Degradation of transparent and pigmented photovoltaic encapsulation materials at the glass/polymer interface
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
EUROCORR 2024
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
One of the major parts of photovoltaic modules is the polymeric encapsulant. Consequently, in this study X-ray photoelectron spectroscopy (XPS), supported by Fourier-transform infrared spectroscopy (FTIR) is used to investigate the ageing and degradation performance of several types of polymer glass laminates. In addition to non-pigmented ethylene vinyl acetate copolymer (EVA) and polyolefin elastomer (POE) grades, also interference pigmented thermoplastic polyolefin (TPO) encapsulants were evaluated.
The interface between polymer and glass was studied after damp heat, UV light or weathering exposure and subsequent compressive shear testing. Fractured surfaces at the polymer side were examined by XPS and FTIR. It is shown that EVA is more prone to degradation than the less polar TPO or POE. The differences were already discernible after 1000h of exposure and significantly increased for longer times up to 10000h. The ageing experiments for the interference pigmented TPO laminates are still ongoing.
The observations were used to propose possible degradation mechanisms for the different materials near to the interface and possibly at regions reaching deeper into the polymer matrix. Under damp heat or weathering exposure, diffusion of Na ions from the glass substrate into the polymer matrix and the formation of Na-based salts at the interface was identified as a cause for degradation and ageing of the encapsulants.
Forschungs-