Preparation method for high open-circuit voltage polycrystalline solar cells

Abstract

The invention relates to a preparation method for high open-circuit voltage polycrystalline solar cells. A temperature-variable deposition high-temperature knot pushing technology is adopted in the diffusion process, and the dense grid design of 90 fine grids is adopted by positive pole printing patterns during the positive-pole printing process. The temperature-variable deposition is the process of increasing the temperature to 860 DEG C, temperature-variable deposition for 10 min is conducted on a silicon wafer during the temperature-increasing process, the mixture gas of large N2, O2 and small N2 is led in, and the proportion, by volume, of the small N2 is 7%; the high-temperature knotting pushing process is that the temperature is kept at 860 DEG C stably, the small N2 is stopped being led in, the large N2 and the O2 are led in for impurity re-distribution, the time is controlled to be within 17 min, and the proportion, by volume, of the O2 is 15%. The preparation method enables the square resistance of the silicon wafer to be from 90omega/sq to 95omega/sq, and compared with one-time constant-temperature deposition diffusion, the polycrystalline solar cells produced under the situation that the cost is not increased can obtain the higher open-circuit voltage.

Description

technical field [0001] The invention belongs to the technical field of polycrystalline silicon solar cells, in particular to a method for preparing polycrystalline solar cells with high open circuit voltage. Background technique [0002] The production process of traditional polycrystalline solar cells mainly includes: texturing, diffusion, wet etching, PE coating, drying, printing back field, drying, printing back electrode, printing positive electrode, sintering and test sorting. The diffusion process directly affects the open circuit voltage of polycrystalline solar cells, and its main influencing factor is the diffusion concentration. Polycrystalline solar cells require a certain diffusion concentration to ensure that the loss caused by the resistance caused by the lateral transport of carriers is small. A high doping concentration will greatly reduce the lifetime of minority carriers, and too deep a junction will increase the recombination loss of minority carriers in t...

AI Technical Summary

Problems solved by technology

Due to the high doping concentration, the lifetime of minority carriers will be greatly reduced, and too deep junction will increase the recombination loss of minority carriers in the process of diffusing to the PN junction.

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