Back contact solar cell, preparation method thereof and photovoltaic module

Abstract

The invention discloses a back contact solar cell, a preparation method thereof and a photovoltaic module. The backlight surface of the battery comprises P regions, spacer regions and N regions which are alternately arranged; the backlight surface comprises at least one first area, other areas except the first area are second areas, the area proportion of the N area in the first area is N1, the area proportion of the N area in the second area is N2, and N1 < lt >; n2, the first region is a region corresponding to the quartz boat print. Therefore, the area occupation ratio of the N region in the first region is small, and the problem of poor EL test of the region corresponding to the quartz boat printing can be relieved and even solved to a certain extent at least.

Description

TECHNICAL FIELD

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

[0002] In the preparation process of a BC (back contact) solar cell, quartz boat marks are prone to occur, and EL (electroluminescence) test failure (EL blackening) is prone to occur in the area corresponding to the quartz boat marks. At present, the quartz boat marks are generally controlled through boat control and process control, but the control cannot well solve the problem of EL test failure in the area corresponding to the quartz boat marks. For example, if the control is poor, 100% EL test failure problem may occur, which becomes a major unstable factor affecting yield.

[0003] Therefore, the problem of EL test failure in the area corresponding to the quartz boat marks of the current back contact solar cell still needs to be improved. SUMMARY

[0004] The present application is made based on the discovery and understanding of the inventors on the following facts and problems:

[0005] Reference Figure 1 The back contact solar cell has four areas corresponding to quartz boat marks (the areas corresponding to the rectangular frames in Figure 1 ), and the area corresponding to the middle rectangular frame is dark (black) when the cell is subjected to EL test. The area corresponding to the quartz boat marks is bright when the cell is subjected to PL (photoluminescence) test. It can be deduced from the PL bright and EL dark of the area corresponding to the quartz boat marks of the cell that the oxide layer (silicon oxide layer) in the N region in the area corresponding to the quartz boat marks is too thick. The silicon oxide layer in this part is relatively thick, so the carriers are not easy to pass through, which finally leads to poor electron collection efficiency in this part and local EL blackening.

[0006] Figure 2 and Figure 3 respectively show part of the structure of a back contact solar cell in the related art. The grid lines 1 of the back contact solar cell are all arranged on the back light surface. In the preparation process of the cell, the quartz boat teeth 2 will be in contact with the cell. The prepared cell can have one or more areas corresponding to quartz boat marks (the areas corresponding to the dashed rectangular frames in Figure 2 and Figure 3 ). The inventors found that the N region in the area corresponding to the quartz boat marks occupies a relatively large area, and EL blackening is prone to occur in the area corresponding to the quartz boat marks during EL test. The problem of EL test failure can be improved by reducing the proportion of the N region in the area corresponding to the quartz boat marks. The present application optimizes the structure and preparation method of the area corresponding to the quartz boat marks to improve the transmission effect of the carriers in this part of the area, which can alleviate or even solve the problem of EL test failure in the area corresponding to the quartz boat marks and improve the preparation yield of the BC solar cell.

[0007] The present application aims to at least partially alleviate or solve at least one of the above-mentioned problems.

[0008] In an aspect of the present application, the present application provides a back contact solar cell. In some embodiments of the present application, the back surface of the back contact solar cell comprises P regions, spacer regions and N regions arranged alternately; the back surface comprises at least one first region, and other regions except the first region are second regions, the area proportion of N regions in the first region is N1, and the area proportion of N regions in the second region is N2, wherein N1 < N2, and the first region corresponds to a quartz boat imprint region. In this way, the area proportion of N regions in the first region is small, which can at least partially alleviate or even solve the problem of EL test failure in the quartz boat imprint region.

[0009] In some embodiments of the present application, the back contact solar cell satisfies one of the following conditions: the first region is composed of P regions; the first region is composed of P regions and spacer regions; the first region is composed of N regions and spacer regions; the first region is composed of N regions, P regions and spacer regions.

[0010] In some embodiments of the present application, the first region is composed of P regions, the first region is composed of a first main grid region and a first auxiliary grid region, the first main grid region comprises a first main grid, the first main grid extends along a first direction, and the first region satisfies one of the following conditions: the grid lines of the first auxiliary grid region are all first fine grid lines, and the first fine grid lines are connected with the first main grid; the grid lines of the first auxiliary grid region are composed of one first fine grid line and at least one second fine grid line, the first fine grid line is connected with the second fine grid line and the first main grid respectively; the grid lines of the first auxiliary grid region are composed of a plurality of first fine grid lines and at least one second fine grid line, the first fine grid line is connected with the second fine grid line and the first main grid respectively; wherein the first fine grid line extends along a second direction, the second fine grid line extends along the first direction, and the second direction intersects with the first direction.

[0011] In some embodiments of the present application, the first region is composed of a P region and a spacer region, in the first region, the P region includes a first main grid region, the first main grid region includes a first main grid, the first main grid extends along a first direction, and the first region satisfies one of the following conditions: the P region is composed of a first main grid region and a first auxiliary grid region, the grid lines of the first auxiliary grid region are all first fine grid lines, and the first fine grid lines are connected with the first main grid; the P region is composed of a first main grid region and a first auxiliary grid region, the grid lines of the first auxiliary grid region are composed of a first fine grid line and at least one second fine grid line, the first fine grid line is connected with the second fine grid line and the first main grid respectively; the P region is composed of a first main grid region and a first auxiliary grid region, the grid lines of the first auxiliary grid region are composed of a plurality of first fine grid lines and at least one second fine grid line, the first fine grid line is connected with the second fine grid line and the first main grid respectively; the P region is composed of a first main grid region; wherein the first fine grid line extends along a second direction, the second fine grid line extends along a first direction, and the second direction intersects with the first direction.

[0012] In some embodiments of the present application, the first region is composed of an N region and a spacer region, and the first region satisfies one of the following conditions: in the first region, the N region is composed of a second main grid region, the second main grid region includes a second main grid, and the second main grid extends along a first direction; in the first region, the N region is composed of a second main grid region and one or two second auxiliary grid regions, the second auxiliary grid region is connected with the second main grid region, and the second auxiliary grid region is not provided with a fine grid line; in the first region, the N region is composed of a second main grid region and one or two second auxiliary grid regions, the second auxiliary grid region is connected with the second main grid region, at least one of the second auxiliary grid regions is provided with a third fine grid line, the third fine grid line extends along a second direction and is connected with the second main grid, and the second direction intersects with the first direction.

[0013] In some embodiments of the present application, the first region is composed of an N region, a P region and a spacer region, the first region is composed of a spacer region, a second auxiliary grid region, a first main grid region and at least one first auxiliary grid region, the second auxiliary grid region is located in the N region, the first main grid region and the first auxiliary grid region are located in the P region, the first main grid region comprises a first main grid, the first main grid extends along a first direction, and the first region satisfies one of the following conditions: each of the first auxiliary grid region is provided with only one first fine grid line, and the first fine grid line is connected with the first main grid; the grid line in at least one of the first auxiliary grid region is composed of a plurality of first fine grid lines, and the first fine grid line is connected with the first main grid; the grid line in at least one of the first auxiliary grid region is composed of a first fine grid line and at least one second fine grid line, the first fine grid line is connected with the first main grid and the second fine grid line respectively; the grid line in at least one of the first auxiliary grid region is composed of a plurality of first fine grid lines and at least one second fine grid line, the first fine grid line is connected with the first main grid and the second fine grid line respectively; wherein the first fine grid line extends along a second direction, the second fine grid line extends along a first direction, and the second direction intersects with the first direction.

