Preparation method of nano silver powder-containing low-temperature conductive silver paste for solar cell

Abstract

The invention discloses a preparation method of nano silver powder-containing low-temperature conductive silver paste for a solar cell, which comprises the following steps: weighing 60-82 parts by weight of nano silver powder, 8-10 parts by weight of epoxy resin, 1-3 parts by weight of curing agent, 0.5-1 part by weight of assistant, 1-6 parts by weight of diluent, 0.7-1.8 parts by weight of adhesion promoter, 0.4-1.4 parts by weight of anti-settling agent and 5-8 parts by weight of solvent; mixing epoxy resin, a curing agent and an auxiliary agent to prepare a precursor; silver powder is mixed with a diluent and a solvent, and silver paste is prepared; mixing the prepared precursor with silver paste, and mixing on a three-roller machine until the fineness of the paste is less than or equal to 3.5 microns to obtain a conductive silver paste coarse material; and adding an adhesion promoter and an anti-settling agent into the prepared conductive silver paste coarse material, and stirring and mixing to obtain a conductive silver paste finished product. The conductive silver paste prepared by the invention has extremely high conductivity, extremely high adhesive ability and outstanding hardness and bending resistance, meets the harsh requirements of use of the solar cell, and improves the photoelectric conversion rate of the solar cell.

Description

technical field [0001] The invention belongs to the technical field of preparation of solar cell electrode materials and conductive silver paste, more specifically, the invention relates to a preparation method of a low-temperature conductive silver paste for solar cells containing nano-silver powder. Background technique [0002] Conductive silver paste, also known as metallized electrode, is an important material for the production of solar cells. Conductive silver paste is usually adhered and cured by printing, vacuum evaporation, electroplating or spraying on the front and back of solar cells to form grid electrodes. A solar cell is a semiconductor device with a "photovoltaic effect". The PN junction of a solar cell generates voltage after being illuminated, that is, the semiconductor material converts light energy into electrical energy. The electric energy generated by the solar cell can only be used after the current is drawn out. Since the conductive silver paste has...

AI Technical Summary

Problems solved by technology

The shape of the silver powder is usually flake or spherical, and the flake silver powder is in contact with the surface or line, which can improve the conductivity of the conductive silver paste. The silver powder content of the conductive silver paste prepared by the general flake silver powder is 50-60wt%. Conductive silver paste with low silver content and high conductivity can be obtained, but the printing performance and bending resistance of the conductive silver paste prepared by flake silver powder will decrease accordingly; point contact between spherical silver powder can improve the rheology of silver paste, which is suitable for For solar panels that have higher requirements on mechanical properties such as printing characteristics and bending resistance, the disadvantage is that the electrical conductivity will decrease accordingly, so higher silver powder content is required. Generally, the silver powder content of this conductive silver paste reaches 60-83 %, at the same time, high silver powder content will also lead to an increase in the viscosity of the conductive silver paste, thereby affecting the printing adaptability of the conductive silver paste

Generally speaking, the smaller the particle size of the silver powder, the greater the fluctuation of the surface state, it is easy to agglomerate, and the dispersion performance becomes poor, which will also affect the conductivity of the conductive silver paste.