A TOPCon cell with SE structure, preparation method thereof and photovoltaic module

Abstract

The present invention provides a TOPCon cell with SE structure, comprising: an N-type crystalline silicon substrate and a P+ doping layer, an aluminum oxide passivation layer, a second SiNx mask layer and a silver aluminum paste sequentially grown on the positive surface of the N-type crystalline silicon substrate. The beneficial effect of the present invention is to use a secondary boron diffusion method to realize a selective emitter structure of boron diffusion, so that the surface of the TOPCon cell has two concentrations of boron diffusion concentration, and can reduce doping and reduce surface recombination rate at non-SE structures, and highly dope the part where the metal and the metallization pattern contact to realize good ohmic contact, so as to realize that the TOPCon cell boron SE structure has both good contact performance and good passivation ability, and replaces the boron diffusion laser SE method to solve the problem of heavy doping of boron diffusion.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and in particular relates to a TOPCon cell with a SE structure, a preparation method thereof, and a photovoltaic module. Background Art

[0002] A solar cell is an electrical device that converts light energy directly into electrical energy through the photovoltaic effect. Currently, the most common solar cell is a large-area PN junction made of silicon. Other possible types of solar cells include dye-sensitized solar cells, organic solar cells, and quantum dot solar cells.

[0003] In the prior art, laser is usually used to form the SE structure of TOPCon battery, which can only form SE structure for the whole TOPCon battery, and cannot realize selective SE structure, resulting in unnecessary high surface recombination rate at the structure. Although the part in contact with the gate line can have better contact ability, the passivation ability is weak. Summary of the invention

[0004] The problem to be solved by the present invention is to provide a TOPCon cell with SE structure, a preparation method thereof and a photovoltaic module, which effectively solves the problem that the SE structure of the TOPCon cell formed by laser in the prior art cannot realize a selective SE structure, resulting in a high surface recombination rate at unnecessary structures, and although the part in contact with the gate line can have good contact ability, the passivation ability is weak.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a TOPCon battery with SE structure, comprising: an N-type crystalline silicon substrate and a P+ doping layer, an aluminum oxide passivation layer, a second SiNx mask layer and a silver-aluminum paste grown in sequence on the front surface of the N-type crystalline silicon substrate.

[0006] Preferably, the P+ doped layer includes a first P+ doped layer and a second P+ doped layer.

[0007] Preferably, the silver-aluminum paste is grown at the metallized gate line position on the second SiNx mask layer.

[0008] A method for preparing a TOPCon battery having a SE structure as described above, characterized in that:

[0009] Performing texturing treatment on the front surface of the N-type crystalline silicon substrate;

[0010] Performing a first boron diffusion treatment on the front surface of the N-type crystalline silicon substrate to form the first P+ doped layer, and further forming a first borosilicate glass layer on the surface of the first P+ doped layer;

[0011] Removing the first borosilicate glass layer and the first P+ doped layer at the back surface and edge extension of the N-type crystalline silicon substrate;

[0012] Depositing a first SiNx mask layer on the surface of the first P+ doped layer;

[0013] Performing laser grooving according to the metallization pattern, removing the first P+ doping layer and the first SiNx mask layer in the metallization pattern area, exposing the front surface of the N-type crystalline silicon substrate, and cleaning the grooved area;

[0014] Performing a second boron diffusion treatment on the grooved portion of the N-type crystalline silicon substrate to form the second P+ doped layer, and further forming a second borosilicate glass layer on the surface of the second P+ doped layer;

[0015] removing the second borosilicate glass layer and the remaining first SiNx mask layer;

[0016] Growing the aluminum oxide passivation layer on the surface of the first P+ doped layer and the second P+ doped layer, and then depositing a second SiNx mask layer on the aluminum oxide passivation layer;

[0017] The silver-aluminum paste is printed according to the metallized grid lines, and then dried and sintered to obtain the TOPCon battery boron SE structure.

[0018] Preferably, the resistivity of the N-type crystalline silicon substrate is 0.5-5Ω·cm, and the thickness is 80-200 μm.

