IBC battery and its manufacturing method

Abstract

This application focuses on the issues of front surface texturing and back surface polishing of silicon wafers that have been ignored in related art, and simultaneously meets the needs of front surface texturing and back surface polishing by providing a protective layer during the manufacturing process of IBC batteries. [Solution] The present invention discloses an IBC battery and a manufacturing method thereof, which includes the steps of (1) texturing an initial silicon wafer, plating a protective layer, and etching the protective layer; (2) polishing the modified silicon wafer, placing the polished silicon wafer in LPCVD to grow a TOPCon battery structure, and then laser windowing; and (3) cleaning the polycrystalline silicon layer and protective layer on the silicon wafer after laser windowing, forming a passivation layer, and then metallizing the IBC battery.

Description

[Technical Field]

[0001] TECHNICAL FIELD The present application relates to the field of solar cells, for example, to IBC cells and methods for their manufacture. [Background technology]

[0002] IBC cells have no busbars on the surface, and both the positive and negative electrodes are on the backside of the cell, eliminating the need for surface metal contacts, thereby optimizing the cell to the maximum. N-type silicon wafers have attracted considerable attention in the photovoltaic industry due to their advantages of low light attenuation and long body minority carrier lifetime. However, compared to P-type silicon wafers, they have a certain price disadvantage. Furthermore, given that most battery manufacturers still focus on P-type PERC cells, P-type IBCs are also attracting attention as a way to extend factory life.

[0003] Between polished and textured surfaces, the polished surface has stronger control over interfacial recombination and a greater possibility of total reflection for different wavelengths of light, especially for longer wavelengths, making the polished surface the first choice for the back surface of the cell. On the other hand, the pyramidal textured surface is the logical choice for the front surface of the cell, as it requires light confinement.

[0004] CN108447947A discloses a method for fabricating a passivated contact IBC battery, which includes growing a rear oxide layer on the rear surface of an N-type crystalline silicon substrate, then growing an intrinsic polycrystalline silicon layer or an intrinsic amorphous silicon layer on the rear oxide layer, then implanting boron ions into the intrinsic polycrystalline silicon layer or the intrinsic amorphous silicon layer, then growing a mask layer, followed by laser recessing to form intersecting p+ and n+ regions, and finally annealing the p+ regions and doping the n+ regions together by phosphorus diffusion, thereby forming alternating p+ and n+ doped regions on the rear surface. The beneficial effects are that the oxide layer can provide good surface passivation to the rear surface of the N-type crystalline silicon substrate, allowing carriers to freely transport through the oxide layer, resulting in a battery with higher open-circuit voltage and conversion efficiency. The rear n+ doped region and the rear p+ doped region are jointly formed in a single high-temperature process, greatly reducing the number of high-temperature processes and saving production costs. However, the method does not address the front surface texturing and back surface polishing of the silicon wafer and ignores the difficulty of manufacturing the structure. Summary of the Invention [Problem to be solved by the invention]

[0005] The following is a summary of the subject matter described in detail herein. This summary does not limit the scope of the claims.

[0006] The embodiments of the present application provide an IBC battery and a manufacturing method thereof. The present application focuses on the issues of front surface texturing and back surface polishing of silicon wafers that have been ignored in the related art, and by providing a protective layer during the manufacturing process of an IBC battery, the needs of a front surface textured surface and a back surface polished surface are simultaneously met. [Means for solving the problem]

[0007] In Aspect 1, an embodiment of the present application is a method for manufacturing an IBC battery, comprising: (1) texturing an initial silicon wafer, plating a protective layer thereon, and then etching and modifying the protective layer; (2) polishing the modified silicon wafer, and then subjecting the polished silicon wafer to LPCVD to grow the TOPCon cell structure, followed by laser window opening; and (3) cleaning the polycrystalline silicon layer and the protective layer on the silicon wafer after the laser window opening, forming a passivation layer, and then metallizing the silicon wafer to obtain the IBC battery. A manufacturing method for IBC batteries is provided.

[0008] The present application provides a method for protecting a silicon wafer with a protective material of a certain thickness after the silicon wafer has been textured, and by using the protective layer, on the one hand, it is possible to avoid damage to the textured surface of the front surface due to polishing of the back surface and provide an optimal process for optical confinement on the front surface, and on the other hand, it is possible to prevent the formation of recombination centers due to inward doping of phosphorus into the polycrystalline silicon layer.

