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CN-122007435-A - TOPCon photovoltaic silver powder and preparation method thereof

CN122007435ACN 122007435 ACN122007435 ACN 122007435ACN-122007435-A

Abstract

The invention provides TOPCon photovoltaic silver powder and a preparation method thereof, and belongs to the technical field of photovoltaic material preparation. According to the invention, a regulating mechanism of 'coordination compound preparation-synchronous dropwise addition' is combined, a double-liquid-phase flow rate ratio is combined, superfine narrow distribution of silver powder can be realized, and through cooperation of a silane coupling agent and stearic acid modification, van der Waals force adhesion among particles is stopped, so that the silver powder is kept monodisperse in an organic slurry system (such as terpineol and ethyl cellulose system), the problem of poor slurry rheological property caused by easy aggregation of superfine silver powder is solved, meanwhile, a siloxane compact film formed by silane hydrolysis and a hydrophobic alkyl base layer of stearic acid are constructed on the surface of the silver powder, contact between air and moisture and the silver powder is isolated, normal-temperature oxidation of the superfine silver powder is effectively inhibited (silver oxide impurities are avoided), and the storage shelf life of the silver powder is greatly prolonged.

Inventors

  • YANG BOWEN
  • LI JUNPENG
  • LI WEI
  • GAN JUN
  • ZHANG XIAOJIE
  • HE ZIJUAN
  • Chen Kaicha
  • YANG ZHIHUA

Assignees

  • 贵研电子材料(云南)有限公司

Dates

Publication Date
20260512
Application Date
20260305

Claims (10)

  1. 1. A preparation method of TOPCon photovoltaic silver powder comprises the following steps: (1) Mixing silver ion solution and chelating agent solution, and chelating to obtain coordination compound; (2) Simultaneously dropwise adding a dispersing agent solution and a solution containing an organic reducing agent and an inorganic reducing agent into the coordination compound obtained in the step (1) to perform a reduction reaction to obtain silver powder, wherein the rate ratio of dropwise adding the dispersing agent solution to the solution containing the organic reducing agent and the inorganic reducing agent is 1 (4-6); (3) Mixing the silver powder obtained in the step (2), stearic acid, a silane coupling agent and a solvent, and carrying out surface modification to obtain TOPCon photovoltaic silver powder.
  2. 2. The method of claim 1, wherein the silver ion solution in step (1) is sonicated prior to use.
  3. 3. The method according to claim 1, wherein the chelating agent in the step (1) is at least one of citric acid, sodium citrate, tartaric acid, potassium sodium tartrate, ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid, dimercaptopropanol, aminotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid and catechols.
  4. 4. The preparation method of claim 1, wherein the organic reducing agent in the step (2) is at least one of ascorbic acid, formaldehyde, acetaldehyde, methylamine, ethylenediamine, glucose, sodium gluconate and linoleic acid, the inorganic reducing agent is at least one of hydrazine hydrate, potassium iodide, ferrous sulfate, ferrous chloride, stannous chloride, sodium sulfite and sodium thiosulfate, and the ratio of the amounts of the organic reducing agent to the inorganic reducing agent is (2-5): 1.
  5. 5. The preparation method according to claim 1, wherein the temperature of the reduction reaction in the step (2) is 39.5-40.5 ℃, the time of the reduction reaction is 20-40 min, and the reduction reaction is performed in a protective atmosphere.
  6. 6. The preparation method of the silver powder according to claim 1, wherein the mass ratio of the stearic acid to the silane coupling agent in the step (3) is (1-2) 1, and the total mass of the stearic acid and the silane coupling agent is 1-2% of the dry weight of the silver powder.
  7. 7. The preparation method of claim 1, wherein the surface modification in the step (3) is performed in a nitrogen-hydrogen mixed gas, the volume ratio of nitrogen and hydrogen in the nitrogen-hydrogen mixed gas is (97-98): (2-3), and the temperature of the nitrogen-hydrogen mixed gas is 45-55 ℃.
  8. 8. The method according to claim 1, wherein the surface modification in the step (3) further comprises a post-treatment comprising filtration, primary centrifugation, secondary centrifugation, tertiary centrifugation and vacuum freeze-drying performed in this order.
  9. 9. The method according to claim 8, wherein the medium used for the three-stage centrifugal separation is a dispersant.
  10. 10. The TOPCon photovoltaic silver powder prepared by the preparation method according to any one of claims 1 to 9.

