skip to main content


Title: Technologies for Profitable Recycling of Si Modules
Solar module recycling is unprofitable today. In this paper potential revenues from waste Si modules are analyzed. The biggest revenue potential comes from the Si cells, extracted intact or broken. The second revenue source is the bulky materials in the modules including Al frame, Cu wiring and glass. The total revenue is estimated between US$11–30/module depending on the percentage of cells extracted intact. This revenue is 4–10 times better than today’s recycling process that recovers only the bulky materials. Experimentally a special furnace has been demonstrated to successfully separate thin commercial Si cells of 160 microns from glass unbroken. From damaged cells a new chemistry has been developed to recover solar-grade Si and Ag. It requires fewer steps than today’s recycling process, with Ag recovery of 97% and Si recovery of 90%. A prototype recycling line is needed to assess the cost of the new process.  more » « less
Award ID(s):
1904544
NSF-PAR ID:
10144076
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Proceedings of 29th International Photovoltaic Science and Engineering Conference
Page Range / eLocation ID:
2384 -2387
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Solar module recycling is unprofitable today. In this paper potential revenues from waste Si modules are analyzed. The biggest revenue potential comes from the Si cells, extracted intact or broken. The second revenue source is the bulky materials in the modules including Al frame, Cu wiring and glass. The total revenue is estimated between US$11–30/module depending on the percentage of cells extracted intact. This revenue is 4–10 times better than today’s recycling process that recovers only the bulky materials. Experimentally a special furnace has been demonstrated to successfully separate thin commercial Si cells of 160 microns from glass unbroken. From damaged cells a new chemistry has been developed to recover solar-grade Si and Ag. It requires fewer steps than today’s recycling process, with Ag recovery of 97% and Si recovery of 90%. A prototype recycling line is needed to assess the cost of the new process. 
    more » « less
  2. Abstract Perovskite photovoltaics are gaining increasing common ground to partner with or compete with silicon photovoltaics to reduce cost of solar energy. However, a cost-effective waste management for toxic lead (Pb), which might determine the fate of this technology, has not been developed yet. Here, we report an end-of-life material management for perovskite solar modules to recycle toxic lead and valuable transparent conductors to protect the environment and create dramatic economic benefits from recycled materials. Lead is separated from decommissioned modules by weakly acidic cation exchange resin, which could be released as soluble Pb(NO 3 ) 2 followed by precipitation as PbI 2 for reuse, with a recycling efficiency of 99.2%. Thermal delamination disassembles the encapsulated modules with intact transparent conductors and cover glasses. The refabricated devices based on recycled lead iodide and recycled transparent conductors show comparable performance as devices based on fresh raw materials. Cost analysis shows this recycling technology is economically attractive. 
    more » « less
  3. Material scarcity is a considerable threat to energy transition towards renewables. Photovoltaics (PV) installations are expected to increase rapidly in the next decade, which may increase the amount of material needed. This study created three scenarios (S 1 , S 2 , & S 3 ) to evaluate the impacts of potential technology improvements on the quantity of materials necessary for manufacturing silicon PV (Si PV) laminate in the next ten years. Our baseline was similar to previous studies, which applied theoretical models on PV historical data and ignored PV technology improvements that can influence future material projections. S 1 considered only market share and module efficiency, while S 2 covered wafer thickness improvements as well. S 3 was the scenario that more likely will occur in the next decade, which included module efficiency, market share, wafer thickness, glass thickness, and potential replacements such as using perovskite/silicon tandem. The material requirement for Si PV laminate manufacturing in S 3 was 22% to 78% lower than the baseline, S 1 , and S 2 . The highest material demand is expected to be for solar glass (74 million metric tons) and Metallurgical grade silicon (3 million metric tons) in the next decade. This study showed the importance of considering technology improvements to project the PV material requirement. 
    more » « less
  4. null (Ed.)
    Copper-antimony-sulfide compounds have desirable earth-abundant compositions for application in renewable energy technologies, such as solar energy and waste heat recycling. These compounds can be synthesized by bottom-up, solution-phase techniques that are more energy and time efficient than conventional solid-state methods. Solution-phase methods typically produce nanostructured materials, which adds another dimension to control optical, electrical, and thermal material properties. This study focuses on a modified-polyol, solution-phase synthesis for tetrahedrite (Cu 12 Sb 4 S 13 ), a promising thermoelectric material with potential also for photovoltaic applications. To dope the tetrahedrite and tune material properties, the utility of the modified polyol synthetic approach has been demonstrated as a strategy to produce phase-pure tetrahedrite that incorporates transition metal (Fe, Co, Ni, Zn, Ag) dopants for Cu, Te dopant for Sb, and Se for S. Six of these reported tetrahedrite compounds have not previously been made by solution-phase methods. For the bottom-up formation of the tetrahedrite nanomaterials, the evolution of the chemical phases has been determined by an investigation of the reaction progress as a function of temperature and time. Digenite (Cu 1.8 S), covellite (CuS), and famatinite (Cu 3 SbS 4 ) are identified as key intermediates and are consistently observed for both undoped and doped tetrahedrites. The effect of nanostructuring and doping tetrahedrite on thermal properties has been investigated. It was found that nanostructured undoped tetrahedrite has reduced thermal stability relative to samples made by solid-state methods, while the addition of dopants for Cu increased the thermal stability of the material. Crystallinity, composition, and nanostructure of products and intermediates were characterized by powder X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy, and transmission electron microscopy. Thermal properties were investigated by differential scanning calorimetry and thermal gravimetric analysis. This synthetic study with thermal property analysis demonstrates the potential of the modified polyol method to produce tetrahedrite and other copper-antimony-sulfide compounds for thermoelectric and photovoltaic applications. 
    more » « less
  5. Abstract

    Degradation from ultraviolet (UV) radiation has become prevalent in the front of solar cells due to the introduction of UV‐transmitting encapsulants in photovoltaic (PV) module construction. Here, we examine UV‐induced degradation (UVID) in various commercial, unencapsulated crystalline silicon cell technologies, including bifacial silicon heterojunction (HJ), interdigitated back contact (IBC), passivated emitter and rear contact (PERC), and passivated emitter rear totally diffused (PERT) solar cells. We performed UV exposure tests using UVA‐340 fluorescent lamps at 1.24 W·m−2(at 340 nm) and 45°C through 4.02 MJ·m−2(2000 h). Our results showed that modern cell architectures are more vulnerable to UVID, leading to a significant power decrease (−3.6% on average; −11.8% maximum) compared with the conventional aluminum back surface field (Al‐BSF) cells (<−1% on average). The power degradation is largely caused by the decrease in short‐circuit current and open‐circuit voltage. A greater power decrease is observed in bifacial cells with rear‐side exposure compared with those with front‐side exposure, indicating that the rear side is more susceptible to UV damage. Secondary ion mass spectroscopy (SIMS) confirmed an increase in hydrogen concentration near the Si/passivation interface in HJ and IBC cells after UV exposure; the excess of hydrogen could result in hydrogen‐induced degradation and subsequently cause higher recombination losses. Additionally, surface oxidation and hot‐carrier damage were identified in PERT cells. Using a spectral‐based analysis, we obtained an acceleration factor of 5× between unpackaged cells (containing a silicon nitride antireflective coating on the front) in the UV test and an encapsulated module (with the front glass and encapsulant blocking 90% of the UV at 294 nm and 353 nm, respectively) in outdoor conditions. From the analytical calculations, we show that a UV‐blocking encapsulant can reduce UV transmission in the module by an additional factor of ~50.

     
    more » « less