[0009] The present invention does not require boron doping for the formation of the P region, and uses a protective layer to protect the textured surface with as low a reflectivity as possible, increasing the short-circuit current. At the same time, by creating a polished state in the laser window opening area, the long-wavelength light transmitted through the cell sheet is reflected to maximize the formation of more carrier excitations, thereby improving the cell conversion efficiency.

[0010] Preferably, the temperature of the texturing treatment described in step (1) is 75 to 82°C, such as 75°C, 76°C, 78°C, 80°C or 82°C.

[0011] Preferably, the time for the texturing process is 400 to 600 seconds, for example, 400 seconds, 450 seconds, 500 seconds, 550 seconds, or 600 seconds.

[0012] Preferably, the texturing treatment is preceded by a pre-alkaline wash.

[0013] Preferably, the texturing lye comprises sodium hydroxide and an additive.

[0014] Preferably, the mass concentration of sodium hydroxide in the alkaline solution is 1.5 to 5%, such as 1.5%, 2%, 3%, 4%, or 5%.

[0015] Preferably, the mass concentration of the additive in the alkaline solution is 0.3 to 1.5%, such as 0.3%, 0.5%, 0.8%, 1% or 1.5%.

[0016] Preferably, the texturing treatment is followed by post-alkali washing, acid washing, slow-pulling and baking treatments.

[0017] Preferably, the material of the protective layer described in step (1) includes silicon nitride.

[0018] Preferably, the thickness of the protective layer is 60 to 200 nm, for example, 60 nm, 80 nm, 100 nm, 150 nm, or 200 nm.

[0019] The thickness of the protective layer affects the performance of the IBC battery, and if it exceeds the above range, stress will be generated, which may cause warping of the silicon wafer and affect the operation of the automation.

[0020] Preferably, the modification treatment described in step (1) includes an etching treatment.

[0021] Preferably, the etching solution used in the etching process contains hydrofluoric acid.

[0022] Preferably, the concentration of the hydrofluoric acid is 75 to 85%, for example, 75%, 78%, 80%, 82%, or 85%.

[0023] Preferably, the duration of the modification treatment is 30 to 60 seconds, for example, 30 seconds, 35 seconds, 40 seconds, 50 seconds, or 60 seconds.

[0024] Preferably, the temperature of the polishing treatment described in step (2) is 68 to 75°C, for example, 68°C, 69°C, 70°C, 72°C, or 75°C.

[0025] Preferably, the polishing time is 200 to 300 seconds, for example, 200 seconds, 220 seconds, 250 seconds, 280 seconds, or 300 seconds.

[0026] Preferably, the mass concentration of sodium hydroxide in the alkaline liquid used in the polishing treatment is 1.5 to 5%, for example, 1.5%, 2%, 3%, 4%, or 5%.

[0027] Preferably, the mass concentration of the additive in the alkaline solution is 0.9 to 1.4%, such as 0.9%, 1%, 1.1%, 1.2%, or 1.4%.

[0028] Preferably, the polishing treatment is followed by alkaline washing, acid washing, slow lifting, and baking.

[0029] Preferably, the thickness of the tunneling layer in the grown TOPCon cell structure described in step (2) is 1.2-1.8 nm, such as 1.2 nm, 1.4 nm, 1.5 nm, 1.6 nm or 1.8 nm.

[0030] Preferably, the thickness of the polycrystalline silicon layer in the grown TOPCon cell structure is 80-180 nm, such as 80 nm, 100 nm, 120 nm, 150 nm or 180 nm.

[0031] Preferably, the concentration of phosphorus in the grown TOPCon cell structure is 1e 20 ~4e 21 / cm 3 For example, 1e 20 / cm 3 , 2e 20 / cm 3 , 3e 21 / cm 3 , 4e 21 / cm 3 etc.

[0032] Preferably, the power of the laser window opening described in step (2) is 20-40W, such as 20W, 25W, 30W, 35W or 40W.

[0033] Preferably, the frequency of the laser window opening is 400 to 800 kHz, such as 400 kHz, 500 kHz, 600 kHz, 700 kHz or 800 kHz.

[0034] Preferably, the busbar width of the laser window opening is 800 to 1000 μm, for example, 800 μm, 850 μm, 900 μm, 950 μm, or 1000 μm.

[0035] Preferably, the busbar spacing of the laser window opening is 15 to 20 mm, for example, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, or 20 mm.

