Capacitor is a component that stores electric charge. The energy storage principle of general capacitor and ultra capacitor (EDLC) is the same, both store charge in the form of electrostatic field, but super capacitor is more suitable for quick release and storage of energy, especially for precision energy control and instantaneous load devices.
Let’s discuss the main differences between conventional capacitors and super capacitors below.
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Comparison Items |
Conventional Capacitor |
Supercapacitor |
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Overview |
Conventional capacitor is a static charge storage dielectric, which may have a permanent charge and is widely used. It is an indispensable electronic component in the field of electronic power. | Supercapacitor, also known as electrochemical capacitor, double layer capacitor, gold capacitor, Faraday capacitor, is an electrochemical element developed from the 1970s and 1980s to store energy by polarizing the electrolyte. |
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Construction |
A conventional capacitor consists of two metal conductors (electrodes) that are close together in parallel but not in contact, with an insulating dielectric in between. | A supercapacitor consists of an electrode, an electrolyte (containing electrolyte salt), and a separator (preventing contact between the positive and negative electrodes). The electrodes are coated with activated carbon, which has tiny pores on its surface to expand the surface area of the electrodes and save more electricity. |
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Dielectric materials |
Aluminum oxide, polymer films or ceramics are used as dielectrics between electrodes in capacitors. | A supercapacitor does not have a dielectric. Instead, it uses an electrical double layer formed by a solid (electrode) and a liquid (electrolyte) at the interface instead of a dielectric. |
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Principle of operation |
The working principle of capacitor is that the charge will be moved by the force in the electric field, when there is a dielectric between the conductors, it hinders the charge movement and makes the charge accumulate on the conductor, resulting in the accumulation of charge storage. | Supercapacitors, on the other hand, achieve double-layer charge energy storage by polarizing the electrolyte as well as by redox pseudo-capacitive charges. The energy storage process of supercapacitors is reversible without chemical reactions, and thus can be repeatedly charged and discharged hundreds of thousands of times. |
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Capacitance |
Smaller capacity. The general capacitance capacity ranges from a few pF to several thousand μF. |
Larger capacity. The capacity of supercapacitor is so large that it can be used as a battery. The capacity of supercapacitor depends on the distance between electrodes and the surface area of electrodes. Therefore, the electrodes are coated with activated carbon to increase the surface area to achieve high capacity. |
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Energy density |
Low | High |
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Specific energy |
<0.1 Wh/kg | 1-10 Wh/kg |
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Specific power |
100,000+ Wh/kg | 10,000+ Wh/kg |
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Charge/discharge time |
The charging and discharging times of conventional capacitors are typically 103-106 seconds. | Ultracapacitors can deliver charge faster than batteries, as fast as 10 seconds, and store more charge per unit volume than conventional capacitors. This is why it is considered between batteries and electrolytic capacitors. |
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Charge/discharge cycle life |
Shorter | Longer (generally 100,000 +, up to 1 million cycles, more than 10 years of application) |
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Charging/discharging efficiency |
>95% | 85%-98% |
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Operating temperature |
-20 to 70℃ | -40 to 70℃ (Better ultra-low temperature characteristics and wider temperature range) |
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Rated voltage |
Higher | Lower (typically 2.5V) |
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Cost |
Lower | Higher |
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Advantage |
Less loss High integration density Active and reactive power control |
Long life span Ultra high capacity Fast charge and discharge time High load current Wider operating temperature range |
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Application |
▶Output smooth power supply; ▶Power Factor Correction (PFC); ▶Frequency filters, high pass, low pass filters; ▶Signal coupling and decoupling; ▶Motor starters; ▶Buffers (surge protectors and noise filters); ▶Oscillators. |
▶New energy vehicles, railroads and other transportation applications; ▶Uninterruptible power supply (UPS), replacing electrolytic capacitor banks; ▶Power supply for cell phones, laptops, handheld devices, etc.; ▶Rechargeable electric screwdrivers that can be fully charged in minutes; ▶Emergency lighting systems and high-power electrical pulse devices; ▶ICs, RAM, CMOS, clocks and microcomputers, etc. |
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Post time: Dec-22-2021