PV Panels: Difference between revisions
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*Carbothermal reduction - Si02 is heated with Carbon (charcoal) in an arc furnace to produce metallurgical grade (impure) silicon | *Carbothermal reduction - Si02 is heated with Carbon (charcoal) in an arc furnace to produce metallurgical grade (impure) silicon | ||
*This silicon can be drawn into a round billet from a melt | *This silicon can be drawn into a round billet from a melt | ||
*Metallurgical grade silicon is purified to solar grade silicon (not as pure as semiconductor grade) by zone refining in vaccuum | *Metallurgical grade silicon is purified to solar grade silicon (not as pure as semiconductor grade) by zone refining in vaccuum [https://ac.els-cdn.com/S1876610212007412/1-s2.0-S1876610212007412-main.pdf?_tid=c157d8fe-104c-11e8-ba08-00000aacb35e&acdnat=1518478428_fcd7e1cc94c844aed22722e0b5859c2c] | ||
:*This is an induction heater traveling up a billet of silicon | :*This is an induction heater traveling up a billet of silicon | ||
:*Vaccuum sucks out light impurities | :*Vaccuum sucks out light impurities | ||
Revision as of 00:20, 13 February 2018
How They are Made
How is Silicon Produced
- Carbothermal reduction - Si02 is heated with Carbon (charcoal) in an arc furnace to produce metallurgical grade (impure) silicon
- This silicon can be drawn into a round billet from a melt
- Metallurgical grade silicon is purified to solar grade silicon (not as pure as semiconductor grade) by zone refining in vaccuum [1]
- This is an induction heater traveling up a billet of silicon
- Vaccuum sucks out light impurities
- Heavy impurities are travel up the melt zone as melt zone travels up the billet
Phosphorus
- If a PV panel, 285W, weighs 19 kg and maybe 1.5 kg silicon - [5] - then .2 ppm -> then 0.3 mg of phosphine per panel. If a bottle of phosphine contains 10 kg phosphine, then one bottle is sufficient for - 30,000,000 panels! Thus, phosphine costs per panel are negligible - 0.002 cent per panel. This may be reduced for inefficiency of diffusion - but still likely to be way under 1 cent per panel.
- $5/lb - [6]