Composite material with enhanced recyclability as encapsulant for photovoltaic modules

Abstract

Encapsulation of photovoltaic cells was carried out using a transparent glass fiber reinforced composite with enhanced chemical recyclability based on a matrix of an epoxy resin containing cleavable functional groups. The current-voltage curves showed a decrease of 6.3% on the short-circuit current (Isc) after encapsulation of the cell, lower than the one observed for the reference non-recyclable standard epoxy composite. Its performance stability under thermal cycling, ultraviolet (UV), and damp-heat exposure was evaluated and compared with the one of the reference standard epoxy. Both resins showed good stability performance under UV exposure and thermal cycling accelerated aging. Moreover, a power loss below the 5% allowed by the photovoltaic standard was observed for the recyclable resin after 1000 h of damp-heat exposure, even the pronounced loss of 4.7% in power remains a concern. Regarding the recyclability, the composite was dissolved in acetic acid dissolution and glass fiber fabrics were successfully recovered. A new module was manufactured with these fabrics, showing this time a loss of 12% in Isc comparing with the non-encapsulated cell. Further work will consider improving the moisture barrier properties of the composite, and adjusting the recycling conditions to allow component recovery valid for new modules.