Supercapacitor energy storage technology and its application

Supercapacitor is a new type of energy storage element developed in recent years, which has the characteristics of high power density, long life, no maintenance and rapid charge and discharge. The classification, energy storage principle and performance characteristics of supercapacitors are describedcurrent application fields of supercapacitors and the problems that need attention in application are introduced .

The principle of energy storage of supercapacitors

According to the principle of energy storage, supercapacitors can be divided into electric double layer capacitors and Faraday quasi-capacitors.

(1) The basic principle of electric double layer capacitor

The basic principle of electric double-layer capacitors is a new type of electronic component that uses the interfacial electric double layer formed between electrodes and electrolytes to store energy. When the electrode is in contact with the electrolyte, due to the action of Coulomb force, intermolecular force or interatomic force, two layers of charges with opposite signs appear at the solid-liquid interface, which is called the interface electric double layer. The energy storage of this capacitor is achieved by electrochemically polarizing the electrolyte solution, and no electrochemical reaction occurs, and this energy storage process is reversible.

(2) The basic principle of Faraday quasi-capacitor

After electric double layer capacitors, Faraday quasi-capacitors, referred to as quasi-capacitors, were developed. The capacitance is a two-dimensional or quasi-two-dimensional space on the electrode surface or bulk phase, where electroactive substances undergo underpotential deposition, and a high degree of chemical adsorption, desorption or redox reaction occurs, resulting in a capacitance related to the electrode charging potential. For the Faraday quasi-capacitance, the process of storing charges not only includes the storage on the electric double layer, but also includes the charge stored in the electrode due to the redox reaction of the ions in the electrolyte in the electrode active material.

Characteristics of supercapacitors

Supercapacitor is a better energy storage element between traditional physical capacitors and batteries, and its huge advantages are as follows: ①High power density. The internal resistance of supercapacitors is small, and rapid charge storage and release can be achieved both at the electrode/solution interface and within the electrode material itself. ② long charge-discharge cycle life. The supercapacitor has no electrochemical reaction during the charging and discharging process, and its cycle life can reach more than 10,000 times. ③The charging time is short. A full charge only takes a few minutes. ④ Achieve high specific power and high specific energy output. ⑤ Long storage life. ⑥ High reliability. Ultracapacitors work with no moving parts and minimal maintenance. ⑦ Ambient temperature has little effect on normal use. The normal operating temperature range of supercapacitors is -25 ℃ ~ 75 ℃. ⑧It can be used in parallel at will to increase the capacitance; if the voltage equalization is adopted, it can also be used in series to improve the voltage level.

Application of supercapacitor energy storage technology

As a high-power physical secondary power supply, supercapacitors are widely used in various fields of the national economy. All developed countries have listed the research on supercapacitors as national key strategic research projects.

Tram power

Due to the very high power density of supercapacitors, it can well meet the power requirements of electric vehicles when starting, accelerating, and climbing, and can be used as acceleration or starting power for hybrid electric vehicles. Using the supercapacitor in parallel with the battery as a power source can reduce the size and weight of the battery and prolong the service life of the battery.

Electronic power supply

Supercapacitors can be used not only as power sources for small devices such as optoelectronic functional electronic watches and computer memory, but also on satellites. The power supply used on satellites is mostly a hybrid power supply composed of solar energy and batteries. Once supercapacitors are installed, the satellite's pulse communication capability will be improved. Due to the fast charging properties of supercapacitors, supercapacitors are undoubtedly an ideal power source for devices that require fast charging, such as power tools and toys. It is introduced that in the field of mobile communication power supply, the electrochemical electric double layer capacitor will be mainly used to mix with other power sources to form a power supply due to its high power density and low energy density, and can also be used for short-term power backup and protection. memory data.

Applications in Power Systems

The vast majority of high-voltage substations and switch stations use electromagnetically operated switch mechanisms, which are specially equipped with capacitor energy storage silicon rectifier switching devices as DC power supplies for switching operation, control and protection. However, the electrolytic capacitor of the capacitor energy storage type has limited capacity and poor reliability.