Composite Insulating Coated Steel Plate for Laser-Scribed PV Modules
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Solution Overview
Problem
Existing insulating film systems on metal substrates are not compatible with inline thin-film photovoltaic modules, particularly due to issues with thermal expansion mismatch, corrosion resistance, and laser scribing processes, which affect the performance and reliability of thin-film photovoltaic cells.
Innovation Solution
A coated steel plate with a composite insulating layer comprising a steel substrate and a layer structure that includes a SiO2 insulating base layer and a Si3N4 laser scribing buffer layer, optimized with specific stoichiometric ratios and metal doping to provide high temperature resistance, corrosion resistance, and effective laser energy absorption, thereby preventing short circuits and maintaining insulation during the laser scribing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer insulating film is used on metal substrate, then the structure is simple and manufacturing is easy, but the film develops pinholes during coating process compromising insulation function
Solution Approach 1:
The patent divides the single-layer insulating film into multiple layers (first insulating layer and second insulating layer) to eliminate pinholes. The first insulating layer is coated on the metal substrate, and the second insulating layer is coated on the first insulating layer, creating a multi-layer structure that prevents pinhole formation while maintaining manufacturing simplicity.
2Adaptability or versatility
If polymer substrates are used for thin-film photovoltaic cells, then flexibility is improved, but heat resistance is insufficient (max 400°C) causing thermal decomposition and contamination
Solution Approach 1:
The patent uses a composite structure combining metal substrate (steel or aluminum alloy) with insulating film layers. The metal substrate provides high heat resistance (steel: 1400-1668°C, aluminum alloy: 660°C) while maintaining flexibility through thin-film deposition, eliminating thermal decomposition issues of polymer substrates.
3Ease of manufacture
If aluminum or aluminum alloy substrates are used, then cost is reduced, but thermal expansion coefficient mismatch (20-30×10−6K−1 vs 8-15×10−6K−1) causes film cracking and adhesion failure
Solution Approach 1:
The patent changes the substrate material parameter from aluminum/aluminum alloy to steel, which has a thermal expansion coefficient (10-12×10−6K−1) closer to the semiconductor light absorption layer (8-15×10−6K−1). This parameter change reduces thermal expansion mismatch, preventing film cracking and adhesion failure while maintaining cost-effectiveness.
4Ease of manufacture
If existing insulating film systems are used on metal substrates, then manufacturing is simplified, but compatibility with laser scribing process is poor causing damage to insulating properties
Solution Approach 1:
The patent applies preliminary action by designing the insulating film system with specific material composition and layer structure before the laser scribing process. The first insulating layer uses materials with high laser damage threshold and appropriate absorption characteristics, preventing laser-induced damage during subsequent scribing operations and preserving insulating properties.
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 solution ensures stable heat resistance, excellent insulation performance, and compatibility with laser scribing, enhancing the reliability and efficiency of thin-film photovoltaic modules by preventing thermal expansion issues and maintaining insulation integrity.
Implementation Method 1
the laser scribing buffer layer contains at least one of the following components: SixNy... and Si1-x′(R)x′Oy′... which provide high temperature resistance and absorb laser energy during the scribing process
Implementation Method 2
the substrate typically needs to be held at a temperature of 500-650° C. for 2-30 minutes... alternative substrate materials must have heat resistance to temperatures above 500° C.
Data Source
AI summary
The present invention provides a coated steel plate suitable for an inline thin-film photovoltaic module, comprising a steel substrate and a composite insulating layer on the surface of the steel substrate. The composite insulating layer comprises an insulating base layer and a laser scribing buffer layer; one side of the insulating base layer is the steel substrate, and the other side is the laser scribing buffer layer. The laser scribing buffer layer contains at least one of the following components: SixNy, where 0.75≤x:y≤1; and Si1-x′(R)x′Oy′, where R is an element selected from Sb, Au, Cu, Sn, and Ag, and 0<x′≤0.05, 1.9≤y′≤2. Since the silicon nitride and the doped silicon dioxide used in the laser scribing buffer layer can exhibit specific colors, part of the energy of the laser can be absorbed during the laser etching process, and the damage and the loss of insulation of the insulating base layer during etching can be avoided, thereby ensuring that the coated steel plate for inline thin-film photovoltaic modules provided by the present invention has stable working performance. Additionally, the present invention further discloses a method for manufacturing the aforementioned coated steel plate.