Aging resistance of silicone coatings in photovoltaic module backsheets
Hits: 148
img
Silicone coatings show excellent aging resistance in photovoltaic module backsheets, mainly through the following core characteristics to ensure the long-term reliability of modules in harsh outdoor environments:
I. Extreme temperature tolerance
Wide temperature range stability: Pure silicone coatings can withstand temperature fluctuations from -80℃ to 250℃, and the upper temperature limit after modification is increased to more than 300℃, which can effectively cope with high temperatures and extreme cold environments in deserts. Its low modulus characteristics (elongation at break of 300%) can relieve thermal cycle stress and avoid brittle cracking of the backsheet. Verified by the IEC 61215 standard, the structural integrity is maintained after 200 thermal cycles from -40℃ to +85℃.
II. UV protection mechanism
Irradiation resistance: The silicon-oxygen bond (-Si-O-Si-) in the silicone molecular chain can absorb more than 90% of ultraviolet rays, and the reflection is enhanced by inorganic fillers such as rutile titanium dioxide, significantly delaying the yellowing and powdering of the backsheet45. Accelerated aging tests show that the transmittance loss after 15kWh/m² UV irradiation is less than 5% (equivalent to more than 10 years outdoors).
III. Moisture and heat resistance and corrosion resistance
Dual 85 environmental adaptability: After 1000 hours of 85℃/85%RH moisture and heat aging, the bonding strength retention rate exceeds 90%, which is much better than traditional backplane materials211. Its three-dimensional mesh structure can block water vapor penetration (water vapor transmission rate <0.5g/(m²·day)) and prevent power attenuation caused by PID effect36.
Chemical inertness: It has strong resistance to salt spray and weak alkaline environment. The paint film does not change after 70 hours of immersion in 5% salt water, and it does not contain organic oil and is naturally mildew-proof.
IV. Mechanical protection and insulation guarantee
Dynamic load resistance: The elastic modulus is maintained above 0.5MPa, and it can pass the 5400Pa mechanical load test to inhibit the expansion of hidden cracks in the battery cell. Electrical safety: Volume resistivity>1×10¹⁴Ω·cm, flame retardant grade reaches UL94 V0, effectively preventing short circuit and fire risks.
