busbar 41 and other second busbars 42 disposed on the side of the back contact cell near the second edge. The length of the second edge busbar 41 along the second direction is less than or equal to the length of the other second busbars 42. The first extended busbar 11 extends along the first direction to a predetermined position of the second edge to form a first busbar protrusion 12. In this case, the second busbar 40 is a continuous busbar. Optionally, the first busbar protrusion 12 protrudes from the second edge busbar 41 or is flush with the second edge busbar 41. Figure 1-3 In the illustrated embodiment, with the dotted line L1 as the boundary, the first extended gate line 11 extends along the first direction to a predetermined position of the second edge to form a first gate line protrusion 12 .

[0069] The utility model extends the auxiliary grid to the GAP area at the edge, and utilizes the first grid line protrusion 12 formed by extending the first extended grid line 11, which can effectively increase the current collection capacity of the area, improve the carrier collection efficiency, effectively reduce the efficiency loss in the edge area of ​​the first edge and / or the second edge, and improve the efficiency of the battery cell.

[0070] It should be noted that the first gate line 10 is used to collect the current in the first polarity region, and the second gate line 20 is used to collect the current in the second polarity region. If the polarities of the first gate line 10 and the second gate line 20 are opposite, then the polarities of the first polarity region and the second polarity region are also opposite. For example, the first gate line 10 is a positive gate line, used to collect the positive current in the positive region, and the second gate line 20 is a negative gate line, used to collect the negative current in the negative region; or, the first gate line 10 is a negative gate line, used to collect the negative current in the negative region, and the second gate line 20 is a positive gate line, used to collect the positive current in the positive region. Wherein, the positive gate line is provided in the P-type doping region of the back contact battery, and the negative gate line is provided in the N-type doping region of the back contact battery.

[0071] The first grid line 10 and the second grid line 20 are alternately arranged, and the first grid line 10 and the second grid line 20 are both horizontal to the edge line of the back contact battery. The first grid line 10 and the second grid line 20 are alternately arranged in the vertical direction, and the first grid line 10 and the second grid line 20 are both horizontal to the upper edge line and the lower edge line of the back contact battery. The back contact battery is substantially rectangular, and the back contact battery that is substantially rectangular can be, for example, a square, or another rectangle, and can have a standard corner, a cut corner or a rounded corner, which is provided according to actual production needs and is not specifically limited here. At the same time, the number of its first grid line 10 and the second grid line 20 is determined according to the actual back contact battery area size, the width of the first grid line 10 and the second grid line 20 and the distance, which is not specifically limited here. The back contact battery can also be processed in slices, for example, with the dotted line in the horizontal direction in the figure as the boundary, to carry out battery cutting.

[0072] Furthermore, the first gate line 10 or the second gate line 20 is an aluminum gate line, a silver gate line, a copper gate line, or a silver-clad copper gate line. It is understood that in the embodiment of the present invention, the first gate line 10 and the second gate line 20 can be selected to be gate lines of the same or different metal types, for example, the first gate line 10 and the second gate line 20 can both be aluminum gate lines; or the first gate line 10 can be aluminum gate lines and the second gate line 20 can be silver gate lines.

[0073] Preferably, see Figure 2 and 3, the length of the first gate line protrusion 12 is d1, and the distance between the first gate line protrusion 12 and the second edge is d2, and the said d1:d2=(2-5):(1-2), which can effectively increase the current collection capacity of the area, improve the carrier collection efficiency, effectively reduce the efficiency loss of the edge area, and improve the efficiency of the battery cell. When d1:d2 is greater than 5:1, the distance between the first gate line protrusion 12 and the second edge is too small, and the distance between the first polarity extension area connected to it and the second edge is also too small, which will reduce the reliability of the battery, and the battery has the risk of edge cracking, short circuit, etc. When d1:d2 is less than 1:1, the current collection capacity of the first gate line protrusion is limited, and the carrier collection efficiency cannot be effectively improved, and the efficiency loss of the edge area still exists.

[0074] More preferably, the ratio d1:d2=(2-3):1 can further improve the carrier collection efficiency and reduce the efficiency loss in the edge region of the first edge and / or the second edge to a large extent.

[0075] It should be noted that, in conjunction with the diagram, the first direction of this embodiment is the horizontal direction, and the second direction is the vertical direction. The first edge is the edge parallel to the first busbar 30 and is located on the right side of the solar cell. The second edge is the edge parallel to the first busbar 30 and is located on the left side of the solar cell.

[0076] The length d1 of the first gate line protrusion can be set according to specific circumstances, preferably in the range of 300-2000 μm, specifically 300, 500, 800, 1000, 1200, 1500, 1800, 2000 μm, etc., but not limited thereto. The distance d2 between the first gate line protrusion 12 and the second edge can also be set according to specific circumstances, preferably in the range of 60-1000 μm, specifically 60, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 μm, etc., but not limited thereto.

[0077] Example 2

[0078] refer to Figure 4 、 Figure 5 and Figure 6 , this embodiment provides an electrode structure of a back-contact battery, including:

[0079] A first grid line 10 for collecting a first polarity region;

[0080] A second grid line 20 for collecting a second polarity region;

[0081] a first busbar 30 connected to the first busbar, the first busbar 30 including a first edge busbar 31 disposed on a side of the back contact cell close to the first edge;

[0082] a second busbar 40 connected to the second busbar line, the second busbar 40 including a second edge busbar 41 disposed on a side of the back contact cell close to the second edge;

[0083] The first gate line 10 includes a first extended gate line 11 connected to an end of the first main gate 30 , and the first extended gate line 11 extends along the first direction to a predetermined position of the first edge and / or the second edge to form a first gate line protrusion 12;

[0084] The second gate line 20 includes a second extended gate line 21 connected to an end of the second main gate 40 . The second extended gate line 21 extends along the first direction to a predetermined position of the first edge and / or the second edge to form a second gate line protrusion 22 .