[0036] Preferably, the finger width of the laser window opening is 180 to 250 μm, such as 180 μm, 190 μm, 200 μm, 220 μm, or 250 μm.

[0037] Preferably, the finger spacing of the laser window opening is 1.1 to 1.5 mm, such as 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm.

[0038] Preferably, the cleaning temperature for the polycrystalline silicon layer in step (3) is 70 to 85°C, such as 70°C, 72°C, 75°C, 80°C, or 85°C.

[0039] Preferably, the cleaning time for the polycrystalline silicon layer is 300 to 450 seconds, such as 300 seconds, 320 seconds, 350 seconds, 400 seconds, or 450 seconds.

[0040] Preferably, the concentration of NaOH in the cleaning solution for the polycrystalline silicon layer is 1.5 to 5%, such as 1.5%, 2%, 3%, 4% or 5%.

[0041] Preferably, the concentration of the additive in the cleaning solution for the polycrystalline silicon layer is 0.5 to 2.5%, such as 0.5%, 1%, 1.5%, 2% or 2.5%.

[0042] Preferably, the concentration of HF in the cleaning solution for the protective layer is 8 to 20%, such as 8%, 10%, 12%, 15% or 20%.

[0043] Preferably, the concentration of HCl in the cleaning solution for the protective layer is 4.5 to 10%, such as 4.5%, 5%, 6%, 8% or 10%.

[0044] Preferably, the cleaning time for the protective layer is 150 to 300 seconds, for example, 150 seconds, 180 seconds, 200 seconds, 250 seconds, or 300 seconds.

[0045] Preferably, the passivation layer described in step (3) comprises an aluminum oxide layer and a silicon nitride layer.

[0046] Preferably, the thickness of the aluminum oxide layer is 2 to 10 nm, such as 2 nm, 4 nm, 6 nm, 8 nm, or 10 nm.

[0047] Preferably, the thickness of the silicon nitride layer is 60 to 180 nm, for example, 60 nm, 80 nm, 100 nm, 150 nm, or 180 nm.

[0048] Preferably, the laser solid line to dashed line ratio of the metallization is (0.5-0.8):0.3, such as 0.5:0.3, 0.6:0.3, 0.7:0.3 or 0.8:0.3.

[0049] Preferably, the aspect ratio of the silver gate line of the metallization is 1:(3-6), such as 1:3, 1:4, 1:5 or 1:6.

[0050] Preferably, the aspect ratio of the aluminum gate line of the metallization is 1:(5-7), such as 1:5, 1:5.5, 1:6, 1:6.5 or 1:7.

[0051] Preferably, the total wet weight of the silver paste of the metallization is 120-170g, such as 120g, 130g, 140g, 150g, 160g or 170g.

[0052] Preferably, the total wet weight of the aluminum paste of the metallization is 120-150 g, for example 120 g, 130 g, 140 g or 150 g.

[0053] In aspect 2, the present embodiment comprises: Produced by the method of embodiment 1, We provide IBC batteries. [Effects of the Invention]

[0054] Compared to the related art, the embodiments of the present application have the following beneficial effects:

[0055] (1) The embodiments of the present application ensure that a structure is formed in which the front surface is textured and the rear surface laser region is polished, thereby more effectively utilizing light in the long wavelength band, increasing the number of carrier excitations, and improving the conversion efficiency of solar cells.

[0056] (2) The efficiency of the IBC battery according to the embodiment of the present application can reach 23.69% or more, and the short-circuit current can reach 13.639A or more.

[0057] Other aspects may be understood upon reading and understanding the drawings and detailed description. [Brief explanation of the drawings]

[0058] The drawings are intended to provide a further understanding of the technical solutions of the present specification, constitute a part of the specification, and are used to interpret the technical solutions of the present specification together with the examples of the present application, but are not intended to limit the technical solutions of the present specification.

[0059] [Figure 1] 1 is a flowchart of the manufacturing process of an IBC battery according to Example 1 of the present application. [Figure 2] FIG. 1 is a schematic diagram illustrating the manufacturing process of an IBC battery according to Example 1 of the present application. [Figure 3] FIG. 1 is a structural schematic diagram of an IBC battery according to Example 1 of the present application. [Figure 4] 1 is a diagram of an IBC battery according to Example 1 of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0060] The technical solution of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the described examples are only for understanding the present application and should not be considered as specific limitations of the present application.

