Pickling method of pickling bath in solar cell texturing process and texturing method

Abstract

The invention relates to a pickling method of a pickling tank for a solar cell texturing process and a texturing method, and belongs to the technical field of solar cell manufacturing. The pickling method comprises the following steps: preparing a pickling solution of a pickling tank, wherein the pickling solution of the pickling tank comprises the following raw materials in percentage by weight: 2-5% of HF, 0.3-0.7% of a pickling additive and the balance of a pure water solvent; the monocrystalline silicon wafer is placed in the pickling solution of the pickling tank for a reaction, the reaction temperature is 15-30 DEG C, the reaction time is 100-140 s, the residual alkali liquor is neutralized, and the monocrystalline silicon wafer is made to be hydrophobic. By using the pickling additive, the consumption of hydrochloric acid and hydrofluoric acid can be reduced, the production cost is reduced, the production efficiency is improved, the production cost is saved, and an ideal hydrophobic effect can be achieved after pickling in the pickling tank.

Description

Technical Field

[0001] The invention relates to the technical field of solar cell manufacturing, in particular to a pickling method for a pickling tank in a texturing process of a solar cell and a texturing method. Background Art

[0002] As global climate change and environmental problems become increasingly serious, the demand for clean energy is becoming more and more urgent. As a clean, renewable and unlimited energy source, solar energy has great development potential. As an important device for converting solar energy into electrical energy, the optimization of the production process and the reduction of costs of solar cells are of great significance to the development of the solar energy industry.

[0003] In the manufacturing process of solar cells, the texturing process is one of the key steps. The main purpose of the texturing process is to form a certain microstructure on the surface of the silicon wafer, thereby increasing the reflection and scattering of light on the surface of the silicon wafer and improving the light absorption efficiency. Among them, the pickling tank also plays a vital role in the texturing process. Its main function is to remove the oxide layer on the surface of the silicon wafer, making the surface of the silicon wafer more hydrophobic, and neutralizing the residual alkali solution. Specifically, the pickling tank uses an acid solution (i.e., a mixed solution containing HCl and HF) for high-purity cleaning. Among them, the role of HCl is to neutralize the residual NaOH, while HF is mainly used to remove the oxide layer on the surface of the silicon wafer to achieve a hydrophobic effect. This process not only helps to improve the surface structure of the silicon wafer and improve the photoelectric conversion efficiency of the battery, but also helps to ensure the smooth progress of subsequent process steps.

[0004] However, the amount of HCl and HF used in the pickling process of the traditional texturing process is relatively high, which greatly increases the manufacturing cost of solar cells. Therefore, how to reduce the amount of acid used and reduce costs has become an urgent problem to be solved. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a pickling method for a pickling tank in a solar cell texturing process and a texturing method thereof. The technical solution of the present invention is as follows:

[0006] In a first aspect, a pickling method for a pickling tank in a solar cell texturing process is provided, comprising:

[0007] S10, preparing a pickling solution for a pickling tank: the pickling solution for the pickling tank is composed of the following raw materials in weight percentage: HF 2%-5%, pickling additive 0.3%-0.7%, and the rest is pure water solvent;

[0008] S20, placing the single crystal silicon wafer in a pickling solution in a pickling tank for reaction, the reaction temperature is 15-30° C., and the reaction time is 100-140 seconds, so as to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic.

[0009] Optionally, the pickling additive is composed of the following raw materials: deionized water, sodium benzoate, surfactant, chelating agent, wetting agent, preservative and penetrant; wherein the content of sodium benzoate is 0.1%, the content of surfactant is 0.1%, the content of deionized water is 96.8%, and the content of other chemical components is 3%.

[0010] Optionally, the surfactant is sodium dodecyl sulfate; the chelating agent is ethylenediaminetetraacetic acid, citric acid or acetic acid; the wetting agent is ethanol; and the preservative is isothiazolinone.

[0011] In a second aspect, a texturing method for a solar cell is provided, which adopts the pickling method of the pickling tank in the texturing process of the solar cell described in the first aspect, comprising:

[0012] S1, preparing the pickling solution of the pickling tank: preparing the pickling solution of the pickling tank according to the components and mass percentage of the pickling solution of the pickling tank;

[0013] S2, pre-cleaning;

[0014] S3, water washing;

[0015] S4, velveting;

[0016] S5, water washing;

[0017] S6, post-cleaning;

[0018] S7, pickling: placing the single crystal silicon wafer in a pickling solution in a pickling tank for reaction at a temperature of 15-30° C. for a reaction time of 100-140 seconds to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic;

[0019] S8, water washing;

[0020] S9, pre-dehydration;

[0021] S11, drying.

[0022] Optionally, the texturing in S4 comprises: immersing the single crystal silicon wafer in a mixed aqueous solution of 0.8-1.4% by mass of NaOH and 0.5-1.0% by mass of a texturing additive at 80-84° C. for 400-440 seconds.