[0014] In some embodiments of the present application, the first region is composed of an N region, a P region and a spacer region, the first region is composed of a spacer region, a second auxiliary grid region, a first main grid region and at least one first auxiliary grid region, the second auxiliary grid region is located in the N region, the first main grid region and the first auxiliary grid region are located in the P region, the first main grid region comprises a first main grid, the first main grid extends along a first direction, and in the first region, at least one of the second auxiliary grid region is provided with a third fine grid line, and the third fine grid line extends along a second direction.

[0015] In some embodiments of the present application, the first region is composed of an N region, a P region and a spacer region, the first region is composed of a second main grid region, a first auxiliary grid region and a spacer region, the second main grid region is located in the N region, the second main grid region comprises a second main grid, the second main grid extends along a first direction, the first auxiliary grid region is located in the P region, and the first region satisfies one of the following conditions: the number of grid lines in each of the first auxiliary grid region in the first region is independently 0 or 1; in the first region, a plurality of grid lines of at least one of the first auxiliary grid region are first fine grid lines; in the first region, the grid line of at least one of the first auxiliary grid region is composed of a first fine grid line and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line; in the first region, the grid line of at least one of the first auxiliary grid region is composed of a plurality of first fine grid lines and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line; wherein the first fine grid line extends along a second direction, the second fine grid line extends along a first direction, and the second direction intersects with the first direction.

[0016] In some embodiments of the present application, the first region is composed of an N region, a P region and a spacer region, the first region is composed of a second main grid region, a second auxiliary grid region, a first auxiliary grid region and a spacer region, the second main grid region and the second auxiliary grid region are located in the N region, the second auxiliary grid region is connected with the second main grid region, the second main grid region comprises a second main grid, the second main grid extends along a first direction, the first auxiliary grid region is located in the P region, and the first region satisfies one of the following conditions: the number of grid lines of each first auxiliary grid region in the first region is independently 0 or 1; in the first region, a plurality of grid lines of at least one first auxiliary grid region are first fine grid lines; in the first region, the grid line of at least one first auxiliary grid region is composed of a first fine grid line and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line; in the first region, the grid line of at least one first auxiliary grid region is composed of a plurality of first fine grid lines and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line; wherein the first fine grid line extends along a second direction, and the second fine grid line extends along the first direction, and the second direction intersects with the first direction.

[0017] In some embodiments of the present application, the first region is composed of an N region, a P region and a spacer region, the first region is composed of a second main grid region, a second auxiliary grid region, a first auxiliary grid region and a spacer region, the second main grid region and the second auxiliary grid region are located in the N region, the second auxiliary grid region is connected with the second main grid region, the second main grid region comprises a second main grid, the second main grid extends along a first direction, the first auxiliary grid region is located in the P region, and in the first region, at least one second auxiliary grid region is provided with a third fine grid line, the third fine grid line extends along a second direction and is connected with the second main grid.

[0018] In some embodiments of the present application, the arrangement mode of the grid lines in the first region is different from the arrangement mode of the grid lines in at least part of the second region, and the grid lines in the second region are distributed in an interdigital manner.

[0019] In another aspect of the present application, the present application provides a method for preparing the back contact solar cell described above, comprising:

[0020] providing a cell substrate, and dividing a back surface of the cell substrate into P regions, spacer regions and N regions arranged alternately;

[0021] placing the cell substrate in a quartz boat, and sequentially forming a first silicon oxide layer and a first polycrystalline silicon layer on the back surface;

[0022] performing boron diffusion and oxidation treatment to form a P-type doped polycrystalline silicon layer and a borosilicate glass layer;

[0023] performing a first laser treatment to remove the borosilicate glass layer of the N region and the spacer region;

[0024] removing the P-type doped polysilicon layer and the first silicon oxide layer of the N region and the spacer region;

[0025] forming a second silicon oxide layer and a second polysilicon layer on the back surface of the solar cell in sequence, the second silicon oxide layer of the P region being located on a side of the borosilicate glass layer away from the cell substrate;

[0026] performing a phosphorus diffusion and oxidation treatment to form an N-type doped polysilicon layer and a phosphosilicate glass layer;

[0027] performing a second laser treatment to remove the phosphosilicate glass layer of the P region and the spacer region;

[0028] removing the N-type doped polysilicon layer and the second silicon oxide layer of the P region and the spacer region;

[0029] The back surface of the solar cell comprises at least one first region, and other regions except the first region are second regions, the area ratio of the N region in the first region is N1, and the area ratio of the N region in the second region is N2, wherein N1 < N2, and the first region corresponds to the quartz boat mark region.

[0030] Therefore, the solar cell prepared by the above method has all the characteristics and advantages of the back contact solar cell described above, which will not be repeated here. The method can improve the preparation yield of the solar cell, and does not need to increase too many operation steps in the preparation process.

[0031] In another aspect of the present application, a photovoltaic module is provided. In some embodiments of the present application, the photovoltaic module comprises the back contact solar cell described above. Therefore, the photovoltaic module has all the characteristics and advantages of the back contact solar cell described above, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0032] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

[0033] Figure 1 A schematic diagram showing EL test failure of a back contact solar cell in the related art is shown;

[0034] Figure 2 A schematic diagram showing part of the structure of a back contact solar cell in the related art is shown;

[0035] Figure 3 A schematic diagram showing part of the structure of a back contact solar cell in the related art is shown;

[0036] Figure 4A partial structural schematic of a back contact solar cell according to one embodiment of the application is shown.

[0037] Figure 5 A partial structural schematic of a back contact solar cell according to another embodiment of the application is shown.

[0038] Figure 6 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0039] Figure 7 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0040] Figure 8 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0041] Figure 9 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0042] Figure 10 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0043] Figure 11 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0044] Figure 12 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0045] Figure 13 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0046] Figure 14 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0047] Figure 15 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0048] Figure 16 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0049] Figure 17 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0050] Figure 18A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0051] Figure 19 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0052] Figure 20 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0053] Figure 21 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0054] Figure 22 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0055] Figure 23 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0056] Figure 24 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0057] Figure 25 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0058] Figure 26 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0059] Figure 27 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0060] Figure 28 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0061] Figure 29 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0062] Figure 30 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0063] Figure 31 A partial structural schematic of a back contact solar cell according to yet another embodiment of the application is shown.

[0064] Figure 32A partial structural schematic diagram of a back contact solar cell according to yet another embodiment of the present application is shown.

[0065] Figure 33 A partial structural schematic diagram of a back contact solar cell according to yet another embodiment of the present application is shown.

[0066] Figure 34 A partial structural schematic diagram of a back contact solar cell according to yet another embodiment of the present application is shown.

[0067] Figure 35 A partial structural schematic diagram of a back contact solar cell according to yet another embodiment of the present application is shown.

[0068] Figure 36 A partial structural schematic diagram of a back contact solar cell according to yet another embodiment of the present application is shown.

[0069] BRIEF DESCRIPTION OF DRAWINGS

[0070] 1: grid line; 2: quartz boat tooth; 100: N region; 110: second main grid region; 111: second main grid; 120: second auxiliary grid region; 121: third fine grid line; 122: fourth fine grid line; 200: spacing region; 300: P region; 310: first main grid region; 311: first main grid; 320: first auxiliary grid region; 321: first fine grid line; 322: second fine grid line. DETAILED DESCRIPTION

[0071] Embodiments of the present application are described in detail below with reference to examples shown in the attached drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the attached drawings are exemplary and are only used to explain the present application and cannot be understood as a limitation of the present application.

[0072] In an aspect of the present application, the present application provides a back contact solar cell. In some embodiments of the present application, with reference to Figures 4 to 9 、 Figures 11 to 36 The back surface of the back contact solar cell includes P regions 300, spacing regions 200 and N regions 100 arranged alternately; the back surface includes at least one first region 400, and other regions except the first region are second regions. The area proportion of the N region in the first region is N1, and the area proportion of the N region in the second region is N2, wherein N1 < N2, and the first region 400 is a quartz boat printing corresponding region. The smaller the area proportion of the N region in the first region, the more conducive to improving or solving the EL test problem.

