Preparation method of TOPCon electroplated battery piece and TOPCon electroplated battery piece prepared by preparation method
By preparing a thick silicon nitride layer on the blue diaphragm of the TOPCon cell and combining laser groove, pickling and PVD processes, the silicon-based damage caused by laser film removal is solved, the cell efficiency is improved and the silver paste consumption is reduced.
Patent Information
- Application Number
- CN202510442848.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-09
- Publication Date
- 2025-07-11
AI Technical Summary
In the existing TOPCon battery metallization electroplating process, the laser film removal process leads to silicon-based damage to the blue diaphragm, reduces the cell efficiency, and increases the silver paste consumption.
A silicon nitride layer with a thickness of more than 120 nm was prepared on both sides of the blue diaphragm. Part of the silicon nitride layer was removed by laser groove and acid washing. A metal alloy layer was formed at the grooves by PVD process, and then a conductive metal gate wire layer was prepared by electroplating.
The damage to the film layer by laser is reduced, the efficiency of the cell is improved, and the metal consumption is reduced, and the metal composite and copper ion barrier properties are optimized.
Smart Images
Figure CN120302756A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of solar cells, and particularly to a preparation method of a TOPCon electroplated cell and a TOPCon electroplated cell prepared therefrom. Background Art
[0002] The photovoltaic technology has developed rapidly, and the production capacity of solar cells has maintained a growth rate of more than 25% per year in recent years. At present, the photovoltaic cell process has rapidly shifted from the PERC process to the TOPCon process, and the conversion efficiency has rapidly increased from more than 23% to more than 26%, greatly improving the power of the cells and modules. However, the increase in the efficiency of solar cells has led to an increase in the consumption of silver paste. The silver paste consumption of Topcon of the same size is 1.5 to 2 times that of PERC, making the electroplated copper grid line replacing the printed silver paste a technology for reducing silver consumption and lowering costs by various photovoltaic companies is developing rapidly.
[0003] At present, the TOPCon battery metallization electroplating process generally electroplates base metals (nickel, copper, tin, zinc, etc.) on the blue film after coating to replace the precious metal silver to achieve the function of collecting current. However, the outermost layers on both the front and back of the blue film are non-conductive silicon nitride layers and cannot be directly electroplated. Part of the silicon nitride layer needs to be removed according to the design of the cell grid lines to make the front and back surfaces satisfy current conduction. This patterning removal process generally uses a laser film removal process. This process has the advantages of high yield, low cost, and high precision, but laser processing has thermal damage and will cause damage to the silicon-based blue film itself, reducing the efficiency of the cell.
[0004] In view of this, the present invention is specifically proposed. Summary of the Invention
[0005] The purpose of the present invention is to provide a preparation method of a TOPCon electroplated cell and a TOPCon electroplated cell prepared therefrom. The main purpose of the present invention is to improve the efficiency of the TOPCon electroplated cell by reducing laser damage and using the PVD method to grow a seed layer.
[0006] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:
[0007] In a first aspect, the present invention provides a preparation method of a TOPCon electroplated cell, and the preparation method of the TOPCon electroplated cell includes:
[0008] Prepare silicon nitride layers on both sides of the blue film, and the thickness of the silicon nitride layers on both sides of the blue film is independently 120 nm or more;
[0009] Form grooves in the silicon nitride layers on both sides of the blue film through a laser grooving process, and the depth of the grooves is 90% or less of the thickness of the silicon nitride layer;
[0010] Remove the remaining silicon nitride layer at the grooves through the first pickling;
[0011] After depositing a metal film layer on the front side of the blue film after the first pickling through a physical vapor deposition process and then performing an annealing treatment, form an alloy layer of metal and silicon at the grooves;
[0012] Remove the metal film layer at non-groove positions through the second pickling;
[0013] Prepare a conductive metal grid line layer on both sides of the blue film after the second pickling through an electroplating process to obtain the TOPCon electroplated cell;
[0014] Preferably, the blue film includes an N-type silicon substrate; the front side of the N-type silicon substrate sequentially includes a boron diffusion layer and an alumina layer from inside to outside; the back side of the N-type silicon substrate sequentially includes a tunneling oxide layer and a polysilicon layer from inside to outside.
[0015] Preferably, the thickness of the N-type silicon substrate is 100 - 150 μm.
[0016] Preferably, the thickness of the boron diffusion layer is 0.3 - 3 μm, and the boron doping concentration is 1.0e 16 ~1.0e 19 cm -3 。
[0017] Preferably, the thickness of the alumina layer is 1 - 10 nm.
[0018] Preferably, the thickness of the tunneling oxide layer is 0.3 - 3 nm.
[0019] Preferably, the thickness of the polysilicon layer is 30 - 300 nm.
[0020] Preferably, the thickness of the silicon nitride layer formed on the front side of the blue film is 120 - 150 nm; the thickness of the silicon nitride layer formed on the back side of the blue film is 120 - 150 nm.
[0021] Preferably, the silicon nitride layer formed on the front side is formed on the surface of the alumina layer, and the silicon nitride layer formed on the back side is formed on the surface of the polysilicon layer.
[0022] Preferably, the plasma enhanced chemical vapor deposition process is used to prepare the silicon nitride layer.
[0023] Preferably, the gases used in the plasma enhanced chemical vapor deposition process include SiH4 and NH3; wherein, the volume flow rate of SiH4 is 300 - 3000 sccm, and the volume flow rate of NH3 is 2000 - 20000 sccm.
[0024] Preferably, the process parameters of the plasma enhanced chemical vapor deposition process include: a pulse duty ratio of 1:(10 - 20), a temperature of 400 - 600 °C, a radio frequency power supply power of 5000 - 20000 W, and a deposition time of 500 - 2000 s.
[0025] Preferably, the depth of the groove is 60 - 90% of the thickness of the silicon nitride layer.
[0026] Preferably, the width of the groove is 5 - 15 μm.
[0027] Preferably, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.0 - 1.3 W, and the laser frequency is 1000 - 5000 MHz.
[0028] Preferably, the pickling reagent used in the first pickling is 2 - 10 wt% hydrofluoric acid.
[0029] Preferably, after the first pickling, all the remaining silicon nitride layer flakes at the grooves on the blue film are removed, and the thickness of the silicon nitride layer at the non-groove areas on the blue film is 60 - 90 nm.
[0030] Preferably, the temperature of the first pickling is 20 - 40 °C, and the time of the first pickling is 3 - 30 min.
[0031] Preferably, the metal film layer includes any one of a nickel film layer, an aluminum film layer, or a titanium film layer.
[0032] Preferably, the thickness of the metal film layer is 30 - 200 nm.
[0033] Preferably, the deposition of the metal film layer is carried out by vacuum sputtering plating.
[0034] Preferably, the deposition rate of the metal film layer is 1 - 10 nm / min, and the temperature of the deposition of the metal film layer is 100 - 200 °C.
[0035] Preferably, the annealing treatment is carried out under a vacuum condition, the temperature of the annealing treatment is 200 - 400 °C, and the time of the annealing treatment is 50 - 200 s.
[0036] Preferably, the pickling reagent used in the second pickling includes, by mass percentage: 10 - 30% hydrogen peroxide and 10 - 30% sulfuric acid, with the balance being water.
