supercapacitor
TRANSCRIPT
SUPERCAPACITORS
By:-NIKHILEEE DEPT.
Guided by:-Dr. K .N. RAVI – PROF. & HEAD , EEE DEPT.
Mrs. LEELA A M - ASSOCIATE PROF ,
EEE DEPT.
CONTENTS:-
Introduction
Basic design
Applications
Advantages
disadvantages
Conclusion
Reference
INTRODUCTIONCAPACITOR:-
A capacitor (originally known as condenser) is a passive two-
terminal electrical component used to store energy in its electric field.
When a capacitor is attached across a battery, an electric field develops
across the dielectric, causing positive charge +Q to collect on one plate
and negative charge −Q to collect on the other plate
SUPERCAPACITOR:-
A supercapacitor is an electrochemical capacitor that
has an unusually high energy density when compared to
common capacitors.
Supercapacitor is also known as Electric Double Layer
Capacitor(EDLC) or Ultra capacitor.
The capacitance range is from 100 Farad to 10KFarad.
Different styles of supercapacitors :-
• Flat style used for
mobile components
• Typical button capacitor for
PCB mounting used for
memory backup
Supercapacitors connected in series
BASIC DESIGN
Super capacitors are constructed with two metal foils, each
coated with an electrode material such as activated carbon.
Typical construction of a supercapacitor: 1) Power source, 2) metal plate, 3) Polarized electrode, 4) Helmholtz double layer, 5) Electrolyte having positive and negative ions, 6) Separator.
The electrodes are kept apart by an ion-
permeable membrane (separator) used as an insulator to protect
the electrodes against short circuits.
The construction is subsequently rolled or folded into a
cylindrical or rectangular shape and is packed in an aluminium
can.
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Electrolyte
Separator
Electric double layer
▬ +
TECHNOLOGY USED:-
Carbon nano tubes are used for supercapacitors plates
or electrodes.
Sodium perchlorate (NaClO4) or lithium perchlorate
(LiClO4) are used as electrolytes.
Polyacrylonitrile(C3H3N)n is used as a
separator(thickness 0.3-0.8 nm).
WHY THESE SUBSTANCES USED:-
Electrodes:-
1)Carbon nanotubes greatly improve capacitor performance, due to the
highly wettable surface area and high conductivity.
2)Highly porous.
Electrolytes:-
1) Wide working temperature (-900c to 4000c).
2)Non flammable , low toxic and also non-corrosive .
Separator:-
1)Electrical conductivity (1.5x104 S/m).
3)Not degraded easily.
APPLICATIONS
In start up mechanism for Automobiles.
Supercapacitors are suitable temporary energy storage devices.
Supercapacitors provide backup or emergency shutdown power
to low-power equipment. e.g., ups.
They used in industrial lasers, medical equipment.
Large supercapacitors are used in wind turbines.
Bus operated on Supercapacitor in Shanghai
Supercapacitor installed in bus
ADVANTAGES
High energy storage.
Wide working temperature(-400c to 600c).
Eco-friendly.
Quick charging time.
Maximum life cycle.
Safe.
DISADVANTAGES
Individual cells have low voltages, and so series
connections are needed to obtain higher voltages.
Having high self – discharge rate.
Cannot be used in AC and high frequency circuits.
Cost is high.
CONCLUSION
Supercapacitors may be used where high power or
energy storage is required that it will replace the
batteries for power storage .
Supercapacitors can be used widely because of their
long life & short charging time.
On the other hand it has limitations due to its high cost,
self discharge, packaging problems etc.
REFERENCES
E.J.Dowgiallo & A.F.Bruke ‘’ Ultracapacitors for electric and
hybrid vehicles: A technology update.’’
B.E.Conway, ‘’Electrochemical Supercapacitors’’, chemical
industry press.
R.Morrison, ‘’The chemical physics of surfaces’’ New York:
Plenum,1990
IEEE transactions on industry applications, vol. 36.
‘’Transient analysis of pulsed charging in Supercapacitors’’
IEEE documentation.