[0073] In some embodiments, the difference between N1 and N2 is greater than or equal to 5%, and exemplarily, the area percentage of the N region in the second region N2 = 40%, the area percentage of the N region in the first region N1 can be set to be ≤ 35%.

[0074] In some embodiments, the area of the N region in the first region, i.e., the area of the overlapping part of the N region 100 and the first region 400, is a, the area of the first region 400 is b, and N1 = a / b ≤ 35%. The area percentage of the N region in the first region is small, and the problem of blackening of the quartz boat mark corresponding area in the EL test process is not prone to occur, which can at least improve or solve the problem of EL test failure and improve the yield of the back contact solar cell.

[0075] In some embodiments, the area percentage of the N region in the second region N2 ≥ 45%, and the area percentage of the N region in the first region N1 can be set to be ≤ 40%.

[0076] In other embodiments, the area percentage of the N region in the first region N1 can be ≤ 33%, ≤ 30%, ≤ 25%, ≤ 20%, ≤ 10%, ≤ 5%, ≤ 3%, or N1 can be 0, and N2 > N1.

[0077] In the present application, the cell substrate in the preparation process of the back contact solar cell is placed in the quartz boat, and the quartz boat teeth are in contact with the cell substrate. The part in contact with the quartz boat teeth and the part in the surrounding area are affected to a certain extent in the process of depositing the silicon oxide layer. The part in contact with the quartz boat teeth and the part in the surrounding area are the first region (quartz boat mark corresponding area). It should be noted that the specific number, position and size of the first region (quartz boat mark corresponding area) are not particularly limited in the present application, and can be set and adjusted as needed in the actual operation process.

[0078] In some specific embodiments, the back surface of the back contact solar cell can have four first regions 400 (dashed box corresponding area). Figures 4 to 9 、 Figures 11 to 36 In other embodiments, the back surface of the back contact solar cell can have one, two, three or other number of first regions 400.

[0079] In some embodiments, the bottom edge length of the quartz boat teeth is 3 mm, the height is 5 mm, the actual contact area of the quartz boat teeth and the cell substrate is about 1 / 3 of the area of the quartz boat teeth, and the contact area is about 2.5 mm 2 . The actual affected area of the quartz boat (the first region) is about 2.25 cm 2 (squaring area of 1.5 cm x 1.5 cm).

[0080] In other embodiments, the area of one first region 400 is about 2 cm2 (1cm x 2cm).

[0081] In some embodiments of the present application, a scanning electron microscope can be used to observe the various regions of the back contact solar cell and measure the area ratio of the N region in the first region and the second region.

[0082] In some embodiments of the present application, the cell substrate (substrate) can be an N-type silicon wafer.

[0083] In some embodiments of the present application, the P region 300 can be provided with grid lines (including main grid lines and fine grid lines), a first silicon oxide layer on the surface of the cell substrate, and a P-type doped polysilicon layer on the side of the first silicon oxide layer away from the cell substrate. The grid lines of the P region are in contact with the P-type doped polysilicon layer for collecting holes. The N region 100 can be provided with grid lines (including main grid lines and fine grid lines), a second silicon oxide layer on the surface of the cell substrate, and an N-type doped polysilicon layer on the side of the second silicon oxide layer away from the cell substrate. The grid lines of the N region are in contact with the N-type doped polysilicon layer for collecting electrons. The spacer region 200 is located between the N region 100 and the P region 300 for spacing the N region 100 and the P region 300.

[0084] In the present application, the first region 400 can have different structures, which will be described in detail below with reference to the drawings. For the case where the cell has a plurality of first regions 400, the structure of each first region 400 can be independently selected from one of the following schemes, and the structures of the plurality of first regions 400 can be the same or different.

[0085] In some embodiments, referring to Figures 4 to 9 , the first region 400 can be composed of a P region. That is, there is no N region and spacer region in the first region 400, and in this case, there is no overlapping part between the N region 100 and the first region 400, and a / b = 0.

[0086] In some embodiments, referring to Figures 4 to 9 , the first region 400 is composed of a first main grid region 310 and a first sub-grid region 320, the first sub-grid region 320 and the first main grid region 310 are connected, and the first main grid region 310 includes a first main grid 311, the first main grid 311 extends along a first direction (such as the Y direction shown in Figures 4 to 9 In some specific embodiments, referring to Figures 4 to 9 , the first region 400 can be composed of one first main grid region 310 and one first sub-grid region 320.

[0087] Regarding the division of the first main grid region 310 and the first sub-grid region 320, referring to Figure 10, in the P region 300, the area corresponding to the dashed box is the first main grid region 310, and the area on the left side of the dashed box is the first auxiliary grid region 320, and the first auxiliary grid region 320 is connected with the first main grid region 310, Figure 10 In the first auxiliary grid region 320, the number of the first auxiliary grid region 320 is 3, the uppermost one, the lowermost one, and the middle one. In the following, the second main grid region and the second auxiliary grid region are also divided in a similar manner.

[0088] In some embodiments, referring to Figure 4 , Figure 5 and Figure 8 , in the first region 400, the grid lines of the first auxiliary grid region 320 are all first fine grid lines 321, the first fine grid lines 321 extend along the second direction (the X direction shown in Figure 4 , Figure 5 and Figure 8 , the second direction (X direction) intersects the first direction (Y direction), and the first fine grid lines 321 are connected with the first main grid 311. In some embodiments, the second direction can be perpendicular or substantially perpendicular to the first direction (for example, the acute angle between the second direction and the first direction can be between 88° and 90°).

[0089] In some embodiments of the present application, referring to Figure 4 , in the first region 400, the first auxiliary grid region 320 is provided with only one first fine grid line 321. In some other embodiments of the present application, referring to Figure 5 and Figure 8 , in the first region 400, the first auxiliary grid region 320 is provided with a plurality of first fine grid lines 321, and the plurality of first fine grid lines 321 can be arranged along the first direction (Y direction) and extend along the second direction (X direction).

[0090] In some embodiments, referring to Figure 6 , in the first region 400, the grid lines of the first auxiliary grid region 320 are composed of one first fine grid line 321 and at least one second fine grid line 322. Wherein, the second fine grid line 322 extends along the first direction (such as the Y direction shown in Figure 6 , and the first fine grid line 321 is connected with the second fine grid line 322 and the first main grid 311, respectively. In the first region, the area of the first auxiliary grid region increases, which may increase the difficulty of collecting carriers. By providing the second fine grid line extending along the Y direction, the collection efficiency of the P region can be ensured. In some embodiments, in the first region 400, the grid lines of the first auxiliary grid region can be composed of one first fine grid line and one second fine grid line. In some other embodiments, referring to Figure 6 , in the first region 400, the grid lines of the first auxiliary grid region 320 can be composed of one first fine grid line 321 and a plurality of second fine grid lines 322.

[0091] In some embodiments of the present application, referring toFigure 7 and Figure 9 In the first region 400, the grid lines of the first sub-grid region 320 can be composed of multiple first fine grid lines 321 and at least one second fine grid line 322. The first fine grid lines 321 are along a second direction (e.g., Figure 7 and Figure 9 The second fine grid line 322 extends along the first direction (as shown in the X direction), extending in the X direction. Figure 7 and Figure 9 Extending in the Y direction (as shown), the second direction intersects the first direction, and the first fine grid line 321 is connected to the second fine grid line 322 and the first main grid 311 respectively.