[0019] Preferably, in the first boron diffusion treatment on the front surface of the N-type crystalline silicon substrate, the boron source is boron tribromide or boron trichloride, and the boron source concentration is 0.5-1*E 19 The source time is 120-240 minutes, the diffusion time is 500-700 seconds, the diffusion temperature is 900-1100° C., the diffusion depth is 0.3-0.8 μm, and the square resistance of the N-type crystalline silicon substrate after the first boron diffusion is 200-500Ω / sqr.

[0020] Preferably, in the step of depositing a first SiNx mask layer on the surface of the first P+ doped layer, PECVD is used to deposit the first SiNx mask layer, and the thickness of the first SiNx mask layer is in the range of 30 cm-80 cm, and the refractive index is 1.8-2.2.

[0021] Preferably, the metallization pattern is a fine grid portion of a metallization grid line.

[0022] Preferably, after laser grooving according to the metallization pattern, HCl or NaOH is used to clean the grooved area.

[0023] Preferably, when the second boron diffusion treatment is performed on the grooves on the N-type crystalline silicon substrate, the boron source is boron tribromide or boron trichloride, and the boron source concentration is 2-4*E 19 The diffusion temperature is 900-1100° C., the source time is 1900-2300 s, the diffusion time is 900-1000 s, the diffusion depth is 0.8-1.1 μm, and the square resistance of the N-type crystalline silicon substrate after the second boron diffusion is 40-100 Ω / sqr.

[0024] Preferably, HF is used to remove the first borosilicate glass layer, the second borosilicate glass layer and the remaining first SiNx mask layer.

[0025] A photovoltaic module contains the TOPCon cell with SE structure as described above or the TOPCon cell with SE structure obtained by the preparation method as described above.

[0026] By adopting the above technical solution and using the secondary boron diffusion method to realize the selective emitter structure of boron diffusion, the TOPCon battery surface can have two concentrations of boron diffusion, which can reduce doping and reduce surface recombination rate at non-SE structures. The parts in contact with the metal and the metallized pattern are highly doped to achieve good ohmic contact, so that the TOPCon battery boron SE structure has both good contact performance and good passivation ability, replacing the boron diffusion laser SE method and solving the problem of heavy doping of boron diffusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of a TOPCon battery with a SE structure according to an embodiment of the present invention.

[0028] In the figure:

[0029] 1. N-type crystalline silicon substrate 2. First P+ doped layer 3. Second P+ doped layer

[0030] 4. Aluminum oxide passivation layer 5. Second SiNx mask layer 6. Silver aluminum paste DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with embodiments and drawings:

[0032] In the description of the embodiments of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "front surface", "back surface", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] like Figure 1 As shown in the structural schematic diagram of a TOPCon battery with a SE structure, a TOPCon battery with a SE structure includes: an N-type crystalline silicon substrate and a P+ doped layer, an aluminum oxide passivation layer 4, a second SiNx mask layer 5 and a silver-aluminum paste 6 grown in sequence on the front surface of the N-type crystalline silicon substrate 1.

[0034] Among them, the P+ doping layer includes a first P+ doping layer 2 and a second P+ doping layer 3. The boron concentration in the first P+ doping layer 2 is lower than the boron concentration in the second P+ doping layer 3. The first P+ doping layer 2 is lightly doped and the second P+ doping layer 3 is heavily doped. A secondary boron diffusion method is used to realize a selective emitter structure of boron diffusion, i.e., a SE structure. This allows the TOPCon battery surface to have two concentrations of boron diffusion, which can reduce doping and surface recombination rate at non-SE structures. The part in contact between the metal and the metallized pattern is highly doped to achieve good ohmic contact.

