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CN-122002943-A - Secondary texturing and efficiency improving process suitable for TOPCon battery

CN122002943ACN 122002943 ACN122002943 ACN 122002943ACN-122002943-A

Abstract

The invention belongs to the technical field of photovoltaic cells, and particularly relates to a secondary texturing and effect improving process suitable for TOPCon cells, which sequentially comprises the steps of pre-cleaning, primary texturing, intermediate water washing, secondary texturing, post-cleaning and acid washing, wherein the primary texturing is performed at a higher temperature to form a basic pyramid textured structure, the secondary texturing is performed at a lower temperature to finely optimize textured surfaces to form a pagoda-type pyramid structure. According to the invention, through specific formula combination, temperature step control and step corrosion strategies, a suede structure with excellent light trapping performance can be stably prepared, a pagoda pyramid structure with better height-width ratio is realized, the light trapping effect is effectively increased, the reflectivity is reduced, the photoelectric conversion efficiency, short circuit current and filling factor of a photovoltaic cell are further improved, and the purposes of improving efficiency and reducing cost are achieved.

Inventors

  • YANG HAO
  • ZHENG TIAN
  • WANG KUI
  • LU JING

Assignees

  • 弘元新材料(徐州)有限公司
  • 弘元绿色能源股份有限公司

Dates

Publication Date
20260508
Application Date
20251222

Claims (9)

  1. 1. A secondary texturing and efficiency improving process suitable for TOPCon batteries is characterized by comprising the following steps: Firstly, pre-cleaning, namely placing a silicon wafer into a pre-cleaning liquid for cleaning; Step two, performing first texturing, namely chemically corroding the pre-cleaned silicon wafer under the action of first texturing liquid, and washing the silicon wafer after forming a basic pyramid textured structure on the surface of the silicon wafer; step three, performing secondary texturing, namely performing chemical corrosion on the silicon wafer after water washing under the action of secondary texturing liquid; step four, cleaning; Step five, acid washing; wherein, the working temperature of the first-time texturing solution is higher than that of the second-time texturing solution.
  2. 2. The secondary texturing and efficiency improving process for TOPCon batteries according to claim 1, wherein in the second step, the first texturing solution comprises the following raw materials in parts by weight: 650-675 parts of deionized water, 6-7 parts of sodium hydroxide solution and 1.5-3 parts of a first composite additive; The concentration of the sodium hydroxide solution is 40% -50%; The first-time texturing is performed at 82+/-3 ℃ for 280-320 seconds; The water washing time in the first texturing is 95-102S.
  3. 3. The secondary texturing and efficiency improving process for TOPCon batteries according to claim 2, wherein the primary texturing liquid comprises the following raw materials in parts by weight: 680 parts of deionized water, 6.5 parts of sodium hydroxide solution and 2 parts of first composite additive; The concentration of the sodium hydroxide solution is 45%; the first-time texturing is performed at 82+/-3 ℃ for 300S; the water washing time in the first texturing is 100S.
  4. 4. The secondary texturing efficiency improving process for TOPCon batteries according to any one of claims 1 to 3, wherein in the third step, the secondary texturing solution comprises the following raw materials in parts by weight: 650-675 parts of deionized water, 1.2-2.5 parts of sodium hydroxide solution and 3-4 parts of a second composite additive; The concentration of the sodium hydroxide solution is 40% -50%; The first-time texturing is performed at a texturing temperature of 60+/-3 ℃ and a texturing time of 280-320S; The water washing time in the first texturing is 85-102S.
  5. 5. The secondary texturing and efficiency improving process for TOPCon batteries according to claim 4, wherein in the third step, the secondary texturing solution comprises the following raw materials in parts by weight: 680 parts of deionized water, 2 parts of sodium hydroxide solution and 3.8 parts of first composite additive; the concentration of the sodium hydroxide solution is 45; the first-time texturing is performed at 60+/-3 ℃ for 300S; the water washing time in the first texturing is 90S.
  6. 6. The secondary texturing and efficiency improving process for TOPCon batteries according to claim 4, wherein in the fourth step, the silicon wafer is cleaned by the post-cleaning liquid; the post-cleaning liquid comprises the following raw materials in parts by weight: 660-680 parts of deionized water, 1.2-1.6 parts of sodium hydroxide solution, 10-14 parts of hydrogen peroxide and 6-7 parts of cleaning auxiliary additive; the concentration of the sodium hydroxide solution is 30% -33%; In the fourth step, the temperature is 68 ℃ plus or minus 3 ℃ when the silicon wafer is cleaned by the post-cleaning liquid, and the cleaning time is 100S-130S; And in the fourth step, the water washing time is 110-125S.
  7. 7. The secondary texturing and efficiency enhancing process for TOPCon cells of claim 6, wherein: the post-cleaning liquid comprises the following raw materials in parts by weight: 673 parts of deionized water, 1.5 parts of sodium hydroxide solution, 12 parts of hydrogen peroxide and 7 parts of cleaning auxiliary additive; the concentration of the sodium hydroxide solution is 31%; in the fourth step, the temperature is 68 ℃ plus or minus 3 ℃ when the silicon wafer is cleaned by the post-cleaning liquid, and the cleaning time is 120S; and the water washing time in the fourth step is 120S.
  8. 8. The secondary texturing and efficiency improving process for TOPCon batteries according to claim 4, wherein in the fifth step, the silicon wafer is pickled by pickling liquid; The pickling liquid medicine comprises the following raw materials in parts by weight: 640-655 parts of deionized water, 12-16 parts of hydrofluoric acid and 10-14 parts of acid pickling auxiliary additive ADD; The concentration of the hydrofluoric acid is 45% -55%; and in the fifth step, the pickling time is 90S-105S when the silicon wafer is pickled by the pickling liquid.
  9. 9. The secondary texturing and efficiency improving process for TOPCon batteries according to claim 8, wherein the pickling liquid comprises the following raw materials in parts by weight: 653 parts deionized water, 15 parts hydrofluoric acid, 12 parts pickling auxiliary additive ADD; The concentration of hydrofluoric acid is 49%; And in the fifth step, the pickling time is 100S when the silicon wafer is pickled by the pickling liquid.

