Method and system for multi-wavelength laser time-sharing ablation of solar cell dielectric film

Abstract

The invention provides a method and a system for multi-wavelength laser time-sharing ablation of a solar cell dielectric film. The method comprises the steps that at least two coaxial lasers with different wavelengths are adopted, the solar cell dielectric film is sequentially ablated in a time-sharing mode, in one period, each laser emits light one time in turn according to a certain light emitting time interval, and light spots formed by all the lasers in the period are overlapped; the energy density of each laser is higher than the damage threshold value of the corresponding ablation material, and the wavelength of each laser is smaller than the cut-off absorption wavelength of the corresponding ablation material. According to the invention, a multi-wavelength method is adopted, the surface passivation layer of the battery piece is damaged by utilizing the laser with one wavelength, the reflection of the laser to the laser with the next wavelength is reduced, and the ablation capability of the laser with the next wavelength can be better exerted, so that the processing speed is improved, and the efficiency and the productivity are improved under the synergistic effect of the twowavelength 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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