Production method for solar cell high-density monodisperse silver powder

Abstract

The invention discloses a production method for solar cell high-density monodisperse silver powder. According to the production method, glyoxal serves as a reducing agent for reducing silver nitrate, and glycolic acid and oxalic acid generated by glyoxal reaction serve as components of silver powder dispersing protective agents. While flow concurrence is performed in a reactor, a glyoxal solution, a sodium hydroxide solution and a silver nitrate solution are added into the reactor, and the molar ratio of the silver nitrate, the glyoxal and sodium hydroxide is controlled to be 1:0.25-0.35:1-1.4, the pH value of a reaction solution is kept at 8-10, the reaction temperature is kept at 20 DEG C-40 DEG C, after feed intake is finished, stirring and reacting are continued for 0.5 hour-1 hour, and therefore reaction is complete, and silver crystal grain crystallization is complete. Silver powder particles are approximately spherical, the surfaces are smooth and glossy, the particle size distribution is narrow, the average particle size is 1.2 micrometers-1.8 micrometers, the apparent density is 2.0 g / cm<3>-2.5 g / cm<3>, the tap density is 4.5 g / cm<3>-5.0 g / cm<3>, and the molar yield is 97-99.5%. The consumption of the reducing agent is small in the process of producing the silver powder, production cost is low, safe and environmentally friendly effects are achieved, the reaction condition is easy to control, product quality is stable, and industrialized application is easy.

Description

technical field [0001] The invention relates to a production method of high-density monodisperse silver powder for solar cells, in particular to a method for reducing silver nitrate by using glyoxal as a reducing agent, and using glycolic acid and oxalic acid, which are reaction products of glyoxal, as silver powder dispersing and protecting agent components. The invention discloses a production method of density monodisperse silver powder, which belongs to the field of new energy and new materials. Background technique [0002] Silver powder is an important part of the positive electrode paste of solar cells. Only the conductive paste prepared with silver powder that meets specific conditions can have good screen printing performance. After sintering, the front silver electrode with high square resistance and fine grid lines can be formed. . The front electrode is divided into a grid electrode line and a main electrode line. The grid line mainly collects carriers gener...

AI Technical Summary

Problems solved by technology

[0010] The shortcomings of the existing silver powder preparation technology are mainly: (1) the reducing agent hydrazine hydrate, formaldehyde and hydroquinone are toxic and highly irritating, and the problems of environmental protection and safety are difficult to solve; (2) the cost of sodium borohydride and hydroquinone reducing agent If it is too high, it will affect the production efficiency of silver powder; (3) the reducing agent ascorbic acid is sensitive to changes in system acidity, concentration and temperature, and the production conditions are not easy to control; (4) the reducing agent is too strong, and usually needs to be dispersed with a large number of polymers (5) The silver powder density of the product is too low and the particle size is unstable, and the particle size distribution range is too wide