Description

TOPCon photovoltaic silver powder and preparation method thereof Technical Field The invention belongs to the technical field of preparation of photovoltaic materials, and particularly relates to TOPCon photovoltaic silver powder and a preparation method thereof. Background TOPCon solar cells (tunnel oxide passivation contact cells) are used as a new generation of high-efficiency photovoltaic technology, and the back electrode of the solar cells has strict requirements on conductivity, sintering activity and morphology control of silver powder. The traditional silver powder preparation method has the problems of wide particle size distribution, insufficient specific surface area, poor oxidation resistance and the like, so that the bonding force between the silver paste and the silicon wafer interface is weak, the contact resistance is high, and the improvement of the conversion efficiency of the battery is restricted. In the prior art, although the cost of the conventional chemical reduction method is controllable, the superfine particle size and the narrow distribution characteristic are difficult to be combined. Therefore, how to improve the preparation method to achieve ultra-fine narrow distribution is a technical problem to be solved in the art. Disclosure of Invention The invention aims to provide TOPCon photovoltaic silver powder and a preparation method thereof. The preparation method provided by the invention can obtain the TOPCon photovoltaic silver powder with superfine narrow distribution. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a preparation method of TOPCon photovoltaic silver powder, which comprises the following steps: (1) Mixing silver ion solution and chelating agent solution, and chelating to obtain coordination compound; (2) Simultaneously dropwise adding a dispersing agent solution and a solution containing an organic reducing agent and an inorganic reducing agent into the coordination compound obtained in the step (1) to perform a reduction reaction to obtain silver powder, wherein the rate ratio of dropwise adding the dispersing agent solution to the solution containing the organic reducing agent and the inorganic reducing agent is 1 (4-6); (3) Mixing the silver powder obtained in the step (2), stearic acid, a silane coupling agent and a solvent, and carrying out surface modification to obtain TOPCon photovoltaic silver powder. Preferably, the silver ion solution in step (1) is subjected to ultrasonic treatment before use. Preferably, the chelating agent in the step (1) is at least one of citric acid, sodium citrate, tartaric acid, potassium sodium tartrate, ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid, dimercaptopropanol, aminotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid and catechol. Preferably, the organic reducing agent in the step (2) is at least one of ascorbic acid, formaldehyde, acetaldehyde, methylamine, ethylenediamine, glucose, sodium gluconate and linoleic acid, the inorganic reducing agent is at least one of hydrazine hydrate, potassium iodide, ferrous sulfate, ferrous chloride, stannous chloride, sodium sulfite and sodium thiosulfate, and the ratio of the amounts of the organic reducing agent to the inorganic reducing agent is (2-5): 1. Preferably, the temperature of the reduction reaction in the step (2) is 39.5-40.5 ℃, the time of the reduction reaction is 20-40 min, and the reduction reaction is carried out in a protective atmosphere. Preferably, the mass ratio of the stearic acid to the silane coupling agent in the step (3) is (1-2): 1, and the total mass of the stearic acid and the silane coupling agent is 1-2% of the dry weight of the silver powder. Preferably, the surface modification in the step (3) is performed in a nitrogen-hydrogen mixed gas, wherein the volume ratio of nitrogen to hydrogen in the nitrogen-hydrogen mixed gas is (97-98): (2-3), and the temperature of the nitrogen-hydrogen mixed gas is 45-55 ℃. Preferably, the surface modification in the step (3) further comprises post-treatment, wherein the post-treatment comprises sequentially performing filtration, primary centrifugal separation, secondary centrifugal separation, tertiary centrifugal separation and vacuum freeze-drying. Preferably, the medium used for the three-stage centrifugal separation is a dispersing agent. The invention also provides TOPCon photovoltaic silver powder prepared by the preparation method. The invention provides a preparation method of TOPCon photovoltaic silver powder, which comprises the steps of mixing silver ion solution and chelating agent solution, chelating to obtain a coordination compound, simultaneously dropwise adding dispersant solution and solution containing organic reducing agent and inorganic reducing agent into the coordination compound, carrying out reduction reaction to obtain silver powder, wherein the rate ratio of dropwis