Characteristics and advantages of supercapacitors

Characteristics and advantages of supercapacitors

The principle of supercapacitors is not a new technology, and most common supercapacitors have a double layer structure. Compared with electrolytic capacitors, this type of supercapacitor has a very high energy density and power density. Compared with traditional capacitors and secondary batteries, supercapacitors have higher capacity to store charge than ordinary capacitors, and are characterized by fast charging and discharging, high efficiency, no pollution to the environment, long cycle life, wide temperature range, and high safety.

Supercapacitors have a wide range of applications. When combined with high energy density materials such as fuel cells, supercapacitors can provide rapid energy release to meet high power requirements, allowing fuel cells to be used solely as energy sources. At present, the energy density of supercapacitors can reach up to 20kW/kg, and they have begun to seize this market share between traditional capacitors and batteries.

In applications that require high reliability but do not require high energy, supercapacitors can be used to replace batteries, or supercapacitors can be combined with batteries for applications that require high energy, allowing for the use of smaller and more economical batteries.

High voltage supercapacitors

The ESR value of supercapacitors is very low, which allows them to output large currents and quickly absorb large currents. Compared with the principle of chemical charging, the working principle of supercapacitors makes the performance of this product more stable, therefore, the service life of supercapacitors is longer. For devices like electric tools and toys that require fast charging, supercapacitors are undoubtedly an ideal power source.

Any supercapacitor will discharge through an internal parallel resistor when energized, and this discharge current is called leakage current, which will affect the self discharge of the supercapacitor unit. Similar to some secondary battery technologies, the voltage of supercapacitors needs to be balanced when used in series because there is leakage current, and the size of the internal parallel resistance will determine the voltage distribution on the series connected supercapacitor units.

When the voltage on the supercapacitor stabilizes, the voltage on each unit will change with different leakage currents, rather than with different capacitance values. The larger the leakage current, the lower the rated voltage; conversely, the smaller the leakage current, the higher the rated voltage. This is because leakage current can cause discharge of supercapacitor units, resulting in a decrease in voltage, which subsequently affects the voltage of other units connected in series with it (assuming that these connected units are powered by the same constant voltage).