[0061] Example 1 This embodiment provides an IBC battery, the manufacturing flow chart of which is shown in FIG. 1, the manufacturing schematic diagram of which is shown in FIG. 2, and the manufacturing method of the IBC battery is as follows.

[0062] (1) The original silicon wafer was placed in a texturing machine and subjected to pre-alkali cleaning followed by texturing. The texturing temperature was 82°C, the time was 600 seconds, the NaOH concentration was 5%, and the additive concentration was 0.3%. After post-alkali cleaning, acid cleaning, slow lifting, and baking, a protective layer was plated on the textured silicon wafer, with a thickness of 200 nm. After the protective layer was plated, the silicon wafer was placed in a chain etching machine with an HF concentration of 85% and a reaction time of 60 seconds.

[0063] (2) The etched silicon wafer is placed in a polishing machine and polished after pre-alkali cleaning. The polishing temperature is 75°C, the time is 300 seconds, the NaOH concentration is 5%, and the additive concentration is 0.9%. After post-alkali cleaning, acid cleaning, slow lifting, and baking, the polished silicon wafer is placed in LPCVD to grow the TOPCon cell structure. The grown tunneling layer is 1.8 nm thick, the polysilicon layer is 180 nm thick, and the phosphorus concentration is 4e. 21 / cm 3 Laser window opening was performed on the silicon wafer after growing the TOPCon cell structure, with the laser rated power of 40W, frequency of 400KHz, busbar width of 1000μm, spacing of 20mm, finger width of 250μm, and finger spacing of 1.5mm.

[0064] (3) After the laser window opening, the polycrystalline silicon layer and the protective layer were cleaned from the silicon wafer. The silicon wafer was then placed in an etching machine to clean the surface PSG, followed by cleaning the polysilicon layer. The reaction temperature was 85°C, the time was 450 seconds, the NaOH concentration was 5%, and the additive concentration was 0.5%. After further alkaline cleaning, the protective layer was cleaned using HF concentration of 20% and HCl concentration of 10%, and the reaction time was 300 seconds. The cleaned silicon wafer was then placed in NCD and PECVD to grow aluminum oxide and silicon nitride, respectively. The aluminum oxide thickness was 10nm and the silicon nitride thickness was 180nm. After metallization, the laser solid line / dashed line ratio was 0.8:0.3, the silver gate line aspect ratio was 1:6, and the aluminum gate line aspect ratio was 1:7. The total wet weight of the silver paste was 170g and the total wet weight of the aluminum paste was 150g, and the IBC battery was obtained. The structural schematic diagram of the IBC battery is shown in Figure 3, and the diagram of the IBC battery is shown in Figure 4.

[0065] Example 2 This embodiment provides an IBC battery, and the manufacturing method of the IBC battery is as follows.

[0066] (1) The original silicon wafer was placed in a texturing machine and textured after pre-alkali cleaning. The texturing temperature was 75°C, the time was 400 seconds, the NaOH concentration was 1.5%, and the additive concentration was 1.5%. After post-alkali cleaning, acid cleaning, slow lifting, and baking, the textured silicon wafer was double-inserted to plate a protective layer. The protective layer was 60 nm thick. After the protective layer was plated, the silicon wafer was placed in a chain etching machine with an HF concentration of 75% and a reaction time of 30 seconds.

[0067] (2) The etched silicon wafer is placed in a polishing machine and polished after pre-alkali cleaning. The polishing temperature is 68°C, the time is 200 seconds, the NaOH concentration is 1.5%, and the additive concentration is 1.4%. After post-alkali cleaning, acid cleaning, slow lifting, and baking, the polished silicon wafer is placed in LPCVD to grow the TOPCon cell structure. The grown tunneling layer is 1.2 nm thick, the polysilicon layer is 80 nm thick, and the phosphorus concentration is 1e. 20 / cm 3 Laser window opening was performed on the silicon wafer after growing the TOPCon cell structure, with the laser rated power of 20W, frequency of 800KHz, busbar width of 800μm, spacing of 15mm, finger width of 180μm, and finger spacing of 1.1mm.

