Method for cleaning TOPcon battery before texturing, texturing method and TOPcon battery
By passing chlorine gas into the pre-cleaning liquid formed in the acidic solution containing HF, the problem of difficult to effectively remove mechanical damage and dirt on the surface of the silicon wafer in the prior art is solved, and a more efficient velvet making is achieved The pre-cleaning effect improves the performance of TOPcon battery.
Patent Information
- Application Number
- CN202411541719.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-02-18
AI Technical Summary
In the prior art, it is difficult to effectively remove mechanical damage and dirt on the surface of the silicon wafer before velvet making, resulting in the impact of battery performance.
The silicon wafer is cleaned by a pre-cleaning solution that passes chlorine into an acidic solution containing HF. Through the strong oxidation of chlorine and the reaction of HF, mechanical damage and dirt on the surface of the silicon wafer are removed.
This method can effectively remove mechanical damage and dirt on the surface of the silicon wafer, improve the velvet making effect, avoid affecting the performance of TOPcon batteries due to incomplete cleaning, and reduce chemical consumption.
Smart Images
Figure CN119480618A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of batteries, and specifically provides a pre-texturing cleaning method of a TOPcon battery, a texturing method and a TOPcon battery. Background Art
[0002] At present, in the field of solar photovoltaic cell manufacturing, the texturing process is the first process of cell preparation. Excellent velvet preparation and good reflectivity facilitate better PN junction formation and film generation uniformity and color difference, thereby achieving excellent performance of electrical parameters. However, as a texturing process, in addition to velvet preparation, better cleaning and decontamination effects and impurity removal can not only reduce the appearance rework of defective sheets, but also reduce minority carrier recombination, which also plays a vital role in the electrical performance of the battery.
[0003] In the prior art, the first liquid alkali washing tank (a mixture of sodium hydroxide / potassium hydroxide + hydrogen peroxide) where the original silicon enters the tank body must not only remove the mechanical damage layer to achieve a rough polishing effect, but also remove organic dirt and other impurities brought by the surface of the original silicon wafer.
[0004] In response to the continuous demand for improving battery efficiency and yield, the reaction effect of silicon wafers is often improved by optimizing the bubbling device of the pre-alkali washing tank and increasing the concentration of the chemical solution, thereby improving the effect of pre-cleaning. For example, in order to better remove mechanical damage, it is necessary to increase the alkali consumption in the alkali washing tank. In order to achieve a better decontamination effect, it is necessary to increase the consumption of hydrogen peroxide, which will lead to an increase in the consumption of chemicals. If the reaction effect of silicon wafers is improved by adjusting the bubbling device, the reaction between the silicon wafers and the alkali solution in the alkali washing tank will cause the reaction to be relatively violent and uneven, and will also increase the risk of fragmentation.
[0005] The present invention urgently needs to provide a pre-texturing cleaning method that can better remove mechanical damage and dirt on the surface of a silicon wafer. Summary of the invention
[0006] The present invention aims to solve the above technical problem at least to a certain extent, that is, to solve the problem of how to more effectively remove mechanical damage and dirt on the surface of silicon wafers at least to a certain extent.
[0007] In a first aspect, the present invention provides a pre-texturing cleaning method for a TOPcon battery, the pre-texturing cleaning method comprising the following steps: S1: introducing chlorine gas into an acidic solution to form a pre-cleaning solution; S2: placing a silicon wafer into the pre-cleaning solution for pre-cleaning treatment.
[0008] In the preferred technical solution of the above-mentioned TOPcon battery pre-texturing cleaning method, the concentration of the chlorine gas is 15-35 ppm, and the amount of the chlorine gas introduced is 1800-3000 sccm.
[0009] In the preferred technical solution of the above-mentioned TOPcon battery pre-texturing cleaning method, the acid solution is formed by mixing HF solution and water, wherein the volume ratio of the HF solution is 1.5%-2.8%.
[0010] In the preferred technical solution of the above-mentioned method for cleaning TOPcon cells before texturing, the concentration of the HF solution is 49%.
[0011] In the preferred technical solution of the pre-texturing cleaning method of the above-mentioned TOPcon battery, the treatment temperature of the pre-cleaning treatment is 35-55°C.
[0012] In the preferred technical solution of the pre-texturing cleaning method of the above-mentioned TOPcon battery, the processing time of the pre-cleaning treatment is 90-140s.
[0013] In a second aspect, the present invention also provides a texturing method for a TOPcon battery, the texturing method comprising the following steps: T1: pre-cleaning the silicon wafer according to any of the pre-texturing cleaning methods described above; T2: texturing the silicon wafer after the pre-cleaning treatment; T3: cleaning and drying the texturized silicon wafer to obtain the texturized silicon wafer.
[0014] In the preferred technical scheme of the texturing method of the above-mentioned TOPcon battery, the step of "texturing the silicon wafer after the pre-cleaning treatment" specifically includes: T21: washing the silicon wafer after the pre-cleaning treatment to remove the pre-cleaning liquid remaining on the surface of the silicon wafer; T22: placing the washed silicon wafer into the texturing solution for texturing.
