This is a kind of capacitor but with more quality & function which is the root cause of its application in plenty of field.

1. Ultracapacitor
By: Abu Talha Siddiqi
Electrical & Electronics

2. CONTENTS
 What is an Ultracapacitor (Introduction)?
 Technological aspects of an Ultrcapacitor
 Principle
 Construction
 Working
 Comparison with batteries and conventional capacitors
 Advantages & Disadvantages
 Applications of Ultracapacitors
 Conclusion
 References

3. INTRODUCTION
 In general, a capacitor is a device which is used to store the
charge in an electrical circuit. Basically a capacitor is made up of
two conductors separated by an insulator called dielectric.
 Ultracapacitors are modern electric energy storage devices with
very high capacity and a low internal resistance.
 Ultracapacitors utilize high surface area electrode materials and
thin electrolytic dielectrics to achieve high capacitance.
 This allows for energy densities greater than those of conventional
capacitors and power densities greater than those of batteries. As
a result, these may become an attractive power solutions for an
increasing number of applications

4. INTRODUCTION (contd..)
 Also known as supercapacitors or double-layer capacitors.
 The capacitance can be as high as 2.6 kF(kilo-farad).
 First commercial development in the Standard Oil of Ohio
Research Centre (SOHIO), in 1961. First high-power capacitors
were developed for military purposes in Pinnacle Research
Institute in early 1980’s.
 Attractive for their high energy and power densities, long
lifetime as well as great cycle number. Recent developments in
basic technology, materials and manufacturability have made
these an imperative tool for short term energy storage in power
electronics.
 Principle:- Energy is stored in ultracapacitor by polarizing the

5.  Store electrical charge in a similar manner to conventional
capacitors, but charges do not accumulate on conductors. Instead
charges accumulate at interface between the surface of a
conductor and an electrolytic solution.
 One layer forms on the charged electrode, and the other layer is
comprised of ions in the electrolyte. The specific capacitance of
such a double-layer given by
C 
A 4d
C is capacitance, A is surface area,  is the relative dielectric
constant of the medium between the two layers (the electrolyte),
and d is the distance between the two layers (the distance from
the electrode surface to the centre of the ion layer).
PRINCIPLE

6. TECHNOLOGICAL ASPECTS
Cell Construction
 An ultracapacitor cell basically
consists of two electrodes, a separator,
and an electrolyte.
 Electrodes are made up of a metallic
collector, which is the high conducting
part, and of an active material, which
is the high surface area part.
The two electrodes are separated by a
membrane, the separator, which allows
the mobility of the charged ions but
forbids the electronic conductance.
Then the system is impregnated with an
electrolyte.

7. ELECTRODES
 Electrochemical inert materials with the highest specific surface
area are utilized for electrodes in order to form a double layer with
a maximum number of electrolyte ions.
 The main difficulties are to find cheap materials, which are
chemically and electrically compatible with the electrolyte.
 As high surface active materials, metal oxides, carbon and graphite
are the most interesting.
 Capacitors for high energy applications require electrodes made of
high surface area activated carbon with appropriate surface. The
electrode capacitance increases linearly with the carbon surface
area.

8. ELECTROLYTE
 The electrolyte may be of the solid, organic or aqueous type.
 Organic electrolytes are produced by dissolving quaternary salts in
organic solvents. Their dissociation voltage may be greater than 2.5
V.
 Aqueous electrolytes are typically KOH or H2SO4, presenting a
dissociation voltage of only 1.23 V.

9. WORKING

10. WORKING(Contd..)
 There are two carbon sheets separated by a separator.
 The geometrical size of carbon sheets is taken in such a way that they have a
very high surface area.
 The highly porous carbon can store more energy than any other electrolytic
capacitor.
 When the voltage is applied to positive plate, it attracts negative ions from
electrolyte. When the voltage is applied to negative plate, it attracts positive
ions from electrolyte.
 Therefore, there is a formation of a layer of ions on both sides of the plate.
This is called ‘Double layer’ formation.
 The ions are then stored near the surface of carbon.

11. WORKING (Contd..)
 The purpose of having
separator is to prevent the
charges moving across the
electrodes.
 The amount of energy
stored is very large as
compared to standard
capacitor because of the
enormous surface area
created by the porous carbon
electrodes and the small
charge separation created by
the dielectric separator.
 The distance between the
plates is in the order of

12. COMPARISON WITH BATTERY &
CONVENTIONAL CAPACITORSThe performance
improvement for an
ultracapacitor is shown in a
graph termed as “Ragone
plot.” This type of graph
presents the power densities
of various energy storage
devices, measured along the
vertical axis, versus their
energy densities, measured
along the horizontal axis.
Ultracapacitors occupy a
region between conventional
capacitors and batteries .
Despite greater capacitances
than conventional capacitors,
ultracapacitors have yet to
match the energy densities of
mid to high-end batteries and
fuel cells.