[0037] Preferably, the temperature of the second pickling is 30-50°C, and the time of the second pickling is 5-20 min.
[0038] Preferably, the conductive metal grid line layer is disposed at the grooves on both sides of the blue film; the conductive metal grid line layer sequentially includes a seed layer, a transmission layer, and an anti-oxidation layer from inside to outside; wherein, the seed layer is a nickel layer or a silver layer; the transmission layer is a copper layer; the anti-oxidation layer is a tin layer or a zinc layer.
[0039] Preferably, the thickness of the seed layer is 0.5-1.0 μm.
[0040] Preferably, the thickness of the transmission layer is 5-15 μm.
[0041] Preferably, the thickness of the anti-oxidation layer is 0.5-2.0 μm.
[0042] In a second aspect, the present invention provides a TOPCon electroplated cell, and the TOPCon electroplated cell is prepared by the preparation method of the TOPCon electroplated cell as described in the first aspect.
[0043] Compared with the prior art, the present invention has the following beneficial effects:
[0044] (1) The silicon nitride layer prepared on both sides of the blue film in the present invention is significantly higher than that of the ordinary blue film, and a lower laser power is used to only remove part of the silicon nitride layer, and then an acid pickling process is used to clean the surface of the silicon nitride, remove the remaining silicon nitride at the grooving position, and then perform the subsequent electroplated grid line process. This process effectively reduces the damage of the laser to the film layer.
[0045] (2) The present invention uses the PVD process to produce a nickel, aluminum or titanium film layer on the surface of the blue film, and then anneals to form an alloy with the silicon exposed at the grooving position to generate an ohmic contact. Then, a mixed solution of sulfuric acid and hydrogen peroxide is used to remove nickel, aluminum or titanium in the non-grooving area, and only the alloy at the grooving position is retained as the bottom layer. The nickel / aluminum film grown by PVD has better densification and uniformity than the electroplating process, which can not only reduce the metal recombination, but also has better blocking property for copper ions. Description of the Drawings
[0046] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0047] Figure 1 Schematic structural diagram of a blue film after preparing a silicon nitride layer on both sides.
[0048] Figure 2 Schematic structural diagram of a blue film after laser grooving.
[0049] Figure 3 Schematic structural diagram of a blue film after the first pickling.
[0050] Figure 4 Schematic structural diagram of a blue film after depositing a metal film layer on the front side.
[0051] Figure 5 Schematic structural diagram of a blue film after annealing treatment.
[0052] Figure 6 Schematic structural diagram of a blue film after the second pickling.
[0053] Figure 7 Schematic structural diagram of a TOPCon electroplated cell prepared by the method of the present invention.
[0054] Among them, 1 is an N-type silicon substrate, 2 is a boron diffusion layer, 3 is an alumina layer, 4 is a tunneling oxide layer, 5 is a polysilicon layer, 6 is a silicon nitride layer, 7 is a metal film layer, 8 is an alloy layer of metal and silicon, 9 is a seed layer, 10 is a transmission layer, and 11 is an anti-oxidation layer. Detailed implementation manners
[0055] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meanings and scopes of the terms should be clear. However, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or extrinsic definition. In this application, unless otherwise specified, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-restrictive.
[0056] Next, the technical solutions of the present invention will be described clearly and completely in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0057] In a first aspect, the present invention provides a method for preparing a TOPCon electroplated cell, and the method for preparing the TOPCon electroplated cell includes:
[0058] Preparing a silicon nitride layer 6 on both sides of the blue film, and the thickness of the silicon nitride layer 6 on both sides of the blue film is independently 120 nm or more (as Figure 1 shown);
[0059] Form grooves in the silicon nitride layers 6 on both sides of the blue film through a laser grooving process, and the depth of the grooves is less than 90% of the thickness of the silicon nitride layer (as Figure 2 shown);
[0060] Remove the remaining silicon nitride layer 6 and the aluminum oxide layer 3 at the grooves through the first pickling, and thin the thickness of the silicon nitride layer 6 at non-grooved areas (as Figure 3 shown);
[0061] Deposit a metal film layer 7 on the front side of the blue film after the first pickling through a physical vapor deposition (PVD) process (as Figure 4 shown), and after annealing treatment, form an alloy layer 8 of metal and silicon at the grooves, while the non-grooved areas remain the metal film layer 7 (as Figure 5 shown);
[0062] Remove the metal film layer 7 at non-grooved areas through the second pickling (as Figure 6 shown);
[0063] Prepare conductive metal grid line layers on both sides of the blue film after the second pickling through an electroplating process to obtain the TOPCon electroplated cell.
[0064] In the present invention, the silicon nitride layers prepared on both sides of the blue film are significantly higher than those of ordinary blue films, and a lower laser power is used to only remove part of the silicon nitride layer. Then, a pickling process is used to clean the silicon nitride surface, remove the remaining silicon nitride at the grooved positions, and then perform subsequent electroplated grid line processes. This process effectively reduces the damage of the laser to the film layer. The present invention uses a PVD process to produce a nickel, aluminum, or titanium film layer on the surface of the blue film, and then anneals to form an alloy with the silicon exposed at the grooved positions to generate an ohmic contact. Then, a mixed solution of sulfuric acid and hydrogen peroxide is used to remove nickel, aluminum, or titanium in the non-grooved area, and only the alloy at the grooved positions is retained as the bottom layer. The nickel / aluminum film grown by PVD has better densification and uniformity than the electroplating process, which can not only reduce metal recombination but also has better blocking performance for copper ions.
[0065] As an optional implementation manner, as Figure 1 shown, before preparing the silicon nitride layers on both sides, the blue film includes an N-type silicon substrate 1; the front side of the N-type silicon substrate 1 sequentially includes a boron diffusion layer 2 and an aluminum oxide layer 3 from inside to outside; the back side of the N-type silicon substrate 1 sequentially includes a tunneling oxide layer 4 and a polysilicon layer 5 from inside to outside.
[0066] As an alternative embodiment, the thickness of the N-type silicon substrate 1 is 100 to 150 μm, for example, it can be 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, etc.
[0067] As an alternative embodiment, the thickness of the boron diffusion layer 2 is 0.3 to 3 μm, and the boron doping concentration is 1.0e 16 ~1.0e 19 cm -3 , for example, it can be 1.0e 16 cm -3 、0.5×1.0e 17 cm -3 、1.0e 17 cm -3 、0.5×1.0e 18 cm -3 、1.0e 18 cm -3 、0.5×1.0e 19 cm -3 、1.0e 19 cm -3 etc.
[0068] As an alternative embodiment, the thickness of the alumina layer 3 is 1 to 10 nm, for example, it can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc.
[0069] As an alternative embodiment, the thickness of the tunneling oxide layer 4 is 0.3 to 3 nm, for example, it can be 0.5 nm, 1 nm, 1.2 nm, 1.5 nm, 1.8 nm, 2 nm, 2.2 nm, 2.5 nm, 2.8 nm, 3 nm, etc.
[0070] As an alternative embodiment, the thickness of the polysilicon layer 5 is 30 to 300 nm, for example, it can be 30 nm, 50 nm, 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm, 220 nm, 240 nm, 260 nm, 280 nm, 300 nm, etc.
