Back passivation matrix dot type laser grooving conductive structure

Abstract

The invention discloses a back passivation matrix dot type laser grooving conductive structure. The structure comprises a silicon wafer substrate, wherein the back face of the silicon wafer substrateis provided with lamination back passivation film, and back electrode main gate regions are arranged at intervals on the lamination back passivation film; laser grooving is carried out on non-back electrode main gate regions on the lamination back passivation film through a lamination back passivation film in a wave band of 500-1200 nanometers to from a repeating dot group structure unit, whereinthe repeating point group structure unit is composed of 2-18 circular-aperture-shaped laser spots overlapping 3%-17% of a circular area region, and the intervals of center points of the repeating point group structure unit are 0.2-1.0 millimeters. The laser grooving conductive structure has the advantage that a back conduction plane can be divided into smaller conductive structure units, so that the photo-generated current conduction path is shortened, the transmission collecting capacity of current carriers is improved, lattice damage and composite damage of the battery silicon wafer substrate caused by the laser grooving can be reduced, and the photovoltaic conversion efficiency and assembly reliability of single polycrystalline silicon back passivation local back contact solar cell areimproved.

Description

technical field [0001] The invention relates to the technical field of backside passivation of silicon wafers, in particular to a backside passivation matrix dot-type laser slotted conductive structure. Background technique [0002] The main efficiency range of conventional single polycrystalline silicon solar cells is 18.6-20.3%. In order to further improve the photoelectric conversion efficiency of crystalline silicon cells, a passivation layer is added on the back of the cell. The efficiency of the battery is increased to 19.3-21.7%, and the corresponding component power generation output power is also greatly improved. [0003] Compared with the conventional single polycrystalline cell process, the backside passivation localized back contact single polycrystalline cell mainly adds three processes: backside passivation, backside SiNx film deposition and laser drilling and slotting. Among them, the laser drilling and grooving process uses a laser with a certain pulse widt...

AI Technical Summary

Problems solved by technology

[0008] The diameter of the round hole-shaped spot of the laser groove is too small, and the particle size of the Al powder that burns through the aluminum paste on the back passivation layer is generally 4-12um, and the mixing volume of the organic carrier, inorganic adhesive and additive is too large , the laser grooved area that cannot completely fill a single circular hole-like spot is easily formed after the slurry is dried and sintered in the later stage. The contact cavity 7 between the conductive aluminum paste 6 and the silicon wafer substrate 1 on the back, as shown in the attached manual Figure 5 As shown, the export of photo-generated carriers generated in the PN junction region is limited, and the conduction resistance increases, which is not conducive to the collection of photo-generated carriers in the direction of the back plane, and will not form a complete local aluminum back field structure.

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