Silver paste for solar cells and preparation method thereof

Abstract

The invention discloses a silver paste for solar cells. The silver paste consists of silver powder, lead-free glass powder and an organic carrier, the organic carrier consists of organic solvent and organic additive, the silver powder is spherical and / or flaky, and the grain sizes of the silver powder are coarse and fine; the lead-free glass powder adopts a lanthanum-boron-zinc glass system, and the components of the lead-free glass powder are La2O3, B2O3, Al2O3, ZnO, Na2O, LiO2, V2O5 and P2O5. A preparation method for the silver paste includes the following steps: after being uniformly mixed, the materials of the lead-free glass powder are put into a high-temperature muffle furnace to heat, the temperature is preserved, and the melted glass powder particles are quenched and then ball-milled; the organic solvent and the organic additive are uniformly mixed and stirred according to proportion; the silver powder, the lead-free glass powder and the organic carrier are weighed, uniformly stirred in a container, put into a three-roll mill and ball-milled, and thereby the uniform silver paste for the solar cells is prepared. Under the premise of meeting the electrical properties of the solar cells, the silver paste also can meet the requirement on lead-free environment-friendliness.

Description

technical field [0001] The invention relates to a silver paste, in particular to a silver paste for solar cells and a preparation method thereof. Background technique [0002] A solar cell is a semiconductor device that can convert solar energy into electrical energy. Under the condition of light, a photogenerated current will be generated inside the solar cell, and the electrical energy can be directly output through the electrodes. [0003] In order to draw out the photo-generated current generated by the solar cell, positive and negative electrodes must be made on the surface of the solar cell. Commonly used electrode manufacturing processes include magnetron sputtering, vacuum evaporation and screen printing sintering, etc., but the production costs of magnetron sputtering and vacuum evaporation methods are too high and the economy is poor. At present, lead-containing solar cell conductive silver paste is widely used in solar cell production enterprises, and electrodes ...

AI Technical Summary

Problems solved by technology

In addition, the particle size of the silver powder used in the existing silver paste is basically the same, so if the particle size of the silver powder is too large, cracks will appear in screen printing, and the contact resistance will increase. If the particle size of the silver powder is too small, the silver powder will appear. The problem of agglomeration affects the uniformity of its silver powder distribution