[0071] As an alternative embodiment, the thickness of the silicon nitride layer 6 formed on the front side of the blue film is 120 to 150 nm, for example, it can be 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, etc.
[0072] As an alternative embodiment, the thickness of the silicon nitride layer 6 formed on the back surface of the blue film is 120 - 150 nm, for example, it can be 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, etc.
[0073] In the present invention, the thickness range of the silicon nitride of the blue film is appropriate. Since pickling to remove the film also corrodes the silicon nitride on the front surface during the process, it is necessary to thicken the silicon nitride layer for protection. Moreover, importantly, a lower laser power is adopted to only remove part of the silicon nitride layer, and then the pickling process is used to clean the surface of the silicon nitride, remove the remaining silicon nitride at the grooving position, and then perform the subsequent electroplating grid line process. This process significantly reduces the damage of the laser to the film layer.
[0074] As an alternative embodiment, as Figure 1 shown, the silicon nitride layer 6 formed on the front surface is formed on the surface of the alumina layer 3, and the silicon nitride layer 6 formed on the back surface is formed on the surface of the polysilicon layer 5.
[0075] As an alternative embodiment, the plasma enhanced chemical vapor deposition process is used to prepare the silicon nitride layer.
[0076] As an alternative embodiment, the gases used in the plasma enhanced chemical vapor deposition process include SiH4 and NH3; among them, the volume flow rate of SiH4 is 300 - 3000 sccm, for example, it can be 300 sccm, 400 sccm, 500 sccm, 600 sccm, 700 sccm, 800 sccm, 900 sccm, 1000 sccm, 1200 sccm, 1400 sccm, 1500 sccm, 1600 sccm, 1800 sccm, 2000 sccm, 2200 sccm, 2400 sccm, 2600 sccm, 2800 sccm, 3000 sccm, etc., and the volume flow rate of NH3 is 2000 - 20000 sccm, for example, it can be 2000 sccm, 4000 sccm, 6000 sccm, 8000 sccm, 10000 sccm, 12000 sccm, 13000 sccm, 14000 sccm, 15000 sccm, 16000 sccm, 17000 sccm, 18000 sccm, 19000 sccm, 20000 sccm, etc.
[0077] As an optional implementation manner, the process parameters of the plasma enhanced chemical vapor deposition process include: the pulse switch ratio is 1:(10 - 20), for example, it can be 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, etc.; the temperature is 400 - 600 °C, for example, it can be 400 °C, 420 °C, 440 °C, 460 °C, 480 °C, 500 °C, 520 °C, 540 °C, 560 °C, 580 °C, 600 °C, etc.; the radio frequency power supply power is 5000 - 20000 W, for example, it can be 5000 W, 6000 W, 8000 W, 10000 W, 12000 W, 14000 W, 16000 W, 18000 W, 20000 W, etc.; the deposition time is 500 - 2000 s, for example, it can be 500 s, 600 s, 800 s, 1000 s, 1200 s, 1400 s, 1600 s, 1800 s, 2000 s, etc.
[0078] In the present invention, a relatively thick silicon nitride layer needs to be formed on the front and back surfaces of the blue film. Based on this, by adopting the above - mentioned specific plasma enhanced chemical vapor deposition (PECVD) process, the reaction efficiency is significantly improved. The gas dissociation makes the reactants evenly distributed on the surface of the blue film, ensuring the consistency and uniformity of the film layer. And during the thick film growth, by adjusting parameters such as radio frequency power and gas ratio, the internal stress of the film can be precisely controlled, the stress gradient can be reduced, and phenomena such as cracking, delamination, warping or peeling can be avoided, ensuring complete coverage of the surface of the blue film. In addition, it is convenient for subsequent pickling process to clean the silicon nitride surface and remove the remaining silicon nitride at the grooving position.
[0079] As an optional implementation manner, the depth of the groove is 60 - 90% of the thickness of the silicon nitride layer, for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc.
[0080] As an optional implementation manner, the width of the groove is 5 - 15 μm, for example, it can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc.
[0081] As an optional implementation manner, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.0 - 1.3 W, for example, it can be 1.0 W, 1.05 W, 1.1 W, 1.15 W, 1.2 W, 1.25 W, 1.3 W, etc., and the laser frequency is 1000 - 5000 MHz, for example, it can be 1000 MHz, 1500 MHz, 2000 MHz, 2500 MHz, 3000 MHz, 3500 MHz, 4000 MHz, 4500 MHz, 5000 MHz, etc.
[0082] In the present invention, appropriate process parameters of the laser grooving process can be used to laser-remove most of the silicon nitride layer, leaving 10-40% of the silicon nitride layer at the bottom, so as to form a groove with a depth of 60-90% of the thickness of the silicon nitride layer, minimizing the damage to the silicon substrate. However, too high power and frequency will lead to an intensified thermal effect, possibly completely removing the silicon nitride layer, thus damaging the silicon substrate and forming microcracks or heat-affected zones; too low power and frequency will result in insufficient grooving depth or too small a slot area, having an adverse effect on the subsequent first pickling, and the silicon nitride layer at the groove cannot be completely removed subsequently, affecting the preparation of the subsequent conductive metal gate line layer.
[0083] As an alternative embodiment, the pickling reagent used in the first pickling is 2-10 wt% hydrofluoric acid, for example, it can be 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, etc.
[0084] As an alternative embodiment, after the first pickling, all the remaining silicon nitride layer flakes at the grooves on the blue film are removed, and the thickness of the silicon nitride layer at the non-groove positions on the blue film is 60-90 nm, for example, it can be 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, etc.
[0085] As an alternative embodiment, the temperature of the first pickling is 20-40 °C, for example, it can be 20 °C, 25 °C, 30 °C, 35 °C, 40 °C, etc., and the time of the first pickling is 3-30 min, for example, it can be 3 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, etc.
[0086] In the present invention, pickling the laser-treated blue film with a certain concentration of HF corrodes the entire film thickness of the blue film, so that the thickness of the corroded silicon nitride is restored to 60-90 nm, while ensuring that the silicon nitride at the grooving position is completely cleaned. The combination of laser grooving and pickling grooving can give full play to the advantages of the two processes, forming a complementary effect. First, use laser to complete the high-precision part (such as grooving in key areas), and then use pickling to process the remaining part. It combines the advantages of laser and pickling grooving, and avoids the damage to the grooving part by laser and pickling. Moreover, even if there is a small amount of slag or heat-affected zone remaining after laser grooving, it can be cleaned and the surface can be smoothed by pickling, avoiding deformation or ablation caused by long-term laser action.
[0087] As an alternative embodiment, the metal film layer includes any one of a nickel film layer, an aluminum film layer or a titanium film layer.
[0088] As an alternative embodiment, the thickness of the metal film layer is 30 to 200 nm, for example, it can be 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, etc.
[0089] As an alternative embodiment, the deposition of the metal film layer is carried out by vacuum sputtering.
[0090] As an alternative embodiment, the deposition rate of the metal film layer is 1 to 10 nm / min, for example, it can be 1 nm / min, 2 nm / min, 3 nm / min, 4 nm / min, 5 nm / min, 6 nm / min, 7 nm / min, 8 nm / min, 9 nm / min, 10 nm / min, etc., and the deposition temperature of the metal film layer is 100 to 200 °C, for example, it can be 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, etc.
