Backsheet selection categories: Fluorine-based, Non-fluorine, and Transparent (Source: Douyin). Golden Rule: Choose fluorinated films for hot and humid regions (Source: Zhenshi). Key Point: KPK lifespan is 15–20 years (Source: SurgePV). Caution: PET is prone to hydrolysis and cracking (Source: PW).
I.
Fluorine-based Backsheets
TPT: PVF/PET/PVF three-layer structure (Source: Ooitech); KPK: PVDF/PET/PVDF (Source: Ooitech); KPF: Composite + fluorinated coating (Source: Douyin); Thickness: 300–350 µm (Source: Ooitech); Lifespan: 15–20 years without cracking (Source: SurgePV)—Fluorine-based types: TPT, KPK, KPF (three structures).
II.
Non-fluorine Backsheets
PET: Reinforced polyester PET (Source: Douyin); PA: Polyamide PA (Source: Douyin); PPE: PET/PET/EVA co-extrusion (Source: Solar.red); Cost: Low-cost advantage (Source: Douyin); Risk: Hydrolysis/cracking rate is 2–3 times higher (Source: PW)—Non-fluorine types: PET, PA, PPE (three categories).
III. Transparent Backsheet
Bifacial: For bifacial modules (Source: Morgan); Light Transmission: Transmittance >91% (Source: Docin); Thickness: 300–400 µm (Source: Ooitech); Drawback: Accelerated aging due to yellowing (Source: SurgePV); Lifespan: Visible failure within 5–10 years (Source: SurgePV)—Transparency: Bifaciality + Transmittance + Lifespan (Three-way trade-off).
IV.
Water Barrier Performance
MVTR: Target MVTR <0.5 g/m²·day (Source: Zhenshi); PVDF: PVDF film <0.01 g/m²·day (Source: Patsnap); Heat Resistance: Resistant to high/low temperatures and corrosion (Source: Douyin); Insulation: Dielectric strength >20 kV/mm (Source: Coule); Reflection: High infrared reflectivity lowers module temperature (Source: Douyin)—Water Barrier: MVTR + Insulation + Reflection (Three performance metrics).
V.
Application Scenarios
Single-glass: Standard backsheet for single-glass modules (Source: Zhongneng); Damp-Heat: IEC Zone A (high humidity and temperature) (Source: Zhenshi); Industrial: Acid corrosion resistance for industrial zones (Source: Coule); BIPV: Ultra-lightweight flexible backsheet (Source: Zhenshi); Testing: DH2000 damp-heat test (Source: Zhenshi)—Applications: Single-glass + Damp-Heat + BIPV (Three scenarios).
VI. Key Selection Criteria
Structure: PET adhesive layer for the outer protective layer (Source: Douyin); Fluorine film: PVF accounts for a 20–25% market share (Source: Solar.red); Cost: KPF offers superior cost-performance (Source: Coule); Certification: IEC backsheet standards (Source: Zhenshi); Manufacturer: Leading fluorine-film backsheet suppliers (Source: Chemical)—Selection approach: Structure + Fluorine film + Cost (three-point check).
VII.
Procurement Recommendations
First, consider the environment (choose fluorine for hot and humid conditions); second, determine the structure (KPK/TPT); third, verify water barrier properties (MVTR < 0.5); fourth, test for aging resistance (DH2000);
fifth, prioritize brands (leading manufacturers)—Backsheet essentials: Fluorine content + Water barrier performance + Service life (three key points).