[0023] Optionally, the water washing in S3, S5 and S8 includes: immersing the single crystal silicon wafer in flowing deionized water for 100-140 seconds.

[0024] Optionally, the pre-cleaning in S3 and the post-cleaning in S6 both include: treating the single crystal silicon wafer in a solution containing 1.10% by mass of NaOH and 1.52% by mass of H2O at 68-72°C. 2 O2 Soak in the mixed aqueous solution for 100-160s.

[0025] Optionally, the pre-dehydration in S9 includes: soaking the single crystal silicon wafer in flowing deionized water at 60-80° C. for 20-60 seconds.

[0026] Optionally, the drying in S11 includes: drying the single crystal silicon wafer in an oven at a temperature of 85-95° C. for 600-800 seconds.

[0027] All the above optional technical solutions can be combined arbitrarily, and the present invention does not provide detailed descriptions of the structures after the combinations.

[0028] By means of the above scheme, the beneficial effects of the present invention are as follows:

[0029] The pickling solution of the pickling tank is configured, and the pickling solution of the pickling tank is set to be composed of the following raw materials in weight percentage: HF 2%-5%, pickling additive 0.3%-0.7%, and the rest is pure water solvent; and during pickling, the single crystal silicon wafer is placed in the pickling solution of the pickling tank for reaction, the reaction temperature is 15-30°C, and the reaction time is 100-140s, so as to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic; a pickling method for a pickling tank in a texturing process with optimized HCl and HF dosage is proposed, and the use of the pickling additive can assist in reducing the consumption of hydrochloric acid and hydrofluoric acid, reduce production costs, improve production efficiency, save production costs, and can ensure that the pickling tank achieves an ideal hydrophobic effect after pickling.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of a texturing method for a solar cell provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0033] The embodiment of the present invention provides a pickling method for a pickling tank in a solar cell texturing process, which comprises:

[0034] S10, preparing a pickling solution for a pickling tank: the pickling solution for the pickling tank is composed of the following raw materials in weight percentage: HF 2%-5%, pickling additive 0.3%-0.7%, and the rest is pure water solvent;

[0035] S20, placing the single crystal silicon wafer in a pickling solution in a pickling tank for reaction, the reaction temperature is 15-30° C., and the reaction time is 100-140 seconds, so as to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic.

[0036] It should be noted that the present invention does not specifically limit the components of the pickling additive. For example, a commercially available pickling additive may be selected.

[0037] In a specific embodiment, the pickling additive is composed of the following raw materials: deionized water, sodium benzoate, surfactant, chelating agent, wetting agent, preservative and penetrant; wherein the content of sodium benzoate is 0.1%, the content of surfactant is 0.1%, the content of deionized water is 96.8%, and the content of other chemical components is 3%.

[0038] In a specific embodiment, the surfactant is sodium dodecyl sulfate; the chelating agent is ethylenediaminetetraacetic acid, citric acid or acetic acid; the wetting agent is ethanol; and the preservative is isothiazolinone.

[0039] The content of the chelating agent, wetting agent, preservative and penetrant is not specifically limited in the embodiment of the present invention, and can be flexibly adjusted according to the texturing requirements during the specific implementation. For example, the content of the chelating agent, wetting agent, preservative and penetrant is 0.8%, 1.1%, 1.2% and 0.9% respectively.

[0040] Chelating agents can chelate metal ions, leaving no metal residue on the surface of single crystal silicon wafers. Wetting agents can enhance wettability, making it easier for organic matter to separate from single crystal silicon wafers. Preservatives can prevent additives from rotting and deteriorating. Penetrants can reduce the surface tension of single crystal silicon wafers and deeply clean the pyramid gaps of single crystal silicon wafers.

[0041] like Figure 1 As shown, an embodiment of the present invention further provides a texturing method for a solar cell, which adopts the pickling method of the pickling tank in the above-mentioned texturing process of the solar cell, comprising:

[0042] S1, preparing the pickling solution of the pickling tank: preparing the pickling solution of the pickling tank according to the components and mass percentage of the pickling solution of the pickling tank;

[0043] S2, pre-cleaning;

[0044] S3, water washing;

[0045] S4, velveting;

[0046] S5, water washing;

[0047] S6, post-cleaning;

[0048] S7, pickling, placing the single crystal silicon wafer in a pickling solution in a pickling tank for reaction, the reaction temperature is 15-30° C., and the reaction time is 100-140 seconds, so as to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic;

[0049] S8, water washing;

[0050] S9, pre-dehydration;

[0051] S11, drying.

[0052] In a specific embodiment, the texturing in S4 comprises: immersing the single crystal silicon wafer in a mixed aqueous solution of 0.8-1.4% by mass of NaOH and 0.5-1.0% by mass of a texturing additive at 80-84° C. for 400-440 seconds.