Description

Secondary texturing and efficiency improving process suitable for TOPCon battery Technical Field The invention belongs to the technical field of photovoltaic cells, and particularly relates to a secondary texturing and efficiency improving process suitable for TOPCon cells. Background In photovoltaic cell manufacturing, the texturing process aims at forming a micro textured structure on the surface of a silicon wafer so as to reduce the reflectivity of sunlight and enhance the light capturing capability (namely 'light trapping effect'), thereby improving the photoelectric conversion efficiency of the cell. Conventional texturing processes commonly employ a single chemical etching process, such as forming a randomly distributed pyramid structure in an alkaline solution. However, the pyramid pile formed by the conventional one-step pile process is often not ideal in terms of size uniformity and distribution density, so that the light reflectivity is difficult to further reduce (usually maintained above 10.3%), and the improvement space of the battery efficiency (especially the short-circuit current Isc) is limited. Disclosure of Invention The invention aims to provide a secondary texturing efficiency improving process suitable for TOPCon batteries, which can stably prepare a textured structure with excellent light trapping performance, realize a pagoda pyramid structure with better aspect ratio, effectively increase light trapping effect, reduce reflectivity, further improve photoelectric conversion efficiency, short-circuit current and filling factor of a photovoltaic battery, and achieve the purposes of improving efficiency and reducing cost. The technical scheme adopted by the invention is as follows: a secondary texturing and efficiency improving process suitable for TOPCon batteries comprises the following steps: Firstly, pre-cleaning, namely placing a silicon wafer into a pre-cleaning liquid for cleaning; Step two, performing first texturing, namely chemically corroding the pre-cleaned silicon wafer under the action of first texturing liquid, and washing the silicon wafer after forming a basic pyramid textured structure on the surface of the silicon wafer; step three, performing secondary texturing, namely performing chemical corrosion on the silicon wafer after water washing under the action of secondary texturing liquid, and performing fine adjustment and optimization on the basic pyramid textured structure; step four, cleaning; Step five, acid washing; wherein, the working temperature of the first-time texturing solution is higher than that of the second-time texturing solution. Further, in the first step, the pre-cleaning solution comprises the following raw materials in parts by weight: 640-675 parts of deionized water, 0.45-0.55 part of sodium hydroxide solution, 10-13 parts of hydrogen peroxide and 3-5 parts of cleaning auxiliary additive; Wherein the concentration of the sodium hydroxide solution is 40% -50%, and preferably 45%, and the concentration of the hydrogen peroxide solution is 30% -33%, and preferably 31%; and in the first step, the silicon wafer is placed in a pre-cleaning solution 220S. Further, in the second step, the first texturing solution includes the following raw materials in parts by weight: 650-675 parts of deionized water, 6-7 parts of sodium hydroxide solution and 1.5-3 parts of a first composite additive; Wherein the concentration of the sodium hydroxide solution is 40% -50%, and preferably 45%. Further, the first-time texturing solution comprises the following raw materials in parts by weight: 680 parts of deionized water, 6.5 parts of sodium hydroxide solution and 2 parts of a first composite additive. Further, the first-time texturing is performed at a texturing temperature of 82+/-3 ℃ and a texturing time of 280-320S, preferably 300S. Further, the water washing time in the first texturing is 95-102S, preferably 100S. Further, in the third step, the second texturing solution includes the following raw materials in parts by weight: 650-675 parts of deionized water, 1.2-2.5 parts of sodium hydroxide solution and 3-4 parts of a second composite additive; wherein the concentration of the sodium hydroxide solution is 40% -50%, and preferably 45%. Further, the second texturing solution comprises the following raw materials in parts by weight: 680 parts of deionized water, 2 parts of sodium hydroxide solution and 3.8 parts of first composite additive. Further, the first-time texturing is performed at a texturing temperature of 60+/-3 ℃ and a texturing time of 280-320S, preferably 300S. Further, the water washing time in the first texturing is 85-102S, preferably 90S. Further, in the fourth step, cleaning the silicon wafer through the post-cleaning liquid; the post-cleaning liquid comprises the following raw materials in parts by weight: 660-680 parts of deionized water, 1.2-1.6 parts of sodium hydroxide solution, 10-14 parts of hydrogen peroxide and 6-7 parts of cleaning auxi