[0085] Unlike the first embodiment, the second gate line 20 of the second embodiment includes a second extended gate line 21 connected to the end of the second main grid 40. This invention extends the auxiliary grid to the edge GAP region. The second gate line protrusion 22 formed by the second extended gate line 21 can effectively increase the current collection capacity in this region, improve the carrier collection efficiency, effectively reduce efficiency losses in the edge region, and improve the efficiency of the cell.

[0086] In this embodiment, the first busbar 30 includes a first edge busbar 31 and other first busbars 32 disposed on the side of the back contact cell near the first edge. The length of the first edge busbar 31 along the second direction is less than or equal to the length of the other first busbars 32. The second extended busbar 21 extends along the first direction to a predetermined position of the first edge to form a second busbar protrusion 22. In this case, the first busbar 30 is a continuous busbar. Optionally, the second busbar protrusion 22 protrudes from the first edge busbar 31 or is flush with the first edge busbar 31. Figure 4-6 In the illustrated embodiment, with the dotted line L1 as the boundary, the second extended gate line 21 extends along the first direction to a predetermined position of the first edge to form a second gate line protrusion 22 .

[0087] It should be noted that, in conjunction with the diagram, the first direction of this embodiment is the horizontal direction, and the second direction is the vertical direction. The first edge is the edge parallel to the first busbar 30 and is located on the right side of the solar cell. The second edge is the edge parallel to the first busbar 30 and is located on the left side of the solar cell.

[0088] Preferably, see Figure 5 and Figure 6, the length of the second grid line protrusion 22 is d3, and the distance between the second grid line protrusion 22 and the first edge is d4, and the said d3:d4=(2-5):(1-2), which can effectively increase the current collection capacity of the area, improve the carrier collection efficiency, effectively reduce the efficiency loss in the edge area, and improve the efficiency of the battery cell. When d3:d4 is greater than 5:1, the distance between the second grid line protrusion 22 and the first edge is too small, and the distance between the second polarity extension area connected to it and the first edge is also too small, which will reduce the reliability of the battery, and the battery will have the risk of edge cracking, short circuit, etc. When d3:d4 is less than 1:1, the current collection capacity of the second grid line protrusion 22 is limited, and the carrier collection efficiency cannot be effectively improved, and the efficiency loss in the edge area still exists.

[0089] More preferably, the ratio d3:d4=(2-3):1 can further improve the carrier collection efficiency and reduce the efficiency loss in the edge area to a great extent.

[0090] Specifically, the length d3 of the second gate line protrusion can be set according to specific circumstances, and its preferred range is 300-2000 μm, and specifically can be 300, 500, 800, 1000, 1200, 1500, 1800, 2000 μm, etc., but not limited thereto. The distance d4 between the length d3 of the second gate line protrusion and the first edge can also be set according to specific circumstances, and its preferred range is 60-1000 μm, and specifically can be 60, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 μm, etc., but not limited thereto.

[0091] Regarding the relationship between the extended grid lines and the Pad points, when the main grid is a continuous main grid, the number of extended grid lines is less than the number of PAD points on each main grid. In the above-mentioned embodiment one and embodiment two, a first Pad point 51 is provided on the first main grid 30, and the number of the second extended grid lines 21 is less than the number of the first Pad points 51, specifically, the number of the second extended grid lines 21 is less than the number of the first Pad points 51 on each first main grid 30; a second Pad point 52 is provided on the second main grid 40, and the number of the first extended grid lines 11 is less than the number of the second Pad points 52, specifically, the number of the first extended grid lines 11 is less than the number of the second Pad points 52 on each second main grid 40. The number of the first extended grid lines 11 and the second extended grid lines 21 of the present invention is related to the number of Pad points set on the main grid to ensure that the first extended grid line 11 can pass through the first grid line protrusion 12, better collect carriers, and then merge them into the main grid, and converge through the Pad points, thereby improving the photoelectric conversion efficiency of the solar cell.

[0092] Example 3

[0093] refer to Figure 7 、 Figure 8 and Figure 9 , this embodiment provides an electrode structure of a back-contact battery, including:

[0094] A first grid line 10 for collecting a first polarity region;

[0095] A second grid line 20 for collecting a second polarity region;

[0096] a first busbar 30 connected to the first busbar, the first busbar 30 including a first edge busbar 31 disposed on a side of the back contact cell close to the first edge;

[0097] a second busbar 40 connected to the second busbar line, the second busbar 40 including a second edge busbar 41 disposed on a side of the back contact cell close to the second edge;

[0098] The first gate line 10 includes a first extended gate line 11 connected to an end of the first main gate 30 . The first extended gate line 11 extends along a first direction to a predetermined position of the first edge and / or the second edge to form a first gate line protrusion 12 .

[0099] The utility model extends the auxiliary grid to the GAP area at the edge, and utilizes the first grid line protrusion 12 formed by extending the first extended grid line 11, which can effectively increase the current collection capacity of the area, improve the carrier collection efficiency, effectively reduce the efficiency loss in the edge area, and improve the efficiency of the battery cell.

[0100] In this embodiment, the first busbar 30 is a segmented busbar, wherein the first busbar 30 includes a plurality of first segmented busbars 30A, and the first gate lines 10 include a plurality of first extended gate lines 11 connected to the ends of the first segmented busbars 30A. Each first extended gate line 11 passes through all first segmented busbars 30A arranged along the first direction and extends along the first direction to a predetermined position at the second edge to form a first gate line protrusion 12. The first segmented busbars 30A and the first gate lines 10 are connected as a whole via the first extended gate lines 11. Figure 7-9 In the illustrated embodiment, with the dotted line L1 as the boundary, the first extended gate line 11 extends along the first direction to a predetermined position of the second edge to form a first gate line protrusion 12 .

[0101] The first segmented main gate 30A is connected to the first gate line 10 as a whole through the first extended gate line 11, forming a gate line structure in which the same polarity gate lines and the main gate are connected, constructing a multi-channel collection path, further providing more collection paths for the gate line current. When a short circuit, cold solder joint, etc. occurs in a certain gate line or welding point, current can still be collected through other paths, thereby improving the reliability of current collection.

