Silver paste for front surface of solar battery and preparation method of silver paste

The invention discloses silver paste for the front surface of a solar battery. The silver paste comprises the following components in percentage by weight: 78 to 90 percent of silver powder, 1 to 5 percent of glass powder, 7 to 15 percent of organic bonding agent and 0 to 3 percent of auxiliary agent, wherein the glass powder comprises SiO2, Al2O3, Bi2O3, ZnO, B2O3 and TeO2; the organic bonding agent comprises an organic carrier and an organic solvent. The invention also discloses a method for preparing the silver paste. The method comprises the following steps: weighing each component of the glass powder; performing heating and ball milling on each component to obtain the glass powder with the particle size of less than 5 mu m; mixing, heating, stirring and dissolving the organic bonding agent; adding the silver powder, the glass powder and the auxiliary agent into the organic bonding agent; rolling and grinding the mixture through a three-roller rolling machine until the particle size is less than 5 mu m and the viscosity is 290 to 380 Pa.S to obtain the paste. The silver paste produced by the method is good in printing effect, stable in performance and high in conversion rate; the depth-width ratio of a grid line is large after the silver paste is sintered.