[0092] In some embodiments of this application, the width of the first fine gate line 321 and the second fine gate line 322 can each be independently 20μm-35μm. For example, the width of the first fine gate line 321 and the second fine gate line 322 can each be independently 24μm, 25μm, 26μm, 30μm, 33μm, etc.

[0093] In some embodiments of this application, reference is made to Figures 11 to 17 The first region 400 can be composed of region P 300 and interval region 200. In this case, region N 100 and the first region 400 do not overlap, i.e., a / b = 0.

[0094] In some embodiments of this application, reference is made to Figures 11 to 15 The first region 400 may be composed of a P region 300 and a spacing region 200. In the first region 400, the P region 300 is composed of a first main gate region 310 and a first secondary gate region 320. The first main gate region 310 includes a first main gate 311, which is located along a first direction (e.g., Figures 11 to 15 (Extends in the Y direction as shown).

[0095] In some specific embodiments of this application, reference is made to Figure 11 , Figure 12 and Figure 15 In the first region 400, the grid lines of the first sub-grid region 320 are all first fine grid lines 321, and the first fine grid lines 321 are along the second direction (e.g., Figure 11 , Figure 12 and Figure 15 The first fine grid line 321 is connected to the first main grid 311. (The X direction shown is extended, the second direction intersects the first direction, and the first fine grid line 321 is connected to the first main grid 311.)

[0096] In some embodiments of this application, reference is made to Figure 11 In the first region 400, only one first fine gate line 321 is provided in the first sub-gate region 320. In some other embodiments of this application, refer to Figure 12 and Figure 15In the first region 400, the first sub-gate region 320 includes multiple first fine gate lines 321, all of which are connected to the first main gate 311. In this specification, "multiple lines" means two or more, and "at least one" means one or more.

[0097] In some embodiments of this application, reference is made to Figure 13 In the first region 400, the gate lines of the first sub-gate region 320 consist of a first fine gate line 321 and at least one second fine gate line 322. The first fine gate line 321 extends along a second direction (X direction), and the second fine gate line 322 extends along a first direction (Y direction). Furthermore, the first fine gate line 321 is connected to both the second fine gate line 322 and the first main gate 311. In some specific embodiments, refer to... Figure 13 In the first region 400, the grid lines of the first sub-grid region 320 can be composed of a first fine grid line 321 and multiple second fine grid lines 322.

[0098] In some embodiments of this application, reference is made to Figure 14 In the first region 400, the gate lines of the first sub-gate region 320 consist of multiple first fine gate lines 321 and at least one second fine gate line 322. The first fine gate lines 321 extend along a second direction (X direction), and the second fine gate lines 322 extend along a first direction (Y direction). Furthermore, the first fine gate lines 321 are connected to the second fine gate lines 322 and the first main gate 311, respectively. In some specific embodiments, refer to... Figure 14 In the first region 400, the grid lines of the first sub-grid region 320 can be composed of multiple first fine grid lines 321 and multiple second fine grid lines 322.

[0099] In some embodiments of this application, reference is made to Figure 16 and Figure 17 The first region 400 can be composed of P region 300 and interval region 200. In the first region 400, P region 300 is composed of first main grid region 310.

[0100] In some embodiments, reference Figures 18 to 20 The first region 400 can be composed of N region 100 and interval region 200. The first region 400 is mostly interval region, the area of ​​N region 100 is ≤ 40% of the total area of ​​the first region, and N1 < N2.

[0101] In some embodiments of this application, reference is made to Figure 18 The first region 400 may consist of an N region 100 and a spacing region 200. Within the first region 400, the N region 100 is composed of a second main gate region 110. The second main gate region 110 includes a second main gate 111, which extends along a first direction (e.g., ...). Figure 18 (Extends in the Y direction as shown).

[0102] In some embodiments of the present application, referring to Figure 19 , the first area 400 can be composed of the N area 100 and the interval area 200, in the first area 400, the N area 100 is composed of the second main grid area 110 and one (as shown) or two second auxiliary grid areas 120, the second auxiliary grid area 120 is connected with the second main grid area 110, and the second auxiliary grid area 120 is not provided with a fine grid line. It should be noted that the second auxiliary grid area 120 in the first area 400 can extend to the outside of the first area, and a third fine grid line 121 is arranged outside the first area. Figure 19

[0103] In some embodiments of the present application, referring to Figure 20 , in the first area 400, the N area 100 is composed of the second main grid area 110 and one or two second auxiliary grid areas 120, the second auxiliary grid area 120 is connected with the second main grid area 110, the second main grid area 110 includes the second main grid 111, the second main grid 111 extends along the first direction (Y direction), at least one second auxiliary grid area 120 is provided with a third fine grid line 121, the third fine grid line 121 extends along the second direction (X direction) and is connected with the second main grid 111, and the second direction intersects the first direction.

[0104] In some embodiments of the present application, referring to Figures 21 to 36 , the first area 400 can be composed of the N area 100, the P area 300 and the interval area 200. By adjusting the proportions of the N area 100, the P area 300 and the interval area 200 in the first area 400, the area ratio N1 of the N area in the first area 400 can be less than the area ratio N2 of the N area in the second area.

[0105] In some embodiments of the present application, referring to Figures 21 to 26 , the first area 400 is composed of the N area 100, the P area 300 and the interval area 200, the first area 400 is composed of the interval area 200, the second auxiliary grid area 120, the first main grid area 310 and at least one first auxiliary grid area 320, the second auxiliary grid area 120 is located in the N area 100, the first main grid area 310 and the first auxiliary grid area 320 are located in the P area 300, and the first main grid area 310 includes the first main grid 311, which extends along the first direction (Y direction).

[0106] In some embodiments of the present application, referring to Figure 21 , in the first area 400, each first auxiliary grid area 320 is provided with only one first fine grid line 321, the first fine grid line 321 extends along the second direction (X direction), the second direction intersects the first direction (Y direction), and the first fine grid line 321 is connected with the first main grid 311.

[0107] In some embodiments of the present application, referring to Figure 22 and​Figure 23 In the first area 400, the gate line in the at least one first sub-gate area 320 is composed of a plurality of first fine gate lines 321, the first fine gate lines 321 extend along the second direction (X direction), the second direction intersects the first direction (Y direction), and the plurality of first fine gate lines 321 are connected with the first main gate 311.

[0108] In some embodiments of the present application, referring to Figure 24 In the first area 400, the gate line in the at least one first sub-gate area 320 is composed of a first fine gate line 321 and at least one second fine gate line 322, the first fine gate line 321 extends along the second direction (X direction), the second fine gate line 322 extends along the first direction (Y direction), the second direction intersects the first direction, and the first fine gate line 321 is connected with the first main gate 311 and the second fine gate line 322 respectively.

[0109] In some embodiments of the present application, referring to Figure 25 and Figure 26 In the first area 400, the gate line in the at least one first sub-gate area 320 is composed of a plurality of first fine gate lines 321 and at least one second fine gate line 322, the first fine gate lines 321 extend along the second direction (X direction), the second fine gate line 322 extends along the first direction (Y direction), the second direction intersects the first direction, and the first fine gate line 321 is connected with the first main gate 311 and the second fine gate line 322 respectively.

[0110] In some embodiments of the present application, referring to Figure 21 , Figure 22 , Figure 24 and Figure 26 In the first area 400, the at least one second sub-gate area 120 is provided with a third fine gate line 121, the third fine gate line 121 extends along the second direction (X direction), the third fine gate line 121 extends out of the first area 400, and the third fine gate line 121 is connected with the second main gate 111 located in the second main gate area 110.

