The application of supercapacitors in the field of rail transit is relatively mature. It can realize electric traction regenerative braking, stabilize the voltage of the catenary, save power energy, and ensure the stable power supply of the power system. Whether it is an ordinary capacitor or a supercapacitor, storing electric charge or electrical energy is a critical performance. Supercapacitors have a larger charge storage capacity and can meet the needs of more electronic components. But supercapacitors behave similarly to conventional capacitors during use. The functions of the new capacitor device are concentrated in: bypass, decoupling, energy storage, etc., which have obvious regulation effects on circuit operation or stored charge.

The research on the aging mechanism of supercapacitors in different application fields and the research on the control strategy of supercapacitor energy storage systems will be another research hotspot of supercapacitors, which will help to optimize the design of supercapacitor energy storage systems. Compared with battery energy storage, supercapacitors will have great advantages in power density, maintenance cost, service life and environmental adaptability, and will become an ideal choice for energy storage systems in electrical, power, electronics and other industries.

Think of an electric double-layer supercapacitor as 2 inactive porous plates suspended in an electrolyte, and a voltage is applied to the 2 plates. The potential applied to the positive plate attracts the negative ions in the electrolyte, and the negative plate attracts the positive ions, thus forming an electric double layer capacitor on the surface of the two electrodes. In the field of new energy vehicles, supercapacitors can be used in conjunction with secondary batteries to achieve energy storage and battery protection. Usually, the supercapacitor module is used in conjunction with the lithium-ion battery. The perfect combination of the two forms a power vehicle power supply with stable performance, energy saving and environmental protection, which can be used in hybrid electric vehicles and pure electric vehicles.