Titanium removing method of solar cell and application of titanium removing method

Abstract

The invention provides a titanium removal method of a solar cell and application thereof, and relates to the technical field of solar cell metallization, and the method comprises the following steps: carrying out the sintering of a solar cell with a titanium seed layer, and carrying out the titanium removal through a titanium removal solution under an ultrasonic condition, so as to obtain a titanium-removed solar cell; wherein the ultrasonic power of the ultrasonic condition is 20-40 kW; the titanium stripping solution comprises the following components in percentage by mass: 5-25% of acid, 5-25% of hydrogen peroxide, 1-5% of a dispersing agent and the balance of water. According to the method, the technical problems that unreacted titanium still exists on the surface layer of the sintered battery piece, meanwhile, the titanium easily forms an oxidation film, and adverse effects are generated on the follow-up process are solved, and the technical effects of efficiently and thoroughly removing the titanium and the oxidation film of the titanium and effectively improving the binding force of a metal coating and a base material are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cell metallization, and in particular to a method for de-titaniumizing a solar cell sheet and application thereof. Background Art

[0002] Solar energy is a clean, green, and renewable energy source. Against the backdrop of the increasing depletion of traditional chemical energy sources like coal, oil, and natural gas, solar power generation is gaining increasing attention. To reduce solar cell costs and improve efficiency, electroplating is commonly used to create the metal electrodes of silicon solar cells. Electroplating typically replaces silver paste with a plating solution containing metal ions, thereby reducing silicon solar cell production costs and making the product more competitive.

[0003] Currently, electroplating typically involves first plating a layer of metal as a seed layer at the cell slots, followed by copper and tin as the conductive and protective layers, resulting in a double-sided electroplated solar cell. Therefore, the adhesion of the seed layer to the silicon substrate is crucial, significantly impacting the adhesion of the subsequent electroplated grid lines. Research has shown that achieving excellent adhesion requires the seed layer metal to react with the silicon substrate to form an effective silicon compound.

[0004] Titanium is an ideal material for metal contacts. It not only has very low resistance, but also reacts with silicon to form titanium-silicon. Currently, the process of double-sided copper electroplating on solar cells requires first electroplating titanium on a silicon substrate to prevent copper ions from entering the interior of the cell and damaging the PN junction. However, the interaction between titanium and silicon alone makes it difficult to impart excellent bonding strength to the metal grid lines of the solar cell. Although sintering can cause the titanium deposited on the cell to form a silicon-titanium alloy with silicon, significantly enhancing adhesion and bonding to the silicon substrate, the titanium layer cannot react completely, and unreacted titanium will still exist on the surface of the cell. At the same time, titanium is also prone to forming an oxide film, which is detrimental to subsequent processes. Therefore, only by removing the unreacted titanium and the formed oxide film can the preparation effect of the subsequent process be improved.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] One of the purposes of the present invention is to provide a method for removing titanium from solar cells, which can quickly dissolve unreacted titanium and the oxide film formed thereon, significantly increase the rate of titanium removal, and make titanium removal more thorough.

[0007] A second object of the present invention is to provide an application of a method for removing titanium from a solar cell, which can improve the bonding strength between the metal coating of the cell and the substrate.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0009] In a first aspect, a method for de-titaniumizing a solar cell comprises the following steps:

[0010] After sintering the solar cell with the titanium seed layer, the solar cell is subjected to titanium stripping treatment using a titanium stripping solution under ultrasonic conditions to obtain a titanium stripped solar cell;

[0011] The ultrasonic power of the ultrasonic condition is 20kW-40kW;

[0012] The titanium removal solution includes the following components by mass percentage:

[0013] Acid 5%-25%, hydrogen peroxide 5%-25%, dispersant 1%-5%, and the balance water.

[0014] Furthermore, the acid includes sulfuric acid.

