The Chinese company "Ningbo CSR New Energy Technology", a subsidiary of CSR Zhuzhou Electric Locomotive (the largest train manufacturer in the world) developed graphene supercapacitors with high capacitance.
These new supercapacitors are intended to improve the efficiency of electric buses, trolleybuses and trams with fast recharge and to increase their autonomy.
Thus, a supercapacitor trolleybus should be able to travel 10 km after a charge of one minute, against 6 km for a charge of 30 seconds with the supercapacitor trolleybuses currently operated by the company. The goal is to reduce the number of intermediate charge to better adapt to the requirements of planning and urban construction.
In addition to this improvements to performance, these new supercapacitors are also more energy efficient and environmentally friendly. Ruan Dianbo, deputy technical director of CSR Zhuzhou Electric Locomotive, believes that China can save 584 GWh of electricity and avoid the emission of 6.7 million tons of carbon dioxide per year if all newly added bus (about 60,000 per year) using the new supercapacitors.
The company produced two new types of supercapacitors:
- A supercapacitor 3V / 12,000 farads with electrodes in composite of graphene and activated carbon. The operating voltage of 3V is high and strongly participates in increasing the energy density in comparison with conventional supercapacitors usually have an operating voltage of 2.7V. This supercapacitor obtained an energy density of 11.65 Wh / kg and a power density of 19.01 kW / kg.
- A supercapacitor 2.8V / 30,000 Farads in graphene nano-hybrid with an energy density of 21 Wh / kg and a power density of 2 kW / kg. The low power density may indicate that it is in fact a hybrid supercapacitor-battery or a pseudo-supercapacitor. It would thus be necessary to know if the longevity of this supercondenser is reduced with regard to the million charge cycles usually possible with standard supercapacitors.
For comparison, commercial supercapacitors of 2.7V / 3,000 farads (not 30,000F) tend to have densities of 6 Wh / kg and 13 kW / kg. The excellent supercapacitor DuraBlue Maxwell Technologies reaches 7.7 Wh / kg and 18 kW / kg for the version 2.85V / 3,400 Farads. And the new supercapacitor SkelCap 4,500F of Skeleton Technologies reaches 9.6 Wh / kg and 41 kW / kg for an operating voltage of 2.85V (10.1 Wh / kg for the prismatic version).
Compared to traditional energy storage devices such as batteries, ultracapacitors have a very fast charging time, a long life, do not pollute and do not present a risk of explosion.
With the development of graphene supercapacitors, China intends to be at forefront of global development of this energy storage system known to be used in conjunction with batteries when it does not replace them completely.
CSR Zhuzhou Electric Locomotive Company continues the development of transport means using supercapacitors having recently introduced the electric bus with the fastest charging time in the world (10 seconds thanks to supercapacitors).
Source : www.csrcap.com