Electric double layer capacitors (EDLCs), also known as supercapacitors or ultracapacitors, store energy through static charges in an electric double layer at the interface between electrode and electrolyte surfaces. They resemble conventional capacitors but have much higher energy density. EDLCs use activated charcoal or carbon nanotubes as electrodes to provide a large surface area for charge storage, and ions in the electrolyte form separated layers of charge on either side of the electrode surfaces when a voltage is applied. While having advantages like rapid charging/discharging and long lifecycles, EDLCs also have lower energy density than batteries. They find applications requiring high power delivery like hybrid vehicles and consumer electronics.

1. Electric Double Layer
Capacitors (EDLC)
AnuragYadav
Roll No: 10

2. INTRODUCTION
Electric Double Layer Capacitors (EDLC) are
also called super capacitors or ultra
capacitors.They store energy in the form of
static charges. EDLC resembles the ordinary
capacitors but having high energy density.
EDLC have very low working voltage ,and are
used in hybrid vehicles. EDLC ‘s are rated
from Farads to Kilo Farad ranges
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3. HISTORY & PRESENT
Electric double layer effect was first noticed by
General Electric engineers in 1957. But this
effect is rediscovered and researches are
done by Standard oil of Ohio in 1966. But it is
NEC,who finally marketted the result as
SUPER CAPACTORS.
Due to the development of Material Science in
90’s,this technology improves rapidly.Today ,
electronic devices, Locomotives uses this
technology.
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4. CONSTRUCTION
EDLC’s construction is a little different to that
of ordinary capacitors. EDLC’s doesn't have
any conventional dielectric rather than ,two
plates separated by an inverting substance.
The Super Capacitor uses plates of same
material having same electrical properties
and are called electric double layer.
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6. Main materials used for the construction are
 Activated Charcoal
 CarbonNanoTubes
 Aerogels
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7. EDLC use Activated Charcoal as plates.
It is because
 It’s a powder made of very small & rough
particle
 It’s having a low density particles with holes
 Over all surface area is very much larger than
other materials like Al ,Ti etc.
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But Activated Charcoal is not a perfect
material for EDLC. It's because
• The charge carriers are quite larger than the
pores in the Charcoal .
• Some times too large pore size in charcoal.

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Carbon Nano Tubes are used today.
• They have same charge storage capability as that of
Charcoal
•Having much more mechanically arranged rigid pattern.
•Having much more surface area.

10. PRINCIPLE & WORKING
EDLC store electrical charges similar to that of ordinary
capacitors. But charges doesn't accumulate on electrode,
instead it is stored in the interface between surface of the
conductor and electrolytic solution.
Capacitance of EDLC is given by the equ:
C= A ε / 4 π d
 A- Area of the contact plates
 d- distance between the plates
 ε – dielectric constant of the medium between the plates
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12. ELDC works on the process of double layer
formed between electrode and electrolyte when
a pd is applied.
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13. During charging, electrically charged ions in the
electrolyte moves towards electrodes of
opposite polarity due to electric field between
charged electrode created by pd.Thus two
charged plates are produced.This charged ions
occupy spaces of the electrode and electrolyte
which is separated by a very small distance. Due
to large surface area large number of ions are
formed ,
resulting high
capacitance.
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15. EQUIVALENT CIRCUIT
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16. ADVANTAGES
 Eco friendly
 High Efficiency
 Rapid charging & Discharging
 Low internal Resistance
 High power density
 Reliable in harsh environment
 Virtually unlimited cycle life
 Simple charge methods
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17. Energy Density Vs Power
Density

18. DISADVANTAGES
 Unable to use full energy spectrum
 Low energy density
 High self discharge
 Low working voltage
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19. APPLICATIONS
 UPS systems.
 Laptops.
 Regenerative breaking systems.
 Automotive: hybrid power trains and drive systems
 Consumer electronic devices that demand sudden energy bursts for
wireless communications, processing, and memory storage.
 Industrial: applications requiring energy storage, bridging, delivery, and
smooth transitioning.
 Telecommunications : portable wireless devices, communication
Satellites, cell towers, or off-the-grid electric power generation
 Transportation : vehicles that frequently accelerate and brake use SC.
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20. BATTERY vs. CAPACITORS
 Batteries
 Store energy by converting between electrical and
chemical energy
 Shelf life of a few years
 Not all are rechargeable
 Capacitors
 Store energy as an electric potential between two
surfaces and a dielectric constant (ie. Aluminum)
 Rechargeable
 Long shelf life
 Miniscule amount of energy loss during shelf time
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21. FUTURE SCOPES
 Hybrid Battery
The idea of replacing batteries with capacitors in
conjunction with novel alternative energy
sources became a conceptual umbrella of
“Green Electricity (GEL) Initiative, introduced
by Dr. Alexander Bell.
Hybrid Battery is the one which have the
properties of both capacitor and battery. High
power density of caps and High energy density
of battery is combine together
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22. Hybrid battery system is a new highly reliable
energy storage device.
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23. CONCLUSION
This presentation deals with EDLC as an Energy
storage device.The main advantage of this
ELDCis ,Its having high power density, eco
friendly, used in hybrid vehicles etc.
I hope ,new technologies in the material science
& Nano will make this Super capacitor more
advanced.
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