Bombardier Transportation has selected Maxwell Technologies' ultracapacitors as the energy storage element for its EnerGstor braking energy recuperation system.
The ultracapacitor-based energy storage unit captures and stores energy that otherwise would be wasted in a conventional, friction-based braking system. Maxwell noted each stationary 'wayside' EnerGstor unit incorporates an ultracapacitor array that can store about 2kWh of electrical energy generated by a rail vehicle's braking energy recuperation system.
Maxwell's president and chief executive officer David Schramm said Bombardier Transportation has developed an innovative energy storage system that enhances the efficiency and reliability of rail transit operations. "This opportunity to work closely with a world leader in transportation technology is helping us to better meet the requirements of electric and hybrid vehicles, and continue developing products that deliver superior performance and value," Schramm said.
Bombardier said the EnerGstor braking energy recuperation system offers multiple benefits to rail system operators, including a 20-30% reduction in grid power consumption and improved regulation of line voltage across a multi-stop rail system. The system also results in reduction in brake maintenance expense and backup power to enable vehicles to reach a station in the event of a grid power failure.
Maxwell said that recuperative braking is accomplished by running the vehicle's electric motor backwards, thus stopping the rail with the motor's resistance. The offering features an electric motor running backwards, which acts as an electric energy generator or dynamo that converts kinetic energy into electrical energy that can be stored for future use.
Maxwell noted ultracapacitors also provide long operational life in the demanding public transit environment and function normally at extreme temperatures, thereby contributing to system reliability.
Ultracapacitors store energy in an electric field, unlike batteries, which produce and store energy by means of a chemical reaction.This electrostatic energy storage mechanism enables ultracapacitors to charge and discharge in few seconds, perform normally over a broad temperature range of -40 to +65°C, operate through one million or more charge / discharge cycles, and resist shock and vibration.
Maxwell offers ultracapacitor cells ranging in capacitance from one to 3,000 farads and multi-cell modules ranging from 16V to 125V.
Maxwell ultracapacitors are also being employed in several other transportation applications, including a stop-start idle elimination system developed by Continental for micro-hybrid diesel automobiles now being produced by PSA Peugeot Citroen in Europe.
Caption: Maxwell Technologies manufactures energy storage and ultracapacitors which are used in consumer and industrial electronics, transportation and telecommunications. Credit: Maxwell Technologies.