[0111] In some embodiments of the present application, referring to Figures 27 to 30The first region 400 consists of an N region 100, a P region 300, and a spacing region 200. Specifically, the first region 400 may consist of a second main gate region 110, a first sub-gate region 320, and a spacing region 200. The second main gate region 110 is located in the N region 100 and includes a second main gate 111 extending along a first direction (Y direction). The first sub-gate region 320 is located in the P region. It should be noted that the specific number of first sub-gate regions 320 in the first region 400 is not particularly limited in this application; it can be one, two, three, or other numbers. Furthermore, it should be noted that the first sub-gate region 320 in the first region 400 may not be a complete first sub-gate region.

[0112] In some embodiments of this application, reference is made to Figure 27 The number of grid lines in each of the first sub-grid areas 320 in the first region 400 can be 0 or 1 independently. Figure 27 In the first region 400, there are two first sub-gate areas 320, one of which has 1 grid line and the other has 0 grid lines.

[0113] In some embodiments of this application, reference is made to Figure 28 In the first region 400, at least one of the multiple gate lines in the first sub-gate region 320 are first fine gate lines 321. The first fine gate lines 321 extend along the second direction (X direction) and extend beyond the first region 400, connecting to the first main gate 311 outside the first region 400. In some embodiments of this application, the first region 400 may have one (e.g., Figure 28 As shown, multiple grid lines in one or more first sub-grid regions 320 are all first fine grid lines 321. When the first sub-grid region is relatively wide, setting multiple first fine grid lines is beneficial to improving the collection efficiency of this region and improving the performance of the solar cell.

[0114] In some embodiments of this application, reference is made to Figure 29 In the first region 400, at least one first sub-gate region 320 has a gate line consisting of a first fine gate line 321 and at least one second fine gate line 322. The first fine gate line 321 extends along a second direction (X direction), and the second fine gate line 322 extends along a first direction (Y direction). The second direction intersects the first direction, and the first fine gate line 321 and the second fine gate line 322 are connected. In some specific embodiments of this application, the first region 400 may have one (e.g., Figure 29 (As shown) or multiple first sub-gate regions 320, the gate lines are composed of a first fine gate line 321 and a (as shown) Figure 29The first sub-gate region is wider, and the area is larger, so the collection difficulty is increased. The second fine gate line (horizontal fine gate line) can improve the collection efficiency of the P region.

[0115] In some embodiments of the present application, with reference to Figure 30 , in the first region 400, the gate lines of the at least one first sub-gate region 320 are composed of a plurality of first fine gate lines 321 and at least one second fine gate line 322, the first fine gate line 321 extends along the second direction (X direction), the second fine gate line 322 extends along the first direction (Y direction), the second direction intersects the first direction, and the first fine gate line 321 is connected with the second fine gate line 322. In some specific embodiments of the present application, in the first region 400, there can be one (such as Figure 30 ) or a plurality of first sub-gate regions 320, and the gate lines in the first sub-gate region 320 are composed of a plurality of first fine gate lines 321 and one, two (such as Figure 30 ) or more second fine gate lines 322.

[0116] In some embodiments of the present application, with reference to Figures 31 to 36 , the first region is composed of the N region 100, the P region 300 and the interval region 200, and the first region 400 is composed of the second main gate region 110, the second sub-gate region 120, the first sub-gate region 320 and the interval region 200, wherein the second main gate region 110 and the second sub-gate region 120 are located in the N region 100, the second sub-gate region 120 is connected with the second main gate region 110, the second main gate region 110 includes the second main gate 111, the second main gate 111 extends along the first direction (Y direction), and the first sub-gate region 320 is located in the P region 300.

[0117] In some embodiments of the present application, with reference to Figure 31 and Figure 32 , the number of gate lines of each first sub-gate region 320 in the first region 400 can be independently 0 or 1. In some specific embodiments of the present application, with reference to Figure 31 , there can be a plurality of first sub-gate regions 320 in the first region 400, and the number of gate lines in each first sub-gate region 320 is 1. In some other specific embodiments of the present application, with reference to Figure 32 , there can be two first sub-gate regions 320 in the first region 400, the number of gate lines in one of the first sub-gate regions 320 is 1, and the number of gate lines in the other first sub-gate region 320 is 0.

[0118] In some embodiments of the present application, with reference to Figure 33 and Figure 34 , in the first region 400, the plurality of gate lines of the at least one first sub-gate region 320 are all first fine gate lines 321, and the first fine gate line 321 extends along the second direction (X direction). In some specific embodiments, with reference toFigure 33 In some embodiments, the first region 400 can have two first sub-grid areas 320, and the grid lines in the two first sub-grid areas 320 are all first fine grid lines 321. Figure 34 In some embodiments, the first region 400 can have two first sub-grid areas 320, and the grid lines in one of the two first sub-grid areas 320 are all first fine grid lines 321, and the other first sub-grid area 320 is provided with both first fine grid lines 321 and second fine grid lines 322.

[0119] In some embodiments, the first region 400 can have two first sub-grid areas 320, and the grid lines in the two first sub-grid areas 320 are all first fine grid lines 321. Figure 35 In some embodiments, the first region 400 can have two first sub-grid areas 320, and the grid lines in the two first sub-grid areas 320 are all first fine grid lines 321. Figure 35 In some embodiments, the second sub-grid area 120 in the first region 400 is provided with a third fine grid line 121, the third fine grid line 121 extends along the second direction (X direction), and the third fine grid line 121 is connected with the second main grid 111 in the first region 400; in addition, the third fine grid line 121 in the first region 400 extends outward and is connected with one or more fourth fine grid lines 122 outside the first region, and the fourth fine grid line 122 extends along the first direction (Y direction).

[0120] In some embodiments, the width of the third fine grid line 121 and the fourth fine grid line 122 can be independently 20-35 μm, for example, the width of the third fine grid line and the fourth fine grid line can be independently 24 μm, 26 μm, 30 μm, 33 μm, etc.

[0121] In some embodiments, the first region 400 can have two first sub-grid areas 320, and the grid lines in the two first sub-grid areas 320 are all first fine grid lines 321. Figure 34 and Figure 36 In some embodiments, the first region 400 can have two first sub-grid areas 320, and the grid lines in the two first sub-grid areas 320 are all first fine grid lines 321. Figure 34 In some embodiments, the first region 400 can have two first sub-grid areas 320, and the grid lines in the two first sub-grid areas 320 are all first fine grid lines 321. Figure 36In the first region 400, two first sub-grid regions 320 are provided, and each of the grid lines in the first sub-grid regions 320 is composed of a plurality of first fine grid lines 321 and a plurality of second fine grid lines 322.

[0122] In some embodiments of the present application, the first region 400 is a region other than the second region 500. Figures 31 to 36 In the first region 400, at least one second sub-grid region 120 is provided with a third fine grid line 121, and the third fine grid line 121 extends along the second direction (X direction) and is connected with the second main grid 111.

[0123] In some embodiments of the present application, the back surface further comprises a second region, which is a region other than the first region, wherein, referring to Figures 5 to 9 、 Figures 12 to 14 、 Figures 22 to 25 The grid line arrangement in the first region is different from that in at least part of the second region. In some embodiments, the grid lines in the second region are in an interdigital distribution. By adjusting the grid line arrangement in the first region, the area ratio of the N region in the first region can be reduced, and further, the carrier collection efficiency in the first region can be improved, thereby helping to improve the EL test failure problem.

[0124] In another aspect of the present application, a method for preparing the back contact solar cell described above is provided. In some embodiments of the present application, the method for preparing the back contact solar cell described above can comprise the following steps:

[0125] S10: providing a cell substrate.

[0126] In some embodiments, the cell substrate can be an N-type silicon wafer. The cell substrate has opposite front and back surfaces, and the back surface of the cell substrate can be divided into P regions, interval regions and N regions arranged alternately, and the interval regions are located between the P regions and the N regions.

