Conductive paste for solar cell and preparation method thereof

Abstract

The invention provides a conductive paste and a preparation method thereof. The conductive paste comprises aluminum powder, an inorganic binding agent, an organic carrier and metal-glass composite powder, wherein the metal-glass composite powder is of nano-particles and a core-shell structure, glass is used as a core material, and metal is used as a shell material. The conductive paste disclosed by the invention is good in storage stability and less prone to sedimentation and agglomeration, and the conductive paste is less prone to leakage from a screen during screen printing; after sintering, an aluminum film is smooth in surface and grey white, and has no aluminum vesicles or aluminum beads; and furthermore, the part in contact and superimposition with a back silver electrode, of the aluminum film is wiped by a non-dust cloth, and wiping traces and powder dropping can be avoided. The series resistance of the produced solar cell is reduced obviously, a filling factor is increased obviously, and the average photoelectric conversion efficiency of a monocrystalline silicon cell piece can be above 18.20%. Simultaneously, the conductive paste disclosed by the invention is good in construction performance, a film layer formed after sintering is compact, the sintering thickness is uniform, the bending of a silicon chip is small, the sheet resistance is small and the open circuit voltage (Voc) of the formed cell is high.

Description

technical field [0001] The invention belongs to the field of solar cells, in particular to a conductive paste for solar cells and a preparation method thereof. Background technique [0002] As a kind of green energy, solar energy has attracted more and more attention due to its advantages of inexhaustibility, no pollution, and no limitation of geographical resources. The back of the existing solar cell is an n-type region that can be formed on the back of the silicon wafer, so that the n-type silicon can be reversed into p-type silicon. Generally, an aluminum foil that reflects photons is formed by printing aluminum conductive paste on the back of the solar cell. A back electric field that collects current from the back of the cell. Then print silver conductive paste on the back electric field and the front of the solar cell respectively to form electrode wires, dry and sinter to prepare solar cell electrodes. [0003] Conductive aluminum paste belongs to one of the electr...

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Problems solved by technology

[0005] The present invention solves the phenomenon of leakage in the existing conductive paste, poor construction performance, unstable paste, and easy agglomeration and settlement. At the same time, the aluminum film in the back electric field of the solar cell has aluminum blisters, which overlap with the silicon substrate and the back silver electrode. Part of the problem exists powder drop phenomenon, and the photoelectric conversion efficiency of the cell is not ideal. To provide a kind of non-slipping phenomenon and the slurry is stable, not easy to agglomerate and settle, and the aluminum film of the back electric field of the solar cell prepared at the same time does not produce aluminum Blisters, perfect appearance, good scratch resistance on the part that overlaps with the silicon substrate and the back silver electrode, and a conductive paste for solar cells that improves the photoelectric conversion efficiency of the cell

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