REI Mar-Apr 2012 - Renewable Energy Installer

Knowledge: ET Solar
From silicon to solar panel
The manufacture of a solar panel is a thorough process which in the case of ET
Solar involves over 200 stages of development and checks, says Jane Hughes
EI was invited to see ET Solar’s
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manufacturing process fi rst hand
through ingot, wafer and cell to
fi nished module at the company’s
manufacturing plant in China.
Modules are produced for commercial,
residential and utility applications with
90 | www.renewableenergyinstaller.co.uk
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projected capacity for 2012 year end being
800MW wafer, 1000MW cells and 1600MW of
modules.
The company’s solar panels feature
integrated bypass diodes to protect the solar
cell circuit from hot spots during partial
shadowing. Anodised aluminium frames with
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hexagon drainage holes have strong load
resistance with grounding holes on four sides.
Modules are fi nished in transparent, lowiron
and tempered glass with anti-refl ective
coating.
A selection of the process stages are
illustrated on these pages.
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(1) The silicon which is sourced from Korea is heated to a
melting point of 1420ºC using American equipment.
(2) This solid block of melted silicon can produce 12,000
wafers. The block is fi rst made into 25 smaller blocks or
ingots using a Swiss slicing machine.
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(3) Each ingot is infra red scanned in a laboratory to
check for impurities.
(4) The provenance of each ingot can be tracked via its
unique code.
(5) The ingot undergoes a series of processes to smooth
edges until a glass like fi nish is achieved.
Continued on page 92