[0015] In the preferred technical scheme of the texturing method of the above-mentioned TOPcon battery, the step of "cleaning and drying the silicon wafer after texturing to obtain the silicon wafer after texturing" specifically includes: T31: washing and post-cleaning the silicon wafer after texturing in sequence to remove the texturing solution remaining on the surface of the silicon wafer; T32: washing and acid-washing the silicon wafer after post-cleaning in sequence to remove the post-cleaning solution remaining on the surface of the silicon wafer; T33: washing, slowly pulling and drying the silicon wafer after acid washing in sequence to obtain the silicon wafer after texturing.
[0016] In a third aspect, the present invention further provides a TOPcon cell, wherein the TOPcon cell comprises a silicon wafer prepared by any of the above-mentioned texturing methods.
[0017] In the case of adopting the above-mentioned preferred technical scheme, a pre-cleaning solution is formed by passing chlorine gas into an acidic solution containing HF, and the silicon wafer is placed in the pre-cleaning solution for pre-cleaning treatment. On the one hand, the strong oxidizing property of chlorine gas can react with various organic and inorganic substances on the surface of the silicon wafer, thereby effectively removing dirt on the surface of the silicon wafer. On the other hand, HF can also react with silicon to remove mechanical damage on the surface of the silicon wafer, thereby achieving a rough polishing effect and avoiding the mechanical damage on the surface of the silicon wafer affecting the subsequent texturing effect. Compared with the prior art of using alkaline solution as the pre-cleaning solution, the mechanical damage and dirt on the surface of the silicon wafer can be effectively removed without increasing the consumption of chemicals, thereby avoiding affecting the performance of the TOPcon battery due to incomplete pre-cleaning.
[0018] Furthermore, by reasonably controlling the concentration of chlorine and the amount of chlorine introduced, on the one hand, it is possible to avoid the situation where the dirt on the surface of the silicon wafer cannot be effectively removed due to the low amount of chlorine introduced, resulting in incomplete pre-cleaning and affecting the performance of the TOPcon battery. On the other hand, it is also possible to avoid the situation where the reaction between chlorine and silicon is intensified due to the high amount of chlorine introduced, thereby avoiding the reaction of excessive chlorine with the silicon wafer and affecting the performance of the silicon wafer.
[0019] Furthermore, by reasonably controlling the volume ratio of the HF solution, on the one hand, it is possible to avoid the inability to effectively remove mechanical damage on the surface of the silicon wafer due to too low HF concentration. The residual mechanical damage on the surface of the silicon wafer will affect the formation of the structure of the velvet surface in the texturing process. On the other hand, it is also possible to avoid excessive rough polishing due to too high HF concentration.
[0020] Furthermore, by reasonably controlling the processing temperature of the pre-cleaning treatment, on the one hand, it is possible to avoid the processing temperature of the pre-cleaning treatment being too low, which may cause the pre-cleaning liquid to be unable to effectively react with the surface of the silicon wafer, thereby resulting in poor mechanical damage and dirt removal effects. On the other hand, it is possible to avoid the processing temperature of the pre-cleaning treatment being too high, which may cause the pre-cleaning liquid to react too violently with the silicon wafer. Violent reactions will not only result in excessive rough polishing, affecting the formation of the velvet structure in the subsequent velvet making process, but may also easily cause the tank body to flip outward, thereby posing a safety hazard.
[0021] Furthermore, by reasonably controlling the processing time of the pre-cleaning treatment, the pre-cleaning treatment of the silicon wafer can achieve a better effect of removing mechanical damage and dirt. On the one hand, it can avoid the pre-cleaning treatment time being too short, which leads to the inability to effectively remove the mechanical damage and dirt on the surface of the silicon wafer. On the other hand, it can also avoid the pre-cleaning treatment time being too long, which leads to excessive rough polishing, thereby affecting the formation of the velvet structure in the subsequent velvet making process. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:
[0023] Figure 1 It is a flow chart of the method for cleaning the TOPcon battery before texturing of the present invention;
[0024] Figure 2 is a scanning electron microscope image of the silicon wafers in Examples 1 to 9 and Comparative Example 1 before pre-cleaning treatment;
[0025] Figure 3 is a scanning electron microscope image of the silicon wafers in Examples 1 to 9 after pre-cleaning treatment;
[0026] Figure 4 is a scanning electron microscope image of the silicon wafer in comparative example 1 after pre-cleaning treatment;
[0027] Figure 5 is a comparison diagram of the front images of the silicon wafers in Examples 1 to 9 after the pre-cleaning treatment and the front image of the silicon wafer in Comparative Example 1 after the pre-cleaning treatment, wherein: Figure 5 (a) is a front image of the silicon wafer in Examples 1 to 9 after pre-cleaning treatment; Figure 5 (b) is a front image of the silicon wafer in Comparative Example 1 after pre-cleaning treatment;
[0028] Figure 6 is a comparison diagram of the back side images of the silicon wafers in Examples 1 to 9 after the pre-cleaning treatment and the back side image of the silicon wafer in Comparative Example 1 after the pre-cleaning treatment, wherein: Figure 6 (a) is an image of the back side of the silicon wafer in Examples 1 to 9 after the pre-cleaning treatment; Figure 6 (b) is an image of the back side of the silicon wafer in Comparative Example 1 after the pre-cleaning treatment;
[0029] Figure 7 This is an image of the silicon wafer in Comparative Example 10 after pre-cleaning treatment. DETAILED DESCRIPTION
[0030] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.
