Front film layer structure capable of improving conversion efficiency of PERC battery and preparation method

Abstract

The invention discloses a front film layer structure capable of improving the conversion efficiency of a PERC battery. The front film layer structure comprises a silicon wafer, wherein the thickness of a first silicon nitride film is 10+ / -2nm and the refractive index is 2.67+ / -0.05; the thickness of a second silicon nitride film is 15+ / -2nm and the refractive index is 1.91+ / -0.05; the thickness ofa third silicon nitride film is 5+ / -2nm and the refractive index is 1.33+ / -0.05; and the thickness of a fourth silicon nitride film is 50+ / -3nm and the refractive index is 0.86+ / -0.05. The inventionfurther discloses a preparation method used for preparing the front film layer structure capable of improving the conversion efficiency of the PERC battery. The method comprises the following steps of(S1) silicon wafer pretreatment; (S2) preparation of the first silicon nitride film; (S3) preparation of the second silicon nitride film; (S4) preparation of the third silicon nitride film; and (S5)preparation of the fourth silicon nitride film. According to the film layer structure, short-wave response of the battery can be improved, light absorption of the battery can be improved, short-circuit current of the battery is increased, improvement of the photoelectric conversion efficiency of the battery is finally achieved and the target of improving the efficiency is achieved.

Description

technical field [0001] The invention relates to the technical field of photovoltaic cells, in particular to a front film structure and a preparation method for improving the conversion efficiency of PERC cells. Background technique [0002] With the continuous advancement of battery technology, the path to achieve high conversion efficiency has been pursued by industry researchers. At present, the conventional PERC battery process route is basically mature, but the front coating process based on the high square resistance process needs to be improved and optimized. The current PERC battery front coating method The conventional P-type aluminum back field (BSF) battery front coating method is adopted. [0003] For PERC batteries, the battery conversion efficiency is closely related to the structure of the front film layer. Different film layers, film thicknesses and film layer refractive indices all have an impact on the battery conversion efficiency. In the prior art, the app...

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Problems solved by technology

[0003] For PERC batteries, the battery conversion efficiency is closely related to the structure of the front film layer. Different film layers, film thicknesses and film layer refractive indices all have an impact on the battery conversion efficiency. In the prior art, the application number is " 2011101824819", the preparation method of double-layer silicon nitride anti-reflection film, the preparation method of a PERC battery front anti-reflection film with application number "2016111688207", the solar cell front film structure with application number "2013200124804", and the application number For the three-layer silicon nitride thin-film cell of "2017200134734", the PERC cell made of the front film structure of the above-mentioned cells has low diffusion resistance, deep junction depth, and poor short-wave response of the PERC cell. The short-circuit current and open-circuit voltage of the battery are both low, which cannot improve efficiency or reduce costs, and is a waste of resources

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