Solar Cell Laser Trench Passivation During Cutting
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Solution Overview
Problem
Existing solar cell cutting processes result in exposed and unstable trenches due to incomplete coverage by protective layers, leading to material decomposition and potential short-circuits, increasing costs and reducing the service life of solar cells.
Innovation Solution
A solar cell cutting and passivation integrated processing method where a protective layer is applied before laser cutting, allowing the material to melt and infiltrate the trench during processing, eliminating the need for post-cutting protective layer application and reducing exposure time, while improving trench morphology and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is added after P3 laser processing to cover the trench, then the light absorption layer is protected from air exposure, but this requires an additional procedure that increases costs and the protective layer material has difficulty entering the trench completely
Solution Approach 1:
The protective layer is applied before laser cutting instead of after, allowing it to be present during the critical exposure period and eliminating the need for post-processing application steps
Solution Approach 2:
The protective layer material undergoes phase transition from solid to liquid during laser processing, enabling it to flow into and completely fill the structured trench, ensuring complete coverage and protection
2Manufacturing precision
If existing P3 cutting is performed to obtain the structured trench, then the back electrode layer is cut off, but edge collapse occurs at both side edges of the trench making the edges rough
Solution Approach 1:
The protective layer material melts during laser processing and flows into the trench, filling edge defects and collapse, thereby repairing the trench edges and achieving smooth, flat surfaces
Solution Approach 2:
The protective layer is applied beforehand to cushion and support the trench edges during laser cutting, preventing edge collapse before it occurs
3Productivity
If the light absorption layer is directly exposed to air after P3 cutting, then no additional protective layer procedure is needed, but the exposed light absorption layer reacts with air ingredients causing decomposition and reducing service life
Solution Approach 1:
The protective layer is applied in advance before laser cutting, ensuring protection is in place during and after the process without requiring post-processing steps, thus maintaining high productivity while ensuring reliability
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
This method reduces production costs and time, enhances trench coverage, prevents edge collapse, and extends the service life of solar cells by ensuring complete protection of the light absorption layer and preventing impurities from entering the trench.
Implementation Method 1
A material of the protective layer is partially molten due to a localized high temperature generated by the laser processing in a laser structured cutting process
Implementation Method 2
A material of the protective layer is partially molten due to a localized high temperature generated by the laser processing
Implementation Method 3
A material of the protective layer is partially molten due to a localized high temperature generated by the laser processing in a laser structured cutting process and infiltrates into an underlying corresponding structured trench
Data Source
AI summary
Disclosed are a solar cell cutting and passivation integrated processing method and a solar cell prepared using the method. The solar cell includes a substrate (1), a front electrode layer (2), a light absorption layer (3) and a back electrode layer (4) from bottom to top. Before laser structured cutting is performed for the back electrode layer (4), a protective layer (5) is disposed on a surface of the back electrode layer (4), and then laser structured cutting is performed for the back electrode layer (4), or the back electrode layer (4) and the light absorption layer (3) simultaneously through the protective layer (5) to obtain a corresponding structured trench (P3) while the protective layer (5) is kept from being cut by laser, and a material of the protective layer (5) is partially molten due to a localized high temperature generated by the laser processing in a laser structured cutting process and infiltrates into an underlying corresponding structured trench (P3). In this method, at the time of performing laser cutting processing, passivation is performed for newly-processed trench at the same time, reducing production costs, saving processing time. Further, the trench edges after cutting are repaired to improve the morphology of the processed trench, improving the stability of the cell and extending the service life of the cell.