[0035] A method for preparing a TOPCon battery having a SE structure, comprising:

[0036] S1: Select an N-type crystalline silicon substrate with a resistivity of 0.5-5Ω·cm and a thickness of 80-200μm, and perform a texturing treatment on the front surface of the N-type crystalline silicon substrate 1;

[0037] S2: performing a first boron diffusion treatment on the front surface of the N-type crystalline silicon substrate 1 to form a first P+ doped layer 2, and further forming a first borosilicate glass layer on the surface of the first P+ doped layer 2; wherein,

[0038] In the first boron diffusion treatment of the front surface of the N-type crystalline silicon substrate 1, the boron source is boron tribromide or boron trichloride, and the boron source concentration is 0.5-1*E 19 The source-on time, i.e., the time for introducing the boron source, is 120-240 min, the boron diffusion time is 500-700 s, the diffusion temperature is 900-1100° C., the diffusion depth is 0.3-0.8 μm, and the first P+ doped layer 2 and the first borosilicate glass layer are formed. The square resistance of the N-type crystalline silicon substrate 1 after the first boron diffusion is 200-500 Ω / sqr.

[0039] S3: Use HF to remove the entire first borosilicate glass layer on the front surface, back surface and edge expansion of the N-type crystalline silicon substrate 1, and remove the first borosilicate glass layer and the first P+ doped layer 2 on the back surface and edge expansion of the N-type crystalline silicon substrate 1; only retain the first P+ doped layer 2 on the front surface of the N-type base silicon substrate 1.

[0040] S4: depositing a first SiNx mask layer on the surface of the first P+ doped layer 2; wherein the first SiNx mask layer is deposited by PECVD method, with a thickness ranging from 30 to 80 nm and a refractive index of 1.8 to 2.2.

[0041] S5: laser grooving is performed according to the metallization pattern, the first P+ doping layer 2 and the first SiNx mask layer in the metallization pattern area are removed, the front surface of the N-type crystalline silicon substrate 1 is exposed, and the grooved area is cleaned; wherein,

[0042] The metallized graphic area is the fine gate portion of the metallized gate line; after the fine gate portion of the metallized gate line is laser grooved, HCl or NaOH is used to clean the grooved portion, mainly cleaning the remaining first P+ doping layer 2, the first SiNx mask layer and other impurities, and cleaning the inner surface of the grooved portion.

[0043] S6: performing a second boron diffusion treatment on the grooved portion of the N-type crystalline silicon substrate 1 to form a second P+ doped layer 3, and further forming a second borosilicate glass layer on the surface of the second P+ doped layer 3; wherein,

[0044] When the second boron diffusion treatment is performed on the grooves on the N-type crystalline silicon substrate 1, the boron source is boron tribromide or boron trichloride, and the boron source concentration is 2-4*E 19 The boron source is turned on for 1900-2300s, the diffusion temperature is 900-1100°C, the diffusion time is 900-1000s, the diffusion depth is 0.8-1.1μm, and a second P+ doped layer 3 and a second borosilicate glass layer are formed. The square resistance of the N-type crystalline silicon substrate 1 after the second boron diffusion is 40-100Ω / sqr.

[0045] S7: Use HF with a concentration range of 5-20% to remove all second borosilicate glass layers at the grooves and other locations of the N-type crystalline silicon substrate 1, as well as all second P+ doped layers 3 of the N-type crystalline silicon substrate 1 except the grooves; only retain the second P+ doped layer 3 at the grooves of the N-type base silicon substrate 1.

[0046] S8: growing an aluminum oxide passivation layer 4 on the surface of the first P+ doped layer 2 on the surface of the N-type crystalline silicon substrate 1 and the surface of the second P+ doped layer 3 at the groove, and then depositing a second SiNx mask layer 5 on the aluminum oxide passivation layer 4, wherein the thickness of the aluminum oxide passivation layer 4 is 1-5 nm, and the second SiNx mask layer 5 deposited on the aluminum oxide passivation layer 4 is 1-5 nm. x The thickness of the anti-reflection passivation layer 5 is 30-80 nm, and the refractive index is 1.8-2.2.

[0047] S9: Printing silver aluminum paste 6 according to the metallization grid lines, and drying and sintering, to obtain a TOPCon battery with a SE structure.

[0048] For the SE structure of TOPCon cells, the secondary boron diffusion method is used to realize the selective emitter structure of boron diffusion, which can make the surface of TOPCon cells have two concentrations of boron diffusion, reduce doping and reduce surface recombination rate at non-SE structures, and highly dope the parts where metal and metallization patterns are in contact to achieve good ohmic contact. The boron SE structure of TOPCon cells has both good contact performance and good passivation ability, replacing the boron diffusion laser SE method to solve the problem of heavy boron diffusion doping.