[0015] Furthermore, the dispersant includes at least one of sodium ethylenediaminetetramethylenephosphonate, sodium gluconate and 1-aminocyclopropyl-1-carboxylic acid ethyl ester salt.

[0016] Furthermore, the temperature of the titanium removal treatment is 25° C.-50° C., and the time of the titanium removal treatment is 3 min-15 min.

[0017] Furthermore, the thickness of the titanium seed layer is 0.1um-2um.

[0018] Furthermore, the sintering temperature is 400°C-980°C.

[0019] In a second aspect, a titanium removal method as described in any one of the above is used in the preparation of solar cells.

[0020] Furthermore, the solar cell includes a TOPCon solar cell.

[0021] Furthermore, the method for preparing the solar cell includes the following steps:

[0022] Electroplating the titanium-removed solar cell with a conductive layer and an electroplated protective layer in sequence to obtain a metallized solar cell;

[0023] Preferably, the conductive layer comprises a copper layer;

[0024] Preferably, the protective layer comprises a tin layer.

[0025] Furthermore, the electroplating method includes electroplating on both sides of the solar cell;

[0026] Preferably, the thickness of the copper layer is 9um-12um;

[0027] Preferably, the thickness of the tin layer is 1um-2um.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] The titanium stripping method for solar cells provided by the present invention uses a titanium stripping solution with a specific composition to accelerate the dissolution of titanium and its oxide film. At the same time, under specific ultrasonic conditions, it can not only increase the titanium stripping rate and reduce the operation time, but also promote more thorough titanium stripping. In short, the titanium stripping method of the present invention is not only simple and easy to perform and does not damage the substrate, but also can efficiently and thoroughly remove titanium and its oxide film under the coordinated cooperation of various parameters.

[0030] The application of the titanium stripping method for solar cell provided by the present invention can improve the density of the coating, thereby enhancing the bonding strength between the metal coating of the entire cell and the substrate. DETAILED DESCRIPTION

[0031] The technical solutions of the present invention are described clearly and completely below with reference to the embodiments. It is obvious that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0032] According to a first aspect of the present invention, a method for removing titanium from a solar cell is provided, comprising the following steps:

[0033] After sintering the solar cell with the titanium seed layer, the solar cell is subjected to titanium stripping treatment using a titanium stripping solution under ultrasonic conditions to obtain a titanium stripped solar cell;

[0034] The ultrasonic power of the ultrasonic condition is 20kW-40kW, and typical but non-limiting ultrasonic powers include 20kW, 22kW, 24kW, 26kW, 28kW, 30kW, 32kW, 34kW, 36kW, 38kW, and 40kW. Appropriate ultrasonic power can not only significantly increase the titanium removal rate, but also promote complete titanium removal.

[0035] The titanium removal solution includes the following components by mass percentage:

[0036] Acid 5%-25%, hydrogen peroxide 5%-25%, dispersant 1%-5%, and the balance water;

[0037] The method for removing titanium from solar cells provided by the present invention uses a titanium removal solution with a specific composition to accelerate the dissolution of titanium and its oxide film. At the same time, under specific ultrasonic conditions, it can not only increase the titanium removal rate and reduce the operation time, but also promote more thorough titanium removal.

[0038] In summary, the titanium removal method of the present invention is not only simple and easy to implement and does not damage the substrate, but also can efficiently and thoroughly remove titanium and its oxide film with the coordinated cooperation of various parameters.

[0039] In the present invention, typical but non-limiting mass percentages of acid are, for example, 5%, 10%, 15%, 20%, and 25%; typical but non-limiting mass percentages of hydrogen peroxide are, for example, 5%, 10%, 15%, 20%, and 25%; and typical but non-limiting mass percentages of dispersant are, for example, 1%, 2%, 3%, 4%, and 5%.

[0040] In the present invention, the acid includes but is not limited to sulfuric acid, which is beneficial to further improve the titanium removal effect.