[0031] Unless otherwise specified, the terms used in this application have the commonly known meanings generally understood by those skilled in the art. Unless otherwise specified, the numerical values of the various parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the examples of this application).
[0032] The experimental methods in the following examples are conventional methods unless otherwise specified; the raw materials, reagents, etc. used in the following examples are commercially available products unless otherwise specified.
[0033] A list of items connected by the term "at least one of" or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single component or multiple components. Item B may contain a single component or multiple components. Item C may contain a single component or multiple components.
[0034] The present application is further described below in conjunction with specific implementations. It should be understood that these specific implementations are only used to illustrate the present application and are not used to limit the scope of the present application.
[0035] Specifically, in a first aspect, the present invention provides a method for cleaning a TOPcon battery before texturing, the method comprising the following steps:
[0036] S1: passing chlorine gas into the acidic solution to form a pre-cleaning solution;
[0037] S2: placing the silicon wafer into the pre-cleaning solution for pre-cleaning treatment;
[0038] The acidic solution at least includes HF.
[0039] By passing chlorine into an acidic solution to form a pre-cleaning liquid, and using the pre-cleaning liquid to pre-clean the silicon wafer, on the one hand, the strong oxidizing property of chlorine can react with various organic and inorganic substances on the surface of the silicon wafer to achieve a good decontamination effect; on the other hand, HF in the acidic solution can react with silicon to remove mechanical damage on the surface of the silicon wafer, achieving a rough polishing effect. Compared with the use of alkaline solution as a pre-cleaning liquid in the prior art, the mechanical damage and dirt on the surface of the silicon wafer can be effectively removed without increasing the consumption of chemicals, thereby avoiding affecting the performance of the TOPcon battery due to incomplete pre-cleaning.
[0040] Specifically, the present invention introduces chlorine gas into a pre-cleaning tank containing an acid solution through a pipeline to form a pre-cleaning solution.
[0041] It should be noted that, in practical applications, the present invention does not impose any particular limitation on the concentration of chlorine. For example, the concentration of chlorine can be set to 15ppm, 17ppm, 20ppm, 22ppm, 25ppm, 27ppm, 30ppm, 32ppm, 35ppm or a range consisting of any two of these values.
[0042] In some embodiments, the concentration of chlorine gas is 15-35 ppm.
[0043] It should be noted that, in practical applications, the present invention does not impose any particular limitation on the amount of chlorine gas introduced. For example, the amount of chlorine gas introduced can be set to 1800sccm, 2000sccm, 2200sccm, 2400sccm, 2600sccm, 2800sccm, 3000sccm or a range consisting of any two of these values.
[0044] In some embodiments, the amount of chlorine gas introduced is 1800-3000 sccm.
[0045] By properly controlling the concentration and amount of chlorine introduced, on the one hand, it is possible to avoid the inability to effectively remove dirt from the silicon wafer surface due to too low a chlorine introduction, and to avoid incomplete pre-cleaning treatment affecting the performance of the TOPcon battery. On the other hand, it is also possible to avoid the intensified reaction between chlorine and silicon due to too high a chlorine introduction, thereby avoiding the reaction of excessive chlorine with the silicon wafer and affecting the performance of the TOPcon battery.
[0046] It should be noted that, in practical applications, the specific setting type of the acidic solution of the present invention is not limited, as long as the acidic solution includes HF. For example, the acidic solution can be set to include only HF, or the acidic solution can be set to include HF and HCl, or the acidic solution can be set to include HF and any other possible substances, etc. Such adjustments and changes to the specific setting type of the acidic solution do not deviate from the principle and scope of the present invention, and should be included in the protection scope of the present invention.
[0047] Preferably, the acidic solution is formed by mixing HF solution with water, wherein the concentration of the HF solution is 49%.
[0048] It should be noted that the acidic solution is not limited to the 49% HF solution mixed with water. For example, any other possible concentration of HF solution can be mixed with water to form the acidic solution, and so on. Such adjustment and change of the specific concentration of the HF solution does not deviate from the principle and scope of the present invention and should be included in the protection scope of the present invention. Of course, preferably, the acidic solution is formed by mixing a 49% HF solution with water.
[0049] It should be noted that, in practical applications, the present invention does not impose any particular limitation on the volume ratio of the HF solution. For example, the volume ratio of the HF solution can be set to 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8% or a range consisting of any two of these values.
[0050] In some embodiments, the volume ratio of the HF solution is 1.5%-2.8%.
[0051] It should be noted that the volume ratio of the HF solution is expressed as the ratio between the volume V1 of the HF solution and the volume V2 of the acidic solution.