[0102] In addition, after connecting the same polarity grid lines and the main grid corresponding to each pad point in the direction parallel to the same grid line as a whole, when welding with the welding ribbon, the pad points in the same polarity area can also be connected through the welding ribbon, so that more same polarity grid lines on the battery cell are connected into a whole, further reducing the risk of short circuit and cold welding, and improving the reliability of current collection.

[0103] Preferably, the second gridline 20 includes a second extended gridline 21 connected to the end of the second main grid 40. The second extended gridline 21 extends along the first direction to a predetermined position at the first edge and / or the second edge to form a second gridline protrusion 22. The present invention extends the auxiliary grid to the GAP area at the edge. The second gridline protrusion 22 formed by the second extended gridline 21 can effectively increase the current collection capacity in this area, improve the carrier collection efficiency, effectively reduce efficiency loss in the edge area, and improve the efficiency of the cell.

[0104] In this embodiment, the second busbar 40 is a segmented busbar, wherein the second busbar 40 includes a plurality of second segmented busbars 40A, and the second gate lines 20 include a plurality of second extended gate lines 21 connected to the ends of the second segmented busbars 40A. Each second extended gate line 21 passes through all the second segmented busbars 40A arranged along the first direction and extends along the first direction to a predetermined position at the first edge to form a second gate line protrusion 22. The second segmented busbars 40A and the second gate lines 20 are connected as a whole via the second extended gate lines 21. Figure 7-9 In the illustrated embodiment, with the dotted line L1 as the boundary, the second extended gate line 21 extends along the first direction to a predetermined position of the first edge to form a second gate line protrusion 22 .

[0105] The second segmented main gate 40A is connected to the second gate line 20 through the second extended gate line 21, forming a gate line structure in which the same polarity gate lines and the main gate are connected, constructing a multi-channel collection path, further providing more collection paths for the gate line current. When a short circuit, cold solder joint, etc. occurs in a certain gate line or welding point, current can still be collected through other paths, thereby improving the reliability of current collection.

[0106] In addition, after connecting the same polarity grid lines and the main grid corresponding to each pad point in the direction parallel to the same grid line as a whole, when welding with the welding ribbon, the pad points in the same polarity area can also be connected through the welding ribbon, so that more same polarity grid lines on the battery cell are connected into a whole, further reducing the risk of short circuit and cold welding, and improving the reliability of current collection.

[0107] Regarding the relationship between extended gate lines and pad points, when the main gate is a segmented main gate, the number of same-sex extended gate lines is less than the number of all PAD points of the segmented main gate on the same straight line; the number of opposite-sex extended gate lines is less than the number of all PAD points.

[0108] In this embodiment, the first segmented busbar 30A is provided with third pad points 53, and the number of the second extended gate lines 21 is less than the number of the third pad points 53. Specifically, the number of the second extended gate lines 21 is less than the number of all third pad points 53 of the first segmented busbar 30A on the same straight line.

[0109] The second segmented busbar 40A is provided with fourth pad points 54. The number of the first extended gate lines 11 is less than the number of the fourth pad points 54. Specifically, the number of the first extended gate lines 11 is less than the number of all fourth pad points 54. The first extended gate lines 11 are heterodyne gate lines with opposite polarity to the silicon wafer, referred to as heterodyne extended gate lines, while the second extended gate lines 21 are homodyne gate lines with the same polarity as the silicon wafer, referred to as homodyne extended gate lines.

[0110] It should be noted that when the first extended gate line 11 includes a first edge extended gate line 11A and a first middle extended gate line 11B, the first middle extended gate line 11B is arranged between the fourth Pad points 54, and the first edge extended gate line 11A is arranged on the side of the back contact battery close to the third edge and / or the fourth edge. At this time, the number of first extended gate lines 11 is less than the number of all fourth Pad points 54.

[0111] When the first extended gate line 11 only includes the first middle extended gate line 11B, and the first gate line arranged on the side of the back contact battery close to the third edge and / or the fourth edge is not extended, the number of first extended gate lines 11 is less than the number of all fourth Pad points 54 of the second segmented main grid 40A on the same straight line.

[0112] It should also be noted that, in conjunction with the diagram, the first direction of this embodiment is the horizontal direction, and the second direction is the vertical direction. The first edge is the edge parallel to the first main grid 30 and is located on the right side of the solar cell. The second edge is the edge parallel to the first main grid 30 and is located on the left side of the solar cell. The third edge and the fourth edge are respectively parallel to the two edges of the first grid line 10 and are located on the upper and lower sides of the solar cell.

[0113] Example 4

[0114] In order to better increase the effective power generation area of ​​the silicon wafer, generate more photogenerated carriers, increase the short-circuit current, and thus effectively improve the battery conversion efficiency. Based on the third embodiment, the first extended gate lines 11 of the fourth embodiment are heterosexual gate lines with opposite polarity to the silicon wafer, referred to as heterosexual extended gate lines, and the second extended gate lines 21 are homosexual gate lines with the same polarity as the silicon wafer, referred to as homosexual extended gate lines. The number of the first extended gate lines 11 is greater than the number of the second extended gate lines 21, that is, the number of heterosexual extended gate lines is greater than the number of homosexual extended gate lines.

[0115] The present invention controls the number of electrodes corresponding to the one with a different polarity from the silicon wafer in the first polarity region and the second polarity region to be greater than the number of electrodes corresponding to the one with the same polarity as the silicon wafer in the first polarity region and the second polarity region, thereby controlling the total length of the electrodes corresponding to the one with a different polarity from the silicon wafer in the first polarity region and the second polarity region to be greater than the total length of the electrodes corresponding to the one with the same polarity as the silicon wafer in the first polarity region and the second polarity region, thereby effectively increasing the effective power generation area of ​​the silicon wafer, generating more photogenerated carriers, increasing the short-circuit current, and thus effectively improving the battery conversion efficiency.

[0116] Preferably, the first extended gate lines 11 are heterogeneous gate lines with opposite polarity to the silicon wafer, and the number is N1; the second extended gate lines 21 are homogeneous gate lines with the same polarity as the silicon wafer, and the number is N2, where N1 - N2 = (1 - 2). Compared to the second extended gate lines 21, the extra first extended gate lines 11 can be located at the edge or in the middle, and their location can be adjusted according to the electrode pattern design.

