Inorganic adhesive for aluminum paste of silicon solar cells and preparation method thereof

Abstract

The invention provides inorganic adhesive for the aluminum paste of silicon solar cells and a preparation method thereof. The inorganic adhesive comprises the following components by the weight part: 10% to 20% of SiO2, 15% to 30% of B2O3, 5% to 15% of Al2O3, 15% to 35% of Bi2O3, 10% to 18% of ZrO2, 10% to 25% of ZnO and 1% to 8% of MoO with the total amount being 100%. The preparation method comprises the following steps: putting the components forming the inorganic solvent into a mixer to mix the components uniformly; loading the mixed components into a porcelain crucible and placing the porcelain crucible into a baking oven to be dried at the temperature of 120 to 150 DEG C for 3 to 5 hours; then, placing the porcelain crucible into a high-temperature furnace to melt at the temperature of 800 to 1,100 DEG C for melting for 1 to 2 hours; carrying out water-quenching and oven-drying; milling the components with a planetary ball mill until the particle size is lower than 10 mum; and oven-drying the components to obtain the final product of the inorganic adhesive. The glass powder has lower softening temperature and high adhesion when the aluminum paste prepared from the inorganic solvent is used for sintering, so that the aluminum powder layer can be firmly adhered to silicon chips; the expansion coefficient is lower after sintering; the bending degree of cell chips is lower; and the breakage rate is reduced.

Description

technical field [0001] The invention relates to crystalline silicon solar cells, in particular to an inorganic binder for aluminum paste of silicon solar cells and a preparation method thereof. Background technique [0002] In the preparation process of crystalline silicon solar cells, the aluminum paste is printed on the back of the silicon wafer, and after sintering, the aluminum back electric field electrode is formed on the back of the silicon wafer of the solar cell, which can reduce the contact resistance and improve the photoelectric conversion efficiency of the cell. [0003] Aluminum paste is mainly composed of aluminum powder, organic binder, inorganic binder and additives. Among them, the aluminum powder is a conductive phase, which forms a good ohmic contact with the silicon chip after sintering; among them, the organic binder is used as a carrier to make the aluminum powder, glass powder, additives and other solid powders in the aluminum paste easy to agglomerat...

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Problems solved by technology

Glass powder has the function of adjusting the sintering temperature of the aluminum paste. A higher softening point means that the sintering temperature of the aluminum paste is high, which may cause the breakdown of the p-n junction of some solar cells and increase the probability of solar cell failure.

[0006] (2) The aluminum paste is printed on the back of the silicon wafer, and after drying and firing, the expansion coefficient of the molten glass layer formed is high, and the expansion coefficient of the molten glass layer measured according to the GB / T 16920-1997 method is >6.0×10 -6 / ℃, and the expansion coefficient of the silicon substrate (about 3.5×10 -6 / °C) does not match, resulting in large bending of the battery sheet after sintering, which is easy to fragment, which is not conducive to the production of subsequent components

[0007] (3) There are few components in the glass powder component that can reduce the surface tension, the wettability is not good enough, the adhesion is low, and the peeling strength of the aluminum back electric field electrode is low, which will shorten the service life of the silicon solar cell

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