[0091] As an alternative embodiment, the annealing treatment is carried out under a vacuum state, the temperature of the annealing treatment is 200 to 400 °C, for example, it can be 200 °C, 220 °C, 230 °C, 240 °C, 250 °C, 260 °C, 280 °C, 300 °C, 320 °C, 340 °C, 350 °C, 360 °C, 380 °C, 400 °C, etc., and the time of the annealing treatment is 50 to 200 s, for example, it can be 50 s, 60 s, 80 s, 100 s, 120 s, 140 s, 150 s, 160 s, 180 s, 200 s, etc.
[0092] As an alternative embodiment, the pickling reagent used for the second pickling comprises, by mass percentage: 10 to 30% hydrogen peroxide and 10 to 30% sulfuric acid, with the balance being water.
[0093] Based on the total mass of the pickling reagent used for the second pickling being 100%, the content of hydrogen peroxide is 10 to 30%, for example, it can be 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, etc.
[0094] Based on the total mass of the pickling reagent used for the second pickling being 100%, the content of sulfuric acid is 10 to 30%, for example, it can be 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, etc.
[0095] As an alternative embodiment, the temperature of the second pickling is 30 to 50 °C, for example, it can be 30 °C, 32 °C, 34 °C, 36 °C, 38 °C, 40 °C, 42 °C, 44 °C, 46 °C, 48 °C, 50 °C, etc., and the time of the second pickling is 5 to 20 min, for example, it can be 5 min, 6 min, 8 min, 10 min, 12 min, 14 min, 15 min, 16 min, 18 min, 20 min, etc.
[0096] As an alternative embodiment, as Figure 7 shown, the conductive metal grid line layer is disposed at the grooves on both sides of the blue film; the conductive metal grid line layer sequentially includes a seed layer 9, a transmission layer 10, and an anti-oxidation layer 11 from the inside to the outside.
[0097] As an alternative embodiment, the seed layer 9 is a nickel layer or a silver layer.
[0098] As an alternative embodiment, the transmission layer 10 is a copper layer.
[0099] As an alternative embodiment, the anti-oxidation layer 11 is a tin layer or a zinc layer.
[0100] As an alternative embodiment, the thickness of the seed layer 9 is 0.5 to 1.0 μm, for example, it can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, etc.
[0101] As an alternative embodiment, the thickness of the transmission layer 10 is 5 to 15 μm, for example, it can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc.
[0102] As an alternative embodiment, the thickness of the anti-oxidation layer 11 is 0.5 to 2.0 μm, for example, it can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, etc.
[0103] As an alternative embodiment, the finally prepared TOPCon electroplated cell also needs to use an IV tester to test the efficiency of the electroplated cell and classify it according to different powers.
[0104] In a second aspect, the present invention provides a TOPCon electroplated cell, and the TOPCon electroplated cell is prepared by the preparation method of the TOPCon electroplated cell as described in the first aspect.
[0105] The present invention will be further described below with reference to embodiments. Unless otherwise specified, the materials in the embodiments are prepared according to existing methods or directly purchased from the market.
[0106] The specification parameters of the blue film used in the following embodiments are as follows:
[0107] The blue film includes an N-type silicon substrate (with a thickness of 130 μm); the front side of the N-type silicon substrate sequentially includes a boron diffusion layer (with a thickness of 0.9 μm and a boron doping concentration of 4.0e 18 cm -3 ) and an alumina layer (with a thickness of 5 nm); the back side of the N-type silicon substrate sequentially includes a tunneling oxide layer (with a thickness of 1.4 nm) and a polysilicon layer (with a thickness of 110 nm).
[0108] Example 1
[0109] This embodiment provides a preparation method for a TOPCon electroplated cell. The preparation method for the TOPCon electroplated cell includes the following steps:
[0110] S1. PECVD growth of silicon nitride:
[0111] A silicon nitride layer with a thickness of 135 nm is formed on the front side of the blue film by the PECVD process; a silicon nitride layer with a thickness of 135 nm is formed on the back side of the blue film;
[0112] Among them, the gases used in the PECVD process include SiH4 and NH3. The volume flow rate of SiH4 is 1200 sccm, and the volume flow rate of NH3 is 10000 sccm; among them, the process parameters of the plasma-enhanced chemical vapor deposition process include: a pulse switch ratio of 1:15, a temperature of 500 °C, a radio frequency power supply power of 14000 W, and a deposition time of 1300 s.
[0113] S2. Laser grooving:
[0114] Grooves are formed in the silicon nitride layers on both sides of the blue film by the laser grooving process. The depth of the grooves formed on the front side of the blue film is 100 nm, and the width is 6 μm; the depth of the grooves formed on the back side of the blue film is 100 nm, and the width is 10 μm;
[0115] Among them, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.15 W, and the laser frequency is 3000 MHz.
[0116] S3. First pickling:
[0117] Remove the remaining 30 nm silicon nitride layer and the aluminum oxide layer in the grooves on both sides of the blue film through the first pickling, and thin the silicon nitride layer in the non-grooved area, so that the thickness of the silicon nitride layer formed on the front side is reduced to 75 nm, and the thickness of the silicon nitride layer formed on the front side is reduced to 75 nm;
[0118] Among them, the pickling reagent used in the first pickling is 6 wt% hydrofluoric acid, the temperature of the first pickling is 25 °C, and the time of the first pickling is 8 min.
[0119] S4. Physical vapor deposition - annealing:
[0120] After depositing a nickel metal film layer on the front side of the blue film after the first pickling through a physical vapor deposition process, and then performing an annealing treatment, an alloy layer of nickel metal and silicon is formed in the grooves, while the non-grooved area remains a nickel metal film layer;
[0121] Among them, the deposition specifically includes: using nickel with a purity of 99.99% as the target, and adopting the method of vacuum sputtering plating to deposit a nickel metal film layer with a thickness of 100 nm on the front side of the blue film, the lamination rate is set at 5 nm / min, and the deposition temperature is 150 °C; the annealing treatment specifically includes: after deposition, annealing at 250 °C for 120 s in a vacuum state.
[0122] S5. Second pickling:
[0123] Remove the nickel metal film layer in the non-grooved area through the second pickling;
[0124] Among them, the pickling reagent used in the second pickling includes, by mass percentage: 20% hydrogen peroxide and 30% sulfuric acid, and the balance is water; the temperature of the second pickling is 50 °C, and the time of the second pickling is 15 min.
[0125] S6. Prepare the conductive metal grid line layer:
[0126] Prepare the conductive metal grid line layer on both sides of the blue film after the second pickling through an electroplating process to obtain the TOPCon electroplated cell;
[0127] Among them, the seed layer is a nickel layer with a thickness of 0.8 μm, the transmission layer is a copper layer with a thickness of 10 μm, and the anti-oxidation layer is a tin layer with a thickness of 1.0 μm.
