Recent progress and future prospects of silicon solar module recycling

Silicon solar modules are only 10–15 wt% circular with today's recycling technologies. A 90 wt% circularity requires that all the inorganic materials in silicon modules be recovered for reuse in solar or similar applications. Major technical barriers to a 90 wt% circularity for silicon modules include: 1) removal of the fluoropolymer back sheet; 2) detachment of silicon cells from glass; 3) removal of the encapsulant on silicon cells; and 4) mild chemistry and minimization of chemical waste along with high material recovery rates. Noticeable progress in recycling technologies in the last few years includes: 1) mechanical milling to remove the fluoropolymer back sheet; 2) laser debonding of the encapsulant from silicon cells; 3) dissolution of the encapsulant with a base; 4) mild chemistry for silver and lead recovery; and 5) regenerative chemistry to reuse some of the chemicals in silicon cell recycling.