Solar Cell Module Back Sheet Contraction Prevention
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Solution Overview
Problem
Solar cell modules experience back sheet contraction over time, leading to deformation and reduced adhesion between the encapsulant and the back sheet, resulting in structural instability.
Innovation Solution
A solar cell module design featuring a back sheet with a polytetrafluoroethylene film layer on its lower surface and a polyethylene film layer on its upper surface, bonded to a polyethylene terephthalate substrate, which prevents contraction and enhances adhesion with the encapsulant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional back sheet (PET film with fluorine-based films) is used, then heat resistance and weather resistance are improved, but contraction occurs during long-term use causing deformation and reduced adhesion
Solution Approach 1:
The back sheet is constructed as a composite material consisting of a PET base substrate (providing heat resistance) combined with a polyethylene surface layer (providing dimensional stability and preventing contraction). This composite structure integrates the advantages of different materials to simultaneously achieve heat resistance, weather resistance, and dimensional stability without the contraction problems of conventional back sheets.
2Duration of action of moving object
If the solar cell module is used for a long period of time, then energy generation continues, but the back sheet contracts causing deformation and adhesion loss
Solution Approach 1:
The invention changes the material parameter of the back sheet's surface layer from conventional fluorine-based films to polyethylene, which has superior dimensional stability and resistance to contraction under long-term thermal and environmental stress. This parameter change allows the back sheet to maintain its shape and adhesion properties throughout the extended service life of the solar cell module.
Data Source
Figure 1~2
AI summary
A solar cell module includes: a transparent member (10); an encapsulant (20) allowing the transparent member to be bonded to an upper surface thereof; a plurality of solar cells (30) fixed within the encapsulant; and a back sheet (40) bonded to a lower surface of the encapsulant (23), wherein the back sheet includes a substrate (43); a polytetrafluoroethylene film layer (45) formed on a lower surface of the substrate; and a surface layer (41) formed on an upper surface of the substrate and formed of polyethylele or polytetrafluoroethylene. As described above, according to the solar cell module of the present invention, since the back sheet used in a solar cell module is formed of polytetrafluoroethylene (PTFE), even though the solar cell module is used for a long period of time, contraction of the back sheet is prevented, and thus, the solar cell module may be prevented from being deformed in an outer appearance thereof due to contraction of the back sheet.