| |
Articles
1. What is silicon. Where does all the silicon come from
?
2. How are solar Cells manufactured ?
|
1. What is silicon. Where does all the
silicon come from ? |
| |
Silicon is a non-metallic chemical element. Chemical symbol - Si
It has two forms, a brown amorphous form, and a dark crystalline
form.
Discovery of the element is usually credited to J. J. Berzelius,
who in 1824 prepared fairly pure amorphous silicon.
Well that's fine, but where all do we use silicon.
It is used in the steel industry as ferrosilicon, used to make
alloys (compound materials made from 2 or more chemicals, so that
the new product, has the properties of all these chemicals).
Silicon contributes to hardness and corrosion resistance in
these alloys.
It is used in the manufacture of glass, used in manufacturing
semiconductor devices which include almost all the electronic
components that we know of, and,
Of course in solar cell manufacture.
Finally, anything and everything around contains silicon. The
brick on the wall, the ceramics, clay ....etc.,
So, wondering where does all the silicon come from.
Silicon is the second most abundant element of the earth's
crust; it makes up about 28% of the crust by weight. And hence
all the silicon comes from the earth, the ground below.
Silicon is widely extracted and distributed as silica and
silicates. These are compound metals that have silicon as a
constituent. example: silica is the composition of oxygen and silicon
and silicate is the compositions of oxygen, metals and silicon.
Silicon is obtained commercially by heating sand and coke in an
electric furnace; Hey, not the coke u drink, this is
different. :-) |
|
TOP |
|
2. How are solar Cells manufactured ? |
| |
Solar cells are manufactured through various methods.
The final cell that is packaged on to a module, is a special
type silicon wafer that has gone through a lot of complex
processes, for increasing the efficiency of the final product.
This article tries to enlist these processes briefly, giving
the reader first-hand information of what goes behind the
manufacture of a solar module, and why this great idea of
harvesting sun's energy has not seen much good days yet.
Silicon is extracted, purified of other chemicals in its
combined form,
crystallized, cut in to thin wafers (wafers, are very very thin
slices of semiconductor material; in this case silicon is the
semiconductor material.)
The wafers are cut into required shapes, sizes. A collection of
these photovoltaic wafers are aligned to form a solar cell.
100's and thousands of cells thus manufactured and connected to
form a circuit (an electric path) will become a solar module.
Theoretically, that's the process.
But practically, extracting silicon and purifying it to the
extent that it can be satisfactorily used on solar cells, itself
is an industry.
Usually one company extracts silicon, another purifies it, cuts
it into wafers, and another company buys these wafers, makes
solar cells. Finally, one more company buys these cells, and
manufactures solar modules.
Every process enlisted requires very sophisticated machinery and
equipment, and every process has its own wastages and losses to
account.
To add to all these, solar cells have to be manufactured from
really pure silicon wafers, to attain a minimum efficiency of
32%. That means 32% of the sunlight being converted to usable or
storable electricity.
This is the reason for solar cells not being able to support the
electricity market. Researches around the world are focusing on
low-cost manufacture, of average efficiency silicon wafers. Some
researches have yielded good results to support the growth of
the solar industry. Some specific methods of purifying silicon
has proven to provide slightly more efficient silicon wafers.
And some special type silicon wafers with some other chemical
ingredients on it, to add to the efficiency are also being
developed.
|
|
TOP |
|
Useful Links: |
|
1. |
How to make a solar cell on your own. -
http://www.scitoys.com/scitoys/scitoys/echem/echem2.html |
|
2. |
Solar education center -
http://www.mrsolar.com/ |
|
3. |
Manufacturer
of equipments relating to solar cell manufacture -
http://www.crystalox.com/core/fs-home.htm |
|
4. |
Online material information
database -
http://www.matweb.com/ |
|
5. |
A company popular for low
cost solar cell manufacture -
http://www.firstsolar.com |
| |
|
|