[0128] Example 2
[0129] This example provides a method for preparing a TOPCon electroplated cell, and the method for preparing the TOPCon electroplated cell includes the following steps:
[0130] S1. PECVD growth of silicon nitride:
[0131] The thickness of the silicon nitride layer formed on the front side of the blue film by the PECVD process is 130 nm; the thickness of the silicon nitride layer formed on the back side of the blue film is 130 nm;
[0132] Among them, the gases used in the plasma enhanced chemical vapor deposition process include SiH4 and NH3. The volume flow rate of SiH4 is 1100 sccm, and the volume flow rate of NH3 is 9000 sccm. Among them, the process parameters of the plasma enhanced chemical vapor deposition process include: the pulse switch ratio is 1:15, the temperature is 500 °C, the radio frequency power supply power is 14000 W, and the deposition time is 1200 s.
[0133] S2. Laser grooving:
[0134] Grooves are formed in the silicon nitride layers on both sides of the blue film by the laser grooving process. The depth of the grooves formed on the front side of the blue film is 110 nm, and the width is 10 μm; the depth of the grooves formed on the back side of the blue film is 110 nm, and the width is 12 μm;
[0135] Among them, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.1 W, and the laser frequency is 2500 MHz.
[0136] S3. First pickling:
[0137] The remaining 20 nm of the silicon nitride layer and the aluminum oxide layer at the grooves on both sides of the blue film are removed by the first pickling, and the thickness of the silicon nitride layer at non-groove areas is thinned, so that the thickness of the silicon nitride layer formed on the front side is reduced to 70 nm, and the thickness of the silicon nitride layer formed on the front side is reduced to 70 nm;
[0138] Among them, the pickling reagent used in the first pickling is 8 wt% hydrofluoric acid, the temperature of the first pickling is 25 °C, and the time of the first pickling is 7 min.
[0139] S4. Physical vapor deposition - annealing:
[0140] After depositing a nickel metal film layer on the front side of the blue film after the first pickling by the physical vapor deposition process and then performing an annealing treatment, an alloy layer of nickel metal and silicon is formed at the grooves, while the non-groove areas remain nickel metal film layers;
[0141] Among them, the deposition specifically includes: using aluminum with a purity of 99.99% as the target, and adopting the method of vacuum sputtering plating to deposit a nickel metal film layer with a thickness of 80 nm on the front side of the blue film, the lamination rate is set at 3 nm / min, and the deposition temperature is 120 °C; the annealing treatment specifically includes: after deposition, annealing at 250 °C for 150 s in a vacuum state.
[0142] S5. Second pickling:
[0143] Remove the nickel metal film layer at non-groove positions through the second pickling.
[0144] Among them, the pickling reagent used in the second pickling includes, by mass percentage: 10% hydrogen peroxide and 15% sulfuric acid, and the balance is water; the temperature of the second pickling is 45 °C, and the time of the second pickling is 18 min.
[0145] S6. Prepare the conductive metal grid line layer:
[0146] Prepare the conductive metal grid line layer on both sides of the blue film after the second pickling through an electroplating process to obtain the TOPCon electroplated cell.
[0147] Among them, the seed layer is a nickel layer with a thickness of 0.8 μm, the transmission layer is a copper layer with a thickness of 10 μm, and the anti-oxidation layer is a tin layer with a thickness of 1.0 μm.
[0148] Example 3
[0149] This example provides a method for preparing a TOPCon electroplated cell, and the method for preparing the TOPCon electroplated cell includes the following steps:
[0150] S1. PECVD growth of silicon nitride:
[0151] The thickness of the silicon nitride layer formed on the front side of the blue film through the PECVD process is 130 nm; the thickness of the silicon nitride layer formed on the back side of the blue film is 140 nm;
[0152] Among them, the gases used in the plasma enhanced chemical vapor deposition process include SiH4 and NH3, the volume flow rate of SiH4 is 900 sccm, and the volume flow rate of NH3 is 12000 sccm; among them, the process parameters of the plasma enhanced chemical vapor deposition process include: the pulse switch ratio is 1:20, the temperature is 500 °C, the radio frequency power supply power is 12000 W, and the deposition time is 1500 s.
[0153] S2. Laser grooving:
[0154] Grooves are formed in the silicon nitride layers on both sides of the blue film through a laser grooving process. The depth of the grooves formed on the front side of the blue film is 125 nm, and the width is 15 μm. The depth of the grooves formed on the back side of the blue film is 125 nm, and the width is 15 μm.
[0155] Among them, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.3 W, and the laser frequency is 3500 MHz.
[0156] S3. First pickling:
[0157] The remaining 15-nm silicon nitride layer at the grooves on both sides of the blue film and the aluminum oxide layer at the grooves are removed through the first pickling, and the thickness of the silicon nitride layer at non-groove areas is thinned, so that the thickness of the silicon nitride layer formed on the front side is reduced to 80 nm, and the thickness of the silicon nitride layer formed on the front side is reduced to 80 nm.
[0158] Among them, the pickling reagent used in the first pickling is 4 wt% hydrofluoric acid, the temperature of the first pickling is 25 °C, and the time of the first pickling is 7 min.
[0159] S4. Physical vapor deposition - annealing:
[0160] After depositing a nickel metal film layer on the front side of the blue film after the first pickling through a physical vapor deposition process and then performing an annealing treatment, an alloy layer of nickel metal and silicon is formed at the grooves, while the non-groove areas remain nickel metal film layers.
[0161] Among them, the deposition specifically includes: using titanium with a purity of 99.99% as a target, and adopting the method of vacuum sputtering plating to deposit a nickel metal film layer with a thickness of 120 nm on the front side of the blue film, the laminating rate is set at 8 nm / min, and the deposition temperature is 150 °C. The annealing treatment specifically includes: annealing at 300 °C for 90 s in a vacuum state after deposition.
[0162] S5. Second pickling:
[0163] The nickel metal film layer at non-groove areas is removed through the second pickling.
[0164] Among them, the pickling reagent used in the second pickling includes, by mass percentage: 20% hydrogen peroxide and 20% sulfuric acid, and the balance is water. The temperature of the second pickling is 40 °C, and the time of the second pickling is 20 min.
[0165] S6. Preparation of a conductive metal grid line layer:
[0166] A conductive metal grid line layer is prepared on both sides of the blue film after the second pickling through an electroplating process to obtain the TOPCon electroplated solar cell.
[0167] Among them, the seed layer is a nickel layer with a thickness of 0.8 μm, the transmission layer is a copper layer with a thickness of 10 μm, and the anti-oxidation layer is a tin layer with a thickness of 1.0 μm.
[0168] Example 4
[0169] This example provides a preparation method of a TOPCon electroplated cell. The difference from Example 1 is that in S6, the seed layer is a silver layer with a thickness of 0.8 μm, the transmission layer is a copper layer with a thickness of 10 μm, and the anti-oxidation layer is a zinc layer with a thickness of 1.0 μm.
[0170] Example 5
[0171] This example provides a preparation method of a TOPCon electroplated cell. The preparation method of the TOPCon electroplated cell includes the following steps:
[0172] S1. PECVD growth of silicon nitride:
[0173] The thickness of the silicon nitride layer formed on the front side of the blue film by the PECVD process is 160 nm; the thickness of the silicon nitride layer formed on the back side of the blue film is 160 nm;
[0174] Among them, the gases used in the plasma-enhanced chemical vapor deposition process include SiH4 and NH3. The volume flow rate of SiH4 is 1200 sccm, and the volume flow rate of NH3 is 10000 sccm; among them, the process parameters of the plasma-enhanced chemical vapor deposition process include: pulse switch ratio of 1:15, temperature of 500 °C, radio frequency power of 14000 W, and deposition time of 1700 s.