[0049] Here are some specific examples:

[0050] Example 1

[0051] S1: Select an N-type crystalline silicon substrate with a resistivity of 2Ω·cm and a thickness of 150μm, and perform a texturing treatment on the front surface of the N-type crystalline silicon substrate 1;

[0052] S2: performing a first boron diffusion treatment on the front surface of the N-type crystalline silicon substrate 1 to form a first P+ doped layer 2, and further forming a first borosilicate glass layer on the surface of the first P+ doped layer 2; wherein,

[0053] In the first boron diffusion treatment of the front surface of the N-type crystalline silicon substrate 1, boron tribromide is used as the boron source, and the boron source concentration is 0.8*E 19 The source-on time, i.e., the time for introducing the boron source, is 200 min, the boron diffusion time is 600 s, the diffusion temperature is 1000°C, the diffusion depth is 0.6 μm, and the first P+ doped layer 2 and the first borosilicate glass layer are formed. The square resistance of the N-type crystalline silicon substrate 1 after the first boron diffusion is 350 Ω / sqr.

[0054] S3: Use HF with a concentration of 5% to remove the entire first borosilicate glass layer on the front surface, back surface and edge expansion of the N-type crystalline silicon substrate 1, and remove the first borosilicate glass layer and the first P+ doped layer 2 on the back surface and edge expansion of the N-type crystalline silicon substrate 1; only retain the first P+ doped layer 2 on the front surface of the N-type base silicon substrate 1.

[0055] S4: depositing a first SiNx mask layer on the surface of the first P+ doped layer 2; wherein the first SiNx mask layer is deposited by PECVD method, with a thickness in the range of 50nm and a refractive index of 2.

[0056] S5: laser grooving is performed according to the metallization pattern, the first P+ doping layer 2 and the first SiNx mask layer in the metallization pattern area are removed, the front surface of the N-type crystalline silicon substrate 1 is exposed, and the grooved area is cleaned; wherein,

[0057] The metallized graphic area is the fine gate portion of the metallized gate line; after the fine gate portion of the metallized gate line is laser grooved, HCl is used to clean the groove, mainly cleaning the remaining first P+ doping layer 2, the first SiNx mask layer and other impurities, and cleaning the inner surface of the groove.

[0058] S6: performing a second boron diffusion treatment on the grooved portion of the N-type crystalline silicon substrate 1 to form a second P+ doped layer 3, and further forming a second borosilicate glass layer on the surface of the second P+ doped layer 3; wherein,

[0059] When the second boron diffusion treatment is performed on the grooves on the N-type crystalline silicon substrate 1, the boron source is boron tribromide, and the boron source concentration is 3*E 19 The boron source is turned on for 2200s, the diffusion temperature is 1000°C, the diffusion time is 1000s, the diffusion depth is 1μm, and a second P+ doped layer 3 and a second borosilicate glass layer are formed. The square resistance of the N-type crystalline silicon substrate 1 after the second boron diffusion is 60Ω / sqr.

[0060] S7: Use HF to remove all the second borosilicate glass layers at the grooves and other positions of the N-type crystalline silicon substrate 1, and all the second P+ doped layers 3 of the N-type crystalline silicon substrate 1 except the grooves; only the second P+ doped layer 3 at the grooves of the N-type base silicon substrate 1 is retained.

[0061] S8: growing an aluminum oxide passivation layer 4 on the surface of the first P+ doped layer 2 on the surface of the N-type crystalline silicon substrate 1 and the surface of the second P+ doped layer 3 at the groove, and then depositing a second SiNx mask layer 5 on the aluminum oxide passivation layer 4, wherein the thickness of the aluminum oxide passivation layer 4 is 3 nm, and the second SiNx mask layer 5 deposited on the aluminum oxide passivation layer 4 is 3 nm. x The thickness of the anti-reflection passivation layer 5 is 50 nm, and the refractive index is 2.

