Statistics show that automobiles account for more than 70% of urban pollutant gas emissions, and countries all over the world are looking for alternative fuels for automobiles. Due to the increasingly serious shortage of oil, people have gradually realized the importance of developing new energy vehicles, that is, the need to reduce dependence on oil and reduce exhaust gas emissions, so electric vehicles have developed rapidly in recent years.
Supercapacitors have high power density, short charging and discharging time, good high-current charging and discharging characteristics, long life, and low-temperature characteristics better than batteries. These excellent properties make it have a good application prospect in electric vehicles.
As a substitute for batteries, super capacitors have been continuously used in electric vehicles. Super capacitor electric vehicles generally refer to electric vehicles powered by super capacitors.
In terms of the two performance parameters of energy and power, the supercapacitor is located between the battery and the traditional capacitor, and its cycle life and charging and discharging efficiency are much higher than that of the battery. Because the service life usually exceeds the service life of electric vehicles. Therefore, super capacitors need not be maintained for life, and after use, they have loose environmental requirements and no pollution, so they are also called green energy.
Compared with chemical batteries, supercapacitor storage devices for vehicles are green energy sources and have no secondary pollution to the environment. The cycle life is long (about 100,000 times), and the cycle life of the chemical battery is short (200 to 1,000 times), and it is easy to damage. The charging speed is fast (0.3s～15min); the charging time of chemical batteries is long, generally 3～10h. The charge and discharge efficiency is high (98%), and the charge and discharge efficiency of chemical batteries is low (70%). High power density (1000～10000W/kg), low power density of chemical battery (300W/kg).
The super capacitor is completely maintenance-free and has a wide operating temperature range (-40～+70℃). The capacity change is small. When the lead-acid battery electric vehicle is used at sub-zero temperature, the driving range is reduced by 90%, while the super capacitor is only reduced by 10%.
Electric buses have high braking regenerative energy recovery efficiency. During conventional braking, the super capacitor recovery is as high as 70%, and the chemical battery energy recovery efficiency is only 5%, with relatively low cost. The price of super capacitors is twice that of lead-acid batteries, but because the lifespan of super capacitors is 100 times longer than that of chemical batteries, the overall operating cost of supercapacitor electric vehicles is much lower than that of chemical batteries.
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