[0175] S2. Laser grooving:
[0176] Grooves are formed in the silicon nitride layers on both sides of the blue film by the laser grooving process. The depth of the grooves formed on the front side of the blue film is 120 nm, and the width is 10 μm; the depth of the grooves formed on the back side of the blue film is 120 nm, and the width is 10 μm;
[0177] Among them, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.15 W, and the laser frequency is 3000 MHz.
[0178] S3. First pickling:
[0179] Remove the remaining 40-nm-thick silicon nitride layer and the aluminum oxide layer in the grooves on both sides of the blue film through the first pickling, and thin the silicon nitride layer in the non-grooved areas, reducing the thickness of the silicon nitride layer formed on the front side to 75 nm and the thickness of the silicon nitride layer formed on the front side to 75 nm;
[0180] Among them, the pickling reagent used in the first pickling is 6 wt% hydrofluoric acid, the temperature of the first pickling is 30 °C, and the time of the first pickling is 20 min.
[0181] S4. Physical vapor deposition - annealing:
[0182] After depositing a nickel metal film layer on the front side of the blue film after the first pickling through physical vapor deposition process, and through annealing treatment, an alloy layer of nickel metal and silicon is formed in the grooves, while the non-grooved areas remain nickel metal film layers;
[0183] Among them, the deposition specifically includes: using nickel with a purity of 99.99% as the target, and adopting the method of vacuum sputtering plating to deposit a 100-nm-thick nickel metal film layer on the front side of the blue film, with the laminating rate set at 5 nm / min and the deposition temperature at 150 °C; the annealing treatment specifically includes: annealing at 300 °C for 120 s in a vacuum state after deposition.
[0184] S5. Second pickling:
[0185] Remove the nickel metal film layer in the non-grooved areas through the second pickling;
[0186] Among them, the pickling reagent used in the second pickling includes by mass percentage: 20% hydrogen peroxide and 20% sulfuric acid, with the balance being water; the temperature of the second pickling is 40 °C, and the time of the second pickling is 12 min.
[0187] S6. Prepare the conductive metal grid line layer:
[0188] Prepare the conductive metal grid line layer on both sides of the blue film after the second pickling through electroplating process to obtain the TOPCon electroplated cell;
[0189] Among them, the seed layer is a nickel layer with a thickness of 0.8 μm, the transmission layer is a copper layer with a thickness of 10 μm, and the anti-oxidation layer is a tin layer with a thickness of 1.0 μm.
[0190] Example 6
[0191] This example provides a method for preparing a TOPCon electroplated cell, and the method for preparing the TOPCon electroplated cell includes the following steps:
[0192] S1. PECVD growth of silicon nitride:
[0193] The thickness of the silicon nitride layer formed on the front side of the blue film by the PECVD process is 100 nm; the thickness of the silicon nitride layer formed on the back side of the blue film is 100 nm;
[0194] Among them, the gases used in the plasma enhanced chemical vapor deposition process include SiH4 and NH3. The volume flow rate of SiH4 is 1100 sccm, and the volume flow rate of NH3 is 9000 sccm. Among them, the process parameters of the plasma enhanced chemical vapor deposition process include: the pulse switch ratio is 1:15, the temperature is 500 °C, the radio frequency power supply power is 12000 W, and the deposition time is 1000 s.
[0195] S2. Laser grooving:
[0196] Grooves are formed in the silicon nitride layers on both sides of the blue film by the laser grooving process. The depth of the grooves formed on the front side of the blue film is 80 nm, and the width is 10 μm; the depth of the grooves formed on the back side of the blue film is 80 nm, and the width is 10 μm;
[0197] Among them, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.15 W, and the laser frequency is 3000 MHz.
[0198] S3. First pickling:
[0199] The remaining 10 nm of silicon nitride layer and the aluminum oxide layer at the grooves on both sides of the blue film are removed by the first pickling, and the thickness of the silicon nitride layer at non-groove areas is thinned, so that the thickness of the silicon nitride layer formed on the front side is reduced to 75 nm, and the thickness of the silicon nitride layer formed on the front side is reduced to 75 nm;
[0200] Among them, the pickling reagent used in the first pickling is 6 wt% hydrofluoric acid, the temperature of the first pickling is 25 °C, and the time of the first pickling is 5 min.
[0201] S4. Physical vapor deposition - annealing:
[0202] After depositing a nickel metal film layer on the front side of the blue film after the first pickling by the physical vapor deposition process and then performing an annealing treatment, an alloy layer of nickel metal and silicon is formed at the grooves, while the non-groove areas remain nickel metal film layers;
[0203] Among them, the deposition specifically includes: using nickel with a purity of 99.99% as the target, and adopting the method of vacuum sputtering plating to deposit a nickel metal film layer with a thickness of 100 nm on the front side of the blue film, the lamination rate is set at 5 nm / min, and the deposition temperature is 150 °C; the annealing treatment specifically includes: after the deposition is completed, annealing is carried out at 300 °C for 120 s in a vacuum state.
[0204] S5. Second pickling:
[0205] Remove the nickel metal film layer at non-groove positions through the second pickling.
[0206] Among them, the pickling reagent used in the second pickling includes, by mass percentage: 20% hydrogen peroxide and 20% sulfuric acid, and the balance is water; the temperature of the second pickling is 40 °C, and the time of the second pickling is 12 min.
[0207] S6. Prepare the conductive metal grid line layer:
[0208] Prepare the conductive metal grid line layer on both sides of the blue film after the second pickling through the electroplating process to obtain the TOPCon electroplated solar cell.
[0209] Among them, the seed layer is a nickel layer with a thickness of 0.8 μm, the transmission layer is a copper layer with a thickness of 10 μm, and the anti-oxidation layer is a tin layer with a thickness of 1.0 μm.
[0210] Example 7
[0211] This example provides a method for preparing a TOPCon electroplated solar cell. The difference from Example 1 is only that in S1, the gases used in the PECVD process include SiH4 and NH3, the volume flow rate of SiH4 is 2000 sccm, and the volume flow rate of NH3 is 8000 sccm; among them, the process parameters of the plasma-enhanced chemical vapor deposition process include: the pulse switching ratio is 1:5, the temperature is 400 °C, the radio frequency power supply power is 8000 W, and the deposition time is 80 s.
[0212] Example 8
[0213] This example provides a method for preparing a TOPCon electroplated solar cell. The difference from Example 1 is only that in S1, the gases used in the PECVD process include SiH4 and NH3, the volume flow rate of SiH4 is 4000 sccm, and the volume flow rate of NH3 is 4000 sccm; among them, the process parameters of the plasma-enhanced chemical vapor deposition process include: the pulse switching ratio is 1:10, the temperature is 500 °C, the radio frequency power supply power is 25000 W, and the deposition time is 2000 s.