[0117] More preferably, the first extended gate lines 11 are heterogeneous gate lines with opposite polarity to the silicon wafer, and the number is N1; the second extended gate lines 21 are homogeneous gate lines with the same polarity as the silicon wafer, and the number is N2, N1-N2=2, and the first extended gate lines 11 are arranged at the two edges and the middle area of ​​the battery.

[0118] In this embodiment, the first extended gate lines 11 include first edge extended gate lines 11A and first middle extended gate lines 11B. The first middle extended gate lines 11B are located between the fourth pad points 54, and the first edge extended gate lines 11A are located on the side of the back contact cell close to the third edge and / or the fourth edge. The second extended gate lines 21 include second middle extended gate lines 21A, which are located between the third pad points 53. The number of the first extended gate lines 22 is greater than the number of the second extended gate lines 21.

[0119] Since the solar cell can be made of N-type silicon or P-type silicon, when the back contact cell is made of N-type silicon, the first polarity region is a P-type doped region, and the first extended gate line is a P-type gate line; the second polarity region is an N-type doped region, and the second extended gate line is an N-type gate line;

[0120] When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the first extended gate line is an N-type gate line; the second polarity region is a P-type doped region, and the second extended gate line is a P-type gate line.

[0121] Preferably, when the back contact cell is N-type silicon, the first polarity region is a P-type doped region, and the total length of all P-type gate lines is greater than the total length of all N-type gate lines;

[0122] When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the total length of all N-type gate lines is greater than the total length of all P-type gate lines.

[0123] Further preferably, when the back contact cell is N-type silicon, the first polarity region is a P-type doped region, and the ratio a of the total length of all P-type gate lines to the total length of all N-type gate lines is 1<a≤1.2;

[0124] When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the ratio b of the total length of all N-type gate lines to the total length of all P-type gate lines is 1<b≤1.2.

[0125] Within this range, it is possible to better balance the collection of electron-hole pairs while ensuring sufficient effective power generation area.

[0126] Exemplarily, when the back contact cell is N-type silicon, the ratio a of the total length of all P-type gate lines to the total length of all N-type gate lines is 1.001, 1.002, 1.005, 1.008, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19 or 1.2, but is not limited thereto.

[0127] Exemplarily, when the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the ratio b of the total length of all N-type gate lines to the total length of all P-type gate lines is 1.001, 1.002, 1.005, 1.008, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19 or 1.2, but is not limited thereto.

[0128] When a or b is less than or equal to 1, the effective power generation area is insufficient. When a or b is greater than 1.2, it is difficult to balance the collection of electron-hole pairs, affecting the battery conversion efficiency.

[0129] Example 5

[0130] Based on the fourth embodiment, the first extended gate lines 11 of the fifth embodiment are heterodyne gate lines with a polarity opposite to that of the silicon wafer, the second extended gate lines 21 are homodyne gate lines with a polarity identical to that of the silicon wafer, and the number of the first extended gate lines 22 is greater than the number of the second extended gate lines 21. Furthermore, the first polarity region has a polarity opposite to that of the silicon wafer, while the second polarity region has a polarity identical to that of the silicon wafer. The electrical conductivities of the silicon wafer, the first polarity region, and the second polarity region increase in sequence.

[0131] The utility model realizes a larger potential gradient between the first polarity region through the silicon wafer and then to the second polarity region by limiting the relationship between the number and length of the gate lines and the conductivity of the polarity regions, thereby strengthening the separation of photogenerated electron-hole pairs, and the collected charges can be transferred more quickly to the metal collection electrode corresponding to the metal gate line, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor.

[0132] For example, the silicon wafer is N-type silicon, the first polarity region is a P-type doped layer, and the second polarity region is an N-type doped layer. By controlling the conductivity of the N-type silicon wafer, the P-type doped layer, and the N-type doped layer to increase in sequence, a larger potential gradient is achieved from the P-type doped layer through the silicon wafer to the N-type doped layer, thereby enhancing the separation of photogenerated electron-hole pairs. Among them, the one of the N-type doped layer and the P-type doped layer with the same polarity as the silicon wafer forms a high-low junction with the silicon wafer, and the one of the N-type doped layer and the P-type doped layer with a different polarity from the silicon wafer forms a pn junction with the silicon wafer. The larger potential gradient is conducive to the rapid entry of electrons into the N-type doped layer and the rapid entry of holes into the P-type doped layer, and the collected charges can be transmitted more quickly to the metal collection electrode corresponding to the metal grid line, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor; at the same time, by controlling the total length of the electrode corresponding to the one of the N-type doped layer and the P-type doped layer with a different polarity from the silicon wafer to be longer than the total length of the electrode corresponding to the one of the N-type doped layer and the P-type doped layer with the same polarity as the silicon wafer, the effective power generation area of ​​the silicon wafer is increased, more photogenerated carriers are generated, the short-circuit current is increased, and the battery conversion efficiency is effectively improved.

[0133] Example 6

[0134] Based on the fourth embodiment, the first extended gate lines 11 of the sixth embodiment are heterodyne gate lines with opposite polarity to the silicon wafer, the second extended gate lines 21 are homodyne gate lines with the same polarity as the silicon wafer, and the number of the first extended gate lines 22 is greater than the number of the second extended gate lines 21. Furthermore, the first polarity region has an opposite polarity to the silicon wafer, while the second polarity region has the same polarity as the silicon wafer. The electrical conductivities of the silicon wafer, the first polarity region, and the second polarity region increase in sequence, and the width of the second polarity region is greater than the width of the first polarity region.

[0135] The utility model realizes a larger potential gradient between the first polarity region through the silicon wafer and then to the second polarity region by limiting the relationship between the number and length of the gate lines and the conductivity and width of the polarity regions, thereby strengthening the separation of photogenerated electron-hole pairs, and the collected charges can be transmitted more quickly to the metal collection electrode corresponding to the metal gate line, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor.

