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CN-121983389-A - Preparation method of conductive paste for solar cell

CN121983389ACN 121983389 ACN121983389 ACN 121983389ACN-121983389-A

Abstract

The application discloses a preparation method of conductive paste for a solar cell, and relates to the technical field of solar cell preparation. The preparation method comprises the steps of adding a copper source, a surfactant, a dispersing agent and a brightening modifier into a solvent to obtain a first mixed solution, adding a reducing agent and a chelating agent into the solvent to obtain a second mixed solution, mixing the first mixed solution and the second mixed solution according to a preset volume ratio to obtain a third mixed solution, adding seed copper powder with a preset mass fraction into the third mixed solution, sequentially carrying out sedimentation cooling treatment, centrifugal treatment, drying treatment and grinding treatment on the reacted third mixed solution to obtain micron-sized copper powder, depositing a conductive silver layer on the surface of the micron-sized copper powder by utilizing a chemical reduction reaction to obtain silver-coated copper powder, and preparing the conductive slurry by utilizing the silver-coated copper powder. The micron-sized copper powder prepared by the method can meet the requirement of higher yield of a target size interval, and has low preparation cost and high process compatibility.

Inventors

  • SU XIAODONG
  • ZHOU JINPENG
  • ZOU SHUAI
  • ZHANG LIHAI
  • LU ZHENG

Assignees

  • 苏州大学

Dates

Publication Date
20260505
Application Date
20260403

Claims (10)

  1. 1. The preparation method of the conductive paste for the solar cell is characterized by comprising the following steps of: Adding a copper source, a surfactant, a dispersing agent and a brightening modifier into a solvent, and stirring to obtain a first mixed solution; adding a reducing agent and a chelating agent into the solvent, and stirring to obtain a second mixed solution; mixing the first mixed solution and the second mixed solution according to a preset volume ratio to obtain a third mixed solution, and adding seed copper powder with a preset mass fraction into the third mixed solution to perform seed-induced chemical reduction reaction under a preset reaction condition, wherein the particle size D50 of the seed copper powder is any value of 1-2 mu m; Sequentially carrying out sedimentation cooling treatment, centrifugal treatment, drying treatment and grinding treatment on the reacted third mixed solution to prepare micron-sized copper powder with the particle size D50 of 3-5 mu m, the particle size D10 of more than 2 mu m and the particle size D90 of less than or equal to 8 mu m; Depositing a conductive silver layer on the surface of the micron-sized copper powder by utilizing a chemical reduction reaction, preparing silver-coated copper powder, and preparing the conductive slurry by utilizing the silver-coated copper powder, The mass fraction of the brightening modifier in the first mixed solution is any value of 5-10wt%, the mass fraction of the chelating agent in the second mixed solution is any value of 15-30wt%, and the preset mass fraction is any value of 4-8wt%.
  2. 2. The method for producing a conductive paste for solar cells according to claim 1, wherein, The reaction temperature of the preset reaction condition is any value of 60-90 ℃ and the reaction time is any value of 1-5 h.
  3. 3. The method for producing a conductive paste for solar cells according to claim 2, wherein, The stirring speed of the seed-induced chemical reduction reaction is any value from 80rpm/min to 90 rpm/min.
  4. 4. The method for producing a conductive paste for solar cells according to claim 3, wherein, The chelating agent is at least one of ethylenediamine, ethylenediamine tetraacetic acid or citric acid.
  5. 5. The method for producing a conductive paste for a solar cell according to claim 4, wherein, The brightening modifier is at least one of polyethylene glycol, polyethylenimine, 2' -bipyridine, phenanthroline, cetyltrimethylammonium bromide, sodium dodecyl sulfate and polyacrylic acid.
  6. 6. The method for producing a conductive paste for a solar cell according to claim 5, wherein, The preset volume ratio is any value of 2:1-3:1.
  7. 7. The method for producing a conductive paste for solar cells according to any one of claims 1 to 6, wherein, The copper source is at least one of pentahydrate copper sulfate, anhydrous copper sulfate, hexahydrate copper nitrate or copper nitrate.
  8. 8. The method for producing a conductive paste for solar cells according to claim 7, wherein, The dispersing agent is a mixture of polyvinylpyrrolidone and beta-cyclodextrin, and the mass ratio of the polyvinylpyrrolidone to the beta-cyclodextrin is any value of (10-1): 1.
  9. 9. The method for producing a conductive paste for solar cells according to claim 8, wherein, The sedimentation cooling treatment time is any one value of 6-24 h, the drying treatment temperature is any one value of 50-80 ℃, and the drying time is any one value of 2-8 h.
  10. 10. The method for producing a conductive paste for solar cells according to claim 9, wherein, The reducing agent is at least one of sodium hypophosphite, ascorbic acid, hydrazine hydrate or formaldehyde, and the mass ratio of the reducing agent to the solvent is 1 (4-10).

