The production of photovoltaics PV, batteries and other electrical components requires micro-nano metal powders, such as gold powder, silver powder and copper powder. These ultrafine metal powders are generally obtained by mechanical grinding or chemical synthesis. In the subsequent drying and transportation process, air flow crushing is required to prevent the ultrafine powder from agglomerating during pneumatic conveying and storage.
For example, PV silver paste is an indispensable core auxiliary material for the construction of solar cells, and its quality directly affects the performance of solar cells. PV silver paste is a formula product. Its main production raw materials include silver powder, resin bonding phase, solvent, additives, glass powder, etc. to form a formula together, which is also the key to preparing excellent paste. Among them, the silver powder content in silver paste accounts for the highest proportion, usually accounting for 80%~90%. Therefore, silver powder is also considered to be the most core material in silver paste.
The silver powder of solar cell conductive silver paste mainly includes spherical silver powder and flake silver powder. Generally speaking, spherical and quasi-spherical silver powders are often prepared by chemical synthesis, and flake silver powders are mainly prepared by mechanical ball milling. Spherical silver powder has a relatively uniform particle distribution, which can improve the light absorption and PV conversion efficiency of solar cells and has a wide range of applications in the production of solar cells. Spherical silver powder is mainly produced by liquid phase reduction method.
The ultrafine metal powder airflow crushing and collection system designed by our company consists of four parts: fluidized bed airflow crushing system, cyclone separator, metal film dust removal system, and induced fan. The fluidized bed airflow crushing system is designed with a material classification wheel. Silver powder with particle size that meets the requirements is discharged from the fluidized bed outlet. Silver powder with a particle size larger than the required value returns to the fluidized bed and is crushed again to ensure that the subsequent silver powder particle size meets the use requirements. The filter element used in the metal film dust removal system is a metal short fiber sintered filter element with high precision, large flux and good regeneration. The metal film dust removal system is designed with an online backflush function, which can backflush while working to ensure continuous operation of the system.
