N-type TOPCon battery efficiency improvement method based on RCA monitoring

Abstract

The invention provides an N-type TOPCon battery efficiency improving method based on RCA monitoring, and relates to the technical field of batteries. Comprising the following steps: carrying out PSG treatment on a TOPCon battery, and then measuring a sheet resistance value a of a boron-doped surface and a sheet resistance value b of a phosphorus-doped surface of a silicon wafer after PSG treatment; carrying out RCA treatment on the silicon wafer, and then measuring the sheet resistance value A of the boron-doped surface and the sheet resistance value B of the phosphorus-doped surface (back surface) of the silicon wafer after RCA treatment; measuring the side microcosmic tower footing side length C of the silicon wafer; calculating 1 and 2; and setting the control ranges of the side lengths C, 1 and 2, and respectively adjusting parameters in the RCA treatment process when the values exceed the set control ranges. The surface sheet resistance before and after the RCA etching process is monitored, the periodic stability of the tower footing on the side surface of the silicon wafer and the periodic stability of the surface sheet resistance are synchronously monitored, the influence of abnormal etching on the efficiency is reduced, the stability of the process period is improved, and the efficiency and the yield of a production line are improved.

Description

Technical Field

[0001] The present application relates to the technical field of TOPCon batteries, and in particular to a method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring. Background Art

[0002] In order to solve the environmental bottleneck faced by my country's energy development and actively respond to environmental changes, it is necessary to speed up the optimization of the energy structure, change the current fossil energy-based to electricity-based, and reduce the use of fossil fuels. As a clean secondary energy source, the large-scale use of electricity and the replacement of other energy sources (including electricity for oil, electricity for coal, etc.) play an important role in improving the environment and reducing the emission of atmospheric pollutants. Photovoltaic power generation directly converts light energy into electrical energy using the photoelectric effect, which is a clean energy source. The raw material of solar cells is sunlight, which is not only widely distributed, but more importantly, it is endless and will never run out. Improving the conversion efficiency of solar cells and reducing production costs are the goals that the photovoltaic industry has always pursued. N-type high-efficiency solar cells are one of the main directions that the photovoltaic industry is currently promoting because of their higher conversion efficiency.

[0003] In the existing N-type TOPCON battery PSG+RCA process, the main functional tanks include: chain etching and plating, alkaline etching / post-cleaning / acid pickling 1 / acid pickling 2 / slow pulling. At present, the acid tank adopts a double HF method. The primary purpose of pickling 1 is to etch the front protective layer BSG and the back protective layer MASK, and then remove the metal ions and alkali residues remaining in the previous functional tank; the primary purpose of pickling 2 is to clean the natural oxide layer formed in the water tank, and form a Si-H bond dehydration surface on the front and back surfaces. However, due to the mismatch of the etching concentrations of various functional tanks, the etching functions of the functional tanks are disordered, and the correct etching functions cannot be performed, resulting in the high-concentration tank etching the incompletely crystallized POLY, making the TOPCon back passivation invalid, and thus affecting the production line efficiency. Summary of the invention

[0004] The purpose of this application is to provide an N-type TOPCon battery efficiency improvement method based on RCA monitoring, which improves the stability of the process cycle and improves the efficiency and yield of the production line.

[0005] In order to solve the above technical problems, the technical solution adopted in this application is:

[0006] The present application provides a method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring, comprising the following steps:

[0007] S1. Perform PSG treatment on the TOPCon cell, and then measure the square resistance value a of the boron-doped surface (front side) and the square resistance value b of the phosphorus-doped surface (back side) of the silicon wafer after PSG;

[0008] S2, performing RCA treatment on the silicon wafer after step S1, and then measuring the square resistance value A of the boron-doped surface (front side) and the square resistance value B of the phosphorus-doped surface (back side) of the silicon wafer after RCA;

[0009] S3, measure the side length C of the microscopic tower base on the side of the silicon wafer; calculate △1 = square resistance value A-square resistance value a; △2 = square resistance value B-square resistance value b;

[0010] S4. Set the control range of the side length C, △1 and △2. When the above values ​​exceed the established control range, adjust the parameters in the RCA processing process respectively.