[0041] In the present invention, the dispersant in a specific ratio contained in the titanium stripping solution can significantly accelerate the dissolution of titanium and its oxide film.

[0042] In a preferred embodiment, the dispersant includes but is not limited to at least one of sodium ethylenediaminetetramethylenephosphonate, sodium gluconate and 1-aminocyclopropyl-1-carboxylic acid ethyl ester, which is beneficial to further accelerate the dissolution of titanium and its oxide film.

[0043] In a preferred embodiment, the temperature of the titanium removal treatment can be 25°C-50°C, for example, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, but not limited thereto; the time of the titanium removal treatment can be 3min-15min, for example, 3min, 5min, 7min, 9min, 11min, 13min, 15min, but not limited thereto.

[0044] The temperature and time of the titanium removal treatment of the present invention are more conducive to fully removing titanium and its oxide film.

[0045] In the present invention, the thickness of the titanium seed layer may be 0.1 um-2 um, and typical but non-limiting thicknesses include 0.1 um, 0.5 um, 1 um, 1.5 um, and 2 um.

[0046] The titanium seed layer on the battery cell can be sintered to form a silicon-titanium alloy with silicon. The silicon-titanium alloy not only has a uniform distribution of components, few impurities and high purity, but also has higher oxidation resistance and can enhance adhesion to the substrate, thereby effectively improving the bonding strength between the battery cell electrodes and the grid lines.

[0047] In a preferred embodiment, the sintering temperature can be 400°C-980°C, and typical but non-limiting temperatures include 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, and 980°C, which are more conducive to further improving the formation effect of silicon-titanium alloy and further improving the bonding strength between the battery cell electrodes and the grid lines.

[0048] A typical method for removing titanium from a solar cell comprises the following steps:

[0049] (a) depositing a passivation film on the surface of a silicon substrate of a solar cell to a thickness of 80 nm to 100 nm to obtain a coated sheet;

[0050] The front and back surfaces of the solar cell silicon substrate are sequentially laser-cut to form patterned grooves with a width of 5um-50um and a depth of 50nm-100nm.

[0051] (b) washing the back and front sides of the grooved solar cell in sequence, and then depositing a titanium seed layer to obtain a solar cell having a titanium seed layer;

[0052] The pickling solution for water washing is a hydrofluoric acid solution, the amount of hydrofluoric acid added is 10mL / L-20mL / L, the pickling solution temperature is 25°C-38°C, and the silicon substrate floats in the pickling solution for 5s-50s;

[0053] The titanium seed layer is deposited by physical vapor deposition, including but not limited to vacuum magnetron sputtering technology or ion sputtering technology, and the thickness of the titanium seed layer is 0.1um-2um;

[0054] (c) sintering the solar cell with the titanium seed layer at a sintering temperature of 400° C. to 980° C., then de-titaniumizing the solar cell with a de-titanium solution under ultrasonic conditions at a de-titanium temperature of 25° C. to 50° C. for a de-titanium time of 3 min to 15 min, then soaking the solar cell in clean water, and drying the solar cell to obtain a de-titaniumized solar cell;

[0055] The titanium stripping solution comprises the following components by mass percentage: 5%-25% acid, 5%-25% hydrogen peroxide, 1%-5% dispersant, and the balance water;

[0056] The acid may be sulfuric acid, and the dispersant may be one or more of sodium ethylenediaminetetramethylenephosphonate, sodium gluconate, and 1-aminocyclopropyl-1-carboxylic acid ethyl ester salt, which can accelerate the dissolution of titanium and its oxide film;

[0057] Among them, the ultrasonic power of the ultrasonic condition is 20kW-40kW, which can accelerate the reaction and peeling of titanium and its oxide film with the titanium stripping solution.

[0058] In summary, with the coordinated cooperation of the above steps and their process parameters, the present invention solves the technical problem that unreacted titanium still exists on the surface of the battery cell after sintering, and titanium easily forms an oxide film, which leads to adverse effects on subsequent processes. It achieves the technical effect of efficiently and thoroughly removing titanium and its oxide film and effectively improving the bonding strength between the metal coating and the substrate.

