AFS Trinity Power, a small company in Bellevue, Wash., says it has the problem licked. In January, the company rolled out a small S.U.V. that uses lithium-ion batteries nursed along by common electrical storage devices called capacitors.
Capacitors take a trickle of energy and store it up so it can be released in great bursts. They can also take a huge slug of energy quickly, and then deliver it slowly. This is at the heart of AFS Trinity's innovation.
Electrically speaking, the capacitors, which look like an 18-pack of shrink-wrapped Red Bull cans, sit between the batteries and the wheels, so the flow into or out of the batteries is always fairly gentle, even if the car is making jackrabbit starts or panic stops.
Together, they store very little energy -- less than one kilowatt-hour, a tiny fraction of what the lithium-ion batteries do -- but they can charge and discharge almost instantly, almost forever, without damaging themselves, said Edward W. Furia, chief executive of AFS Trinity.