[0011] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects:

[0012] This application adds surface square resistance monitoring before and after the RCA etching process under the basic monitoring of the TOPCon side tower base, and simultaneously monitors the cycle stability of the TOPCon side tower base and the cycle stability of the surface square resistance, thereby reducing the impact of abnormal etching on efficiency, thereby improving the stability of the process cycle and improving the efficiency and yield of the production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 Schematic diagram of five points for measuring square resistance value for this application;

[0015] Figure 2 This is a diagram showing the etching state of the side edge of the cell in the control group of the experimental example of this application;

[0016] Figure 3 This is a diagram of the etching status of the side edge of the battery cell in the experimental group of the experimental example of this application. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to specific embodiments.

[0019] A method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring comprises the following steps:

[0020] S1. Perform PSG treatment on the TOPCon cell, and then measure the square resistance value a of the boron-doped surface (front side) and the square resistance value b of the phosphorus-doped surface (back side) of the silicon wafer after PSG;

[0021] S2, performing RCA treatment on the silicon wafer after step S1, and then measuring the square resistance value A of the boron-doped surface (front side) and the square resistance value B of the phosphorus-doped surface (back side) of the silicon wafer after RCA;

[0022] S3, measure the side length C of the microscopic tower base on the side of the silicon wafer; calculate △1 = square resistance value A-square resistance value a; △2 = square resistance value B-square resistance value b;

[0023] S4. Set the control range of the side length C, △1 and △2. When the above values ​​exceed the established control range, adjust the parameters in the RCA processing process respectively.

[0024] In some embodiments of the present application, the PSG processing in the above-mentioned step S1 is specifically single-sided etching of the TOPCon cell edge MASK wrap plating and part of the BSG protective layer.

[0025] In some embodiments of the present application, the PSG treatment in the above-mentioned step S2 specifically includes the following processes: alkaline etching, one water wash, post-washing, two water washes, one acid wash, three water washes, two acid washes, four water washes, slow pulling with hot water, and drying. The solution used for alkaline etching is KOH + additives, the concentration of KOH is 2.5-4.5% (wt%), the concentration of additives is 0.5-0.8% (wt%), the temperature of alkaline etching is 65-70°C, the time is 5-8min, and circulation + bubbling is used to ensure that the solution is uniform, remove the POLY plating and tunnel plating on the edge of the TOPCon battery, and etch a certain silicon substrate to prevent leakage. The purpose of one water wash is to remove some of the alkali and additives remaining on the surface of the TOPCon battery cell. The solution used for post-cleaning is KOH+H2O2, the concentration of KOH is 0.5-1% (wt%), the concentration of H2O2 is 2.5-4.5% (wt%), the temperature is 55-65℃, and the time is 1-3min. The purpose is to remove the alkali and additives remaining on the surface of the TOPCon battery. The second water wash is used to remove the silicate remaining on the surface of the TOPCon battery. The first acid wash uses HF with a concentration of 25-35% (wt%) and a time control of 80-150s. The first acid wash removes the front BSG protective layer and the back MASK mask layer; the purpose of the third water wash is to remove the acid and impurity residues remaining on the surface of the TOPCon battery. The second acid wash uses HF with a concentration of 8-15% (wt%) and a time control of 60-120s. The second acid wash removes the natural oxide layer and improves the hydrophobicity of the battery surface. The fourth water wash is to remove the acid residue remaining on the surface of the TOPCon battery. Slow pulling with hot water makes the surface of the TOPCon battery free of obvious water residue, which is convenient for subsequent hot air drying. Hot air drying makes the surface of TOPCon cells dry.