[0214] Example 9
[0215] This embodiment provides a method for preparing a TOPCon electroplated cell. The difference from Embodiment 1 is only that in S2, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.5 W, and the laser frequency is 5000 MHz; the depth of the groove formed on the front of the blue film is 140 nm, and the width is 15 μm; the depth of the groove formed on the back of the blue film is 140 nm, and the width is 15 μm.
[0216] Embodiment 10
[0217] This embodiment provides a method for preparing a TOPCon electroplated cell. The difference from Embodiment 1 is only that in S2, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 0.5 W, and the laser frequency is 1000 MHz; the depth of the groove formed on the front of the blue film is 45 nm, and the width is 3 μm; the depth of the groove formed on the back of the blue film is 45 nm, and the width is 3 μm.
[0218] Embodiment 11
[0219] This embodiment provides a method for preparing a TOPCon electroplated cell. The difference from Embodiment 1 is only that in S4, a nickel metal film layer with a thickness of 40 nm is deposited on the front of the blue film, the layer deposition rate is set at 0.5 nm / min, and the deposition temperature is 80 °C; the annealing treatment specifically includes: annealing at 180 °C for 300 s in a vacuum state after deposition.
[0220] Embodiment 12
[0221] This embodiment provides a method for preparing a TOPCon electroplated cell. The difference from Embodiment 1 is only that in S4, a nickel metal film layer with a thickness of 210 nm is deposited on the front of the blue film, the layer deposition rate is set at 15 nm / min, and the deposition temperature is 250 °C; the annealing treatment specifically includes: annealing at 450 °C for 300 s in a vacuum state after deposition.
[0222] Comparative Example 1
[0223] This comparative example provides a method for preparing a TOPCon electroplated cell. The method for preparing the TOPCon electroplated cell includes the following steps:
[0224] S1. PECVD growth of silicon nitride:
[0225] The thickness of the silicon nitride layer formed on the front of the blue film by the PECVD process is 75 nm; the thickness of the silicon nitride layer formed on the back of the blue film is 75 nm;
[0226] Among them, the gases used in the PECVD process include SiH4 and NH3. The volume flow rate of SiH4 is 1200 sccm, and the volume flow rate of NH3 is 10000 sccm. Among them, the process parameters of the plasma enhanced chemical vapor deposition process include: the pulse switch ratio is 1:15, the temperature is 500 °C, the RF power is 14000 W, and the deposition time is 800 s.
[0227] S2. Laser grooving:
[0228] Through the laser grooving process, grooves are formed in the silicon nitride layers on both sides of the blue film. The depth of the grooves formed on the front side of the blue film is 75 nm, and the width is 10 μm. The depth of the grooves formed on the back side of the blue film is 75 nm, and the width is 10 μm.
[0229] Among them, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 2.5 W, and the laser frequency is 1000 MHz.
[0230] S3. Physical vapor deposition - annealing:
[0231] After depositing a nickel metal film layer on the front side of the blue film after laser grooving through the physical vapor deposition process, and then performing an annealing treatment, an alloy layer of nickel metal and silicon is formed at the grooves, while the non - groove areas remain nickel metal film layers.
[0232] Among them, the deposition specifically includes: using nickel with a purity of 99.99% as the target, and adopting the method of vacuum sputtering plating to deposit a nickel metal film layer with a thickness of 100 nm on the front side of the blue film, the laminating rate is set at 5 nm / min, and the deposition temperature is 150 °C. The annealing treatment specifically includes: after deposition, annealing is carried out at 250 °C for 120 s in a vacuum state.
[0233] S4. Second pickling:
[0234] Remove the nickel metal film layer in the non - groove areas through the second pickling.
[0235] Among them, the pickling reagent used in the second pickling includes, by mass percentage: 20% hydrogen peroxide and 30% sulfuric acid, and the balance is water. The temperature of the second pickling is 40 °C, and the time of the second pickling is 15 min.
[0236] S5. Preparation of the conductive metal grid line layer:
[0237] Prepare the conductive metal grid line layer on both sides of the blue film after the second pickling through the electroplating process to obtain the TOPCon electroplated solar cell.
[0238] Wherein, the seed layer is a nickel layer with a thickness of 0.8 μm, the transmission layer is a copper layer with a thickness of 10 μm, and the anti-oxidation layer is a tin layer with a thickness of 1.0 μm.
[0239] Comparative Example 2
[0240] This comparative example provides a method for preparing a TOPCon electroplated cell, which differs from Example 1 only in that, in S2, the depth of the groove formed on the front side of the blue film is 130 nm; the depth of the groove formed on the back side of the blue film is 130 nm.
[0241] Comparative Example 3
[0242] This comparative example provides a method for preparing a TOPCon electroplated cell, which differs from Example 1 only in that the depth of the groove directly formed on the front side of the blue film by S2 is 135nm; the depth of the groove formed on the back side of the blue film is 135nm; but the first acid pickling of S3 is not performed, therefore, the silicon nitride in the non-groove areas on the front and back sides of the blue film in this comparative example is not thinned, and the thickness is still 135nm.
[0243] Comparative Example 4
[0244] This comparative example provides a method for preparing a TOPCon electroplated cell, which differs from Example 1 only in that the S4 physical vapor deposition-annealing step is not performed.
[0245] Test Case
[0246] Test samples: TOPCon electroplated cells provided in Examples 1 to 12, and TOPCon electroplated cells provided in Comparative Examples 1 to 4.
[0247] Test method: Use IV tester to perform efficiency test, and the characterization contents include open circuit voltage (Uoc), short circuit current (Isc), series resistance (Rser), parallel resistance (Rshunt), fill factor (FF) and photoelectric conversion efficiency (Eta).
[0248] The test results are shown in Table 1 below:
[0249] Table 1
[0250]
[0251]
[0252] As shown in Table 1, the main object of the present invention is to improve the efficiency of TOPCon electroplated solar cells by reducing laser damage and using PVD to grow a seed layer. Usually, the laser stripping process uses a certain power to open both silicon nitride and part of the silicon to achieve the effect of pattern stripping. However, in the present invention, a lower laser power is used to only remove part of the silicon nitride layer, and then an acid pickling process is used to clean the surface of the silicon nitride and remove the remaining silicon nitride at the grooving position. Then, the subsequent electroplated grid line process is carried out. This process effectively reduces the laser damage to the film layer. Secondly, a nickel, aluminum or titanium film layer is produced on the surface of the blue film by PVD process, and then annealed to form an alloy with the silicon exposed at the grooving position to produce ohmic contact. Then, a mixed solution of sulfuric acid and hydrogen peroxide is used to remove nickel, aluminum or titanium in the non-grooving area, and only the alloy at the grooving position is retained as the bottom layer. The nickel / aluminum film grown by PVD has better density and uniformity than the electroplating process, which can not only reduce metal recombination, but also has better blocking property for copper ions.
[0253] From the comparison between Example 1 and Examples 7-8, it can be seen that the PECVD process parameters in S1 are not within the preferred range of this application, and the properties of the deposited silicon nitride layer are poor. Therefore, the open-circuit voltage, short-circuit current, fill factor, photoelectric conversion efficiency, etc. finally obtained all decrease extremely significantly.
