The document provides a comprehensive overview of supercapacitors, their evolution, principles, types, construction, electrical parameters, standards, applications, and market opportunities. Supercapacitors are energy storage devices characterized by high energy and power density, capable of undergoing extensive charge-discharge cycles. Key applications include consumer electronics, transportation, and energy harvesting, with ongoing research aimed at enhancing their performance and reducing costs.

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