[0026] In some embodiments of the present application, the square resistance values ​​in the above steps S1 and S2 are measured using a four-probe method, specifically, 5 points are set on the silicon wafer, namely the center point and 4 points 1-2 cm away from the corners of the silicon wafer.

[0027] In some embodiments of the present application, the side length C in the above step S3 is measured using a ZETA 3D microscope, specifically by measuring three points on the side of the silicon wafer, namely the center point of the side and two points 1-2 cm away from the corners of the silicon wafer.

[0028] In some embodiments of the present application, in the above step S4, the control range of the side length C is 20 to 25 μm, the control range of △1 is -5 to 0Ω, and the control range of △2 is 0 to 5Ω.

[0029] In some embodiments of the present application, the adjustment method in the above step S4 includes: when △1>0Ω, the concentration of HF or the etching time in the pickling step is increased; when △1<-5Ω, the concentration of HF or the etching time in the pickling step is reduced. The adjustment range is 10% of the original etching time as a step (for example, the original etching time is 100s, and it is adjusted to 100±10s according to the result).

[0030] In some embodiments of the present application, the adjustment method in the above step S4 includes: when △2<0Ω, the concentration of HF or the etching time in the pickling step is increased; when △2>5Ω, the concentration of HF or the etching time in the pickling step is reduced. The adjustment range is 5% of the original etching time as a step (for example, the original etching time is 100s, and it is adjusted to 100±5s according to the result).

[0031] In some embodiments of the present application, the adjustment method in the above step S4 includes: when the side micro-tower base side length C>25μm, then reduce the concentration of the alkaline etching solution or the etching time, when the side micro-tower base side length C<20μm, then increase the concentration of the alkaline etching solution or the etching time. The adjustment range is 5% of the original etching time as a step (for example, the original etching time is 400s, and it is adjusted to 400±20s according to the results).

[0032] The principle of adopting the above adjustment in this application is:

[0033] 1. When testing square resistance a, the front BSG protective layer contains a boron-rich layer (inactive boron doping), which causes the square resistance to be high when the four-probe square resistance is tested. When testing square resistance A subsequently, the theoretical front BSG protective layer is completely removed, so that the square resistance decreases theoretically when the four-probe square resistance is tested. If it does not decrease, it means that the BSG has not been completely removed and the formula needs to be adjusted.

[0034] 2. When testing square resistance b, the outermost doping layer in the back MASK protective layer (the highest concentration of doping and activated by annealing) causes the square resistance to be low when the four-probe square resistance test is performed; when testing square resistance B subsequently, when the back MASK protective layer is just completely removed, the square resistance theoretically increases by 0 to 5Ω when the four-probe square resistance test is performed; if the increase in square resistance is too large, it proves that the etching amount is too much (high concentration HF actually has an etching effect on polysilicon, and excessive etching will weaken the passivation effect), and the formula needs to be adjusted.

[0035] 3. The etching effect of high concentration alkali on the monocrystalline silicon substrate is mainly to break through the tunneling layer and etch part of the doped substrate to prevent leakage of the TOPCon battery product. If the side micro-tower base is larger than the control range, the etching time or concentration of the alkali etching tank is reduced; if the side micro-tower base is smaller than the control range, the etching time or concentration of the alkali etching tank is increased.

[0036] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0037] Example 1

[0038] A method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring comprises the following steps:

[0039] S1. Perform PSG treatment on TOPCon cells: single-sided etching of the MASK plating around the edge of the TOPCon cell and part of the BSG protective layer. Use the four-probe method to test the square resistance value a of the boron-doped surface (front) and the square resistance value b of the phosphorus-doped surface (back) of the silicon wafer after PSG. Test 5 points on the monitoring chip, namely the center point and four points 1-2 cm away from the corners of the monitoring chip;

[0040] S2, performing RCA treatment on the silicon wafer after step S1, specifically:

[0041] RCA-1, alkaline etching, the solution used is KOH + additives, the concentration of KOH is 3wt%, the concentration of additives is 0.6wt%, the temperature of alkaline etching is 68°C, the time is 6min, circulation + bubbling;

[0042] RCA-2, one water wash (immersion wash) to remove some of the alkali and additives remaining on the surface of the TOPCon battery cell.