[0068] (3) After laser window drilling, the silicon wafer was subjected to cleaning of the polysilicon layer and protective layer. The surface PSG was cleaned by placing it in an etching machine, and then the polysilicon layer was cleaned. The reaction temperature was 70°C, the time was 300 seconds, the NaOH concentration was 1.5%, and the additive concentration was 2.5%. After a post-alkali cleaning, the protective layer was cleaned using HF concentration 8% and HCl concentration 4.5%, and the reaction time was 150 seconds. The cleaned silicon wafer was then sequentially placed in NCD and PECVD to grow aluminum oxide and silicon nitride. The aluminum oxide thickness was 2nm and the silicon nitride thickness was 60nm. Metallization was performed, with a laser solid line / dashed line ratio of 0.5:0.3, a silver gate line aspect ratio of 1:3, and an aluminum gate line aspect ratio of 1:5. The total wet weight of the silver paste was 120g, and the total wet weight of the aluminum paste was 120g. The IBC battery was obtained.

[0069] Example 3 This embodiment provides an IBC battery, and the manufacturing method of the IBC battery is as follows.

[0070] (1) The original silicon wafer was placed in a texturing machine and textured after pre-alkali cleaning. The texturing temperature was 78°C, the time was 500 seconds, the NaOH concentration was 3.0%, and the additive concentration was 1.0%. After post-alkali cleaning, acid cleaning, slow lifting, and baking, the textured silicon wafer was double-inserted to plate a protective layer. The protective layer was 120 nm thick. After the protective layer was plated, the silicon wafer was placed in a chain etching machine with an HF concentration of 80% and a reaction time of 45 seconds.

[0071] (2) The etched silicon wafer is placed in a polishing machine and polished after pre-alkali cleaning. The polishing temperature is 72°C, the time is 250 seconds, the NaOH concentration is 3.5%, and the additive concentration is 1.1%. After post-alkali cleaning, acid cleaning, slow lifting, and baking, the polished silicon wafer is placed in LPCVD to grow the TOPCon cell structure. The grown tunneling layer is 1.5 nm thick, the polysilicon layer is 120 nm thick, and the phosphorus concentration is 6e. 20 / cm 3 Laser window opening was performed on the silicon wafer after growing the TOPCon cell structure, with the laser rated power of 30W, frequency of 600KHz, busbar width of 900μm, spacing of 18mm, finger width of 220μm, and finger spacing of 1.3mm.

[0072] (3) After the laser window opening, the polycrystalline silicon layer and the protective layer were cleaned from the silicon wafer. The silicon wafer was then placed in an etching machine to clean the surface PSG, followed by cleaning the polysilicon layer. The reaction temperature was 75°C, the time was 360 seconds, the NaOH concentration was 3.5%, the additive concentration was 1.5%, and after post-alkali cleaning, the protective layer was cleaned with HF concentration of 15% and HCl concentration of 7.5%, and the reaction time was 220 seconds. The cleaned silicon wafer was then placed in NCD and PECVD to grow aluminum oxide and silicon nitride, respectively, with aluminum oxide thicknesses of 6nm and silicon nitride thicknesses of 120nm. Metallization was performed with a laser solid line / dashed line ratio of 0.6:0.3, silver gate line aspect ratio of 1:4.5, and aluminum gate line aspect ratio of 1:6. The total wet weight of the silver paste was 140g, the total wet weight of the aluminum paste was 135g, and the total wet weight of the aluminum paste was 120g, to obtain the IBC battery.

[0073] (Comparative Example 1) In this comparative example, an IBC battery is provided, and the manufacturing method of the IBC battery is as follows.

[0074] (1) The original silicon wafer was placed in the texturing machine and subjected to pre-alkali cleaning followed by texturing. The texturing temperature was 82°C, the time was 600 seconds, the NaOH concentration was 5%, and the additive concentration was 0.3%. Then, the wafer was subjected to post-alkali cleaning, acid cleaning, slow lifting, and baking.

[0075] (2) The textured silicon wafer was placed in LPCVD to grow the TOPCon cell structure. The grown tunneling layer had a thickness of 1.8 nm, the polysilicon layer had a thickness of 180 nm, and the phosphorus concentration was 4e. 21 / cm 3 After growing the TOPCon cell structure, laser window opening was performed on the silicon wafer. The laser rated power was 40W, the frequency was 400KHz, the busbar width was 1000um, the spacing was 20mm, the finger width was 250um, and the finger spacing was 1.5mm.

