PV Panels: Difference between revisions
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=How is Silicon Produced= | =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 | |||
:*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= | =Phosphorus= | ||
Revision as of 00:12, 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
- 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 - [4] - 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 - [5]