EU PVSEC Programme Online
EU PVSEC 2021, 6 - 10 September 2021
Presentation: 4AV.1.35 Crosslinking Kinetics of Photovoltaic Module Encapsulants – Investigation of Selected EVA and POE Grades
Type: Visual
Date: Monday, 6th September 2021
15:15 - 16:45
Author(s): B. Adothu, R. Pugstaller, M. Tiefenthaler, F.R. Costa, S. Mallick, G.M. Wallner
Presenter / Speaker: B. Adothu, Johannes Kepler University, Linz, Austria
Event: Conference Conference
Session: 4AV.1 PV Module Design, Components and Ageing
Topic: 4. 1 PV Module Design, Manufacture, Performance and Reliability
Keywords: Crosslinking, Kinetics, Encapsulant/s, Photovoltaic (PV), Activation Energies, Dynamic Mechanical Analysis
Summary / Abstract: Solar photovoltaic (PV) module encapsulation technology has grown rapidly worldwide in the last few years. Various novel encapsulation materials have been introduced in the PV market. Thermoplastic polyolefin elastomer (POE) encapsulant is a highly relevant alternative to the most commonly used crosslinking ethylene-vinyl acetate copolymer (EVA). During lamination, encapsulation materials are frequently crosslinked or cured, which allows for reducing creep at elevated temperatures. Crosslinking agents based on organic peroxides are well established. The main objective of this paper was to implement an isothermal, dynamic-mechanical analysis (DMA) method to investigate and compare the crosslinking kinetics of EVA and POE encapsulants. Isothermal experiments were carried out in torsional mode at different temperatures. The gelation point was deduced from the crossover-point of the real and imaginary part of the modulus. Comparable activation energies (Ea) of 149 and 152 kJ/moles were obtained for EVA and POE, respectively. By assessment of complex viscosity, the degree of crosslinking was deduced. Interestingly, the degree of crosslinking at gelation point was a factor of about three higher for POE, which revealed a significantly lower viscosity in the fully cured state. This paper will help in understanding the crosslinking kinetics, which is very beneficial for the PV industry and encapsulant manufacturers for quickly assessing the modification of any encapsulant crosslinking process.