[0076] (3) After laser window drilling, the silicon wafer was subjected to cleaning of the polycrystalline layer and protective layer, and then placed in an etching machine to clean the surface PSG, followed by cleaning of the polycrystalline silicon layer. The reaction temperature was 85°C, the time was 450 seconds, the NaOH concentration was 5%, the additive concentration was 0.5%, and after post-alkali cleaning, the protective layer was cleaned using HF concentration of 20% and HCl concentration of 10%, and the reaction time was 300 seconds. The cleaned silicon wafer was then placed in NCD and PECVD to grow aluminum oxide and silicon nitride, respectively, with aluminum oxide thicknesses of 10nm and silicon nitride thicknesses of 180nm. Metallization was performed, with a laser solid line / dashed line ratio of 0.8:0.3, an aspect ratio of the silver gate line of 1:6, and an aspect ratio of the aluminum gate line of 1:7. The total wet weight of the silver paste was 170g, and the total wet weight of the aluminum paste was 150g. The IBC battery was obtained.

[0077] (Comparative Example 2) In this comparative example, an IBC battery is provided, and the manufacturing method of the IBC battery is as follows.

[0078] (1) The original silicon wafer was placed in the texturing machine and subjected to pre-alkali cleaning followed by texturing. The texturing temperature was 75°C, the time was 400 seconds, the NaOH concentration was 1.5%, and the additive concentration was 1.5%. Then, the wafer was subjected to post-alkali cleaning, acid cleaning, slow lifting, and baking.

[0079] (2) The textured silicon wafer was placed in LPCVD to grow the TOPCon cell structure. The grown tunneling layer had a thickness of 1.2 nm, the polysilicon layer had a thickness of 80 nm, and the phosphorus concentration was 1 e 20 / cm 3 After growing the TOPCon cell structure, laser window opening was performed on the silicon wafer. The laser rated power was 20W, the frequency was 800KHz, the busbar width was 800um, the spacing was 15mm, the finger width was 180um, and the finger spacing was 1.1mm.

[0080] (3) After laser window drilling, the silicon wafer was subjected to cleaning of the polycrystalline layer and protective layer. The surface PSG was cleaned by placing it in an etching machine, and then the polycrystalline silicon layer was cleaned. The reaction temperature was 70°C, the time was 300 seconds, the NaOH concentration was 1.5%, and the additive concentration was 2.5%. After alkaline cleaning, the protective layer was cleaned using HF concentration 8% and HCl concentration 4.5%, and the reaction time was 150 seconds. The cleaned silicon wafer was then placed in NCD and PECVD to grow aluminum oxide and silicon nitride, respectively. The aluminum oxide and silicon nitride thicknesses were 2 nm and 60 nm, respectively. Metallization was performed using a laser solid / dashed line ratio of 0.5:0.3, a silver gate line aspect ratio of 1:3, and an aluminum gate line aspect ratio of 1:5. The total wet weight of the silver paste and the total wet weight of the aluminum paste were 120 g. The IBC battery was then obtained.

[0081] (Performance test) After three batch experiments, the efficiency (Eta), short circuit current (Isc), open circuit voltage (Uoc) and fill factor (FF) of the cell sheet of the final silicon wafer product were tracked, and the test results are shown in Table 1.

[0082] [Table 1]

[0083] As can be seen from Table 1, according to Examples 1 to 3, the efficiency of the IBC battery of the present invention can reach 23.69% or more, and the short-circuit current can reach 13.639 A or more. Compared with the comparative example, the efficiency Eta is improved by 0.16 to 0.22%, and the main improvements come from Isc, Uoc, and FF. In particular, the short-circuit current Isc is improved by 96 mA to 106 mA.

[0084] Comparing Example 1 with Comparative Examples 1 and 2, when a surface protection film was added in Example 1, the laser window opening area on the back surface was a polished surface, while in Comparative Examples 1 and 2, the laser window opening area was a textured surface. There was not much difference in Uoc between the two, but Example 1 had a 96 mA higher Isc, which directly resulted in a difference in Eta of nearly 0.16%.

[0085] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any modifications or replacements that a person skilled in the art can easily conceive within the technical scope disclosed in the present application are all included in the scope of protection and disclosure of the present application. [Explanation of symbols]

[0086] 1. Silicon substrate 2. Oxide layer 3 p-type / n-type polycrystalline silicon layer 4. Aluminum oxide 5. Silicon nitride 6 silver electrode 7. Aluminum electrode

Claims

1. A method for manufacturing an IBC battery, comprising: (1) texturing an initial silicon wafer, plating a protective layer thereon, and then etching and modifying the protective layer; (2) polishing the modified silicon wafer, and then placing the polished silicon wafer in an LPCVD chamber to grow a TOPCon cell structure, followed by laser windowing; (3) cleaning the polycrystalline silicon layer and the protective layer on the silicon wafer after the laser window opening, forming a passivation layer, and then metallizing the IBC battery; Manufacturing method.