[0052] It should be noted that, in actual applications, the present invention does not impose any particular limitation on the processing temperature of the pre-cleaning treatment. For example, the processing temperature of the pre-cleaning treatment can be set to 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C, 53°C, 54°C, 55°C or a range consisting of any two of these values.
[0053] In some embodiments, the pre-cleaning treatment may be performed at a temperature of 35-55°C.
[0054] By reasonably controlling the processing temperature of the pre-cleaning treatment, on the one hand, it can be avoided that the processing temperature of the pre-cleaning treatment is too low, which causes the pre-cleaning liquid to be unable to effectively react with the silicon wafer surface, thereby resulting in poor mechanical damage and dirt removal effect. On the other hand, it can be avoided that the processing temperature of the pre-cleaning treatment is too high, which causes the pre-cleaning liquid to react too violently with the silicon wafer. Violent reactions will not only lead to excessive rough polishing, affecting the formation of the velvet structure in the subsequent velvet making process, but also easily cause the tank body to flip outward, thereby posing a safety hazard.
[0055] It should be noted that, in actual applications, the present invention does not impose any particular limitation on the processing time of the pre-cleaning treatment. For example, the processing time of the pre-cleaning treatment can be set to 90s, 95s, 100s, 105s, 110s, 115s, 120s, 125s, 130s, 135s, 140s or a range consisting of any two of these values.
[0056] In some embodiments, the pre-cleaning treatment may take 90-140 seconds.
[0057] By reasonably controlling the processing time of the pre-cleaning treatment, the pre-cleaning treatment of the silicon wafer can achieve a better effect of removing mechanical damage and dirt. On the one hand, it can avoid the pre-cleaning treatment time being too short, which leads to the inability to effectively remove the mechanical damage and dirt on the surface of the silicon wafer. On the other hand, it can also avoid the pre-cleaning treatment time being too long, which leads to excessive rough polishing, thereby affecting the formation of the velvet structure in the subsequent velvet making process.
[0058] In a second aspect, the present invention also provides a texturing method for a TOPcon battery.
[0059] Specifically, the texturing method of TOPcon battery includes the following steps:
[0060] T1: pre-cleaning the silicon wafer according to any of the pre-texturing cleaning methods described above;
[0061] T2: Texturing the silicon wafer after pre-cleaning treatment;
[0062] T3: Cleaning and drying the silicon wafer after texturing to obtain the silicon wafer after texturing.
[0063] Preferably, the step of “texturing the silicon wafer after the pre-cleaning treatment” specifically includes:
[0064] T21: Wash the silicon wafer after the pre-cleaning treatment with water to remove the pre-cleaning liquid remaining on the surface of the silicon wafer;
[0065] T22: Place the washed silicon wafer into the texturing solution for texturing.
[0066] By washing the silicon wafer after pre-cleaning with water, the pre-cleaning liquid remaining on the surface of the silicon wafer can be removed, avoiding the reaction between the pre-cleaning liquid remaining on the surface of the silicon wafer and the texturing liquid to affect the composition and concentration of various substances in the texturing liquid, thereby avoiding affecting the formation of the velvet structure.
[0067] It should be noted that, in actual applications, the present invention does not impose any limitation on the specific method and number of water washings for washing the silicon wafers after the pre-cleaning treatment, as long as the pre-cleaning liquid remaining on the surface of the silicon wafer can be removed. For example, the number of water washings can be set to 1, 2 or N times (N ≥ 3 and is a positive integer), etc. Such adjustment and change of the number of water washings for washing the silicon wafers does not deviate from the principle and scope of the present invention, and should be included in the protection scope of the present invention.
[0068] Exemplarily, the number of water washings is 1 time.
[0069] Preferably, the step of "cleaning and drying the silicon wafer after texturing to obtain the silicon wafer after texturing" specifically includes:
[0070] T31: Wash and post-clean the silicon wafer after texturing to remove the residual texturing liquid on the surface of the silicon wafer;
[0071] T32: washing and acid washing the silicon wafer after post-cleaning in sequence to remove the post-cleaning liquid remaining on the surface of the silicon wafer;
[0072] T33: The pickled silicon wafer is washed with water, slowly pulled up, and dried to obtain a texturized silicon wafer.
[0073] With such a setting, the texturing liquid remaining on the surface of the silicon wafer can be removed by water washing and post-cleaning the silicon wafer after texturing, thereby avoiding the influence of the texturing liquid remaining on the silicon wafer on the electrical properties of the silicon wafer; the post-cleaning liquid remaining on the surface of the silicon wafer can be removed by water washing and acid washing the silicon wafer after post-cleaning; the acid remaining on the surface of the silicon wafer can be removed by water washing the silicon wafer after acid washing; and the moisture on the surface of the silicon wafer can be removed by slow pulling and drying after water washing, thereby accelerating the drying of the silicon wafer and improving the preparation efficiency of TOPcon batteries.
