6985249 introduction to super capacitors

8/4/2019 6985249 Introduction to Super Capacitors

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ULTRACAPACITOR

BY

LOKESH.E

GUIDE

Smt.bhagya.p


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INTRODUCTION

Supercapacitor or Ultracapacitor are thecommercial names of the devices made byNippon Electric Company (NEC), Japan,

and Pinnacle Research Institute (PRI), USA,respectively.

In technical terms, it is named as

electrochemical double-layer capacitor(EDLC).


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ELECTRIC CHARGE STORAGE

WHAT IS A CAPACITOR?

capacitor is a device used for storing charges and energy in its simplest form.

A capacitor consists of two conducting surfaces separated by an insulating material ( Dielectric).

PRINCIPLE:

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BatteryBatteries have two electrical terminals(electrodes) separated by a chemicalsubstance called an electrolyte.

In a rechargeable battery, such as a lithium-ion power pack used in a laptop computer orMP3 player, the reactions can happily run in

either directionso you can usually chargeand discharge hundreds of times before thebattery needs replacing.


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What are Supercapacitors?

Supercapacitors are an advanced version of capacitors with uniqueability to combine energy storage capabilities of batteries and power

storage behavior of capacitor.Hence fill the gap between batteries and conventional capacitorssuch as the electrolyte capacitors in terms of specific energy as wellas specific power.

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PROPERTIES OF ENERGY STORAGEDEVICES

50-3000.5-5


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Ultracapacitance principle



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Contd.

EDLCs store electrical charge in a similarmanner to the conventional capacitors.

The charges accumulate at the interface

between the surface of a conductor andan electrolytic solution.

The specific capacitance of such a double-layer given by

C/A=e/(4pd)


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Supercapacitor devices consist of twoelectrodes to allow a potential to beapplied across the cell.

The electrodes are made of high effectivesurface-area materials such as porouscarbon or carbon aerogels in order to

maximize the surface-area of the double-layer.


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How do supercapacitors compare tobatteries and ordinary capacitors?

o Batteries store electricity using chemicalreactions happening between an electrolyte.


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Contd.

Capacitors store static electricity by buildingup opposite charges on two metal plates(blue and red) separated by an insulating

material called a dielectric (orange).

The plates create the double-layer bypolarizing the electrolyte (yellow) in between

them.


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TYPES OF SUPERCAPACITORS


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1.EC DOUBLE LAYER CAPACITORS

The term electrochemical double layer capacitor is mostcommonly used for carbon based double layer capacitorsbecause of its high capacitance value.

It generally denotes the supercapacitor having non- faradaicreactions at both electrodes


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CARBON SUPERCAPACITOR


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2.PSUEDOCAPACITOR ORULTRACAPACITOR

In a pseudocapacitor, there are two basic reactions, which leadto electrochemical cell.

Both occur at the interface between a conductor and an

electrolyte and both benefits form very high specific surfaceareas at the electrode.

The first mechanism commonly referred to as chargeseparation, which is well documented as non-faradaic

mechanism and is the basis for EDLC.The second reaction commonly referred to as an oxidation reduction reaction due faradaic mechanism.


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HYBRID CAPACITOR:

Hybrid power system is a new highly reliable energy

storage device. It is a combination of EDLC and a battery. (eg. Cand Li-ion). Hence it is known as capattery (capacitor battery)



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WHY HYBRID?

In supercapacitor two symmetric capacitors are connected in seriesand the total capacitance is halved.

1/Ctotal = 1/C + 1/C

Ctotal = C/2.

But in a hybrid supercapacitor, one of the electrodes is replaced bya battery electrode. So we can get the total capacitance of the

single capacitor electrode with the added advantage of batteryelectrode.


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UC APPLICATIONS

Transmission line:A transmissionUltracapacitor (TUCAP), based on emitterturn-off (ETO) thyristor technology.

Combined UC and battery UPS:

By combining an UC with a battery-basedUPS system, the life of the batteries can beextended.

The UC provides power during short-durationInterruptions.

The batteries provide power only during the

longer interruptions.


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Contd.

Area voltage stabilizer/power conditioner:Larger-scale UC systems could provide briefbursts of energy to filter voltage sags on the

distribution system.System frequency and stability control: Theability to absorb and reject energy quickly canmake UC useful for system stability control and

as a frequency-regulation tool.


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Contd.

Micro grid micro generation:Ultracapacitor is used as an energy storagedevice in a micro source system connected

to micro grid.


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CONCLUSIONS

The supercapacitors energy storage system cansupply the instantaneous power for the back up the

loads even though the voltage may drop up to 100V. The SCESS can supply energy to the line no ofhours in case of steady demand. As the cost of thesupercapacitors is predicted to fall with the time, itis independent of charging and discharging cycle,life is very much high and efficiency is also quitehigh.


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FORMULAE USED

Specific Capacitance =Current x Discharge time

Voltage x weight

Specific Power =Current x Voltage

weight

Specific Energy =Current x Voltage x Discharge time

weight


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FUTURE WORK

Finding the cycle life behavior of this capacitor and variationof properties with cycle life.

Continuing the same work for the LiCoO2 cathode materialprepared by various methods and comparing their results withthe results of LiMn2O4.


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THANK YOU

6985249 introduction to super capacitors

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