[0043] RCA-3, post-cleaning, using KOH+H2O2, with a KOH concentration of 0.8wt%, a H2O2 concentration of 3.5wt%, a temperature of 60°C, and a time of 2min to remove the residual alkali and additives on the surface of the TOPCon battery cell.

[0044] RCA-4, secondary water washing to remove residual silicate on the surface of TOPCon cells.

[0045] RCA-5, one pickling, HF concentration is 30wt%, one pickling to remove the front BSG protection layer and the back MASK mask layer.

[0046] RCA-6, three times of water washing to remove the residual acid and impurities on the surface of the TOPCon battery.

[0047] RCA-7, secondary pickling uses HF at a concentration of 10wt% to remove the natural oxide layer and improve the hydrophobicity of the battery surface.

[0048] RCA-8, four times of water washing to remove the acid residue remaining on the surface of the TOPCon cell.

[0049] RCA-9, slowly pull with hot water to make sure there is no obvious water residue on the surface of the TOPCon cell, which is convenient for subsequent hot air drying.

[0050] RCA-10, hot air drying to dry the surface of TOPCon cells.

[0051] The four-probe method was used to test the square resistance value A of the boron-doped surface (front) and the square resistance value B of the phosphorus-doped surface (back) of the monitoring film after RCA. Five points on the monitoring film were tested, namely the center point and four points 1-2 cm away from the corners of the monitoring film; the points are as follows Figure 1 shown.

[0052] S3. Use ZETA 3D microscope to test the side length C of the micro-tower base of the monitoring piece. Test three points on the monitoring piece, namely the center point of the side and two points 1-2 cm away from the corners of the monitoring piece;

[0053] Calculate △1 = square resistance value A-square resistance value a; △2 = square resistance value B-square resistance value b;

[0054] S4. Set the control range of side length C, △1 and △2 as follows: the control range of side length C is 20-25μm, the control range of △1 is -5-0Ω, and the control range of △2 is 0-5Ω. When the above values ​​exceed the established control range, the parameters in the RCA processing process are adjusted respectively. The specific adjustments include: when △1>0Ω, the concentration of HF or the etching time in the first pickling step is increased; when △1<-5Ω, the concentration of HF or the etching time in the first pickling step is reduced. When △2<0Ω, the concentration of HF or the etching time in the first pickling step is increased; when △2>5Ω, the concentration of HF or the etching time in the first pickling step is reduced. When the side micro-tower base side length C>25μm, the concentration of the alkaline etching solution or the etching time is reduced; when the side micro-tower base side length C<20μm, the concentration of the alkaline etching solution or the etching time is increased.

[0055] Example 2

[0056] A method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring comprises the following steps:

[0057] S1. Perform PSG treatment on TOPCon cells: single-sided etching of the MASK plating around the edge of the TOPCon cell and part of the BSG protective layer. Use the four-probe method to test the square resistance value a of the boron-doped surface (front) and the square resistance value b of the phosphorus-doped surface (back) of the silicon wafer after PSG. Test 5 points on the monitoring chip, namely the center point and four points 1-2 cm away from the corners of the monitoring chip;

[0058] S2, performing RCA treatment on the silicon wafer after step S1, specifically:

[0059] RCA-1, alkaline etching, the solution used is KOH + additives, the concentration of KOH is 3.5wt%, the concentration of additives is 0.7wt%, the temperature of alkaline etching is 70°C, the time is 6min, circulation + bubbling;

[0060] RCA-2, one water wash to remove some of the alkali and additives remaining on the surface of the TOPCon cell.

