Increased competition in the electric vehicle market played a role in Zenn’s decision to not make the cityZENN car.
A press release from Zenn Motor Company.
Greencarcongress indicates that Zenn Motor and EEstor still say first production units of the EESU are expected by the end of the year (2009).
The EESU is a high-power-density multi-layered barium titanate ceramic ultracapacitor that the companies say is expected to provide energy densities of more than 450 Wh/kg and more than 700 Wh/L; charge in minutes; and have extremely long life
Maxwell Technologies and Energ2 Ultracapacitors
Maxwell Technologies (another ultracapacitor company) signed a second deal for thousands-to-tens-of-thousands of units the first year , with significant expansion of the contract in the second year.
Maxwell ultracapacitors are to be used to power stop-start systems, which turn off the internal combustion engine when the vehicle slows or coasts. When the driver accelerates, the ultracapacitor provides bursts of power to re-start the engine, minimizing fuel use and relieving the vehicle's battery of high currents and repeated cycling that can shorten battery life. "It can improve fuel efficiency on a basic level in the 5 to 10 percent range," Sund said. "In heavy stop-start urban driving, it could get up to 20 percent or more savings."
Seattle startup EnerG2 plans to begin shipping ultracapacitors this year for electric rail systems and heavy-duty vehicles. Energ2 article from Venturebeat in late 2008