The supercapacitor technology is very interesting and is an area of research. Here is a ppt that summarises everything pertaining to this field.

1. SUPERCAPACITORS
Submitted by:
SACHIN BANSAL
2K13/EL/075

2.  Introduction
 Evolution
 Principles
 Types
 Construction
 Modelling
 Electrical parameters
 Standards
 Applications
 Market Opportunity
 Conclusion
CONTENTS

3. INTRODUCTION
Supercapacitor is the generic term for a family of
electrochemical capacitors.
They are electrical energy storage devices with relatively high
energy storage density simultaneously with a high power
density. A specific power of 5,000 W/kg can be reached.
They exhibit very high degree of reversibility in repetitive
charge-discharge cycling. Cycle life over 5,00,000 cycles has
been demonstrated.
They support a broad spectrum of applications (low current for
memory backup, short-term energy storage, burst-mode
power delivery, regenerative braking, etc.)
They have many trade/series names: BestCap, BoostCap,
PseudoCap, EVerCAP, Faradcap, GreenCapUltracapacitor, PAS
Capacitor, EneCapTen, etc.

4. EVOLUTION
 1957: H. Becker at General Electric develops first patent,
using porous carbon electrodes.
 1966: SOHIO develops another version.
 1970: Donald Boos prepares disc-shaped electrolytic
capacitor.
 1971: SOHIO licenses technology to NEC, who finally
produce first commercially successful double-layer
capacitors, marketing them as ‘supercapacitors.’
 1975-1980: Brian Conway explains the working principles
through extensive research.
 1978: Panasonic markets ‘Goldcaps’.
 1987: ELNA introduces ‘Dynacaps’.

5.  1982: First low resistance supercapacitor developed by
PRI as “PRI Ultracapacitor”.
 1992: US Department of Energy initiates development
program at Maxwell Laboratories.
 1994: David Evans develops first hybrid supercapacitor.
 2007: FDK pioneers lithium-ion capacitors.
 Current manufacturers:
NEC and Panasonic in Japan
Epcos, Cooper and AVX in USA
Cap-XX in Australia
Tavrima in Canada
ESMA in Russia
Ness Capacitor Co. in Korea
Kold Ban is international marketer

6. PRINCIPLES
 There are 2 electrodes, separated by a separator,
connected by an electrolyte
 Capacitance value is determined by two storage
principles.
I. Double-layer capacitance: electrostatic storage
achieved by charge separation in a Helmholtz double
layer at the electrode-electrolyte interface.

7. II. Pseudocapacitance: Faradaic electrochemical storage with
electron charge transfer achieved by surface redox
reactions
 Both principles contribute to the total capacitance, their
ratio depends upon the electrode design & the electrolyte
composition

8.  The 2 electrodes form a series circuit of two individual capacitors
C1 and C2, so, total capacitance is given by .
 For symmetric capacitors, C1 = C2 = C, so, Ctotal = (0.5) C
 For asymmetric capacitors, C1 << C2, so, Ctotal ≈ C1

9. TYPES
 Different types of supercapacitors, based on the type of
electrode are as follows.
I. Electrochemical double-layer capacitors (EDLCs):
 Have activated carbon electrodes or derivatives
 No charge-transfer, non Faradaic
 Advantages:
 Higher energy density than conventional capacitors,
comparable power densities, greater cyclability
 Disadvantage:
 Cannot match energy density of mid-level batteries
II. Pseudocapacitors:
 Have metal oxide or conducting polymer electrodes
 Ions diffuse into pores, undergo fast, reversible surface
reactions

10.  Advantage:
Higher energy density & capacitance than EDLCs
 Disadvantages:
Lower power density than EDLCs, limited life cycle,
expensive electrode material
III. Hybrid Capacitors:
 combine the advantages & mitigate the disadvantages of
the first 2 types
 3 types of electrodes: composite, asymmetric, battery-
type
 Advantages:
Most flexible performance, high energy and power
density without sacrifices in cycling stability
 Disadvantages:
Relatively new and unproven, more research required

11. CONSTRUCTION
• A supercapacitor cell consists of 2 electrodes, a separator,
and an electrolyte
I. Electrodes:
 Made of metallic collector and, of an active material
 Applied as a paste or powder on metal foils
 Smaller pore size increases capacitance and energy
density but also increases ESR and decreases power
density
II. Electrolytes:
 Provide electrical connection between electrodes
 Should be chemically inert, non-corrosive, less viscous
 Determine operating temperature range, voltage, ESR,
capacitance
 Organic electrolytes give higher energy density, but lower
power density

12.  Aqueous electrolytes have higher power density, conductivity
III. Separators:
 Ion-permeable membrane, allowing charge transfer but
forbidding electronic contact between the electrodes
 Should be porous to ions, chemically inert
 Examples: PAN films, woven glass fibres
• The construction is rolled/folded to cylindrical/rectangular
shape, stacked in Al can, impregnated with electrolyte that
enters electrode pores
• The housing is hermetically sealed to ensure stable bahaviour
C
1
C
2
C
3
C
4
C
5
+
--
Ultracapacitor stack:

13. MODELLING
• A first order approximation of EDLC behaviour is a circuit
consisting of ESR and EPR or Rleakage
• A more accurate model presents a circuit with cascaded RC
elements, containing immediate, delayed and long-term
branches, and Rlea

14. • A treatment of the capacitance in porous electrodes results in
each pore being modelled as a transmission line.
• The transmission line models a distributed double-layer
capacitance and a distributed electrolyte resistance that extends
into the depth of the pore.