[0059] According to a second aspect of the present invention, there is provided an application of any of the above-mentioned titanium removal methods in the preparation of solar cells.

[0060] The application of the titanium stripping method for solar cell provided by the present invention can improve the density of the coating, thereby enhancing the bonding strength between the metal coating of the entire cell and the substrate.

[0061] In the present invention, the solar cell includes but is not limited to a TOPCon solar cell, and may be a double-sided metallized TOPCon solar cell.

[0062] In a preferred embodiment, the method for preparing a solar cell comprises the following steps:

[0063] The solar cell after titanium removal is electroplated with a conductive layer and an electroplated protective layer in sequence to obtain a metallized solar cell.

[0064] In the present invention, a conductive layer and a protective layer are electroplated on both sides of the solar cell; wherein the conductive layer includes but is not limited to a copper layer, and the thickness of the copper layer can be 9um-12um, and its typical but non-limiting thickness is, for example, 9um, 10um, 11um, and 12um; wherein the protective layer includes but is not limited to a tin layer, and the thickness of the tin layer can be 1um-2um, and its typical but non-limiting thickness is, for example, 1um, 1.2um, 1.4um, 1.6um, 1.8um, and 2um.

[0065] In a preferred embodiment, the solar cell after titanium stripping is subjected to double-sided copper-tin electroplating to obtain a double-sided electroplated TOPCon cell, and the bonding strength between the metal coating and the substrate is relatively high.

[0066] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0067] Example 1

[0068] A method for preparing a double-sided metallized TOPCon solar cell comprises the following steps:

[0069] (a) Depositing a passivation film with a thickness of 90 nm on the surface of a silicon substrate of a TOPCon solar cell to obtain a coated sheet;

[0070] Laser cutting is used to form patterned grooves on the front and back of the silicon substrate of the TOPCon solar cell. The width of the patterned grooves is 30 μm and the depth is 75 nm.

[0071] (b) washing the back and front sides of the grooved solar cell in sequence, and then depositing a titanium seed layer to obtain a solar cell having a titanium seed layer;

[0072] The pickling solution for water washing is a hydrofluoric acid solution with an addition amount of 15 mL / L of hydrofluoric acid, a pickling solution temperature of 30°C, and a floating time of the silicon substrate in the pickling solution of 30 seconds.

[0073] The titanium seed layer is deposited by physical vapor deposition using vacuum magnetron sputtering technology, and the deposition thickness of the titanium seed layer is 1 μm.

[0074] (c) sintering the solar cell with the titanium seed layer at a sintering temperature of 700° C., then de-titanating the solar cell with a de-titanating solution under ultrasonic conditions at a de-titanating temperature of 40° C. for 9 minutes, then soaking the solar cell in clean water and drying the resulting de-titanated solar cell;

[0075] Among them, the ultrasonic power of the ultrasonic condition is 30kW;

[0076] The titanium stripping solution comprises the following components by mass percentage: 15% acid, 15% hydrogen peroxide, 3% dispersant, and the balance water; wherein the acid is sulfuric acid and the dispersant is sodium ethylenediaminetetramethylenephosphonate;

[0077] (d) electroplating copper and tin on both sides of the titanium-depleted solar cell to obtain a double-sided electroplated TOPCon cell;

[0078] The electroplated copper layer serves as a conductive layer, and its thickness is 10 μm; the electroplated tin layer serves as a protective layer, and its thickness is 1.6 μm.

