Recycling experimental investigation on end of life photovoltaic panels by application of high voltage fragmentation

With the rapid development of photovoltaic industry, the recycling of waste solar photovoltaic (PV) panels is becoming a critical and global challenge. Considering PV panels recycling is significantly effective and worthwhile to save natural resources and reduce the cost of production, how to selectively recycle valuable components of PV panels is the hot and dominant topic. Different from current mechanical crushing, heat treatment and chemical operation processes, novel and environment-friendly recycling approaches by using high voltage pulse discharge in water, called high voltage fragmentation (HVF), was discussed under different discharge conditions. The results showed that discharging across surface and interior of PV panels produced ablation round holes, sputter metal particles and dendritic channels. The average particle size decreased with the ascent of pulse number and voltage amplitude. Considering the energy consumption, the optimal condition of HVF in this paper was 160 kV for 300 pulses with the energy consumption of 192.99 J/g, crushing the PV panels into particles of 4.1 mm in average (13.7% of the initial size). More particle was distributed among the 0.1–2 mm size fractions as the energy increased. Selective fragmented products, such as Cu, Al, Pb, Ag and Sn, are concentrated on the fractions under 1 mm. Finally, hybrid crushing energy consumption model combined with fractal theory was discussed, which presented close relationship between energy and average particle size. Walker's model (n = 2.047 determined by fractal theory) had the best fitting effect.