2. The temperature of the texturing treatment described in step (1) is 75 to 82°C. The method of claim 1.

3. The texturing process lasts for 400 to 600 seconds. The method according to claim 1 or 2.

4. A pre-alkaline wash is performed before the texturing treatment. The method according to any one of claims 1 to 3.

5. the alkaline solution for the texturing treatment comprises sodium hydroxide and an additive; Preferably, the mass concentration of sodium hydroxide in the alkaline solution is 1.5 to 5%; Preferably, the mass concentration of the additive in the alkaline solution is 0.3 to 1.5%; Preferably, the texturing treatment is followed by post-alkali washing, acid washing, slow-pulling and baking treatments. The method according to any one of claims 1 to 4.

6. The material of the protective layer described in step (1) includes silicon nitride; Preferably, the thickness of the protective layer is 60 to 200 nm. The method according to any one of claims 1 to 5.

7. The modification treatment described in step (1) includes an etching treatment, Preferably, the etching solution used in the etching process contains hydrofluoric acid, Preferably, the concentration of the hydrofluoric acid is 75 to 85%; Preferably, the modification treatment time is 30 to 60 seconds. The method according to any one of claims 1 to 6.

8. The temperature of the polishing treatment described in step (2) is 68 to 75°C; Preferably, the polishing treatment time is 200 to 300 seconds, Preferably, the mass concentration of sodium hydroxide in the alkaline solution used in the polishing treatment is 1.5 to 5%; Preferably, the mass concentration of the additive in the alkaline solution is 0.9 to 1.4%; Preferably, the polishing treatment is followed by alkaline cleaning, acid cleaning, slow lifting, and baking. The method according to any one of claims 1 to 7.

9. The thickness of the tunneling layer in the grown TOPCon cell structure described in step (2) is 1.2-1.8 nm; Preferably, the thickness of the polycrystalline silicon layer in the grown TOPCon cell structure is 80-180 nm; Preferably, the concentration of phosphorus in the grown TOPCon cell structure is 1e ２０ ~4e ２１ / cm ３ That is, The method according to any one of claims 1 to 8.

10. The power of the laser window opening described in step (2) is 20-40 W; Preferably, the frequency of the laser window aperture is between 400 and 800 kHz; Preferably, the busbar width of the laser window opening is 800 to 1000 μm; Preferably, the busbar spacing of the laser window opening is 15 to 20 mm; Preferably, the finger width of the laser window opening is 180 to 250 μm; Preferably, the finger spacing of the laser window opening is 1.1 to 1.5 mm. The method according to any one of claims 1 to 9.

11. The cleaning temperature of the polycrystalline silicon layer described in step (3) is 70 to 85°C; Preferably, the cleaning time of the polycrystalline silicon layer is 300 to 450 seconds; Preferably, the concentration of NaOH in the cleaning solution for the polycrystalline silicon layer is 1.5 to 5%; Preferably, the concentration of the additive in the cleaning solution for the polycrystalline silicon layer is 0.5 to 2.5%; Preferably, the concentration of HF in the cleaning solution for the protective layer is 8 to 20%; Preferably, the concentration of HCl in the cleaning solution for the protective layer is 4.5 to 10%; Preferably, the cleaning time of the protective layer is 150 to 300 s. The method according to any one of claims 1 to 10.

12. The passivation layer according to step (3) comprises an aluminum oxide layer and a silicon nitride layer; Preferably, the thickness of the aluminum oxide layer is 2 to 10 nm; Preferably, the thickness of the silicon nitride layer is 60 to 180 nm; Preferably, the laser solid line to dash line ratio of the metallization is (0.5-0.8):0.3; Preferably, the aspect ratio of the silver gate line of the metallization is 1:(3-6); Preferably, the aspect ratio of the aluminum gate line of the metallization is 1:(5-7); Preferably, the total wet weight of the silver paste of said metallization is between 120 and 170 g; Preferably, the total wet weight of the aluminum paste of said metallization is 120-150 g; The method according to any one of claims 1 to 11.

13. Produced by the method according to any one of claims 1 to 12. IBC battery.

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