Photovoltaic Backsheet Intermediate Film With Staged Resin Cross-Linking
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Solution Overview
Problem
The production process of photovoltaic modules is lengthy and complex due to the slow cross-linking process of resin layers in backsheets, which requires high temperatures and special cross-linking agents, leading to increased production times and costs.
Innovation Solution
The cross-linking process is divided into two sub-steps: partial cross-linking in the coating line ovens and completion during the lamination process, using blocked isocyanates that are activated by temperature, allowing for faster and more controlled cross-linking, and enabling the production of intermediate films that can be wound and stored before final lamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separate-layer lamination is used, then manufacturing complexity is reduced, but manufacturing precision and reliability deteriorate due to misalignment and delamination
Solution Approach 1:
The patent combines multiple separate functional layers (transparent adhesive layer, intermediate layer, and backsheet) into a single integrated intermediate film structure. This merging eliminates the need for separate lamination processes, thereby improving alignment precision while reducing overall process complexity despite the more complex integrated structure.
Solution Approach 2:
The intermediate film is pre-formed with all functional layers integrated before the lamination process. This preliminary integration of layers ensures precise alignment is maintained during subsequent manufacturing steps, preventing misalignment issues that would occur with separate-layer conventional approaches.
2Reliability
If conventional separate-layer lamination is used, then ease of manufacture is improved, but reliability worsens due to delamination and void formation
Solution Approach 1:
By merging the transparent adhesive layer, intermediate layer, and backsheet into one integrated film, the patent eliminates inter-layer interfaces that are prone to delamination and void formation. This single-integration approach significantly improves bonding reliability while maintaining manufacturing ease through reduced lamination steps.
Solution Approach 2:
The patent extracts and eliminates the problematic multi-step lamination process that causes delamination. By removing the need for separate lamination of each layer, the design prevents the formation of voids and delamination at layer interfaces, thereby improving reliability without complicating manufacturing.
3Manufacturing precision
If conventional multi-layer lamination is used, then adaptability is improved for different materials, but manufacturing precision deteriorates due to cumulative alignment errors
Solution Approach 1:
The integration of multiple functional layers into a single intermediate film eliminates cumulative alignment errors by removing multiple lamination interfaces. The single-integration process ensures precise positioning without the compounding errors that occur when laminating separate layers sequentially.
Solution Approach 2:
The intermediate film is designed with spatially differentiated functional zones: a transparent adhesive layer for bonding, an intermediate layer for mechanical support, and a backsheet for protection. Each zone is optimized for its specific function while maintaining overall integration, allowing adaptability to different materials without compromising alignment precision.
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 approach significantly reduces production time and costs by allowing partially cross-linked intermediate films to be completed during the lamination process, maintaining the properties of fully cross-linked resin layers in the final photovoltaic modules.
Implementation Method 1
a blocked isocyanate cross-linking agent having an unblocking temperature and inducing partial cross-linking of the coating resin layer when exposed to a temperature above the unblocking temperature
Implementation Method 2
cross-linking of the resin layer is divided into two sub-steps: a first sub-step of partial cross-linking of the coating resin layer and a second sub-step of completion of the cross-linking of the coating resin layer
Data Source
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AI summary
According to the present invention, an intermediate film for a backsheet for photovoltaic modules is provided, the intermediate film comprising a substrate film, for example, a PET film, and a partially cross-linked layer of coating resin. The corresponding method for producing such an intermediate film is also presented, which involves providing a substrate film, depositing and spreading a layer of coating resin on the substrate film, and partially cross-linking the layer of coating resin. According to this method, the cross-linking of the resin is stopped before it is completed so that the intermediate film is obtained, and it is finished during the subsequent process of laminating the intermediate film to the encapsulant of a photovoltaic module.