[0074] In a third aspect, the present invention further provides a TOPcon cell, wherein the TOPcon cell comprises a silicon wafer prepared by any of the above-mentioned texturing methods.
[0075] The pre-texturing cleaning method, the texturing method and the preparation method of the TOPcon battery of the present invention are described in detail below in conjunction with the following specific embodiments.
[0076] Embodiment 1:
[0077] Step A: Select a silicon wafer.
[0078] A single wafer source was selected, the silicon wafer size was 210 mm × 210 mm × 140 μm, the silicon wafer doping type was gallium-doped, the silicon wafer resistivity was 0.4-1.1 Ω, and the number of silicon wafers was 1000.
[0079] Step B: Pre-cleaning treatment.
[0080] B1: Mix HF solution and water to form an acidic solution, and pass chlorine gas into the acidic solution to form a pre-cleaning solution. The volume of the pre-cleaning solution is 320L;
[0081] The concentration of the HF solution was 49%, the volume ratio of the HF solution was 1.7%, the concentration of the chlorine gas was 20 ppm, and the amount of chlorine gas introduced was 2500 sccm;
[0082] B2: placing the silicon wafer selected in step A into a pre-cleaning solution for pre-cleaning treatment; wherein the treatment temperature of the pre-cleaning treatment is 50° C., and the treatment time of the pre-cleaning treatment is 120 seconds.
[0083] Step C: Velveting.
[0084] C1: washing the silicon wafer after the pre-cleaning treatment in step B with water to remove the pre-cleaning liquid remaining on the surface of the silicon wafer;
[0085] C2: placing the silicon wafer obtained in step C1 into a texturing solution for texturing;
[0086] C3: washing and post-cleaning the silicon wafer after texturing obtained in step C2 in sequence to remove the texturing liquid remaining on the surface of the silicon wafer;
[0087] C4: washing the silicon wafer obtained in step C3 with water and then with acid to remove the residual post-cleaning liquid on the surface of the silicon wafer;
[0088] C5: The silicon wafer obtained in step C4 is sequentially washed with water, slowly pulled up, and dried to obtain a texturized silicon wafer.
[0089] Step D: Preparation of TOPcon cells.
[0090] D1: Boron is diffused into the silicon wafer obtained in step C, and then diffusion oxidation is optimized.
[0091] D2: performing alkali polishing on the back side of the silicon wafer obtained in step D1;
[0092] D3: forming a polysilicon (poly) layer on the back side of the silicon wafer obtained in step D2, and performing annealing treatment;
[0093] D4: chemically mechanically polishing the silicon wafer obtained in step D3, and cleaning it using an RCA process;
[0094] D5: using an ALD process to deposit an aluminum oxide layer on the front and back sides of the silicon wafer obtained in step D4;
[0095] D6: forming an anti-reflection film on the front and back sides of the silicon wafer obtained in step D5;
[0096] D7: Laser groove the silicon wafer obtained in step D6;
[0097] D8: Electrodes are printed on the front and back sides of the silicon wafer obtained in step D7 in sequence, and then sintered to obtain a TOPcon battery.
[0098] Embodiment 2:
[0099] The silicon wafer pre-cleaning method, texturing method and TOPcon battery preparation method in Example 2 are exactly the same as those in Example 1. The difference between Example 2 and Example 1 is that the amount of chlorine gas introduced in step B is different.
[0100] In Example 2, the amount of chlorine gas introduced is 1800 sccm.
[0101] Embodiment 3:
[0102] The silicon wafer cleaning method before texturing, the texturing method and the TOPcon battery preparation method in Example 3 are exactly the same as those in Example 1. The difference between Example 3 and Example 1 is that the amount of chlorine gas introduced in step B is different.
[0103] In Example 3, the amount of chlorine gas introduced is 3000 sccm.
[0104] Embodiment 4:
[0105] The cleaning method before texturing of silicon wafers, the texturing method and the preparation method of TOPcon cells in Example 4 are exactly the same as those in Example 1. The difference between Example 4 and Example 1 is that the volume ratio of the HF solution in step B is different.
[0106] In Example 4, the volume ratio of the HF solution is 1.5%.
[0107] Embodiment 5:
[0108] The cleaning method before texturing of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Example 5 are exactly the same as those in Example 1. The difference between Example 5 and Example 1 is that the volume ratio of the HF solution in step B is different.
[0109] In Example 5, the volume ratio of the HF solution is 2.8%.
[0110] Embodiment 6:
[0111] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Example 6 are exactly the same as those in Example 1. The difference between Example 6 and Example 1 is that the processing temperature of the pre-cleaning treatment in step B is different.
[0112] In Example 6, the treatment temperature of the pre-cleaning treatment was 35°C.
[0113] Embodiment 7:
[0114] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Example 7 are exactly the same as those in Example 1. The difference between Example 7 and Example 1 is that the treatment temperature of the pre-cleaning treatment in step B is different.
[0115] In Example 7, the treatment temperature of the pre-cleaning treatment was 55°C.