[0062] S9: Printing silver aluminum paste 6 according to the metallization grid lines, and drying and sintering, to obtain a TOPCon battery with a SE structure.

[0063] Example 2

[0064] S1: Select an N-type crystalline silicon substrate with a resistivity of 0.5Ω·cm and a thickness of 100μm, and perform a texturing treatment on the front surface of the N-type crystalline silicon substrate 1;

[0065] S2: performing a first boron diffusion treatment on the front surface of the N-type crystalline silicon substrate 1 to form a first P+ doped layer 2, and further forming a first borosilicate glass layer on the surface of the first P+ doped layer 2; wherein,

[0066] In the first boron diffusion treatment of the front surface of the N-type crystalline silicon substrate 1, boron tribromide is used as the boron source, and the boron source concentration is 0.5*E 19The source-on time, i.e., the time for introducing the boron source, is 150 min, the boron diffusion time is 550 s, the diffusion temperature is 950°C, the diffusion depth is 0.4 μm, and the first P+ doped layer 2 and the first borosilicate glass layer are formed. The square resistance of the N-type crystalline silicon substrate 1 after the first boron diffusion is 250 Ω / sqr.

[0067] S3: Use HF with a concentration of 15% to remove the entire first borosilicate glass layer on the front surface, back surface and edge expansion of the N-type crystalline silicon substrate 1, and remove the first borosilicate glass layer and the first P+ doped layer 2 on the back surface and edge expansion of the N-type crystalline silicon substrate 1; only retain the first P+ doped layer 2 on the front surface of the N-type base silicon substrate 1.

[0068] S4: depositing a first SiNx mask layer on the surface of the first P+ doped layer 2; wherein the first SiNx mask layer is deposited by PECVD method, with a thickness in the range of 40 nm and a refractive index of 2.1.

[0069] S5: laser grooving is performed according to the metallization pattern, the first P+ doping layer 2 and the first SiNx mask layer in the metallization pattern area are removed, the front surface of the N-type crystalline silicon substrate 1 is exposed, and the grooved area is cleaned; wherein,

[0070] The metallized graphic area is the fine gate portion of the metallized gate line; after the fine gate portion of the metallized gate line is laser grooved, HCl or NaOH is used to clean the grooved portion, mainly cleaning the remaining first P+ doping layer 2, the first SiNx mask layer and other impurities, and cleaning the inner surface of the grooved portion.

[0071] S6: performing a second boron diffusion treatment on the grooved portion of the N-type crystalline silicon substrate 1 to form a second P+ doped layer 3, and further forming a second borosilicate glass layer on the surface of the second P+ doped layer 3; wherein,

[0072] When the second boron diffusion treatment is performed on the grooves on the N-type crystalline silicon substrate 1, the boron source is boron tribromide, and the boron source concentration is 2.5*E 19 The boron source is turned on for 2000s, the diffusion temperature is 950°C, the diffusion time is 950s, the diffusion depth is 0.9μm, and a second P+ doped layer 3 and a second borosilicate glass layer are formed. The square resistance of the N-type crystalline silicon substrate 1 after the second boron diffusion is 50Ω / sqr.

[0073] S7: Use HF to remove all the second borosilicate glass layers at the grooves and other positions of the N-type crystalline silicon substrate 1, and all the second P+ doped layers 3 of the N-type crystalline silicon substrate 1 except the grooves; only the second P+ doped layer 3 at the grooves of the N-type base silicon substrate 1 is retained.

[0074] S8: growing an aluminum oxide passivation layer 4 on the surface of the first P+ doped layer 2 on the surface of the N-type crystalline silicon substrate 1 and the surface of the second P+ doped layer 3 at the groove, and then depositing a second SiNx mask layer 5 on the aluminum oxide passivation layer 4, wherein the thickness of the aluminum oxide passivation layer 4 is 2 nm, and the second SiNx mask layer 5 deposited on the aluminum oxide passivation layer 4 is 2 nm. x The thickness of the anti-reflection passivation layer 5 is 40 nm, and the refractive index is 2.1.

