A method for optimizing surface passivation of tunnel oxide passivated cells

By using sulfur passivation treatment on the surface of TOPCon batteries, the problems of light absorption in the poly layer and escape of hydrogen passivator are solved, thus improving the passivation performance and efficiency of the batteries.

CN119584674BActive Publication Date: 2025-11-25SHANXI ZHONGLAI PHOTOVOLTAIC BATTERY TECH CO LTD
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Patent Information

Application Number
CN202411676593.3
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2024-11-22
Publication Date
2025-11-25
Estimated Expiration
2044-11-22

AI Technical Summary

Technical Problem

In existing TOPCon batteries, when the TOPCon structure is not fabricated on the front side, the parasitic light absorption of the poly layer leads to a reduction in photocurrent, which affects battery efficiency. Furthermore, the hydrogen passivator is prone to escape during long-term use, resulting in battery performance degradation.

Method used

Before the alumina film is prepared, the battery surface is passivated with sulfur. The silicon wafer surface is treated with (NH4)2S solution to form Si-S-Si bonds to passivate the dangling bonds and accumulate negative charges in the alumina passivation layer to supplement the hydrogen passivation effect.

Benefits of technology

It improves the passivation capability of the battery, reduces the dissipation of dangling bonds, and enhances the long-term performance stability and efficiency of the battery. The battery efficiency is improved by about 0.1%, and the PL brightness is increased by 2.92%.

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Abstract

The application provides a surface passivation treatment method for optimizing a tunneling oxide passivation battery, which comprises the following steps: in a BOE cleaning step, placing an annealed silicon wafer into a mixed solution of a tank cleaning device, cleaning the silicon wafer in the mixed solution for more than 120s, taking out the silicon wafer and cleaning the silicon wafer with sufficient DIW, then placing the silicon wafer into an acid solution, taking out the silicon wafer and cleaning the silicon wafer with a large amount of DIW, and bubbling in the cleaning process, and finally passivating the surface of the silicon wafer by using an (NH4)2S solution; and in a reflection reduction film manufacturing step, the reflection reduction film is divided into three layers for preparation. The application utilizes sulfur passivation of the P-type emitter of the battery, assists accumulation of negative charges of aluminum oxide to enhance the field passivation effect, passivates the silicon surface dangling bond, releases the process window reduction caused by the accumulation of [H] source for hydrogen passivation in the preparation process of silicon nitride, and reduces the performance attenuation caused by the escape of [H] in the long-term use of the battery assembly.
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