All-Black Crystalline Silicon Solar Cell Coating for Edge Blue Control
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Solution Overview
Problem
Existing methods for producing all-black crystalline silicon solar cells face limitations in achieving a uniform black appearance and high conversion efficiency due to inadequate control of refractive indices and deposition processes, particularly with the SiOx layer and lack of consideration for edge effects during back PECVD.
Innovation Solution
A method involving a PECVD-deposited film layer with a specific innermost SiNx layer thickness and refractive index, combined with a gradient linewidth screen printing process to ensure uniform black appearance and high conversion efficiency, addressing the limitations of existing technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional PECVD process is used to deposit the SiOx layer, then the deposition is simple, but the refractive index control is insufficient and edge blue effects occur
Solution Approach 1:
The deposition process is segmented into multiple distinct steps: first depositing the SiNx layer, then depositing the SiOx layer, followed by a specific heating treatment. This segmentation allows precise control of each layer's properties and the interface between layers, resolving the refractive index control issue while managing process complexity through structured methodology.
Solution Approach 2:
The patent applies parameter changes by controlling the heating temperature and duration during the deposition process. By adjusting these parameters, the refractive index of the SiOx layer is precisely controlled to prevent edge blue effects, while the multi-step process manages complexity through controlled parameter variation rather than simple one-step deposition.
2Illumination intensity
If the SiOx layer thickness is increased to improve black appearance, then reflectivity decreases, but conversion efficiency is reduced
Solution Approach 1:
The patent employs a composite structure combining SiNx and SiOx layers with specific thicknesses and refractive indices. This composite material approach allows optimization of both light absorption and conversion efficiency by leveraging the complementary properties of the two materials, achieving the desired black appearance without sacrificing power conversion.
Solution Approach 2:
By precisely controlling the thickness parameters of each layer and the heating treatment parameters, the patent optimizes the balance between light absorption and conversion efficiency. The specific parameter values are selected to achieve maximum performance, resolving the contradiction between appearance and functionality.
3Manufacturing precision
If back PECVD is performed without gradient linewidth screen, then manufacturing is simpler, but color uniformity and black appearance are compromised
Solution Approach 1:
The gradient linewidth screen applies local quality by having different linewidths at different positions during screen printing. This creates localized variations in the deposited material thickness and refractive index, which compensates for edge effects and ensures uniform black appearance across the entire cell surface, resolving the color uniformity issue.
Solution Approach 2:
The gradient linewidth screen changes the printing parameters (linewidth) across different regions of the cell. By adjusting this parameter spatially, the patent achieves uniform color and black appearance while managing manufacturing complexity through a systematic parameter variation approach rather than requiring complex multi-step processes.
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 achieves an all-black crystalline silicon solar cell with high conversion performance and uniform black appearance, resolving issues of edge blue effects and color inconsistencies.
Implementation Method 1
depositing a film layer on the front surface of a silicon wafer by a PECVD method
Implementation Method 2
the absorption and reflection effect of the incident light on the surface of the cell are affected, and almost all of the incident light is absorbed
Implementation Method 3
a method of the screen printing in step (3) comprises: after loading and grooving the wafer, performing a first printing and drying
Data Source
Figure 1~2
AI summary
Disclosed in the present invention are an all-black crystalline silicon solar cell and a preparation method therefor, and a photovoltaic module. The preparation method comprises the following steps: (1) depositing a film layer on the front face of a silicon wafer by means of a PECVD method so as to obtain a silicon wafer having a coated front face, wherein the film layer is of a laminated structure and comprises an innermost SiNx layer having a thickness of 20 nm or more; (2) subjecting the resulting silicon wafer having the coated front face to back-face PECVD and laser beam grooving so as to obtain a coarse silicon solar cell; and (3) subjecting the resulting coarse silicon solar cell to silk-screen printing and electron injection to then obtain an all-black crystalline silicon solar cell. In the preparation method provided in the present application, the film layer is deposited on the front face of the silicon wafer by means of the PECVD method, the material and thickness of the innermost SiNx layer are designed, and particularly when the thickness thereof is 20 nm or more, the absorption and reflection effects of incident light on the surface of the cell are influenced, such that the incident light is almost completely absorbed, and only an extremely small amount of the incident light is reflected; therefore, the all-black crystalline silicon solar cell is obtained.