A method and system for time-sharing ablation of solar cell dielectric film by multi-wavelength laser

Abstract

The invention provides a method and system for time-sharing ablation of solar cell dielectric films by multi-wavelength lasers. At least two coaxial lasers of different wavelengths are used to sequentially ablate solar cell dielectric films in time-sharing. In one cycle, each laser The light is emitted once in turn according to a certain light emission time interval, so that the spots formed by all lasers in this period overlap; the energy density of each laser is higher than the damage threshold of the corresponding ablation material, and the wavelength of each laser is smaller than the cut-off of the corresponding ablation material Absorb wavelength. The present invention adopts a multi-wavelength method, first using a wavelength of laser to destroy the passivation layer on the surface of the cell, reducing its reflection on the next wavelength of laser, which can better exert the ablation ability of the next wavelength of laser, thereby increasing the processing speed. Therefore, the efficiency and production capacity are improved under the synergistic effect of the two wavelength lasers.

Description

technical field [0001] The invention belongs to the technical field of photovoltaics, and in particular relates to a method and a system for time-sharing ablation of a solar cell dielectric film by a multi-wavelength laser. Background technique [0002] In the process of high-efficiency crystalline silicon cells, different dielectric layers are often used as passivation films or anti-reflection films to passivate the surface interface states of silicon wafers, reduce surface recombination, and improve cell conversion efficiency. At the same time, the passivation film is often used as a masking layer to block diffusion and form different diffusion regions or metal contact regions. Laser ablation technology is widely used due to its advantages of simplified process, low cost of use, flexible operation, safety and stability. However, for a specific dielectric layer, the ablation effect of a single-wavelength laser is limited. [0003] For example, the back passivation film la...

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Problems solved by technology

Among them, the 808-1064nm laser has a longer wavelength and better penetration, which can take into account both optical absorption and penetration depth, but the heat has a greater impact during processing, and the damage is more serious, which affects the electrical performance of the battery and increases the risk of solar cell cracks; 355nm-532nm laser The processing heat has little impact, but it is easy to be reflected by the passivation layer on the surface of the cell, resulting in energy loss, resulting in incomplete ablation, affecting the subsequent metallization process, and affecting electrical performance

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