[0127] In some embodiments of the present application, the N-type silicon wafer can be polished on both sides in an alkaline polishing tank. In some embodiments, the alkaline solution can comprise H2O, NaOH and a polishing additive.

[0128] S20: placing the cell substrate in a quartz boat to form a first silicon oxide layer and a first polysilicon layer on the back surface in sequence.

[0129] In some embodiments of the present application, during the process and some subsequent deposition processes, the quartz boat teeth will be in contact with the cell wafer, and the part of the cell wafer in contact with the boat teeth and the surrounding part of the area may form a quartz boat mark.

[0130] In some embodiments, the first oxide layer is located on the surface of the cell substrate, and the first polysilicon layer is located on the surface of the first oxide layer away from the cell substrate.

[0131] S30: Perform boron diffusion and oxidation treatment to form a P-type doped polysilicon layer and a borosilicate glass layer.

[0132] During the boron diffusion process, boron elements diffuse into the first polysilicon layer, converting the first polysilicon layer into a P-type doped polysilicon layer. The oxidation treatment converts part of the P-type doped polysilicon layer into borosilicate glass, forming a borosilicate glass layer.

[0133] After the oxidation treatment, an annealing treatment can be performed to activate the boron elements in the polysilicon layer.

[0134] S40: Perform a first laser treatment to remove the borosilicate glass layer in the N region and the spacer region.

[0135] In some embodiments of the present application, the first laser treatment satisfies at least one of the following conditions: a laser power of 40-50 W, an overlap rate of 50-60%, a frequency of 500-600 kHz, and a pulse width of 0.8-1.2 μs.

[0136] S50: Remove the P-type doped polysilicon layer and the first silicon oxide layer in the spacer region and the N region.

[0137] In some embodiments of the present application, the borosilicate glass layer (BSG) is also formed on the front surface and the side surface of the cell substrate in step S30. An acid solution can be used to remove the borosilicate glass layer on the front surface and the side surface by wet chain processing. In some embodiments, the acid solution can include H2O and HF.

[0138] In some embodiments of the present application, an alkali solution can be used to remove the P-type doped polysilicon layer on the front surface and the side surface and the P-type doped polysilicon layer in the spacer region and the N region by wet tank processing.

[0139] S60: Form a second silicon oxide layer and a second polysilicon layer on the back surface in sequence.

[0140] In some embodiments, the second silicon oxide layer in the P region is located on the side of the borosilicate glass layer away from the cell substrate, and the second silicon oxide layer in the N region and the spacer region is located on the surface of the cell substrate.

[0141] In some embodiments, the thickness of the second silicon oxide layer is less than the thickness of the first silicon oxide layer.

[0142] In some embodiments, the thickness of the second silicon oxide layer in the corresponding area of the quartz boat imprint is greater than the thickness of the second silicon oxide layer in other areas.

[0143] S70: Perform phosphorus diffusion and oxidation treatment to form an N-type doped polysilicon layer and a phosphosilicate glass layer.

[0144] During the phosphorus diffusion process, the phosphorus element will be doped into the second polysilicon layer, so that the second polysilicon layer is converted into an N-type doped polysilicon layer. During the oxidation process, part of the N-type doped polysilicon layer is converted into a phosphosilicate glass layer (PSG).

[0145] S80: Perform a second laser treatment to remove the phosphosilicate glass layer of the P region and the spacing region.

[0146] In some embodiments of the present application, the second laser treatment satisfies at least one of the following conditions: the laser power is 40W-50W, the overlap rate is 50%-60%, the frequency is 500kHz-600kHz, and the pulse width is 0.8μs-1.2μs.

[0147] S90: Remove the N-type doped polysilicon layer and the second silicon oxide layer of the P region and the spacing region.

[0148] In some embodiments of the present application, the front surface and the side surface of the cell substrate also form a second silicon oxide layer, an N-type doped polysilicon layer, and a phosphosilicate glass layer. In some embodiments, the phosphosilicate glass layer on the front surface and the side surface can be removed by a wet chain machine using a hydrofluoric acid solution.

[0149] In some embodiments of the present application, the N-type doped polysilicon layer on the front surface and the side surface and the N-type doped polysilicon layer on the back surface of the P region and the spacing region can be removed by a slot machine.

[0150] In some embodiments, texturing can be performed using an alkali solution to form a pyramid texture on the spacing region and the front surface of the cell substrate.

[0151] The back surface of the back contact solar cell prepared by the method proposed in the present application includes at least one first region, and other regions except the first region are second regions, the area ratio of the N region in the first region is N1, and the area ratio of the N region in the second region is N2, wherein N1<N2, and the first region corresponds to the quartz boat imprint region. Thus, the solar cell prepared by the above method has a high yield, and the EL test problem is significantly improved. Specifically, the solar cell with different structures can be prepared according to actual needs, and the area ratio of the N region in the first region is preferably 10%-30%, and the area ratio of the N region in the second region is preferably 40%-60%. Figures 4 to 36 The back contact solar cell with different structures is prepared.

[0152] In some embodiments of the present application, the method for preparing the above-mentioned back contact solar cell further includes the steps of forming a front surface passivation layer and a back surface passivation layer. In some embodiments of the present application, the front surface passivation layer can include aluminum oxide, and the aluminum oxide passivation layer can be prepared by an atomic layer deposition method. In some embodiments of the present application, the back surface passivation layer can include aluminum oxide, and the aluminum oxide passivation layer can be prepared by an atomic layer deposition method.

[0153] In some embodiments, after forming the front passivation layer, a front film can be formed on the front side of the cell substrate, which can include one or more of silicon nitride, silicon oxynitride, and silicon oxide, and can play an anti-reflection role. In some embodiments, the front film can include a plurality of sub-film layers, each of which can be a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer.

[0154] In some embodiments, a back film can be formed on the back side of the cell substrate, which can include one or more of silicon nitride, silicon oxynitride, and silicon oxide, and can play an anti-reflection role. In some embodiments, the back film can include a plurality of sub-film layers, each of which can be a silicon nitride layer, a silicon oxynitride layer, or a silicon oxide layer.

[0155] In some embodiments of the present application, the method for preparing a back contact solar cell includes the step of forming a metal grid line on the back side. Specifically, an electrode paste is printed on the back side by screen printing, and a grid line is formed by high-temperature sintering, which contacts with the N-type doped polysilicon layer or the P-type doped polysilicon layer for collecting current and leading out. In some embodiments, the metal grid line on the back side can be formed by three printing methods, the first printing a back side main grid, the second printing a part of the back side fine grid, and the third printing another part of the back side fine grid.

[0156] In some embodiments of the present application, referring to Figure 4 and Figure 5 , the first area 400 is composed of the P region 300, and the method for preparing the back contact solar cell described above further includes: forming a first main grid 311 and a first fine grid line 321 in the P region in the first area 400, the first main grid 311 extending along a first direction (Y direction), the first fine grid line 321 extending along a second direction (X direction), and the first fine grid line 321 being connected with the first main grid 311.

[0157] In some embodiments of the present application, referring to Figure 6 and Figure 7 , the first area 400 is composed of the P region 300, and the method for preparing the back contact solar cell described above further includes: forming a first main grid 311, a first fine grid line 321, and a second fine grid line 322 in the P region in the first area 400, the first main grid 311 extending along a first direction (Y direction), the first fine grid line 321 extending along a second direction (X direction), the second fine grid line 322 extending along the first direction (Y direction), the second direction intersecting with the first direction, and the first fine grid line 321 being connected with the second fine grid line 322 and the first main grid 311, respectively.

