Electrical energy storage is electromagnetic energy storage, and electric energy storage is also called power system energy storage. Electrical energy storage mainly includes supercapacitor energy storage and superconducting energy storage.、
1. Supercapacitor energy storage is developed according to the theory of electrochemical double layer, also known as electric double layer capacitor.The distance between the two charge layers is very small (generally less than 0.5mm), and the special electrode structure is used to make the electrode surface area tens of thousands of times increase, resulting in a large capacitance.
Advantages: long life (one million cycles/10 years of DC service life), many cycles; large specific power, 16 kW/kg, fast charge and discharge time, fast response; high efficiency; less maintenance, no rotating parts; Wide operating temperature range, environmental friendliness, etc.
Disadvantages: The dielectric withstand voltage of supercapacitors is very low, and the capacitors made generally have a withstand voltage of only a few volts. The energy storage level is limited by the withstand voltage, so the stored energy is not large; the energy density is low; the investment cost is high; there is a certain self-discharge rate.
2. Superconducting energy storage Energy is stored in the magnetic field in the form of DC current circulating in the superconducting coil.
Advantages: Because the electric energy is directly stored in the magnetic field, there is no energy form conversion, the charging and discharging of energy is very fast (a few milliseconds to tens of milliseconds), and the power density is very high; the extremely fast response speed can improve the electric energy of the distribution network quality.
Disadvantages: superconducting materials are expensive; a large amount of energy is required to maintain low-temperature refrigeration operation; low energy density (can only be maintained in seconds); although commercial low-temperature and high-temperature superconducting energy storage products are available, they are expensive and complicated to maintain , there are few applications in the power grid, and most of them are experimental.