[0116] Embodiment 8:
[0117] The silicon wafer pre-texturing cleaning method, the texturing method and the TOPcon battery preparation method in Example 8 are exactly the same as those in Example 1. The difference between Example 8 and Example 1 is that the processing time of the pre-cleaning treatment in step B is different.
[0118] In Example 8, the treatment time of the pre-cleaning treatment is 90 seconds.
[0119] Embodiment 9:
[0120] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Example 9 are exactly the same as those in Example 1. The difference between Example 9 and Example 1 is that the processing time of the pre-cleaning treatment in step B is different.
[0121] In Example 9, the treatment time of the pre-cleaning treatment is 140 s.
[0122] Comparative Example 1:
[0123] The method for cleaning silicon wafers before texturing and the method for preparing TOPcon cells in Comparative Example 1 are exactly the same as those in Example 1. The difference between Comparative Example 1 and Example 1 lies in the difference in the pre-cleaning liquid used in the pre-cleaning treatment in step B.
[0124] In Comparative Example 1, the pre-cleaning solution is formed by adding sodium hydroxide solution and hydrogen peroxide solution into water, wherein the concentration of the sodium hydroxide solution is 45%, the solution volume ratio of the sodium hydroxide solution is 1.2%, the concentration of the hydrogen peroxide solution is 30%, and the volume ratio of the hydrogen peroxide solution is 4.8%.
[0125] Comparative Example 2:
[0126] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Comparative Example 2 are exactly the same as those in Example 1. The difference between Comparative Example 2 and Example 1 is that the amount of chlorine gas introduced in step B is different.
[0127] In Comparative Example 2, the amount of chlorine gas introduced was 1700 sccm.
[0128] Comparative Example 3:
[0129] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Comparative Example 3 are exactly the same as those in Example 1. The difference between Comparative Example 3 and Example 1 is that the amount of chlorine gas introduced in step B is different.
[0130] In Comparative Example 3, the amount of chlorine gas introduced was 3100 sccm.
[0131] Comparative Example 4:
[0132] The cleaning method before texturing of silicon wafers, the texturing method and the preparation method of TOPcon cells in Comparative Example 4 are exactly the same as those in Example 1. The difference between Comparative Example 4 and Example 1 is that the volume ratio of the HF solution in step B is different.
[0133] In Comparative Example 4, the volume ratio of the HF solution was 1.3%.
[0134] Comparative Example 5:
[0135] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Comparative Example 5 are exactly the same as those in Example 1. The difference between Comparative Example 5 and Example 1 is that the volume ratio of the HF solution in step B is different.
[0136] In Comparative Example 5, the volume ratio of the HF solution is 3%.
[0137] Comparative Example 6:
[0138] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Comparative Example 6 are exactly the same as those in Example 1. The difference between Comparative Example 6 and Example 1 is that the processing temperature of the pre-cleaning treatment in step B is different.
[0139] In Comparative Example 6, the treatment temperature of the pre-cleaning treatment was 30°C.
[0140] Comparative Example 7:
[0141] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Comparative Example 7 are exactly the same as those in Example 1. The difference between Comparative Example 7 and Example 1 is that the processing temperature of the pre-cleaning treatment in step B is different.
[0142] In Comparative Example 7, the treatment temperature of the pre-cleaning treatment was 60°C.
[0143] Comparative Example 8:
[0144] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Comparative Example 8 are exactly the same as those in Example 1. The difference between Comparative Example 8 and Example 1 is that the processing time of the pre-cleaning treatment in step B is different.
[0145] In Comparative Example 8, the treatment time of the pre-cleaning treatment is 80 s.
[0146] Comparative Example 9:
[0147] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Comparative Example 9 are exactly the same as those in Example 1. The difference between Comparative Example 9 and Example 1 is that the processing time of the pre-cleaning treatment in step B is different.
[0148] In Comparative Example 9, the treatment time of the pre-cleaning treatment is 150 s.
[0149] Comparative Example 10:
[0150] The pre-texturing cleaning method of the silicon wafer, the texturing method and the preparation method of the TOPcon battery in Comparative Example 10 are exactly the same as those in Example 1. The difference between Comparative Example 10 and Example 1 lies in the difference in the pre-cleaning solution in step B.
[0151] In comparative example 10, HCl solution and water are mixed to form an acidic solution, and ozone is introduced into the acidic solution to form a pre-cleaning solution;
[0152] The concentration of ozone is 50 ppm, the amount of ozone introduced is 3000 sccm, the concentration of HCl solution is 37%, and the volume ratio of HCl solution is 0.5%.
[0153] Test method:
[0154] Test Example 1:
[0155] The surface morphology of the silicon wafers of the above-mentioned embodiments and comparative examples before and after the pre-cleaning treatment was observed by scanning electron microscopy. The scanning electron microscopy images of the silicon wafers in embodiments 1 to 9 and comparative example 1 before the pre-cleaning treatment are as follows: Figure 2 As shown, the scanning electron microscope images of the silicon wafers in Examples 1 to 9 after the pre-cleaning treatment are as follows Figure 3 As shown, the scanning electron microscope image of the silicon wafer in Comparative Example 1 after pre-cleaning is as follows Figure 4 shown.