[0061] RCA-3, post-cleaning, using KOH+H2O2, KOH concentration is 0.6wt%, H2O2 concentration is 4.0wt%, temperature is 60℃, time is 3min, to remove the residual alkali and additives on the surface of TOPCon battery cell.

[0062] RCA-4, secondary water washing to remove residual silicate on the surface of TOPCon cells.

[0063] RCA-5, one pickling, HF concentration is 30wt%, one pickling to remove the front BSG protection layer and the back MASK mask layer.

[0064] RCA-6, three times of water washing to remove the residual acid and impurities on the surface of the TOPCon battery.

[0065] RCA-7, secondary pickling uses HF at a concentration of 10wt% to remove the natural oxide layer and improve the hydrophobicity of the battery surface.

[0066] RCA-8, four times of water washing to remove the acid residue remaining on the surface of the TOPCon cell.

[0067] RCA-9, slowly pull with hot water to make sure there is no obvious water residue on the surface of the TOPCon cell, which is convenient for subsequent hot air drying.

[0068] RCA-10, hot air drying to dry the surface of TOPCon cells.

[0069] The four-probe method was used to test the square resistance value A of the boron-doped surface (front) and the square resistance value B of the phosphorus-doped surface (back) of the monitoring film after RCA. Five points on the monitoring film were tested, namely the center point and four points 1-2 cm away from the corners of the monitoring film;

[0070] S3. Use ZETA 3D microscope to test the side length C of the micro-tower base of the monitoring piece. Test three points on the monitoring piece, namely the center point of the side and two points 1-2 cm away from the corners of the monitoring piece;

[0071] Calculate △1 = square resistance value A-square resistance value a; △2 = square resistance value B-square resistance value b;

[0072] S4. Set the control range of side length C, △1 and △2 as follows: the control range of side length C is 20-25μm, the control range of △1 is -5-0Ω, and the control range of △2 is 0-5Ω. When the above values ​​exceed the established control range, the parameters in the RCA processing process are adjusted respectively. The specific adjustments include: when △1>0Ω, the concentration of HF or the etching time in the first pickling step is increased; when △1<-5Ω, the concentration of HF or the etching time in the first pickling step is reduced. When △2<0Ω, the concentration of HF or the etching time in the first pickling step is increased; when △2>5Ω, the concentration of HF or the etching time in the first pickling step is reduced. When the side micro-tower base side length C>25μm, the concentration of the alkaline etching solution or the etching time is reduced; when the side micro-tower base side length C<20μm, the concentration of the alkaline etching solution or the etching time is increased.

[0073] Experimental example

[0074] A method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring comprises the following steps:

[0075] S1. Perform PSG treatment on TOPCon cells: single-sided etching of the MASK plating around the edge of the TOPCon cell and part of the BSG protective layer. Use the four-probe method to test the square resistance value a of the boron-doped surface (front) and the square resistance value b of the phosphorus-doped surface (back) of the silicon wafer after PSG. Test 5 points on the monitoring chip, namely the center point and four points 1-2 cm away from the corners of the monitoring chip;

[0076] S2, performing RCA treatment on the silicon wafer after step S1, specifically:

[0077] RCA-1, alkaline etching, the solution used is KOH + additives, the concentration of KOH is 3wt%, the concentration of additives is 0.6wt%, the temperature of alkaline etching is 65°C, the time is 5min, circulation + bubbling;

[0078] RCA-2, one water wash to remove some of the alkali and additives remaining on the surface of the TOPCon cell.

[0079] RCA-3, post-cleaning, using KOH+H2O2, with a KOH concentration of 0.8wt%, a H2O2 concentration of 3.8wt%, a temperature of 62°C, and a time of 1 min to remove the residual alkali and additives on the surface of the TOPCon battery cell.

[0080] RCA-4, secondary water washing to remove residual silicate on the surface of TOPCon cells.

[0081] RCA-5, one pickling, HF concentration is 30wt%, one pickling to remove the front BSG protection layer and the back MASK mask layer.

