Ethylene-Vinyl Acetate Potential Problems for Photovoltaic Packaging

Conference · Sun Jan 01 04:00:00 EST 2006

OSTI ID:944469

Kempe, M D; Jorgensen, G J; Terwilliger, K M; McMahon, T J; Kennedy, C E; Borek, T T

Photovoltaic (PV) devices are typically encapsulated using ethylene-vinyl acetate (EVA) to provide mechanical support, optical coupling, electrical isolation, and protection against environmental exposure. Under exposure to atmospheric water and/or ultraviolet radiation, EVA will decompose to produce acetic acid, lowering the pH and increasing the surface corrosion rates of embedded devices. Even though acetic acid is produced at a very slow rate, it may not take much to catalyze reactions that lead to rapid module deterioration. Another consideration is that the glass transition of EVA, as measured using dynamic mechanical analysis, begins at temperatures of about -15 degC. Temperatures lower than this can be reached for extended periods of time in some climates. Because of increased moduli below the glass transition temperature, a module may be more vulnerable to damage if a mechanical load is applied by snow or wind at low temperatures. Modules using EVA should not be rated for use at such low temperatures without additional low-temperature mechanical testing beyond the scope of UL1703.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO.
• Sponsoring Organization: USDOE
• DOE Contract Number: AC36-99GO10337
• OSTI ID: 944469
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
ACETATES
ACETIC ACID
CLIMATES
CORROSION
ENERGY CONVERSION
ENVIRONMENTAL EXPOSURE
GLASS
PACKAGING
SNOW
Solar Energy - Photovoltaics
TESTING
TRANSITION TEMPERATURE
ULTRAVIOLET RADIATION
WATER