[0075] S9: Printing silver aluminum paste 6 according to the metallization grid lines, and drying and sintering, to obtain a TOPCon battery with a SE structure.

[0076] Example 3

[0077] S1: Select an N-type crystalline silicon substrate with a resistivity of 5Ω·cm and a thickness of 200μm, and perform a texturing treatment on the front surface of the N-type crystalline silicon substrate 1;

[0078] S2: performing a first boron diffusion treatment on the front surface of the N-type crystalline silicon substrate 1 to form a first P+ doped layer 2, and further forming a first borosilicate glass layer on the surface of the first P+ doped layer 2; wherein,

[0079] In the first boron diffusion treatment of the front surface of the N-type crystalline silicon substrate 1, boron trichloride is used as the boron source, and the boron source concentration is 1*E 19 The source-on time, i.e., the time for introducing the boron source, is 150 min, the boron diffusion time is 700 s, the diffusion temperature is 1050°C, the diffusion depth is 0.7 μm, and the first P+ doped layer 2 and the first borosilicate glass layer are formed. The square resistance of the N-type crystalline silicon substrate 1 after the first boron diffusion is 300 Ω / sqr.

[0080] S3: Use HF with a concentration of 10% to remove the entire first borosilicate glass layer on the front surface, back surface and edge expansion of the N-type crystalline silicon substrate 1, and remove the first borosilicate glass layer and the first P+ doped layer 2 on the back surface and edge expansion of the N-type crystalline silicon substrate 1; only retain the first P+ doped layer 2 on the front surface of the N-type base silicon substrate 1.

[0081] S4: depositing a first SiNx mask layer on the surface of the first P+ doped layer 2; wherein the first SiNx mask layer is deposited by PECVD method, with a thickness range of 70nm and a refractive index of 1.9.

[0082] S5: laser grooving is performed according to the metallization pattern, the first P+ doping layer 2 and the first SiNx mask layer in the metallization pattern area are removed, the front surface of the N-type crystalline silicon substrate 1 is exposed, and the grooved area is cleaned; wherein,

[0083] The metallized graphic area is the fine gate portion of the metallized gate line; after the fine gate portion of the metallized gate line is laser grooved, NaOH is used to clean the grooved portion, mainly cleaning the remaining first P+ doping layer 2, the first SiNx mask layer and other impurities, and cleaning the inner surface of the grooved portion.

[0084] S6: performing a second boron diffusion treatment on the grooved portion of the N-type crystalline silicon substrate 1 to form a second P+ doped layer 3, and further forming a second borosilicate glass layer on the surface of the second P+ doped layer 3; wherein,

[0085] When the second boron diffusion treatment is performed on the grooves on the N-type crystalline silicon substrate 1, boron trichloride is used as the boron source, and the boron source concentration is 3.5*E 19 The boron source is turned on for 2200s, the diffusion temperature is 1100°C, the diffusion time is 900-1000s, the diffusion depth is 1μm, and a second P+ doped layer 3 and a second borosilicate glass layer are formed. The square resistance of the N-type crystalline silicon substrate 1 after the second boron diffusion is 80Ω / sqr.

[0086] S7: Use HF to remove all the second borosilicate glass layers at the grooves and other positions of the N-type crystalline silicon substrate 1, and all the second P+ doped layers 3 of the N-type crystalline silicon substrate 1 except the grooves; only the second P+ doped layer 3 at the grooves of the N-type base silicon substrate 1 is retained.

[0087] S8: growing an aluminum oxide passivation layer 4 on the surface of the first P+ doped layer 2 on the surface of the N-type crystalline silicon substrate 1 and the surface of the second P+ doped layer 3 at the groove, and then depositing a second SiNx mask layer 5 on the aluminum oxide passivation layer 4, wherein the thickness of the aluminum oxide passivation layer 4 is 4 nm, and the second SiNx mask layer 5 deposited on the aluminum oxide passivation layer 4 is 4 nm. x The thickness of the anti-reflection passivation layer 5 is 80 nm, and the refractive index is 1.8.

[0088] S9: Printing silver aluminum paste 6 according to the metallization grid lines, and drying and sintering, to obtain a TOPCon battery with a SE structure.