[0254] From the comparison between Example 1 and Examples 9-10, it can be seen that the laser power and frequency in S2 are not within the range of this application, and the quality of the formed grooves is poor. Therefore, the open-circuit voltage, short-circuit current, fill factor, photoelectric conversion efficiency, etc. finally obtained all decrease relatively significantly.
[0255] From the comparison between Example 1 and Examples 11-12, it can be seen that the physical vapor deposition-annealing process in S4 is not within the preferred range, and the quality of the formed nickel metal film layer is poor. Therefore, the open-circuit voltage, short-circuit current, fill factor, photoelectric conversion efficiency, etc. finally obtained all decrease relatively significantly.
[0256] From the comparison between Example 1 and Comparative Examples 1-2, it can be seen that only when the silicon nitride thickness range of the blue film is appropriate, it is beneficial to use a lower laser power to only remove part of the silicon nitride layer. Otherwise, it is difficult to control the removal process, and thus the open-circuit voltage, short-circuit current, fill factor, photoelectric conversion efficiency, etc. finally obtained all decrease extremely significantly.
[0257] From the comparison between Example 1 and Comparative Example 3, it can be seen that if the first acid pickling is not carried out, the silicon nitride in the non-groove area is too thick, and thus the open-circuit voltage, short-circuit current, fill factor, photoelectric conversion efficiency, etc. finally obtained all decrease extremely significantly.
[0258] From the comparison between Example 1 and Comparative Example 4, it can be seen that the compactness and uniformity of the nickel film grown by PVD are better than those of the electroplating process. It can not only reduce metal recombination, but also has better blocking performance for copper ions. On the contrary, the open circuit voltage, short circuit current, fill factor, photoelectric conversion efficiency, etc. finally obtained all decrease extremely significantly.
[0259] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A preparation method of a TOPCon electroplated battery chip, characterized in that, The preparation method of the TOPCon electroplated cell includes: Prepare silicon nitride layers on both sides of the blue film, and the thickness of the silicon nitride layers on both sides of the blue film is independently 120 nm or more; Form grooves in the silicon nitride layers on both sides of the blue film through a laser grooving process, and the depth of the grooves is 90% or less of the thickness of the silicon nitride layer; Remove the remaining silicon nitride layer at the grooves through the first pickling; After depositing a metal film layer on the front side of the blue film after the first pickling through a physical vapor deposition process and performing an annealing treatment, form an alloy layer of metal and silicon at the grooves; Remove the metal film layer at non-groove areas through the second pickling; Prepare conductive metal grid line layers on both sides of the blue film after the second pickling through an electroplating process to obtain the TOPCon electroplated cell.
2. The preparation method of the TOPCon electroplated solar cell according to claim 1, wherein, The blue film includes an N-type silicon substrate; the front side of the N-type silicon substrate sequentially includes a boron diffusion layer and an alumina layer from inside to outside; the back side of the N-type silicon substrate sequentially includes a tunneling oxide layer and a polysilicon layer from inside to outside.
3. The preparation method of the TOPCon electroplated cell according to claim 2, wherein, The thickness of the N-type silicon substrate is 100 - 150 μm; Preferably, the thickness of the boron diffusion layer is 0.3 to 3 μm, and the boron doping concentration is 1.0e 16 ~1.0e 19 cm -3 ; Preferably, the thickness of the alumina layer is 1 - 10 nm; Preferably, the thickness of the tunneling oxide layer is 0.3 - 3 nm; Preferably, the thickness of the polysilicon layer is 30 - 300 nm.
4. The preparation method of the TOPCon electroplated cell according to claim 1 or 2, characterized in that, The thickness of the silicon nitride layer formed on the front side of the blue film is 120 - 150 nm; the thickness of the silicon nitride layer formed on the back side of the blue film is 120 - 150 nm; Among them, the silicon nitride layer formed on the front side is formed on the surface of the alumina layer, and the silicon nitride layer formed on the back side is formed on the surface of the polysilicon layer; Preferably, the plasma enhanced chemical vapor deposition process is used to prepare the silicon nitride layer; Preferably, the gases used in the plasma enhanced chemical vapor deposition process include SiH4 and NH3; among them, the volume flow rate of SiH4 is 300 - 3000 sccm, and the volume flow rate of NH3 is 2000 - 20000 sccm; Preferably, the process parameters of the plasma enhanced chemical vapor deposition process include: the pulse switch ratio is 1:(10 - 20), the temperature is 400 - 600 °C, the radio frequency power supply power is 5000 - 20000 W, and the deposition time is 500 - 2000 s.
5. The preparation method of the TOPCon electroplated solar cell according to claim 1, wherein The depth of the grooves is 60 - 90% of the thickness of the silicon nitride layer; Preferably, the width of the grooves is 5 - 15 μm; Preferably, the process parameters of the laser grooving process include: the laser is a picosecond laser, the laser power is 1.0 - 1.3 W, and the laser frequency is 1000 - 5000 MHz.
6. The preparation method of the TOPCon electroplated battery chip according to claim 1, wherein, The pickling reagent used in the first pickling is 2 - 10 wt% hydrofluoric acid; Preferably, after the first pickling, all the remaining silicon nitride layer flakes at the grooves on the blue film are removed, and the thickness of the silicon nitride layer at non-groove areas on the blue film is 60 - 90 nm; Preferably, the temperature of the first pickling is 20 - 40 °C, and the time of the first pickling is 3 - 30 min.
7. The preparation method of the TOPCon electroplated cell according to claim 1, wherein The metal film layer includes any one of a nickel film layer, an aluminum film layer, or a titanium film layer; Preferably, the thickness of the metal film layer is 30 - 200 nm; Preferably, the deposition of the metal film layer is carried out by vacuum sputtering plating; Preferably, the deposition rate of the metal film layer is 1 - 10 nm / min, and the temperature of the deposition of the metal film layer is 100 - 200 °C; Preferably, the annealing treatment is carried out under vacuum conditions, the temperature of the annealing treatment is 200 - 400 °C, and the time of the annealing treatment is 50 - 200 s.
8. The preparation method of the TOPCon electroplated battery sheet according to claim 1, wherein, The pickling reagent used for the second pickling comprises, by mass percentage: 10 - 30% hydrogen peroxide and 10 - 30% sulfuric acid, with the balance being water; Preferably, the temperature of the second pickling is 30 - 50 °C, and the time of the second pickling is 5 - 20 min.
9. The preparation method of the TOPCon electroplated solar cell according to claim 1, wherein, The conductive metal grid line layer is disposed at the grooves on both sides of the blue film; the conductive metal grid line layer sequentially includes a seed layer, a transmission layer, and an anti-oxidation layer from inside to outside; wherein, the seed layer is a nickel layer or a silver layer; the transmission layer is a copper layer; the anti-oxidation layer is a tin layer or a zinc layer; Preferably, the thickness of the seed layer is 0.5 - 1.0 μm; Preferably, the thickness of the transmission layer is 5 - 15 μm; Preferably, the thickness of the anti-oxidation layer is 0.5 - 2.0 μm.
10. A TOPCon electroplated cell, characterized in that, The TOPCon electroplated solar cell is prepared by the preparation method of the TOPCon electroplated solar cell according to any one of claims 1 - 9.