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Electrochemical
Capacitors
Patents and Technical
Papers
Overview

Electrochemical
capacitors (ECs) have been an important development in recent years in the field
of energy storage. These devices operate between rechargeable batteries and
electrolytic capacitors with respect to energy and power performance.
Electrochemical capacitors differ from batteries in that they do not store
energy in redox reactions that occur in the electrode structure. Electrochemical capacitors store energy through electrostatic
interactions that occur in the electrode and solution interface region, also
known as the double layer. Ionix manufactures a variety of cell
designs and configurations for high reliability applications. Please contact
us for more information concerning our products.
| Performance Characteristics of
Energy Storage Technologies |
| Performance Parameter |
Lead Acid Battery |
Ultracapacitor |
Conventional Capacitor |
| Charge Time |
1 to 5 hours |
0.3 to 30 seconds |
10-3
to 10-6 seconds |
| Discharge Time |
0.3 to 3 hours |
0.3 to 30 seconds |
10-3
to 10-6 seconds |
| Energy Density (Wh/kg) |
10 to 100 |
1 to 10 |
< 0.1 |
| Cycle Life |
1,000 |
> 500,000 |
> 500,000 |
| Specific Power (W/kg) |
> 100 |
> 1,000 |
> 10,000 |
| Charge/Discharge Efficiency |
70% to 85% |
85% to 98% |
> 95% |
A key advantage of this technology is the reversible
nature of this process. As a result, an electrochemical capacitor can be charged and
discharged hundred of thousands of times in comparison to batteries, which can
only withstand thousands of discharge cycles. At Ionix we are developing advanced materials that improve
the performance of these emerging devices. In addition to their unique combination of power and energy
and their high cycle life there are a host of additional characteristics that
make electrochemical capacitor attractive in a variety of applications.
These characteristics are outlined in the table below.
| Primary Characteristics |
Secondary Characteristics |
|
• High Power Density |
• Long Life
Cycle (Greater than 100,000) |
|
- Competitive with high power |
• Excellent cold
temperature performance (-45 °C) |
| rechargeable batteries |
• Fast recharge
capability |
|
• High Energy Density |
• Easily
monitored state of charge |
|
- Order of magnitude higher than |
• Low cost base
materials |
|
electrolytic capacitors |
• High cycling
efficiency |
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• Leakage
current is stable over life |
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•
Significant surge capability (2.7V) |
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• No
charge/discharge memory |
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• High
reliability |

There are many applications that can benefit from the
unique combination of high reliability, power, and energy provided by
electrochemical capacitor technology. Several applications have drawn
considerable attention. These applications include:
regenerative braking in hybrid vehicles, cold engine starting, load leveling PEM
fuel cells, ride-through backup power systems, and digital electronic devices.
Each one of these applications represents a multi-billion dollar opportunity, if
the technology can be successfully commercialized.
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