Solar Cell Back Sheet Fluorine Polymer Coating Adhesion
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Solution Overview
Problem
Existing solar cell modules face challenges with adhesion between the back sheet and the ethylene/vinyl acetate copolymer sealant, leading to inadequate mechanical strength and water impermeability, particularly with fluorine-containing polymer coatings that lack functional groups and require high-temperature processing.
Innovation Solution
A solar cell module with a back sheet featuring a cured coating film of a fluorine-containing polymer having curable functional groups, which improves adhesion to the water-impermeable sheet and includes pigments for enhanced appearance and performance, allowing for a thinner, lighter design without compromising mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fluorine-containing polymer coating without functional groups is used, then weather resistance and electrical insulation are improved, but adhesion to the water-impermeable sheet and sealant deteriorates
Solution Approach 1:
The patent applies composite materials by combining fluorine-containing polymer particles (providing weather resistance and electrical insulation) with a polyester resin matrix (providing adhesion to the water-impermeable sheet and sealant). This composite coating layer integrates the advantages of both materials: the fluorine polymer ensures durability and insulation properties, while the polyester resin ensures strong bonding to adjacent layers, thereby resolving the contradiction between weather resistance and adhesion.
2Reliability
If resin sheets with thickness of 20 to 100 μm are used, then weather resistance and electrical insulation are satisfied, but weight increases
Solution Approach 1:
The patent employs a thin film approach by using a resin coating layer with thickness of 3 to 20 μm, which is significantly thinner than conventional resin sheets (20 to 100 μm). This thin coating still provides adequate weather resistance and electrical insulation when formulated with fluorine-containing polymer particles, thereby reducing the overall weight of the back sheet while maintaining required performance standards.
3Strength
If a coating layer is formed to improve adhesion, then mechanical strength is improved, but the structure becomes more complex
Solution Approach 1:
The patent merges multiple functions into a single coating layer applied to the water-impermeable sheet. This coating layer simultaneously provides adhesion to the sheet, adhesion to the sealant, weather resistance through fluorine-containing polymer particles, and electrical insulation. By consolidating these functions into one layer rather than using separate sheets for each function, the overall structure is simplified while maintaining mechanical strength.
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 enhances adhesion and weather resistance, reduces steam permeation, and maintains mechanical strength while enabling a thinner, lighter back sheet structure, addressing the limitations of previous technologies.
Implementation Method 1
a cured coating film of a coating material comprising a fluorine-containing polymer having curable functional group
Implementation Method 2
fluorine-containing polymer having curable functional group, wherein the cured coating film is adhered directly to the water-impermeable sheet
Implementation Method 3
a white pigment or a black pigment is dispersed in the cured coating film
Implementation Method 4
a function of preventing water (steam) from permeating the sealant layer 2
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
There is provided a back sheet (4) of solar cell (1) having excellent adhesion of a water-impermeable sheet (5). The back sheet (4) of solar cell module has, at least on either surface of a water-impermeable sheet (5), a cured coating film (6) comprising a coating material of a fluorine-containing polymer having curable functional group.