Positive electrode silver paste for back passivation silicon solar cell and preparation method thereof

Abstract

The invention discloses positive electrode silver paste for a back passivation silicon solar cell and a preparation method thereof. The positive electrode silver paste comprises, in mass percent, 3%-15% of organic carriers, 80%-95% of silver powders and 1%-5% of inorganic glass materials. The inorganic glass materials are prepared by compounding Pb-V-Te glass and Bi-W-Si glass; and the silver powders are prepared by compounding first silver powders and second silver powders. Through introduction of nanometer silver powders, sintering activity of a silver powder system is improved, and compactness of silver grid lines under low-temperature sintering is improved; by adjusting softening temperature, viscosity and surface tension of the glass materials, liquidity and wetting ability of glass liquid are improved, etching capacity of the glass liquid to a front-surface antireflection layer is ensured and silver powder fusion and reprecipitation capability is improved; precipitation of silver nanometer colloid particles on the surface of a silicon wafer helps to promote the glass layer to form good ohmic contact with the silicon wafer, and thus conversion efficiency is improved; and through introduction of the second component glass powders, bonding strength between the glass layer and a silicon substrate is enhanced.

Description

technical field [0001] The invention relates to the field of electrode silver paste for silicon solar cells, in particular to a positive electrode silver paste for back passivated silicon solar cells (PERC) and a preparation method thereof. Background technique [0002] As a clean energy, solar energy plays an increasingly important role in the energy structure of human society. Compared with traditional fossil fuels, solar energy is inexhaustible and inexhaustible, and will not produce any environmental pollution during use. As a semiconductor device that uses solar energy to generate electricity, crystalline silicon solar cells are prepared by processes such as texturing, diffusion, etching, coating, printing electrodes, and sintering. Under the action, hole-electron pairs are formed, and under the influence of the built-in electric field, they flow to the p-region and n-region respectively, and a current is formed after the external load is connected. [0003] In recent...

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Problems solved by technology

[0005] The low-temperature sintering window of the mainstream front-side silver paste in the existing market is narrow, and lowering the sintering temperature will affect the etching effect of the glass frit in the paste on SiNx, the sintering quality of the silver wire and the formation of ohmic contact, which will eventually reduce the conversion efficiency

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