13. COMPARISON(Contd..)

14. COMPARISON(Contd..)

15. COMPARISON WITH BATTERIES
 Very high rates of charge and discharge
Ultracapacitor charges within seconds whereas batteries takes hours.
 Little degradation over hundreds of thousands of cycles
Batteries degrade within a few thousand charge-discharge cycles.
Ultracapacitors can have more than 300,000 charging cycles, which is far more
than a battery can handle.
 Can effectively fulfil the requirement of high current pulses that can kill a battery
if used instead
Batteries fail where high charging discharging takes place whereas
ultracapacitor fares extremely well.
 Ultracapacitors are much more effective at rapid, regenerative energy storage than
batteries.

16. COMPARISON WITH CONVENTIONAL
CAPACITORS
 Differ in constructional features with respect to conventional capacitors.
 Has ability to store tremendous charge.
 Capacitance ranges up to 5000F!
 Ultracapacitors are able to attain greater energy densities while still maintaining
the characteristic high power density of conventional capacitors.
 Conventional capacitors have relatively high power densities, but relatively low
energy densities when compared to batteries. That is, a battery can store more
total energy than a capacitor, but it cannot deliver it very quickly, which means its
power density is low.
 Capacitors store relatively less energy per unit mass or volume, but what electrical
energy they do store can be discharged rapidly to produce a lot of power, so their
power density is usually high.

17. ADVANTAGES
 Long life: It works for large number of cycles without wear and aging
 Rapid charging: It takes a second to charge completely
 High power storage: It stores huge amount of energy in a small volume
 Faster release: Release the energy much faster than battery
 Low toxicity of materials used
 High cycle efficiency (95% or more)

18. DISADVANTAGES
 High self-discharge
The rate is considerably higher than that of a battery
 The amount of energy stored per unit weight is considerably lower than that of
an electrochemical battery (3-5 W.h/kg for an ultracapacitor compared to 30-40
W.h/kg for a battery).
 The voltage varies with the energy stored. To effectively store and recover
energy it requires sophisticated electronic control and switching equipment.
 Cells have low voltages
Series connections are needed to obtain higher voltages
 Low energy density
Typically holds one-fifth to one-tenth the energy of battery

19. APPLICATIONS OF ULTRACAPACITORS
 Considered as environmentally friendly solutions because they can
perform reliably in all weather conditions without having to be replaced
and disposed to landfills.
 Function well in temperatures as low as -40 oC , they can give electric
cars a boost in cold weather, when batteries are at their worst.
 Used in military projects such as starting the engines of battle tanks and
submarines or replacing batteries in missiles.
 A bank of ultracapacitors releases a burst of energy to help a crane heave
its load aloft; they then capture energy released during descent to
recharge.

20. APPLICATIONS (Contd..)
 Heavy transportation vehicles - such as
trains, metros - place particular demands on
energy storage devices. Such devices must be
very robust and reliable, displaying both long
operational lifetimes and low maintenance
requirements.

21. APPLICATIONS(Contd..)
 China is experimenting with a new form of electric bus that
runs without powerlines using power stored in large onboard
ultracapacitors. A few prototypes were being tested in
Shanghai in early 2005. In 2006, two commercial bus routes
began to use ultracapacitor buses.
 Esma-cap, Russia, developed two experimental vehicles.
Electric bus with 50 passengers capacity, maximum speed 20
km.h-1.Electric truck with payload limit 1,000 kg, maximum
speed 70 km.h-1.

22. CONCLUSION
 Ultracapacitors may be used wherever high power delivery or electrical
energy storage is required. Therefore numerous applications are
possible.
 In particular, ultracapacitors have great potential for applications that
require a combination of high power, short charging time, high cycling
stability, and long life.
 Thus, ultracapacitors may emerge as the solution for many application-
specific power systems.
 Despite the advantages of ultracapacitors in these areas, their
production and implementation has been limited to date. There are a
number of possible explanations for this lack of market penetration,
including high cost, packaging problems, and self-discharge.

23. REFERENCES
 M. Jayalakshmi, K. Balasubramanian, “Simple Capacitors to
Supercapacitors - An Overview”, Int. J. Electrochem. Sci., 3 (2008) 1196 –
1217
 John R. Miller, Patrice Simon, “Supercapacitors : Fundamentals Of
Electrochemical Capacitor Design And Operation”, The Electrochemical
Society Interface . Spring 2008
 Conway, B. E., “Electrochemical Supercapacitors: Scientific Fundamentals
and Technological Applications” , New York, Kluwer-Plenum (1999).
 Burke, A.. "Ultracapacitors: why, how, and where is the technology." Journal
of Power Sources 91(1): 37-50 (2000).
 Kotz, R. and M. Carlen "Principles and applications of electrochemical
capacitors." Electrochimica Acta 45(15-16): 2483-2498 (2000).
 Marin S. Halper, James C. Ellenbogen, “Supercapacitors: A Brief Overview”,
March 2006
 http://www.maxwell.com/pdf/uc/app_notes/ultracap_product_guide.pdf :
last accessed on 25th October 2013.

24. Thank You