Flexible Photovoltaic Apparatus Multi-Layered Substrate
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Solution Overview
Problem
High temperatures during the deposition process for flexible photovoltaic apparatuses using polyimide substrates can reduce the elastic modulus of the substrate, leading to softness and increased risk of cracks in the absorber and metallic back contact layers, making it difficult to form reliable photovoltaic devices.
Innovation Solution
A multi-layered substrate with a polymer base layer and additional metallic layers on both sides is used to enhance the elastic modulus and mechanical strength, preventing cracks and deformations during high-temperature processing and handling, while also serving as a moisture barrier to improve device reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperatures are used during deposition to facilitate precursor element deposition onto polyimide substrate, then deposition efficiency is improved, but the elastic modulus of the polyimide substrate is reduced causing softness and potential cracking
Solution Approach 1:
The patent employs a multi-layered composite substrate structure consisting of a polyimide base layer combined with metallic layers (such as stainless steel, aluminum, or titanium). This composite structure allows the polyimide to provide flexibility and formability while the metallic layers contribute high elastic modulus and thermal stability, enabling the substrate to withstand high-temperature deposition processes without excessive softening or cracking.
Solution Approach 2:
The patent modifies the substrate's physical parameters by introducing metallic layers that have different thermal properties compared to pure polyimide. These metallic layers maintain dimensional stability and elastic modulus at deposition temperatures (300-500°C), thereby changing the overall thermal-mechanical parameters of the substrate system to accommodate high-temperature processing.
2Ease of manufacture
If polyimide substrate is used to provide flexibility and durability, then ease of manufacture is improved, but crack resistance during high-temperature processing deteriorates
Solution Approach 1:
The patent creates a composite substrate system where the polyimide base layer provides flexibility, durability, and ease of handling, while integrated metallic layers provide crack resistance and structural integrity during high-temperature deposition and subsequent processing steps.
Solution Approach 2:
The metallic layers are deposited onto the polyimide substrate beforehand to create a protective framework that cushions and prevents crack propagation in the absorber layer and metallic back contact during high-temperature processing and mechanical handling.
3Productivity
If thin-film photovoltaic layers are deposited on flexible substrate to enable roll-to-roll processing, then productivity is improved, but manufacturing precision deteriorates due to substrate softness at high temperatures
Solution Approach 1:
The multi-layered composite substrate maintains the flexibility needed for roll-to-roll processing while the metallic layers provide dimensional stability and rigidity at deposition temperatures, ensuring precise alignment of photovoltaic layers during manufacturing.
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 multi-layered substrate design increases the elastic modulus of the polymer base layer at high temperatures, reducing crack formation and deformation, thereby enhancing the yield, lifetime, and efficiency of the photovoltaic module by maintaining alignment and preventing shunts during processing and use.
Implementation Method 1
The metallic layers can include any suitable combination of metals, metal alloys, and metallic nitrides, and can be deposited using any suitable deposition technique. In one embodiment, the metallic layers increase the elastic modulus of the polymer base layer at high temperatures.
Implementation Method 2
The multi-layered substrate also acts as a moisture barrier to prevent water from getting into the photovoltaic module, which can further degrade the module's performance.
Data Source
AI summary
Embodiments of the present disclosure generally relate to flexible photovoltaic modules that include a multi-layered substrate. In some embodiments, the multi-layered substrate includes one or more layers that are configured to improve the elastic modulus, rigidity, or stiffness of a flexible substrate of a flexible photovoltaic module during a deposition process step at an elevated temperature that is used to form the flexible photovoltaic module. The one or more layers of the multi-layered substrate may also provide improved barrier properties that prevent environmental contaminants from affecting the performance of a formed photovoltaic module, which includes the multi-layered substrate, during normal operation.