[0053] In a specific embodiment, the water washing in S3, S5 and S8 includes: immersing the single crystal silicon wafer in flowing deionized water for 100-140 seconds.

[0054] In a specific embodiment, the pre-cleaning in S3 and the post-cleaning in S6 both include: treating the single crystal silicon wafer in a solution of 1.10% by mass NaOH and 1.52% by mass H2O at 68-72°C. 2 O 2 Soak in the mixed aqueous solution for 100-160s.

[0055] In a specific embodiment, the pre-dehydration in S9 includes: immersing the single crystal silicon wafer in flowing deionized water at 60-80° C. for 20-60 seconds.

[0056] In a specific embodiment, the drying in S11 includes: drying the single crystal silicon wafer in an oven at a temperature of 85-95° C. for 600-800 seconds.

[0057] In order to verify the beneficial effects of the pickling method of the pickling tank in the texturing process of the solar cell provided by the embodiment of the present invention, the following examples and comparative examples are provided below.

[0058] Example

[0059] The solar cell texturing method provided in this embodiment comprises the following steps:

[0060] S1, preparing a pickling solution for a pickling tank: preparing a pickling solution for a pickling tank according to the components and mass percentages of the pickling solution for the pickling tank described above;

[0061] The pickling solution of the pickling tank is composed of the following raw materials in weight percentage: HF 2.7%, pickling additive 0.5%, and the rest is pure water solvent; the pickling additive is composed of the following raw materials: deionized water, sodium benzoate, surfactant, chelating agent, wetting agent, preservative and penetrant; wherein the content of sodium benzoate is 0.1%, the content of surfactant is 0.1%, the content of deionized water is 96.8%, and the content of other chemical components is 3%;

[0062] S2, water washing: immerse the single crystal silicon wafer in flowing deionized water for 120s;

[0063] S3, pre-cleaning: at 70°C, wash the single crystal silicon wafer in 1.1% by mass NaOH and 1.52% by mass H 2 O 2 Immerse in the mixed aqueous solution for 120s;

[0064] S4, texturing, immersing the single crystal silicon wafer in a mixed aqueous solution of 1.2% by mass NaOH and 0.61% by mass texturing additive at 82° C. for 420 s;

[0065] S5, water washing, immersing the single crystal silicon wafer in flowing deionized water for 120 seconds;

[0066] S6, post-cleaning: The single crystal silicon wafer is washed with 1.1% by mass NaOH and 1.52% by mass H at 70°C. 2 O 2 Immerse in the mixed aqueous solution for 120s;

[0067] S7, pickling: placing the single crystal silicon wafer in the pickling solution of the pickling tank for reaction at a temperature of 25° C. for a reaction time of 120 seconds to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic;

[0068] S8, water washing, immersing the single crystal silicon wafer in flowing deionized water for 120 seconds;

[0069] S9, pre-dehydration: immerse the single crystal silicon wafer in flowing deionized water at 70°C for 20s;

[0070] S11, drying: drying the single crystal silicon wafer in an oven at a temperature of 95° C. for 700 seconds.

[0071] Comparative Example

[0072] The texturing method of the solar cell provided in this comparative example comprises the following steps:

[0073] S1, preparing a pickling solution for a pickling tank: preparing a pickling solution for a pickling tank according to the components and mass percentages of the pickling solution for the pickling tank;

[0074] The pickling solution of the pickling tank is composed of the following raw materials in weight percentage: HF 6.7%, HCl 0.94%, and the rest is pure water solvent, without pickling additives;

[0075] S2, water washing: immerse the single crystal silicon wafer in flowing deionized water for 120s;

[0076] S3, pre-cleaning: at 70°C, wash the single crystal silicon wafer in 1.10% by mass NaOH and 1.52% by mass H 2 O 2 Immerse in the mixed aqueous solution for 120s;

[0077] S4, texturing, immersing the single crystal silicon wafer in a mixed aqueous solution of 1.2% by mass NaOH and 0.61% by mass texturing additive at 82° C. for 420 s;

[0078] S5, water washing: immersing the single crystal silicon wafer in flowing deionized water for 120 seconds;

[0079] S6, post-cleaning: The single crystal silicon wafer is washed with 1.10% by mass NaOH and 1.52% by mass H at 70°C. 2 O 2 Immerse in the mixed aqueous solution for 120s;

[0080] S7, pickling: placing the single crystal silicon wafer in the pickling solution of the pickling tank for reaction at a temperature of 25° C. for a reaction time of 120 seconds to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic;

[0081] S8, water washing: immersing the single crystal silicon wafer in flowing deionized water for 120 seconds;

[0082] S9, pre-dehydration: immerse the single crystal silicon wafer in flowing deionized water at 70°C for 20s;

[0083] S11, drying: drying the single crystal silicon wafer in an oven at a temperature of 95° C. for 700 s.