[0158] In some embodiments, referring to Figure 11 and Figure 12The first region 400 is composed of a P region, a spacer region, and an N region. The method for manufacturing the back contact solar cell further comprises: forming the first main grid 311 and the first fine grid line 321 in the P region in the first region 400, and forming the third fine grid line 121 in the N region in the first region 400.

[0159] In some embodiments of the present application, referring to Figure 13 and Figure 14 The first region 400 is composed of a P region, a spacer region, and an N region. The method for manufacturing the back contact solar cell further comprises: forming the first main grid 311 and the first fine grid line 321 in the P region in the first region 400, and forming the third fine grid line 121 in the N region in the first region 400.

[0160] In some embodiments, referring to Figure 21 and Figure 22 The first region 400 is composed of a P region, a spacer region, and an N region. The method for manufacturing the back contact solar cell further comprises: forming the first main grid 311 and the first fine grid line 321 in the P region in the first region 400, and forming the third fine grid line 121 in the N region in the first region 400.

[0161] In some embodiments of the present application, referring to Figure 26 The first region 400 is composed of a P region, a spacer region, and an N region. The method for manufacturing the back contact solar cell further comprises: forming the first main grid 311 and the first fine grid line 321 in the P region in the first region 400, and forming the third fine grid line 121 in the N region in the first region 400.

[0162] In some embodiments of the present application, referring to Figure 31 The first region 400 is composed of a P region, a spacer region, and an N region. The method for manufacturing the back contact solar cell further comprises: forming the first main grid 311 and the first fine grid line 321 in the P region in the first region 400, and forming the third fine grid line 121 in the N region in the first region 400.

[0163] In the present application, the specific manufacturing conditions and parameters not mentioned in the method for manufacturing the back contact solar cell can be selected and set according to actual needs.

[0164] The method for manufacturing the back contact solar cell is used to optimize the drawings and screen fine grid screen used in the first laser treatment and the second laser treatment in the manufacturing process, change the structure of the first region (the corresponding region of the quartz boat mark), so that the first region has no N region or the area ratio of the N region is less than that in the second region, thereby improving the problem of EL test blackening in the corresponding region of the quartz boat mark and improving the manufacturing yield of the back contact solar cell. For example, Figures 4 to 6As shown in the structure, in the original first laser processing, the borosilicate glass layer in the N region and the interval region in the first region needs to be etched, and after adjusting to the structure of Figures 4 to 6 , the first region in the first laser processing does not need to be etched, and the borosilicate glass layer in the first region is retained, and in the second laser processing, the phosphosilicate glass layer in the first region is removed, and finally the local patterning is realized. Further, referring to Figure 6 , the screen fine grid screen is adjusted, and part of the transverse fine grid lines (second fine grid lines 322) are added to reduce the collection difficulty of the first region and improve the collection efficiency of the P region in the first region.

[0165] In another aspect of the present application, a photovoltaic module is provided. In some embodiments of the present application, the photovoltaic module can include the back contact solar cell described above. Thus, the photovoltaic module has all the features and advantages of the back contact solar cell described above. In general, the photovoltaic module has a quartz boat printing corresponding area EL test that is not prone to blackening problems, and has a high yield.

[0166] In some embodiments of the present application, the photovoltaic module can include a plurality of back contact solar cells described above.

[0167] The present application will be described in detail below through specific embodiments. It should be understood by those skilled in the art that the specific embodiments below are only for illustrative purposes, and do not limit the scope of the present application in any way. In addition, in the following examples, unless otherwise specified, the materials and equipment used are commercially available. If the specific processing conditions and methods are not explicitly described in the following examples, the conditions and methods known in the art can be used for processing.

[0168] Example 1

[0169] In Example 1, part of the structure of the back surface of the back contact solar cell is as shown in Figure 4 , the first region is composed of a P region, and the P region is only provided with a first main grid 311 and a first fine grid line 321, and the width of the first fine grid line 321 is 24 μm.

[0170] Example 2

[0171] Different from Example 1, part of the structure of the back surface of the back contact solar cell in Example 2 is as shown in Figure 6 , the first region is provided with a first main grid 311, a first fine grid line 321 and a second fine grid line 322, and the width of the second fine grid line 322 is 24 μm.

[0172] Example 3

[0173] Different from Example 2, part of the structure of the back surface of the back contact solar cell in Example 3 is as shown inFigure 7 As shown in FIG. 1, the first region is provided with the first main grid 311, the first plurality of fine grid lines 321 and the second plurality of fine grid lines 322.

[0174] Example 4

[0175] Different from Example 1, in Example 4, the partial structure of the back surface of the back contact solar cell is as shown in FIG. 4. Figure 23 As shown in FIG. 4, the first region includes the N region, the P region and the interval region, and the area ratio of the N region in the first region is 3%.

[0176] Example 5

[0177] Different from Example 2, in Example 5, the partial structure of the back surface of the back contact solar cell is as shown in FIG. 5. Figure 24 As shown in FIG. 5, the area ratio of the N region in the first region is 15%, and the width of the third fine grid line 121 is 24 μm.

[0178] Example 6

[0179] Different from Example 2, in Example 6, the partial structure of the back surface of the back contact solar cell is as shown in FIG. 6. Figure 36 As shown in FIG. 6, the first region includes the N region, the P region and the interval region, the area ratio of the N region in the first region is 33%, and the width of the third fine grid line 121 is 24 μm.

[0180] Example 7

[0181] Different from Example 6, in Example 7, the area ratio of the N region in the first region is 30%.

[0182] Example 8

[0183] Different from Example 2, in Example 8, the partial structure of the back surface of the back contact solar cell is as shown in FIG. 8. Figure 29 As shown in FIG. 8, the first region includes the N region, the P region and the interval region, and the area ratio of the N region in the first region is 25%.

[0184] Example 9

[0185] Different from Example 2, in Example 9, the partial structure of the back surface of the back contact solar cell is as shown in FIG. 9. Figure 30 As shown in FIG. 9, the first region includes the N region, the P region and the interval region, and the area ratio of the N region in the first region is 25%.

[0186] Comparative Example 1

[0187] Different from Example 1, in Comparative Example 1, the partial structure of the back surface of the back contact solar cell is as shown in FIG. 10. Figure 2The first region includes an N region, a P region and a spacer region, and the area ratio of the N region in the first region is 43%, which is the same as the area ratio of the N region in the second region.

[0188] The area ratio of the N region in the first region of the back contact solar cell in each of embodiments 1-9 is less than the area ratio of the N region in the second region. EL (electroluminescence) tests are performed on the solar cells in each of the embodiments and the comparative examples, and it is found that the back contact solar cell in comparative example 1 is EL blackened, and the back contact solar cells in embodiments 1-9 are not EL blackened. Therefore, it is known that the structure of the corresponding region of the quartz boat mark can effectively improve the problem of EL test blackening of the back contact solar cell, and improve the preparation yield of the back contact solar cell.

[0189] In the description of the present application, the terms "first direction", "second direction", "front surface", "back surface" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and do not require the present application to be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0190] In the description of the present application, the description of the terms "one embodiment", "another embodiment" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment are included in at least one embodiment of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction. In addition, it should be noted that in the present specification, the terms "first", "second", "third", "fourth" are for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. In the present specification, "a plurality of" means two or more.

[0191] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and cannot be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A back contact solar cell, characterized by, The back surface of the battery comprises P region, interval region and N region arranged alternately; The back surface comprises at least one first region, and other regions except the first region are second regions, The area proportion of N region in the first region is N1, and the area proportion of N region in the second region is N2, Wherein, N1 < N2, the first region is a quartz boat mark corresponding region.

2. The back contact solar cell of claim 1, wherein, The back contact solar cell satisfies one of the following conditions: The first region is composed of P region; The first region is composed of P region and interval region; The first region is composed of N region and interval region; The first region is composed of N region, P region and interval region.