[0082] RCA-6, three times of water washing to remove the residual acid and impurities on the surface of the TOPCon battery.

[0083] RCA-7, secondary pickling uses HF at a concentration of 10wt% to remove the natural oxide layer and improve the hydrophobicity of the battery surface.

[0084] RCA-8, four times of water washing to remove the acid residue remaining on the surface of the TOPCon cell.

[0085] RCA-9, slowly pull with hot water to make sure there is no obvious water residue on the surface of the TOPCon cell, which is convenient for subsequent hot air drying.

[0086] RCA-10, hot air drying to dry the surface of TOPCon cells.

[0087] The four-probe method was used to test the square resistance value A of the boron-doped surface (front side) and the square resistance value B of the phosphorus-doped surface (back side) of the monitoring film after RCA. Five points on the monitoring film were tested, namely the center point and four points 1-2 cm away from the corners of the monitoring film.

[0088] S3. Use ZETA 3D microscope to test the side length C of the micro-tower base of the monitoring piece. Test three points on the monitoring piece, namely the center point of the side and two points 1-2 cm away from the corners of the monitoring piece;

[0089] Calculate △1 = square resistance value A-square resistance value a; △2 = square resistance value B-square resistance value b;

[0090] If the △1 front side resistance difference is positive, the etching time or concentration of the RCA-5HF groove is increased; if the △1 front side resistance difference is <-5Ω, the etching time or concentration of the RCA-5HF groove is reduced; the adjustment range is 10% of the original etching time as a step.

[0091] If the △2 back side resistance difference is negative, the etching time or concentration of the RCA-5HF groove is increased; if the △1 back side resistance difference is greater than 5Ω, the etching time or concentration of the RCA-5HF groove is reduced; the adjustment range is 5% of the original etching time as a step.

[0092] If the side micro-tower base is larger than the control range, the etching time or concentration of the RCA-1 alkaline etching tank is reduced; if the side micro-tower base is smaller than the control range, the etching time or concentration of the RCA-1 alkaline etching tank is increased. The adjustment range is 5% of the original etching time as a step. The parameter values ​​of this experimental example before and after the above adjustment are shown in Table 1 and Table 2.

[0093] Table 1

[0094] Group a A b B C Before adjustment 346.33 348.16 46.34 47.15 17.5-19.8um After adjustment 349.72 347.39 47.53 49.40 21.3-24.5um

[0095] Table 2

[0096] Group RCA-1 RCA-5 RCA-7 △1 △2 C Before adjustment 350s 120s 120s 1.83 0.81 17.5-19.8um After adjustment 385s 144s 120s -2.33 1.87 21.3-24.5um

[0097] A control group was also set up in this experimental example. The PSG+RCA process of the control group was the same as that of the experimental group before monitoring and adjustment. The difference between the control group and the experimental group was that the control group only tested and adjusted the side tower base of the TOPCon battery edge in the same way as the experimental group, and did not adjust the square resistance of the silicon wafer after the PSG+RCA process of the TOPCon battery.

[0098] Figure 2 and Figure 3 The etching status diagrams of the side edges of the battery cells for the control group and the experimental group respectively.

[0099] from Figure 2 It can be seen that RCA only monitors the edge side tower base and does not centrally monitor its periodic changes. It is unable to make corresponding adjustments to the process concentration changes in time, and may cause the edge poly to be incompletely etched, thereby affecting the leakage yield; the etching concentrations of various functional slots are not matched, resulting in disordered etching functions of the functional slots; the correct etching functions cannot be performed, resulting in high-concentration slots that etch incompletely crystallized POLY, causing TOPCon back passivation to fail, thereby affecting production line efficiency.

[0100] from Figure 3 It can be seen that after adopting the monitoring method proposed in the embodiment of the present application, five-point monitoring of the surface square resistance before and after the RCA etching process is added, the periodic stability of the TOPCon side tower base and the periodic stability of the surface square resistance are monitored synchronously, the edge poly is completely etched, and the impact of abnormal etching on efficiency is reduced, thereby improving the stability of the process cycle and improving the efficiency and yield of the production line.