15. ELECTRICALPARAMETERS
I. Capacitance:
 DC capacitance is measured using the formula:
 AC capacitance varies greatly with frequency and is
measured using the formula:
 Discharge current is calculated using the standards given
for different application conditions.
II. Operating voltage:
 Vrated- max. DC voltage within specified temp. range,
includes safety margin for electrolyte breakdown voltage

16. Applications require values more than Vrated, so, series
connection is required, for which balancing is also needed
III. Internal resistance:
 DC resistance is calculated using the formula:
 This is not same as ESR(rated value).
 It is time-dependent & affects charge/discharge currents
and times.
IV. Current load and cycle stability:
 Much higher than for rechargeable batteries
 Internal heat generated:
 Lower current load increases life, number of cycles
 For “peak-power current”, robust design is required

17. V. Energy density and power density:
 Energy,
 Effective realized energy,
 Maximum theoretical power,
 Realistic effective power,
 In these terms, supercapacitors bridge the gap b/w
batteries & classical capacitors.
 Ragone chart shows relation b/w energy density & power
density, used to compare performance

18. VI. Lifetime:
 Depends on capacitor temperature & voltage applied
 Higher temp. causes faster evaporation of electrolyte
 Acc. to standards, capacitance reduction of 30% &
resistance increase of 4 times is a “wear-out failure”
 Manufacturers specify it as “tested time(hrs)/max. temp.”,
using endurance test
 For every 10 ̊C rise in temp., estimated life doubles.
 Development of gas depends on the voltage.
 No general formula relates voltage to lifetime.

19. VII. Self-discharge:
 Caused because of surface irregularities in electrodes
 Known as leakage current
 Depends on capacitance, voltage, temperature &
chemical stability of electrode/electrolyte combination
 It is low at room temp.,specified in hours, days or weeks
VIII.Polarity:
 In theory, supercapacitors have no polarity, but
recommended practice is to maintain the prod. polarity
 Polarities differ for capacitors and batteries.
 A –ve bar in the insulating sleeve identifies the cathode.

20. STANDARDS
 IEC/EN 62391-1, for use in electronic equipment
(further has 4 application classes)
 IEC 62391-2, for power application
 IEC 62576, for use in hybrid vehicles
 BS/EN 61881-3, railway applications, rolling stock
equipment

21. APPLICATIONS
• Time t a supercapacitor can deliver constant current is
given as
• For constant power P, this time is given by
• Potential applications: pulse power systems (defibrillators,
detonators, lasers), load levelling, UPS, quick charge
applications (wireless power tools), high cycle and long life
systems (sensors, metro buses), all-weather applications
• In general, there are 2 domains of application.
I. High power applications, where short time power peaks
are required. Examples: HEVs, starters
II. Low power applications, where batteries have
insufficient lifetime performance. Examples: UPS,
security systems

22. • Typical applications:
Consumer electronics
Tools
Buffer power
Voltage stabiliser
Energy harvesting
Medical
Transport
Energy recuperation

23. MARKETOPPORTUNITY
Obstacles to
grow
• Relatively high cost
• Competition with batteries well established on
the market
• Consumer conservatism
Factors to growth
• New market opportunities like HEVs, Smart Grid,
Alternative/Renewable Energy
• Growing ecology restrictions for competitors
• Operation in a wide temperature range
• Good prospects or a combined power supply
$560 mln.
Fig. 5. Annual Sales divided by segments
(Ultracapacitors - A Global Industry and Market
Analysis, Innovative Research and Products , Inc. 2006)
70.8
144.8
111.4
161.489.6
254.4
0
100
200
300
400
500
600
2006 2011
Electronics UPS and power tools Transportation
$272 mln.
World Supercapacitors Market, $ mln.

24. CONCLUSION
• Supercapacitors may be used wherever high power delivery
or electrical energy storage is required. Hence, numerous
applications are possible.
• Their use allows a complementation of normal batteries. In
combination with batteries, they can improve maximum
instantaneous output power and battery lifetime.
• Major areas of R&D in supercapacitors (future of
supercaps):
Reduction of material impurities (that cause self-discharge)
Improvement in fabrication & packaging methods
Reduction in the ESR to increase power
Optimization of electrolytes & electrodes
Further exploration of hybrid capacitors- the most
promising, but least developed supercap technology

25. THANK YOU