A laser-induced bifacial localized tunneling oxidation passivation cell and its fabrication method

By applying laser-induced technology to remove the poly layer on the front and back of the TOPCon battery to form an oxide layer, the problem of achieving a passivation structure on the front of the TOPCon battery is solved, improving battery efficiency and simplifying the process.

CN118571982BActive Publication Date: 2025-10-31SHANXI ZHONGLAI PHOTOVOLTAIC BATTERY TECH CO LTD
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Patent Information

Application Number
CN202410685441.3
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2024-05-30
Publication Date
2025-10-31
Estimated Expiration
2044-05-30

AI Technical Summary

Technical Problem

Existing TOPCon batteries cannot use passivation structures on the front side due to their complex and costly manufacturing process, and their efficiency on the back side is affected by parasitic light absorption in the poly layer, which cannot meet the market demand for bifacial batteries.

Method used

Laser-induced oxidation technology was used to remove poly in the p+poly non-gateway region on the front side of the battery and to thin the poly in the n+poly non-gateway region on the back side. Combined with LIO technology, TOPCon passivation structures were prepared on the front and back sides. An oxide layer was formed at the Si/SiO interface by laser-induced oxidation to reduce light absorption and improve passivation capability.

Benefits of technology

It significantly improves open-circuit voltage (Voc) and short-circuit current (Isc), thereby enhancing battery efficiency, simplifying the process, and reducing costs.

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Abstract

This invention provides a laser-induced bifacial localized tunneling oxide passivation solar cell and its fabrication method, comprising a silicon wafer substrate, front / back silicon nitride layers, and front / back metal electrodes. On the front side of the silicon wafer substrate, a front tunneling oxide layer and a p+poly layer are sequentially disposed from the inside out, with a front LIO etched groove array formed on the surface of the p+poly layer. On the back side, a back tunneling oxide layer and an n+poly layer are sequentially disposed from the inside out, with a back LIO etched groove array formed on the surface of the n+poly layer. This invention utilizes LIO technology to remove poly in the non-gateway p+poly region on the front side of the cell. A TOPCon passivation structure can also be used on the front side with a simple process, significantly improving the open-circuit voltage Voc. Furthermore, LIO technology is used again to thin the poly in the non-gateway n+poly region on the back side of the cell, reducing parasitic light absorption, increasing the short-circuit current Isc, and improving cell efficiency.
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