[0136] For example, the silicon wafer is N-type silicon, the first polarity region is a P-type doped layer, and the second polarity region is an N-type doped layer. By controlling the conductivity of the N-type silicon wafer, the P-type doped layer, and the N-type doped layer to increase in sequence, a larger potential gradient is achieved from the P-type doped layer through the silicon wafer to the N-type doped layer, thereby enhancing the separation of photogenerated electron-hole pairs. Among them, the one of the N-type doped layer and the P-type doped layer with the same polarity as the silicon wafer forms a high-low junction with the silicon wafer, and the one of the N-type doped layer and the P-type doped layer with a different polarity from the silicon wafer forms a pn junction with the silicon wafer. The larger potential gradient is conducive to the rapid entry of electrons into the N-type doped layer and the rapid entry of holes into the P-type doped layer, and the collected charges can be transmitted more quickly to the metal collection electrode corresponding to the metal grid line, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor; at the same time, by controlling the total length of the electrode corresponding to the one of the N-type doped layer and the P-type doped layer with a different polarity from the silicon wafer to be longer than the total length of the electrode corresponding to the one of the N-type doped layer and the P-type doped layer with the same polarity as the silicon wafer, the effective power generation area of ​​the silicon wafer is increased, more photogenerated carriers are generated, the short-circuit current is increased, and the battery conversion efficiency is effectively improved.

[0137] Due to the higher conductivity of the N-type doped layer compared to the P-type doped layer, the N-type doped layer has a stronger lateral transmission capability than the P-type doped layer, allowing for a greater transmission distance. Therefore, by using a low-concentration doped silicon wafer and setting the width of the N-type doped layer to be greater than the width of the P-type doped layer, carrier transmission distances can be matched based on the corresponding lateral transmission capabilities of the two, balancing current collection to achieve a lower series resistance and a higher fill factor, further improving conversion efficiency. At the same time, because the highly doped N-type doped layer has better passivation characteristics than the P-type doped layer, by reducing the width of the P-type doped layer and increasing the width of the N-type doped layer, the proportion of the passivation contact area of ​​the N-type polysilicon material layer is increased, which can improve the overall passivation level of the battery and reduce the recombination loss, further improving conversion efficiency.

[0138] Example 7

[0139] A back-contact battery comprises the electrode structure of the first embodiment, wherein the electrode structure is arranged on the backlight surface of the back-contact battery.

[0140] The back contact battery includes a first polarity region and a second polarity region. The first polarity region includes a first polarity extension region. The first polarity extension region extends along a first direction to form a first polarity protrusion. The first extension gate line is electrically connected to the first polarity region.

[0141] The first polarity region includes a first doped layer and a passivation film layer arranged on the first doped layer, the second polarity region includes a second doped layer and a passivation film layer arranged on the second doped layer, the first polarity extension region includes a first extension doped layer and a passivation film layer arranged on the first extension doped layer, and the first gate line, the second gate line, and the first extended gate line are arranged on the passivation film layer.

[0142] On the areas corresponding to the first gate line, the second gate line, and the first extended gate line (i.e., on the projection areas of the first gate line, the second gate line, and the first extended gate line on the passivation film layer), openings are opened on the passivation film layer at positions corresponding to the first doped layer and the second doped layer, and the first gate line, the second gate line, and the first extended gate line are in contact with the first doped layer and the second doped layer through the openings.

[0143] Preferably, the first polarity extension region is provided with a first opening, and the first extended gate line is electrically connected to the first doped layer through the first opening.

[0144] Specifically, the first openings can be formed in the passivation film layer by laser drilling. To maximize current collection, the first openings are preferably formed in all first extended doped layers. The first extended gate lines then contact all first extended doped layers through the first openings to maximize current collection. Of course, in some embodiments, the first openings can also be formed in some first extended doped layers, and this is not limited to this specific method.

[0145] Preferably, the width of the first opening is 150-450 nm, and specifically can be 150 nm, 180 nm, 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, 320 nm, 350 nm, 380 nm, 400 nm, 420 nm, or 450 nm, but is not limited thereto. The width of the first opening provided in the first polarity extension region can be the same as the width of the openings in the other first polarity regions and the second polarity regions, or can be slightly smaller than the width of the openings in the other first polarity regions and the second polarity regions.

[0146] Example 8

[0147] A back-contact battery comprises the electrode structure of the second embodiment, wherein the electrode structure is arranged on the backlight surface of the back-contact battery.

[0148] The back-contact battery includes a first polarity region and a second polarity region, the first polarity region includes a first polarity extension region, the first polarity extension region extends along a first direction to form a first polarity protrusion, and the first extended gate line is electrically connected to the first polarity region; the second polarity region includes a second polarity extension region, the second polarity extension region extends along the first direction to form a second polarity protrusion, and the second extended gate line is electrically connected to the second polarity region.

[0149] The first polarity region includes a first doped layer and a passivation film layer provided on the first doped layer, the second polarity region includes a second doped layer and a passivation film layer provided on the second doped layer, the first polarity extension region includes a first extended doped layer and a passivation film layer provided on the first extended doped layer, the second polarity extension region includes a second extended doped layer and a passivation film layer provided on the second extended doped layer, the first gate line, the second gate line, the first extended gate line, and the second extended gate line are provided on the passivation film layer. On the regions corresponding to the first gate line, the second gate line, the first extended gate line, and the second extended gate line (i.e., on the projection regions of the first gate line, the second gate line, the first extended gate line, and the second extended gate line on the passivation film layer), openings are provided on the passivation film layer at positions corresponding to the first doped layer and the second doped layer, and the first gate line, the second gate line, the first extended gate line, and the second extended gate line are in contact with the first doped layer and the second doped layer through the openings.

[0150] Preferably, the first polarity extension region is provided with a first opening, and the first extended gate line is electrically connected to the first doped layer through the first opening; the second polarity extension region is provided with a first opening, and the second extended gate line is electrically connected to the second doped layer through the first opening.