[0089] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a TOPCon battery with a SE structure, characterized in that: Performing texturing treatment on the front surface of the N-type crystalline silicon substrate; The front surface of the N-type crystalline silicon substrate is subjected to a first boron diffusion treatment to form a first P + doped layer, and in the first P + A first borosilicate glass layer is also formed on the surface of the doped layer. The resistivity of the N-type crystalline silicon substrate is 0.5-5Ω·cm and the thickness is 80-200μm. In the first boron diffusion treatment on the front surface of the N-type crystalline silicon substrate, boron tribromide or boron trichloride is used as the boron source, and the boron source concentration is 0.5*E 19 -1*E 19 , the source time is 120-240min, the diffusion time is 500-700s, the diffusion temperature is 900-1100°C, the diffusion depth is 0.3-0.8μm, and the square resistance of the N-type crystalline silicon substrate after the first boron diffusion is 200-500Ω / sqr; Remove the first borosilicate glass layer and the back surface of the N-type crystalline silicon substrate and the first P + doping layer, removing all the first borosilicate glass layers on the front surface, the back surface and the edge expansion of the N-type crystalline silicon substrate; In the first P + A first SiN is deposited on the surface of the doped layer x mask layer; Laser grooving is performed according to the metallization pattern, and the first P + The doping layer and the first SiN x A mask layer is formed to expose the front surface of the N-type crystalline silicon substrate and clean the grooves; The grooves on the N-type crystalline silicon substrate are subjected to a second boron diffusion treatment to form a second P + doped layer, and in the second P + A second borosilicate glass layer is also formed on the surface of the doped layer. When the second boron diffusion treatment is performed on the groove on the N-type crystalline silicon substrate, the boron source is boron tribromide or boron trichloride, and the boron source concentration is 2*E 19 -4*E 19 , the diffusion temperature is 900-1100°C, the source time is 1900-2300s, the diffusion time is 900-1000s, the diffusion depth is 0.8-1.1μm, and the square resistance of the N-type crystalline silicon substrate after the second boron diffusion is 40-100Ω / sqr; Remove the second borosilicate glass layer and the remaining first SiN x The mask layer is used to remove the second borosilicate glass layer at the groove and other positions of the N-type crystalline silicon substrate, and the second P + doping layer, only retaining the second P + doping layer; In the first P + doped layer and the second P + An aluminum oxide passivation layer is grown on the surface of the doped layer, and then a second SiN x mask layer; Silver aluminum paste is printed according to the metallization grid lines, and then dried and sintered to obtain the TOPCon battery boron SE structure.

2. The method for preparing a TOPCon battery with a SE structure according to claim 1, characterized in that: In the first P + A first SiN is deposited on the surface of the doped layer x In the step of forming a mask layer, the first SiN x The mask layer, the first SiN x The thickness of the mask layer ranges from 30cm to 80cm, and the refractive index ranges from 1.8 to 2.

2.

3. The method for preparing a TOPCon battery with a SE structure according to claim 1, characterized in that: The metallization pattern is the fine grid part of the metallization grid line; after laser grooving is performed according to the metallization pattern, HCl or NaOH is used to clean the grooved part.

4. The method for preparing a TOPCon battery with a SE structure according to claim 1, characterized in that: HF is used to remove the first borosilicate glass layer, the second borosilicate glass layer, and the remaining first SiN x Mask layer.

5. A TOPCon battery with a SE structure prepared by the preparation method according to claim 1, characterized in that: include: The N-type crystalline silicon substrate and the P + doping layer and the aluminum oxide passivation layer, the second SiN x mask layer and silver aluminum paste, the P + The doped layer includes the first P + The doped layer and the second P + doping layer, the aluminum oxide passivation layer is arranged on the first P + The doped layer and the second P + The silver aluminum paste is grown on the upper part of the doped layer of the second SiN x At the metallized gate line position on the mask layer.

6. A photovoltaic module, comprising a TOPCon cell with a SE structure obtained by the preparation method according to any one of claims 2 to 4 or a TOPCon cell with a SE structure according to claim 5.

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