Maxwell Technologies has declared that its ultracapacitors have been selected to be used as an energy storage component for Bombardier Transportation's braking energy recuperation system called EnerGstor.
Each EnerGstor stationary 'wayside' unit integrates an array of Maxwell ultracapacitors that can store up to 2 kWh of electrical energy produced by the braking energy recuperation system of a rail vehicle. Recuperative braking can be achieved by backward rotation of the electric motor of a vehicle, which causes the vehicle to stop due to the resistance of the motor. Moreover, the backwardly running electric motor operates as a dynamo or an electric energy generator, which transforms kinetic energy into electrical energy.
An energy storage unit based on ultracapacitors can be used to store the energy released by a braking system. An ultracapacitor is capable of operating at very high temperature, thus enabling system reliability and reducing operating costs. Its long operating life makes it suitable for public transit environment.
Contrary to energy production and storage by batteries through a chemical reaction, energy is stored in an electric field by ultracapacitors. This electrostatic energy storage method allows ultracapacitors to charge and release within a fraction of a second. Ultracapacitors reliably run through ³ 1 million charge/discharge cycles at temperatures ranging between -40°C and +65°C. They also resist vibration and shock. Maxwell Technologies provides ultracapacitor cells with a capacitance range between 1 and 3,000 F and multi-cell modules with a voltage range between 16 and 125 V.
Source: http://www.maxwell.com