[0084] The comparison results of the electrical properties of the solar cells obtained by the texturing of the embodiment and the comparative example are shown in Table 1.

[0085] Table 1

[0086] Electrical properties Eta Uoc Isc FF R R IRV2 Example 26.118 0.73177 13.80 86.55 0.000976 1270.56 0.05959 Comparative Example 26.124 0.73182 13.80 86.60 0.000972 1253.50 0.05414 Gain(%) 0.006 0.00005 -0.0054 0.0480 -0.000004 -17.062 -0.0054

[0087] As shown in Table 1, the efficiency gain of the embodiment is 0.006% over the comparative example, which is reflected in the FF gain of 0.0480%, and other electrical properties are equivalent. The single crystal silicon wafer after pickling in the embodiment has good hydrophobicity, and the finished single crystal solar cell has no abnormal appearance.

[0088] In addition, the pickling method and texturing method of the pickling tank in the texturing process of solar cells provided by the embodiments of the present invention can reduce the amount of acid used and reduce costs while ensuring the ideal hydrophobic effect after the acid tank is cleaned, as shown in the chemical consumption comparison table of the embodiment and the comparative example shown in Table 2 below.

[0089] Table 2

[0090]

[0091] As shown in Table 2, the embodiment saves 3.67 L of HF solution per 10,000 pieces, and the saving rate is 46.16%, and the saving rate is 100% for HCl solution per 10,000 pieces. That is to say, the present invention is particularly suitable for cleaning single crystal solar cells with low chemical consumption and low cost.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A pickling method for a pickling tank in a solar cell texturing process, characterized in that: include: S10, preparing a pickling solution for a pickling tank: the pickling solution for the pickling tank is composed of the following raw materials in weight percentage: HF 2%-5%, pickling additive 0.3%-0.7%, and the rest is pure water solvent; S20, placing the single crystal silicon wafer in a pickling solution in a pickling tank for reaction, the reaction temperature is 15-30° C., and the reaction time is 100-140 seconds, so as to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic.

2. The pickling method of the pickling tank in the solar cell texturing process according to claim 1, characterized in that: The pickling additive is composed of the following raw materials: deionized water, sodium benzoate, surfactant, chelating agent, wetting agent, preservative and penetrant; wherein the content of sodium benzoate is 0.1%, the content of surfactant is 0.1%, the content of deionized water is 96.8%, and the content of other chemical components is 3%.

3. The pickling method of the pickling tank in the solar cell texturing process according to claim 1, characterized in that: The surfactant is sodium dodecyl sulfonate; the chelating agent is ethylenediaminetetraacetic acid, citric acid or acetic acid; the wetting agent is ethanol; and the preservative is isothiazolinone.

4. A method for making a texture of a solar cell, characterized in that: The pickling method of the pickling tank in the solar cell texturing process according to any one of claims 1 to 3 comprises: S1, preparing the pickling solution of the pickling tank: preparing the pickling solution of the pickling tank according to the components and mass percentage of the pickling solution of the pickling tank; S2, pre-cleaning; S3, water washing; S4, velveting; S5, water washing; S6, post-cleaning; S7, pickling: placing the single crystal silicon wafer in a pickling solution in a pickling tank for reaction at a temperature of 15-30° C. for a reaction time of 100-140 seconds to neutralize the residual alkali solution and make the single crystal silicon wafer hydrophobic; S8, water washing; S9, pre-dehydration; S11, drying.

5. The method for making a texturing process for a solar cell according to claim 4, characterized in that: The texturing in S4 comprises: soaking the single crystal silicon wafer in a mixed aqueous solution of 0.8-1.4% by mass of NaOH and 0.5-1.0% by mass of a texturing additive at 80-84° C. for 400-440 seconds.

6. The method for making a texturing process for a solar cell according to claim 4, characterized in that: The water washing in S3, S5 and S8 includes: immersing the single crystal silicon wafer in flowing deionized water for 100-140 seconds.

7. The method for texturing a solar cell according to claim 4, characterized in that: The pre-cleaning in S3 and the post-cleaning in S6 both include: immersing the single crystal silicon wafer in a mixed aqueous solution of 1.10% by mass NaOH and 1.52% by mass H2O2 at 68-72°C for 100-160s.

8. The method for texturing a solar cell according to claim 4, characterized in that: The pre-dehydration in S9 includes: soaking the single crystal silicon wafer in flowing deionized water at 60-80° C. for 20-60 seconds.

9. The method for texturing a solar cell according to claim 4, characterized in that: The drying in S11 includes: drying the single crystal silicon wafer in an oven at a temperature of 85-95° C. for 600-800 seconds.

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