TOPCon Battery Substrate Repair for Low-Damage Double-Sided Electroplating
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Solution Overview
Problem
The traditional laser grooving method for double-sided electroplated TOPCon solar cells causes damage to the silicon substrate, leading to open circuit voltage loss and reduced conversion efficiency.
Innovation Solution
A method involving thermal repair treatment and double-sided light injection is applied to the silicon matrix of TOPCon solar cells, followed by laser grooving using a top-hat beam laser, to minimize substrate damage and enhance the quality of PN junctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser grooving is performed on the front side to remove silicon nitride film, then the electroplating process can be carried out, but the silicon substrate is damaged and open circuit voltage is lost
Solution Approach 1:
The patent applies preliminary thermal field treatment before laser grooving to prepare the silicon substrate. This pre-treatment modifies the substrate's thermal and structural properties, making it more resistant to damage during subsequent laser grooving, thus preventing PN junction destruction while still enabling electroplating
Solution Approach 2:
The patent introduces a cushioning mechanism by applying thermal field treatment that creates a protective state in the silicon substrate before laser grooving. This pre-conditioning reduces the impact of laser energy on the substrate, cushioning against potential damage to the PN junctions while allowing necessary film removal for electroplating
2Ease of manufacture
If laser grooving is performed on the texturing surface, then the silicon nitride film is removed, but the pyramid structure is damaged reducing conversion efficiency
Solution Approach 1:
The patent applies preliminary thermal field treatment to the texturing surface before laser grooving. This pre-treatment prepares the pyramid structure to withstand laser exposure, enabling film removal while preserving the light-trapping geometry that is critical for high conversion efficiency
3Device complexity
If traditional screen printing process is used, then the manufacturing process is simple, but the height-width ratio of front finger cannot be improved and production cost is high
Solution Approach 1:
The patent replaces the mechanical screen printing process with a combination of thermal field treatment and laser grooving followed by electroplating. This substitution enables precise control of finger geometry (height-width ratio) while reducing silver paste consumption and production costs, despite increased process steps
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method improves the open circuit voltage by 4-10 mV and increases the photoelectric conversion efficiency by 0.2-0.8% after horizontal double-sided electroplating.
Implementation Method 1
applying thermal repair treatment to the silicon matrix
Implementation Method 2
performing light injection treatment on the front side and the back side of the silicon matrix
Implementation Method 3
laser grooving using a top-hat beam laser
Data Source
AI summary
A method for preparing TOPCon battery substrate and double-sided electroplated TOPcon battery prepared therefrom are provided. The method includes: providing a double-sided grooved silicon matrix of a TOPCon battery; carrying out thermal repair treatment on the silicon matrix; respectively carrying out light injection treatment on the front side and the back side of the silicon matrix after thermal repair treatment, thereby the TOPCon battery substrate is obtained. Thermal repair treatment can greatly increase the overall lattice thermal motion of the silicon substrate, and light is injected into the front side and the back side in the directions of two different light incidence surfaces, so that both the front side and the back side can absorb light, thereby repairing the defects at the interface between the amorphous silicon and the silicon wafer and improving the quality of the PN junctions.