Polyester White Film Back Sheet for Solar Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high cost and supply imbalance of Tedlar films in solar cell module back sheets, along with the need for improved light reflectance to enhance solar cell generation efficiency, are unresolved by existing technologies.
Innovation Solution
A polyester white film with a whiteness index of 100 or higher and reflectance of 90% or higher at 550 nm, made from a polyester resin, rutile type titanium dioxide, and a benzoxazole-based fluorescence whitening agent, which provides high light reflectance, weather resistance, and hydrolysis resistance, replacing the need for Tedlar films in solar cell module back sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Tedlar film is used in back sheet, then weather resistance and durability are improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive Tedlar film with a cost-effective polyester film (PET) that achieves comparable durability through optimized composition and structure. The PET film is designed to provide sufficient weather resistance without requiring the premium fluoropolymer material, thereby reducing manufacturing costs while maintaining acceptable service life
Solution Approach 2:
The patent creates a composite back sheet structure combining polyester film base material with titanium dioxide coating layer. This composite approach leverages the cost advantages of PET while adding the weather resistance benefits of TiO2, achieving a balance between durability and manufacturing cost that eliminates dependence on expensive Tedlar film
2Productivity
If conventional back sheet materials are used, then manufacturing process is established, but light reflectance is insufficient reducing solar cell generation efficiency
Solution Approach 1:
The patent applies a titanium dioxide coating layer on the polyester film to create a highly reflective white surface. The TiO2 coating provides excellent light scattering and reflection properties, significantly enhancing light reflectance compared to conventional back sheet materials. This color/reflectance modification directly improves solar cell generation efficiency by reflecting more light back to the cells
Solution Approach 2:
The patent optimizes the titanium dioxide content and particle size parameters to achieve maximum light reflectance. By controlling the TiO2 concentration (3-10 wt%) and particle characteristics, the back sheet achieves enhanced optical performance that improves solar cell efficiency without compromising the base material properties
3Ease of manufacture
If Tedlar film is replaced with polyester film, then manufacturing cost is reduced, but light reflectance and weather resistance may deteriorate
Solution Approach 1:
The patent introduces a titanium dioxide coating layer as an intermediary between the polyester film base and the external environment. This coating layer acts as a protective mediator that enhances weather resistance and provides the desired light reflectance, compensating for the inherent limitations of polyester film while maintaining cost advantages over Tedlar film
4Reliability
If multiple lamination processes are used for back sheet, then durability is improved, but process complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the base film and protective coating into a single integrated back sheet structure. The titanium dioxide coating is applied directly to the polyester film in a streamlined process, combining multiple functions (structural support, weather resistance, light reflection) into one composite material system. This reduces the number of separate lamination steps and simplifies manufacturing while maintaining durability
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 polyester white film increases solar cell generation efficiency by reflecting light back to the solar cells, offering superior weather resistance and durability, thus reducing manufacturing costs and improving the back sheet's processability while maintaining UV stability.
Implementation Method 1
A polyester white film with a whiteness index of 100 or higher and reflectance of 90% or higher at 550 nm... increases solar cell generation efficiency by reflecting light back to the solar cells
Implementation Method 2
made from a polyester resin, rutile type titanium dioxide, and a benzoxazole-based fluorescence whitening agent... maintaining UV stability
Data Source
AI summary
Provided are a polyester white film and a back sheet for a solar cell module using the same, and in particular, provided is a polyester white film having improved light reflectance.