[0151] Specifically, a first opening can be formed in the passivation film layer by laser drilling. To maximize current collection, the first opening can be preferably formed in all first and second extended doped layers. The first extended gate lines contact all first extended doped layers through the first openings, and the second extended gate lines contact all second extended doped layers through the first openings, to maximize current collection. Of course, in some embodiments, the first openings can also be formed in part of the first and second extended doped layers, and this is not limited to this specific method.

[0152] Preferably, the width of the first opening is 150-450 nm, and specifically can be 150 nm, 180 nm, 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, 320 nm, 350 nm, 380 nm, 400 nm, 420 nm, or 450 nm, but is not limited thereto. The width of the first opening provided in the first polarity extension region and the second polarity extension region can be the same as the width of the openings in the other first polarity regions and the second polarity regions, or can be slightly smaller than the width of the openings in the other first polarity regions and the second polarity regions.

[0153] Embodiment 9

[0154] A back-contact battery comprises the electrode structure of the third embodiment, wherein the electrode structure is arranged on the backlight surface of the back-contact battery.

[0155] Unlike the seventh and eighth embodiments, the first polarity extension region extends through the back surface of the back-contact cell, the first extended gateline extends through the first segmented busbar, and the first extended gateline and the first polarity extension region are fully connected. The second polarity extension region extends through the back surface of the back-contact cell, the second extended gateline extends through the second segmented busbar, and the second extended gateline and the second polarity extension region are fully connected.

[0156] It should be noted that the first extended gateline is fully connected to the first polarity extension region, and the second extended gateline is fully connected to the second polarity extension region, where the term "fully connected" means fully connected. Because the first polarity extension region and the second polarity extension region extend through the back side of the back-contact battery, the first extended gateline extends through the first segmented busbar, and the second extended gateline extends through the second segmented busbar. The first extended gateline is fully connected to the first polarity extension region, and the second extended gateline is fully connected to the second polarity extension region. This allows for current collection across the entire region, improving carrier collection efficiency.

[0157] Example 10

[0158] A back-contact battery comprises the electrode structure of the fourth embodiment, wherein the electrode structure is arranged on the backlight surface of the back-contact battery.

[0159] In the electrode structure provided in this embodiment, the first gate line includes a first extended gate line connected to the end of the first main grid, and the first extended gate line extends along a first direction to a predetermined position at the first edge and / or the second edge to form a first gate line protrusion. The utility model extends the auxiliary grid to the gap area at the edge, and utilizes the gate line protrusion formed by the extension of the first extended gate line to effectively increase the current collection capacity of this area, improve the carrier collection efficiency, effectively reduce the efficiency loss in the edge area of ​​the first edge and / or the second edge, and improve the efficiency of the solar cell.

[0160] The first busbar is a segmented busbar, comprising several first segmented busbars. The first gate lines include first extended gate lines connected to the ends of the first segmented busbars. Each of the first extended gate lines penetrates all first segmented busbars arranged along the first direction and extends along the first direction to a predetermined position at the second edge, forming a first gate line protrusion. In this case, after each first extended gate line penetrates all first segmented busbars arranged along the first direction, the first segmented busbars and the first gate lines are connected as one through the first extended gate lines, providing multiple current collection paths and improving the reliability of current collection.

[0161] Moreover, the number of electrodes corresponding to the polarity different from that of the silicon wafer in the first polarity region and the second polarity region is greater than the number of electrodes corresponding to the polarity same as that of the silicon wafer in the first polarity region and the second polarity region, thereby controlling the total length of the electrodes corresponding to the polarity different from that of the silicon wafer in the first polarity region and the second polarity region to be higher than the total length of the electrodes corresponding to the polarity same as that of the silicon wafer in the first polarity region and the second polarity region, effectively increasing the effective power generation area of ​​the silicon wafer, generating more photogenerated carriers, increasing the short-circuit current, and thus effectively improving the battery conversion efficiency.

[0162] Example 11

[0163] A back-contact battery comprises the electrode structure of the fifth embodiment, wherein the electrode structure is arranged on the backlight surface of the back-contact battery.

[0164] In the electrode structure provided in this embodiment, the first gate line includes a first extended gate line connected to the end of the first main grid, and the first extended gate line extends along a first direction to a predetermined position at the first edge and / or the second edge to form a first gate line protrusion. The utility model extends the auxiliary grid to the gap area at the edge, and utilizes the gate line protrusion formed by the extension of the first extended gate line to effectively increase the current collection capacity of this area, improve the carrier collection efficiency, effectively reduce the efficiency loss in the edge area of ​​the first edge and / or the second edge, and improve the efficiency of the solar cell.

[0165] The first busbar is a segmented busbar, comprising several first segmented busbars. The first gate lines include first extended gate lines connected to the ends of the first segmented busbars. Each of the first extended gate lines penetrates all first segmented busbars arranged along the first direction and extends along the first direction to a predetermined position at the second edge, forming a first gate line protrusion. In this case, after each first extended gate line penetrates all first segmented busbars arranged along the first direction, the first segmented busbars and the first gate lines are connected as one through the first extended gate lines, providing multiple current collection paths and improving the reliability of current collection.

[0166] Moreover, the number of electrodes corresponding to the polarity different from that of the silicon wafer in the first polarity region and the second polarity region is greater than the number of electrodes corresponding to the polarity same as that of the silicon wafer in the first polarity region and the second polarity region, thereby controlling the total length of the electrodes corresponding to the polarity different from that of the silicon wafer in the first polarity region and the second polarity region to be higher than the total length of the electrodes corresponding to the polarity same as that of the silicon wafer in the first polarity region and the second polarity region, effectively increasing the effective power generation area of ​​the silicon wafer, generating more photogenerated carriers, increasing the short-circuit current, and thus effectively improving the battery conversion efficiency.

[0167] Furthermore, the electrical conductivity of the silicon wafer, the first polarity region and the second polarity region increases successively. The polarity of the first polarity region is opposite to that of the silicon wafer, and the polarity of the second polarity region is the same as that of the silicon wafer. A larger potential gradient is achieved between the first polarity region through the silicon wafer and then to the second polarity region, thereby enhancing the separation of photogenerated electron-hole pairs. The collected charges can be transferred more quickly to the metal collection electrode corresponding to the metal grid line, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor.