3. The back contact solar cell according to claim 1 or 2, characterized in that, The first region is composed of P region, the first region is composed of a first main grid region and a first auxiliary grid region, the first main grid region comprises a first main grid, the first main grid extends along a first direction, and the first region satisfies one of the following conditions: The grid lines of the first auxiliary grid region are all first fine grid lines, and the first fine grid lines are connected with the first main grid; The grid lines of the first auxiliary grid region are composed of one first fine grid line and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line and the first main grid respectively; The grid lines of the first auxiliary grid region are composed of a plurality of first fine grid lines and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line and the first main grid respectively; Wherein, the first fine grid line extends along a second direction, the second fine grid line extends along the first direction, and the second direction intersects with the first direction.

4. The back contact solar cell according to claim 1 or 2, characterized in that, The first region is composed of P region and interval region, and in the first region, the P region comprises a first main grid region, the first main grid region comprises a first main grid, the first main grid extends along a first direction, and the first region satisfies one of the following conditions: The P region is composed of a first main grid region and a first auxiliary grid region, the grid lines of the first auxiliary grid region are all first fine grid lines, and the first fine grid lines are connected with the first main grid; The P region is composed of a first main grid region and a first auxiliary grid region, the grid lines of the first auxiliary grid region are composed of one first fine grid line and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line and the first main grid respectively; The P region is composed of a first main grid region and a first auxiliary grid region, the grid lines of the first auxiliary grid region are composed of a plurality of first fine grid lines and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line and the first main grid respectively; The P region is composed of a first main grid region; Wherein, the first fine grid line extends along a second direction, the second fine grid line extends along the first direction, and the second direction intersects with the first direction.

5. The back contact solar cell of claim 1 or 2, wherein, The first region is composed of N region and interval region, and the first region satisfies one of the following conditions: In the first region, the N region is composed of a second main grid region, the second main grid region comprises a second main grid, and the second main grid extends along a first direction; In the first region, the N region is composed of a second main grid region and one or two second auxiliary grid regions, the second auxiliary grid region is connected with the second main grid region, and the second auxiliary grid region is not provided with fine grid lines; The N region in the first region is composed of a second main grid region and one or two second auxiliary grid regions, the second auxiliary grid region is connected with the second main grid region, and a third fine grid line is arranged in at least one of the second auxiliary grid regions, the third fine grid line extends along a second direction and is connected with the second main grid, and the second direction intersects the first direction.

6. The back contact solar cell of claim 1 or 2, wherein, The first region is composed of an N region, a P region and a spacer region, the first region is composed of a spacer region, a second auxiliary grid region, a first main grid region and at least one first auxiliary grid region, the second auxiliary grid region is located in the N region, the first main grid region and the first auxiliary grid region are located in the P region, the first main grid region comprises a first main grid, the first main grid extends along a first direction, and the first region satisfies one of the following conditions: Each of the first auxiliary grid regions is provided with only one first fine grid line, and the first fine grid line is connected with the first main grid; The grid line in at least one of the first auxiliary grid regions is composed of a plurality of first fine grid lines, and the first fine grid lines are connected with the first main grid; The grid line in at least one of the first auxiliary grid regions is composed of a first fine grid line and at least one second fine grid line, and the first fine grid line is respectively connected with the first main grid and the second fine grid line; The grid line in at least one of the first auxiliary grid regions is composed of a plurality of first fine grid lines and at least one second fine grid line, and the first fine grid lines are respectively connected with the first main grid and the second fine grid line; Wherein, the first fine grid line extends along a second direction, and the second fine grid line extends along a first direction, and the second direction intersects the first direction.

7. The back contact solar cell of claim 6, wherein, In the first region, at least one of the second auxiliary grid regions is provided with a third fine grid line, and the third fine grid line extends along a second direction.

8. The back contact solar cell of claim 1 or 2, wherein, The first region is composed of an N region, a P region and a spacer region, the first region is composed of a second main grid region, a first auxiliary grid region and a spacer region, the second main grid region is located in the N region, the second main grid region comprises a second main grid, the second main grid extends along a first direction, the first auxiliary grid region is located in the P region, and the first region satisfies one of the following conditions: The number of grid lines in each of the first auxiliary grid regions in the first region is independently 0 or 1; In the first region, the plurality of grid lines of at least one of the first auxiliary grid regions are all first fine grid lines; In the first region, the grid line of at least one of the first auxiliary grid regions is composed of a first fine grid line and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line; In the first region, the grid line of at least one of the first auxiliary grid regions is composed of a plurality of first fine grid lines and at least one second fine grid line, and the first fine grid lines are connected with the second fine grid line; Wherein, the first fine grid line extends along a second direction, and the second fine grid line extends along a first direction, and the second direction intersects the first direction.

9. The back contact solar cell of claims 1 or 2, wherein, The first region is composed of an N region, a P region and a spacer region, the first region is composed of a second main grid region, a second auxiliary grid region, a first auxiliary grid region and a spacer region, the second main grid region and the second auxiliary grid region are located in the N region, the second auxiliary grid region is connected with the second main grid region, the second main grid region comprises a second main grid, the second main grid extends along a first direction, the first auxiliary grid region is located in the P region, and the first region satisfies one of the following conditions: The number of grid lines of each first auxiliary grid region in the first region is independently 0 or 1; In the first region, the plurality of grid lines of at least one first auxiliary grid region are first fine grid lines; In the first region, the grid line of at least one first auxiliary grid region is composed of a first fine grid line and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line; In the first region, the grid line of at least one first auxiliary grid region is composed of a plurality of first fine grid lines and at least one second fine grid line, and the first fine grid line is connected with the second fine grid line; Wherein, the first fine grid line extends along a second direction, the second fine grid line extends along a first direction, and the second direction intersects the first direction.

10. The back contact solar cell of claim 9, wherein, In the first region, at least one second auxiliary grid region is provided with a third fine grid line, the third fine grid line extends along a second direction and is connected with the second main grid.

11. The back contact solar cell of claims 1 or 2, wherein, The grid line arrangement mode in the first region is different from the grid line arrangement mode in at least part of the second region, and the grid lines in the second region are distributed in an interdigital manner.

12. A method of manufacturing a back contact solar cell according to any one of claims 1 to 11, characterized in that Comprising: A battery substrate is provided, and a back light surface of the battery substrate is divided into P regions, spacer regions and N regions arranged alternately; The battery substrate is placed in a quartz boat, and a first silicon oxide layer and a first polysilicon layer are formed on the back light surface in sequence; Boron diffusion and oxidation treatment are performed to form a P-type doped polysilicon layer and a boron-silicon glass layer; First laser treatment is performed to remove the boron-silicon glass layer in the N region and the spacer region; The P-type doped polysilicon layer and the first silicon oxide layer in the spacer region and the N region are removed; A second silicon oxide layer and a second polysilicon layer are formed on the back light surface in sequence, and the second silicon oxide layer of the P region is located on the side of the boron-silicon glass layer away from the battery substrate; Phosphorus diffusion and oxidation treatment are performed to form an N-type doped polysilicon layer and a phosphorus-silicon glass layer; Second laser treatment is performed to remove the phosphorus-silicon glass layer in the P region and the spacer region; The N-type doped polysilicon layer and the second silicon oxide layer in the P region and the spacer region are removed; The back light surface of the battery comprises at least one first region, and other regions except the first region are second regions, the area ratio of the N region in the first region is N1, and the area ratio of the N region in the second region is N2, wherein N1 < N2, and the first region is a quartz boat printing corresponding region.

13. A photovoltaic module, characterized by The back contact solar cell of any one of claims 1-11. The back contact solar cell of any one of claims 1-11.

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