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.

-------------------

++++++++++++

+

+

+

+

+

++

+

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.