[0156] Depend on Figures 2 to 4 The test results show that the silicon wafers in Examples 1 to 9 and Comparative Example 1 have relatively rough surfaces and many mechanical damages (such as Figure 2As shown, after the pre-cleaning treatment, the surfaces of the silicon wafers in Examples 1 to 9 are relatively flat and the mechanical damage disappears. After the pre-cleaning treatment, the surface of the silicon wafer in Comparative Example 1 is relatively flat compared with that before the pre-cleaning treatment, but there are still concave-convex structures, and the mechanical damage is not completely removed. It can be seen that the pre-cleaning method of the present invention can effectively remove the mechanical damage on the surface of the silicon wafer, and the effect of removing mechanical damage is significantly better than that of the pre-cleaning solution (a mixture of sodium hydroxide / potassium hydroxide + hydrogen peroxide) in the prior art.
[0157] Test Example 2:
[0158] The surface state of the silicon wafers in the above-mentioned embodiments and comparative examples after the pre-cleaning treatment was photographed by a camera, wherein the front images of the silicon wafers in embodiments 1 to 9 after the pre-cleaning treatment are as follows: Figure 5 As shown in (a), the front image of the silicon wafer in Comparative Example 1 after pre-cleaning is as follows Figure 5 As shown in (b), the back images of the silicon wafers in Examples 1 to 9 after the pre-cleaning treatment are as follows Figure 6 As shown in (a), the back image of the silicon wafer in Comparative Example 1 after the pre-cleaning treatment is as follows Figure 6 As shown in (b), the image of the silicon wafer in Comparative Example 10 after pre-cleaning treatment is as follows Figure 7 shown.
[0159] 1. By Figure 5 to Figure 6 It can be seen from the test results that there is no dirt on the front and back sides of the silicon wafers in Examples 1 to 9 after pre-cleaning, and the images of the front and back sides of the silicon wafer in Comparative Example 1 after pre-cleaning are not much different. It can be seen that the pre-cleaning method of the present invention can be used to pre-clean the silicon wafer, which can effectively remove dirt on the surface of the silicon wafer.
[0160] 2. By Figures 5 to 7 It can be seen from the test results that the silicon wafers in Examples 1 to 9 are free of dirt after pre-cleaning, while the silicon wafer in Comparative Example 10 is still dirty after pre-cleaning ( Figure 7 Therefore, the effect of removing dirt by using the pre-cleaning method of the present invention to pre-clean the silicon wafer is significantly better than that of the pre-cleaning method in Comparative Example 10, that is, the cleaning effect of using chlorine gas introduced into an acidic solution as a pre-cleaning liquid to clean the silicon wafer before texturing is significantly better than that of using ozone introduced into an acidic solution as a pre-cleaning liquid to clean the silicon wafer before texturing.
[0161] Test Example 3:
[0162] The conversion efficiency and electrical performance of the TOPcon cells prepared in Examples 1 to 9 and Comparative Examples 1 to 9 were tested using a HALM tester. The test results are shown in Table 1 below:
[0163] Table 1: Test data of embodiments and comparative examples
[0164] From the data in Table 1, we can see that:
[0165] 1. Comparing the data of Examples 1 to 9 with that of Comparative Example 1, the conversion efficiency of the TOPcon cells made of the silicon wafers in Examples 1 to 9 is significantly higher than the conversion efficiency of the TOPcon cells made of the silicon wafers in Comparative Example 1. It can be seen that pre-cleaning the silicon wafers using the pre-cleaning method of the present invention can more effectively remove dirt and mechanical damage on the surface of the silicon wafers. After the silicon wafers are pre-cleaned using the pre-cleaning method of the present invention, the conversion efficiency of the prepared TOPcon cells is significantly higher than the conversion efficiency of the TOPcon cells prepared after the silicon wafers are pre-cleaned using the pre-cleaning solution (a mixture of sodium hydroxide / potassium hydroxide + hydrogen peroxide) in the prior art.
[0166] 2. Comparing the data of Examples 1 to 3 with those of Comparative Examples 2 to 3, the conversion efficiency of the TOPcon cells in Examples 1 to 3 is significantly higher than that of the TOPcon cells in Comparative Examples 2 to 3. It can be seen that when the amount of chlorine gas introduced is 1800-3000sccm, the conversion efficiency of the TOPcon cells prepared by pre-cleaning the silicon wafer is higher, and when the amount of chlorine gas introduced is 2500sccm, the effect of pre-cleaning the silicon wafer is best, and the conversion efficiency of the TOPcon cells prepared by pre-cleaning the silicon wafer is the highest.
[0167] 3. Comparing the data of Example 1, Example 4 and Example 5 and Comparative Examples 4 to Comparative Examples 5, the conversion efficiency of the TOPcon cells in Example 1, Example 4 and Example 5 is significantly higher than the conversion efficiency of the TOPcon cells in Comparative Examples 4 to Comparative Examples 5. It can be seen that when the volume ratio of the HF solution is 1.5-2.8%, the effect of pre-cleaning treatment on the silicon wafer is better, and the conversion efficiency of the TOPcon cell made from the silicon wafer after the pre-cleaning treatment is higher. When the volume ratio of the HF solution is 1.7%, the effect of pre-cleaning treatment on the silicon wafer is best, and the conversion efficiency of the TOPcon cell made by pre-cleaning the silicon wafer is the highest.