[0079] Example 2

[0080] This embodiment provides a method for preparing a double-sided metallized TOPCon solar cell, which differs from Example 1 in that, in step (c), the ultrasonic power of the ultrasonic condition is 20 kW;

[0081] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0082] Example 3

[0083] This embodiment provides a method for preparing a double-sided metallized TOPCon solar cell, which differs from Example 1 in that, in step (c), the ultrasonic power of the ultrasonic condition is 40 kW;

[0084] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0085] Example 4

[0086] This embodiment provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the titanium stripping solution comprises the following components by mass percentage: 5% acid, 5% hydrogen peroxide, 1% dispersant, and the balance water;

[0087] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0088] Example 5

[0089] This embodiment provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the titanium stripping solution comprises the following components by mass percentage: 25% acid, 25% hydrogen peroxide, 5% dispersant, and the balance water;

[0090] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0091] Example 6

[0092] This embodiment provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the dispersant contained in the titanium stripping solution is sodium gluconate;

[0093] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0094] Example 7

[0095] This embodiment provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the dispersant contained in the titanium stripping solution is 1-aminocyclopropyl-1-carboxylic acid ethyl ester salt;

[0096] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0097] Example 8

[0098] This embodiment provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the temperature condition for titanium stripping is 25°C;

[0099] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0100] Example 9

[0101] This embodiment provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the temperature condition for titanium removal is 50°C;

[0102] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0103] Comparative Example 1

[0104] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell, which differs from Example 1 in that, in step (c), ultrasonic conditions are not used during the titanium removal process;

[0105] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0106] Compared with Example 1, the drawback of this comparative example is that, to obtain the same treatment effect, the required titanium removal time is longer, which directly leads to a reduction in production capacity.

[0107] Comparative Example 2

[0108] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell, which differs from Example 1 in that, in step (c), the ultrasonic power of the ultrasonic condition is 15 kW;

[0109] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0110] Compared with Example 1, the defect of this comparative example is that the ultrasonic power is too low, resulting in incomplete titanium removal or increased process time, affecting the subsequent process effects and causing worse bonding strength.

[0111] Comparative Example 3

[0112] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell, which differs from Example 1 in that, in step (c), the ultrasonic power of the ultrasonic condition is 45 kW;

[0113] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0114] Compared with Example 1, the defect of this comparative example is that the ultrasonic power is too high, which may damage the silicon wafer and may even damage or peel off the seed layer.

[0115] Comparative Example 4

[0116] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell, which differs from Example 1 in that, in step (c), the titanium stripping solution does not contain acid;

[0117] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0118] Compared with Example 1, the defect of this comparative example is that the titanium stripping solution cannot chemically react with the unreacted titanium or oxide film on the surface, resulting in failure to achieve the purpose of titanium stripping and failure to enhance the bonding force.

[0119] Comparative Example 5

[0120] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell, which differs from Example 1 in that, in step (c), the titanium stripping solution does not contain hydrogen peroxide;

[0121] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0122] Compared with Example 1, the defect of this comparative example is that the absence of hydrogen peroxide will weaken the synergistic effect of other components in the titanium stripping solution, resulting in a weakened chemical reaction or even no chemical reaction; in addition, hydrogen peroxide also has a cleaning effect, and the absence of hydrogen peroxide will also reduce the ability to remove pollutants on the substrate surface.

[0123] Comparative Example 6

[0124] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell, which differs from Example 1 in that, in step (c), the titanium stripping solution does not contain a dispersant;

[0125] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0126] Compared with Example 1, the defect of this comparative example is that the absence of a dispersant will slow down the chemical reaction rate and the stripping speed of the excess titanium layer, resulting in poor titanium stripping effect and slow speed.

[0127] Comparative Example 7

[0128] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the titanium stripping solution comprises the following components by mass percentage: 30% acid, 5% hydrogen peroxide, 1% dispersant, and the balance water;

[0129] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0130] Compared with Example 1, the drawback of this comparative example is that the acid concentration is too high. On the one hand, it will damage the coating layer on the surface of the silicon wafer, resulting in a decrease in the opening voltage; on the other hand, the acid will over-react with titanium, causing the seed layer to peel off.