[0168] Example 12

[0169] A back-contact battery comprises the electrode structure of embodiment 6, wherein the electrode structure is arranged on the backlight surface of the back-contact battery.

[0170] In the electrode structure provided in this embodiment, the first gate line includes a first extended gate line connected to the end of the first main grid, and the first extended gate line extends along a first direction to a predetermined position at the first edge and / or the second edge to form a first gate line protrusion. The utility model extends the auxiliary grid to the gap area at the edge, and utilizes the gate line protrusion formed by the extension of the first extended gate line to effectively increase the current collection capacity of this area, improve the carrier collection efficiency, effectively reduce the efficiency loss in the edge area of ​​the first edge and / or the second edge, and improve the efficiency of the solar cell.

[0171] The first busbar is a segmented busbar, comprising several first segmented busbars. The first gate lines include first extended gate lines connected to the ends of the first segmented busbars. Each of the first extended gate lines penetrates all first segmented busbars arranged along the first direction and extends along the first direction to a predetermined position at the second edge, forming a first gate line protrusion. In this case, after each first extended gate line penetrates all first segmented busbars arranged along the first direction, the first segmented busbars and the first gate lines are connected as one through the first extended gate lines, providing multiple current collection paths and improving the reliability of current collection.

[0172] Moreover, the number of electrodes corresponding to the polarity different from that of the silicon wafer in the first polarity region and the second polarity region is greater than the number of electrodes corresponding to the polarity same as that of the silicon wafer in the first polarity region and the second polarity region, thereby controlling the total length of the electrodes corresponding to the polarity different from that of the silicon wafer in the first polarity region and the second polarity region to be higher than the total length of the electrodes corresponding to the polarity same as that of the silicon wafer in the first polarity region and the second polarity region, effectively increasing the effective power generation area of ​​the silicon wafer, generating more photogenerated carriers, increasing the short-circuit current, and thus effectively improving the battery conversion efficiency.

[0173] Furthermore, the electrical conductivity of the silicon wafer, the first polarity region and the second polarity region increases successively. The polarity of the first polarity region is opposite to that of the silicon wafer, and the polarity of the second polarity region is the same as that of the silicon wafer. A larger potential gradient is achieved between the first polarity region through the silicon wafer and then to the second polarity region, thereby enhancing the separation of photogenerated electron-hole pairs. The collected charges can be transferred more quickly to the metal collection electrode corresponding to the metal grid line, and can effectively reduce the series resistance, reduce the power loss inside the battery, and improve the fill factor.

[0174] Furthermore, the width of the N-type doped layer is greater than that of the P-type doped layer. Based on the corresponding lateral transmission capabilities of the two, the carrier transmission distance is matched, and the current collection is balanced to obtain a smaller series resistance and a higher fill factor, further improving the conversion efficiency. At the same time, because the passivation characteristics of the highly doped N-type doped layer are better than those of the P-type doped layer, by reducing the width of the P-type doped layer and increasing the width of the N-type doped layer, the proportion of the passivation contact area of ​​the N-type polysilicon material layer is increased, which can make the overall comprehensive passivation level of the battery higher and the composite loss lower, further improving the conversion efficiency.

[0175] Example 13

[0176] A back-contact battery assembly comprises the back-contact battery described in the above embodiments 7 to 12.

[0177] In the electrode structure provided in this embodiment, the utility model extends the auxiliary gate to the GAP area of ​​the edge, and utilizes the gate line protrusion formed by extending the first extended gate line to effectively increase the current collection capacity of the area, improve the carrier collection efficiency, effectively reduce the efficiency loss in the edge area of ​​the first edge and / or the second edge, and improve the efficiency of the battery cell.

[0178] Example 14

[0179] A back-contact battery system includes the back-contact battery assembly of the thirteenth embodiment.

[0180] In the electrode structure provided in this embodiment, the utility model extends the auxiliary gate to the GAP area of ​​the edge, and utilizes the gate line protrusion formed by extending the first extended gate line to effectively increase the current collection capacity of the area, improve the carrier collection efficiency, effectively reduce the efficiency loss in the edge area of ​​the first edge and / or the second edge, and improve the efficiency of the battery cell.

[0181] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An electrode structure for a back contact battery, characterized in that: The electrode structure comprises: a first grid line for collecting a first polarity region; a second grid line for collecting a second polarity region; a first busbar connected to the first busbar, the first busbar comprising a first edge busbar disposed on a side of the back contact cell close to the first edge; a second busbar connected to the second busbar, the second busbar comprising a second edge busbar disposed on a side of the back contact cell close to the second edge; The first gate line includes a first extended gate line connected to an end of the first main gate, and the first extended gate line extends along a first direction to a predetermined position of the first edge and / or the second edge to form a first gate line protrusion.

2. The electrode structure of the back contact battery according to claim 1, characterized in that: The second main grid includes a second edge main grid and other second main grids arranged on the side of the back contact battery close to the second edge. The length of the second edge main grid along the second direction is less than or equal to the length of the other second main grids. The first extended grid line extends along the first direction to a preset position of the second edge to form a first grid line protrusion.

3. The electrode structure of the back contact battery according to claim 2, characterized in that: The first gate line protrusion protrudes from the second edge bus bar, or is flush with the second edge bus bar.

4. The electrode structure of the back contact battery according to claim 1, characterized in that: The length of the first gate line protrusion is d1, and the distance between the first gate line protrusion and the second edge is d2, wherein d1:d2=(2-5):(1-2).

5. The electrode structure of the back contact battery according to claim 4, characterized in that: The length d1 of the first gate line protrusion is 300-2000 μm.

6. The electrode structure of the back contact battery according to claim 1, characterized in that: The second gate line includes a second extended gate line connected to an end of the second main gate, and the second extended gate line extends along the first direction to a predetermined position of the first edge and / or the second edge to form a second gate line protrusion.

7. The electrode structure of the back contact battery according to claim 6, characterized in that: The first main grid includes a first edge main grid and other first main grids arranged on the side of the back contact battery close to the first edge, the length of the first edge main grid along the second direction is less than or equal to the length of the other first main grids, and the second extended grid line extends along the first direction to a preset position of the first edge to form a second grid line protrusion.