Description

Preparation method of conductive paste for solar cell Technical Field The invention relates to the technical field of solar cell preparation, in particular to a preparation method of conductive paste for a solar cell. Background With the rapid development of the photovoltaic industry, the market demand for conductive paste for solar cells continues to increase. Silver powder is always the main conductive material of the photovoltaic slurry due to the excellent conductivity, but silver is high in price, so that the slurry cost is high. In order to reduce the cost and maintain good conductivity, the silver-coated copper powder is an ideal material for replacing pure silver powder due to a core-shell structure with cheap copper as a core and a silver layer coated on the surface, and has wide application prospect in the field of photovoltaic slurry. The properties of silver-coated copper powder depend to a large extent on the particle size and morphology of the core copper powder. The photovoltaic slurry has extremely strict requirements on copper powder, the particle size distribution needs to be highly concentrated, the D50 is generally required to be 3-5 mu m, the D10 is more than 2 mu m, and the D90 is not more than 8 mu m. Too fine particles tend to cause unstable coating of silver shell, unstable viscosity of paste and poor printing performance, while too coarse particles affect ink permeability of paste and forming ability of grid lines. Thus, obtaining micron-sized copper powder with concentrated particle size distribution is a key to preparing high-performance conductive paste. Currently, the dominant methods of industrially producing copper powder are physical methods, including physical vapor deposition and atomization. Although the method has the advantages of large yield, high purity and good sphericity, the randomness of nucleation and growth is involved in the preparation process, so that the particle size distribution of the obtained copper powder is wider, and the narrow-distribution copper powder meeting the requirements of photovoltaic slurry is difficult to obtain, so that a large amount of copper powder needs to be removed by screening, and the yield is reduced and the production cost is increased. In order to solve the problems, the prior art usually adopts mechanical screening, ball milling modification or chemical hydrothermal treatment to regulate and control the particle size, but the mechanical screening is difficult to fundamentally improve the particle size distribution, the ball milling treatment is easy to introduce impurities and has limited particle size control, while the hydrothermal method can improve the distribution but needs high temperature and high pressure conditions, and has complex process and higher energy consumption. In addition, the existing chemical reduction method generally uses copper ions as a starting material, and it is difficult to efficiently regulate and utilize the existing copper powder by a physical method. Meanwhile, in the design of a reduction system and a complexing system in the prior art, a reducing agent and a chelating agent are often directly mixed, so that the reduction process and the complexing regulation process are coupled, the release and reduction of copper ions are difficult to precisely control, instantaneous nucleation and particle aggregation are easy to generate, the defects in the aspect of cooperative regulation of a dispersing agent and other functional components exist, and the fine control of the reaction process is difficult to realize. Disclosure of Invention The invention aims to provide a preparation method of conductive paste for a solar cell, which solves the technical problems that in the prior art, the particle size distribution of copper powder prepared by a physical method is wide, and copper powder with narrow particle size distribution meeting the requirements of photovoltaic paste in high proportion is difficult to obtain, so that the material yield is low, the resource utilization rate is low and the production cost is high. Another object of the invention is to obtain copper powder materials with concentrated particle size distribution, uniform morphology and compact structure. According to the purpose of the invention, the invention provides a preparation method of conductive paste for a solar cell, which comprises the following steps: Adding a copper source, a surfactant, a dispersing agent and a brightening modifier into a solvent, and stirring to obtain a first mixed solution; adding a reducing agent and a chelating agent into the solvent, and stirring to obtain a second mixed solution; mixing the first mixed solution and the second mixed solution according to a preset volume ratio to obtain a third mixed solution, and adding seed copper powder with a preset mass fraction into the third mixed solution to perform seed-induced chemical reduction reaction under a preset reaction condition, wherein the particle