[0101] The efficiency of the experimental group and the control group is shown in Table 3.

[0102] Table 3

[0103] Test items Eta Uoc Isc FF Control group 26.671 0.7393 14.084 85.73 Experimental Group 26.742 0.7391 14.102 85.87 △ 0.071 0.000 0.017 0.137

[0104] It can be seen from Table 2 that the efficiency is improved by 0.071% before and after monitoring, mainly due to the improvement of ISC and FF.

[0105] To summarize, an N-type TOPCon battery efficiency improvement method based on RCA monitoring in an embodiment of the present application has the following advantages: the present application adds surface square resistance monitoring before and after the RCA etching process under basic monitoring such as the TOPCon side tower base, and simultaneously monitors the periodic stability of the TOPCon side tower base and the periodic stability of the surface square resistance, thereby reducing the impact of abnormal etching on efficiency, thereby improving the stability of the process cycle and improving the efficiency and yield of the production line.

[0106] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present application.

Claims

1. A method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring, characterized in that: The following steps are involved: S1. Perform PSG treatment on the TOPCon cell, and then measure the square resistance a of the boron-doped surface of the silicon wafer and the square resistance b of the phosphorus-doped surface after PSG; S2, performing RCA treatment on the silicon wafer after step S1, and then measuring the square resistance value A of the boron-doped surface and the square resistance value B of the phosphorus-doped surface of the silicon wafer after RCA; S3, measuring the side length C of the microscopic tower base on the side of the silicon wafer; Calculate △1 = square resistance value A-square resistance value a; △2 = square resistance value B-square resistance value b; S4. Set the control range of the side lengths C, △1 and △2. When C, △1 and △2 exceed the established control range, adjust the parameters in the RCA processing process respectively.

2. The method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring according to claim 1, characterized in that: The PSG treatment in step S1 is specifically single-sided etching of the TOPCon cell edge MASK wrap plating and part of the BSG protective layer.

3. The method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring according to claim 1, characterized in that: The PSG treatment in step S2 specifically includes the following processes: Alkaline etching, one water wash, post-wash, two water washes, one acid wash, three water washes, two acid washes, four water washes, hot water slow pull and drying.

4. The method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring according to claim 3, characterized in that: The square resistance values ​​in steps S1 and S2 are measured by a four-probe method, specifically, five points are set on the silicon wafer, namely, the center point and four points 1-2 cm away from the corners of the silicon wafer.

5. The method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring according to claim 3, characterized in that: In step S3, the side length C is measured using a ZETA 3D microscope, specifically at three points on the side of the silicon wafer, namely the center point of the side and two points 1-2 cm away from the corners of the silicon wafer.

6. The method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring according to claim 3, characterized in that: In the step S4, the control range of the side length C is 20 to 25 μm, the control range of △1 is -5 to 0Ω, and the control range of △2 is 0 to 5Ω.

7. The method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring according to claim 6, characterized in that: The adjustment method in step S4 includes: when △1>0Ω, increasing the HF concentration or etching time in a pickling step; when △1<-5Ω, reducing the HF concentration or etching time in a pickling step.

8. The method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring according to claim 6, characterized in that: The adjustment method in step S4 includes: when Δ2<0Ω, increasing the HF concentration or etching time in a pickling step; when Δ2>5Ω, reducing the HF concentration or etching time in a pickling step.

9. The method for improving the efficiency of an N-type TOPCon battery based on RCA monitoring according to claim 6, characterized in that: The adjustment method in step S4 includes: when the side micro-tower base side length C>25μm, reducing the concentration of the alkaline etching solution or etching time; when the side micro-tower base side length C<20μm, increasing the concentration of the alkaline etching solution or etching time.

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