[0168] 4. Comparing the data of Example 1, Example 6 and Example 7 as well as Comparative Example 6 and Comparative Example 7, the conversion efficiency of the TOPcon cells in Example 1, Example 6 and Example 7 is significantly higher than the conversion efficiency of the TOPcon cells in Comparative Example 6 and Comparative Example 7. It can be seen that when the treatment temperature during the current cleaning treatment is 35-55°C, the effect of pre-cleaning treatment on the silicon wafer is better, and the conversion efficiency of the TOPcon cells made of the silicon wafers after the pre-cleaning treatment is higher. When the treatment temperature during the current cleaning treatment is 50°C, the effect of pre-cleaning treatment on the silicon wafer is best, and the conversion efficiency of the TOPcon cells made by pre-cleaning the silicon wafers is the highest.
[0169] 5. Comparing the data of Example 1, Example 8 and Example 9 and Comparative Example 8 and Comparative Example 9, the conversion efficiency of the TOPcon cells in Example 1, Example 8 and Example 9 is significantly higher than the conversion efficiency of the TOPcon cells in Comparative Example 8 and Comparative Example 9. It can be seen that when the processing time during the current cleaning treatment is 90-140s, the effect of pre-cleaning treatment on the silicon wafer is better, and the conversion efficiency of the TOPcon cells made of the silicon wafer after the pre-cleaning treatment is higher. When the processing time during the current cleaning treatment is 120s, the effect of pre-cleaning treatment on the silicon wafer is best, and the conversion efficiency of the TOPcon cells made by pre-cleaning the silicon wafer is the highest.
[0170] 6. Comparing the data of Example 1 with those of Comparative Example 10, the conversion efficiency of the TOPcon battery in Example 1 is significantly higher than the conversion efficiency of the TOPcon battery in Comparative Example 10. It can be seen that the pre-cleaning treatment of silicon wafers by passing chlorine gas into an acidic solution as a pre-cleaning liquid has a pre-cleaning effect that is significantly better than the pre-cleaning treatment of silicon wafers by passing ozone into an acidic solution as a pre-cleaning liquid.
[0171] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.
Claims
1. A method for cleaning a TOPcon battery before texturing, characterized in that: The pre-texturing cleaning method comprises the following steps: S1: passing chlorine gas into the acidic solution to form a pre-cleaning solution; S2: placing the silicon wafer into the pre-cleaning solution for pre-cleaning treatment; Wherein, the acidic solution at least includes HF.
2. The method for cleaning TOPcon cells before texturing according to claim 1, characterized in that: The concentration of the chlorine gas is 15-35 ppm, and the flow rate of the chlorine gas is 1800-3000 sccm.
3. The method for cleaning TOPcon cells before texturing according to claim 1, characterized in that: The acidic solution is formed by mixing HF solution and water, wherein the volume ratio of the HF solution is 1.5%-2.8%.
4. The method for cleaning TOPcon cells before texturing according to claim 3, characterized in that: The concentration of the HF solution was 49%.
5. The method for cleaning TOPcon cells before texturing according to claim 1, characterized in that: The treatment temperature of the pre-cleaning treatment is 35-55°C.
6. The method for cleaning TOPcon cells before texturing according to claim 1, characterized in that: The processing time of the pre-cleaning treatment is 90-140s.
7. A method for making a TOPcon battery, characterized in that: The texturing method comprises the following steps: T1: pre-cleaning the silicon wafer according to the pre-texturing cleaning method according to any one of claims 1 to 6; T2: Texturing the silicon wafer after pre-cleaning treatment; T3: Cleaning and drying the silicon wafer after texturing to obtain the silicon wafer after texturing.
8. The texturing method according to claim 7, characterized in that: The steps of "texturing the silicon wafer after the pre-cleaning treatment" specifically include: T21: Wash the silicon wafer after the pre-cleaning treatment with water to remove the pre-cleaning liquid remaining on the surface of the silicon wafer; T22: Place the washed silicon wafer into the texturing solution for texturing.
9. The texturing method according to claim 7, characterized in that: The step of "cleaning and drying the silicon wafer after texturing to obtain the silicon wafer after texturing" specifically includes: T31: Wash and post-clean the silicon wafer after texturing to remove the residual texturing liquid on the surface of the silicon wafer; T32: washing the silicon wafer after post-cleaning with water and acid in sequence to remove the residual post-cleaning liquid on the surface of the silicon wafer; T33: The pickled silicon wafer is sequentially washed with water, slowly pulled up, and dried to obtain a texturized silicon wafer.
10. A TOPcon battery, characterized in that: The TOPcon cell comprises a silicon wafer prepared by the texturing method according to any one of claims 7 to 9.