8. The electrode structure of the back contact battery according to claim 7, characterized in that: The second gate line protrusion protrudes from the first edge bus bar, or is flush with the first edge bus bar.

9. The electrode structure of the back contact battery according to claim 6, characterized in that: The length of the second gate line protrusion is d3, and the distance between the second gate line protrusion and the first edge is d4, wherein d3:d4=(2-5):(1-2).

10. The electrode structure of the back contact battery according to claim 9, characterized in that: The length d3 of the second gate line protrusion is 300-2000 μm.

11. The electrode structure of the back contact battery according to claim 6, characterized in that: The first main grid is provided with first Pad points, and the number of the second extended gate lines is less than the number of the first Pad points; the second main grid is provided with second Pad points, and the number of the first extended gate lines is less than the number of the second Pad points.

12. The electrode structure of the back contact battery according to claim 1, characterized in that: The first main gate is a segmented main gate, wherein the first main gate includes several first segmented main gates, and the first gate line includes several first extended gate lines connected to the ends of the first segmented main gates. Each of the first extended gate lines passes through all the first segmented main gates arranged along the first direction and extends along the first direction to a preset position of the second edge to form a first gate line protrusion.

13. The electrode structure of the back contact battery according to claim 12, characterized in that: The first segmented main gate and the first gate line are connected as one through a first extended gate line.

14. The electrode structure of the back contact battery according to claim 12, characterized in that: The second main gate is a segmented main gate, wherein the second main gate includes several second segmented main gates, and the second gate line includes several second extended gate lines connected to the ends of the second segmented main gates. Each of the second extended gate lines passes through all the second segmented main gates arranged along the first direction and extends along the first direction to a preset position of the first edge to form a second gate line protrusion.

15. The electrode structure of the back contact battery according to claim 14, characterized in that: The second segmented main gate and the second gate line are connected as one through a second extended gate line.

16. The electrode structure of the back contact battery according to claim 14, characterized in that: A third Pad point is provided on the first segmented main gate, and the number of the second extended gate lines is less than the number of the third Pad point; a fourth Pad point is provided on the second segmented main gate, and the number of the first extended gate lines is less than the number of the fourth Pad point.

17. The electrode structure of the back contact battery according to claim 6 or 14, characterized in that: The first extended gate lines are heterogeneous gate lines with opposite polarity to the silicon wafer, and the second extended gate lines are homogeneous gate lines with the same polarity as the silicon wafer. The number of the first extended gate lines is greater than the number of the second extended gate lines.

18. The electrode structure of the back contact battery according to claim 17, characterized in that: The first extended gate lines are heterogeneous gate lines with opposite polarity to the silicon wafer, and the number is N1; the second extended gate lines are homogeneous gate lines with the same polarity as the silicon wafer, and the number is N2, where N1-N2=(1-2).

19. The electrode structure of the back contact battery according to claim 18, characterized in that: When the back contact cell is N-type silicon, the first polarity region is a P-type doped region, and the first extended gate line is a P-type gate line; the second polarity region is an N-type doped region, and the second extended gate line is an N-type gate line; When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the first extended gate line is an N-type gate line; the second polarity region is a P-type doped region, and the second extended gate line is a P-type gate line.

20. The electrode structure of the back contact battery according to claim 19, characterized in that: When the back contact cell is N-type silicon, the first polarity region is a P-type doped region, and the total length of all P-type gate lines is greater than the total length of all N-type gate lines; When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the total length of all N-type gate lines is greater than the total length of all P-type gate lines.

21. The electrode structure of the back contact battery according to claim 20, characterized in that: When the back contact cell is N-type silicon, the first polarity region is a P-type doped region, and the ratio a of the total length of all P-type gate lines to the total length of all N-type gate lines is 1<a≤1.2; When the back contact cell is P-type silicon, the first polarity region is an N-type doped region, and the ratio b of the total length of all N-type gate lines to the total length of all P-type gate lines is 1<b≤1.

2.

22. The electrode structure of the back contact battery according to claim 16, characterized in that: The first extended gate lines include first edge extended gate lines and first middle extended gate lines. The first middle extended gate lines are arranged between the fourth Pad points, and the first edge extended gate lines are arranged on the side of the back contact battery close to the third edge and / or fourth edge.

23. The electrode structure of the back contact battery according to claim 16, characterized in that: The second extended gate lines include second middle extended gate lines, and the second middle extended gate lines are arranged between the third Pad points.

24. A back contact battery, characterized in that The back contact cell comprises the electrode structure according to any one of claims 1 to 23, and the electrode structure is arranged on the backlight surface of the back contact cell.

25. The back contact cell according to claim 24, characterized in that The back contact battery includes a first polarity region and a second polarity region. The first polarity region includes a first polarity extension region. The first polarity extension region extends along a first direction to form a first polarity protrusion. The first extension gate line is electrically connected to the first polarity region.

26. The back contact cell according to claim 25, characterized in that The first polarity extension region runs through the back side of the back contact cell, the first extension grid line runs through the first segmented main grid, and the first extension grid line is fully connected to the first polarity extension region.

27. The back contact cell according to claim 25, characterized in that The second polarity region includes a second polarity extension region, the second polarity extension region extends along the first direction to form a second polarity protrusion, and the second extended gate line is electrically connected to the second polarity region.

28. The back contact cell according to claim 27, characterized in that The second polarity extension region runs through the back side of the back contact cell, the second extension grid line runs through the second segmented main grid, and the second extension grid line is fully connected to the second polarity extension region.

29. The back contact cell according to claim 27, characterized in that The first polarity extension region and / or the second polarity extension region is provided with a first opening.

30. The back contact cell according to claim 29, characterized in that The width of the first opening is 150-450 nm.

31. A back contact battery assembly, characterized in that: It comprises a back contact cell as claimed in any one of claims 24 to 30.

32. A back contact battery system, characterized in that: It includes the back contact battery assembly as described in claim 31.

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