[0131] Comparative Example 8

[0132] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the titanium stripping solution comprises the following components by mass percentage: 5% acid, 30% hydrogen peroxide, 1% dispersant, and the balance water;

[0133] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0134] Compared with Example 1, the drawback of this comparative example is that the concentration of hydrogen peroxide is too high, which leads to strong oxidizing properties and is also corrosive, which can additionally lead to oxidation of the seed layer and even damage the silicon wafer.

[0135] Comparative Example 9

[0136] This comparative example provides a method for preparing a double-sided metallized TOPCon solar cell. The difference from Example 1 is that in step (c), the titanium stripping solution comprises the following components by mass percentage: 5% acid, 5% hydrogen peroxide, 10% dispersant, and the balance water;

[0137] The remaining steps and process parameters are the same as those in Example 1, and a double-sided electroplated TOPCon battery is obtained.

[0138] Compared with Example 1, the drawback of this comparative example is that the concentration of the dispersant is too high, which may lead to poor stability of the titanium stripping solution and may cause flocculation in the solution, thereby affecting the titanium stripping effect.

[0139] Test example

[0140] The double-sided electroplated TOPCon cells obtained in Examples 1-9 and Comparative Examples 1-9 were tested, and the results are shown in Tables 1 and 2, respectively.

[0141] Test methods: (1) Electrical performance test: Off-line solar IV tester;

[0142] (2) Welding tension under low temperature conditions: tensile force gauge.

[0143] Table 1

[0144]

[0145] Table 2

[0146]

[0147] It can be seen that the titanium removal method of the present invention, through the coordinated cooperation of various steps and process parameters, solves the technical problem that unreacted titanium still exists on the surface of the battery cell after sintering, and titanium easily forms an oxide film, which leads to adverse effects on subsequent processes. It achieves the technical effect of efficiently and thoroughly removing titanium and its oxide film and effectively improving the bonding strength between the metal coating and the substrate.

[0148] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, 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 method for de-titaniumizing a solar cell, characterized in that: The following steps are involved: After sintering the solar cell with the titanium seed layer, the solar cell is subjected to titanium stripping treatment using a titanium stripping solution under ultrasonic conditions to obtain a titanium stripped solar cell; The ultrasonic power of the ultrasonic condition is 20kW-40kW; The titanium removal solution includes the following components by mass percentage: Acid 5%-25%, hydrogen peroxide 5%-25%, dispersant 1%-5%, and the balance water.

2. The titanium removal method according to claim 1, characterized in that: The acid includes sulfuric acid.

3. The titanium removal method according to claim 1, characterized in that: The dispersant includes at least one of sodium ethylenediaminetetramethylenephosphonate, sodium gluconate and 1-aminocyclopropyl-1-carboxylic acid ethyl ester salt.

4. The titanium removal method according to any one of claims 1 to 3, characterized in that: The temperature of the titanium removal treatment is 25° C.-50° C., and the time of the titanium removal treatment is 3 min-15 min.

5. The titanium removal method according to any one of claims 1 to 3, characterized in that: The thickness of the titanium seed layer is 0.1um-2um.

6. The titanium removal method according to claim 5, characterized in that: The sintering temperature is 400°C-980°C.

7. Use of the titanium removal method according to any one of claims 1 to 6 in the preparation of solar cells.

8. The use according to claim 7, characterized in that The solar cell includes a TOPCon solar cell.

9. The use according to claim 7, characterized in that The method for preparing the solar cell comprises the following steps: Electroplating the titanium-removed solar cell with a conductive layer and an electroplated protective layer in sequence to obtain a metallized solar cell; Preferably, the conductive layer comprises a copper layer; Preferably, the protective layer comprises a tin layer.

10. The use according to claim 9, characterized in that The electroplating method includes electroplating on both sides of the solar cell; Preferably, the thickness of the copper layer is 9um-12um; Preferably, the thickness of the tin layer is 1um-2um.

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