ABSTRACT
Supercapacitors (or ultracapacitors or electrochemical capacitors) are a relatively new energy storage system which was the object of an important scientifi c and industrial development during the last years. Supercapacitors provide a higher energy density than dielectric capacitors and a higher power density than batteries. They are particularly adapted for applications which require energy pulses during short periods of time, e.g., seconds or tens of seconds. They are recommended for automobiles, tramways, buses (being able to boost the system during acceleration and to recover energy during braking, the so-called regenerative braking), cranes, forklifts, wind turbines, electricity load leveling in stationary and transportation systems, etc. In the case of automobiles, they are combined to another power source (lead-acid battery, nickel-metal hydride battery, lithium-ion battery, internal combustion engine, fuel cell) which enables the autonomy of the system (Figure 8.1).
