Back electric field structure of MWT solar cell and manufacturing method of back electric field structure

Abstract

The invention discloses a back electric field structure of an MWT solar cell. The back electric field structure comprises a front silicon nitride film, a silicon dioxide film, a PN junction, a siliconwafer, an aluminum oxide film and a back silicon nitride film which are all sequentially stacked from top to bottom; the front surface of the silicon wafer is provided with positive electrode silvergrid lines and a through hole electrode front surface; the back surface of the silicon wafer is provided with an all-aluminum back surface field, a through hole electrode back surface and uniformly-distributed back electrodes; the all-aluminum back surface field is provided with aluminum grid line back surface fields; through hole isolation grooves are arranged between the aluminum grid line backsurface fields and a back surface through hole electrode. The invention discloses a manufacturing method of the back electric field of the MWT solar cell. The manufacturing method comprises the following steps of: laser drilling; texturing; diffusion; mask printing; etching; annealing; film coating ; back surface laser grooving; screen printing; and sintering. The design mode of combining the all-aluminum back surface field and the aluminum grid lines is realized on the back surface of the MWT cell in ingeniously; the consumption of Al metal slurry is reduced while conversion efficiency not influenced; the influence of Al metal powder residues on the through hole electrode is greatly avoided; and the safe, efficient and continuous operation of the MWT solar cell is ensured.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a back electric field structure of a MWT solar cell and a manufacturing method thereof. Background technique [0002] According to data, it is a technical challenge that the photovoltaic industry has been facing to achieve higher conversion efficiency of crystalline silicon solar cells while reducing production costs. According to the basic structure and working process analysis of crystalline silicon solar cells, the technical factors affecting the conversion efficiency of crystalline silicon solar cells include three aspects: 1. Optical loss in the absorption process, referred to as optical loss; 2. Photoexcited electron space in the photoconversion process The recombination of hole pairs is referred to as recombination loss; 3. The loss in the current output process is referred to as electrical loss. The influencing factors of the optical loss include the shallow surface ...

AI Technical Summary

Problems solved by technology

[0005] The present invention mainly solves the original technical problems that Al metal consumption is large and through-hole electrodes are affected by Al metal, and provides a back electric field structure and manufacturing method of MWT solar cells, creating an all-aluminum back field and aluminum grid on the back of MWT cells. The design of the combination of wires reduces the consumption of Al metal paste without affecting the conversion efficiency, and the all-aluminum back field is designed as an aluminum grid line outside the isolation groove in the through-hole electrode area on the back of the battery, which reduces the number of through-hole electrodes. The area of ​​the Al back field outside the regional isolation groove greatly prevents Al metal powder residue from affecting the through-hole electrodes, ensuring the safe and efficient continuous operation of MWT solar cells

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