VANCOUVER – Nissan Motor Co. Ltd. is unsure if its Leaf electric vehicle will be redone as often as more conventional models on the market.

Most cars sold in the U.S. today with internal-combustion engines go through a full redesign every four or five years.

But Larry Dominique, Nissan North America Inc.’s chief product planner, says whether the Leaf will see a next generation that soon remains undecided.

The car goes on sale in December in select U.S. states, mostly in the West, before undergoing a national rollout in 2011.

“(There are a) lot of open questions right now,” Dominique tells Ward’s in an interview here. “Do you go for an extended lifecycle of six, seven years, or do you just do a normal lifecycle?”

The former, longer-range scheme would involve Nissan upgrading the Leaf’s charging and motor technology, two things already being worked on with what Dominique says will take “limited investment.”

“We’re already going to increase the size of the onboard charger so it can charge faster, (and) we’re looking to see if we can get more efficiency out of the motor during the lifecycle.”

The Leaf takes eight hours to charge via a 220V outlet and has an AC motor producing 80 kW (107 hp) of power and 206 lb.-ft. (280 Nm) of torque.

Dominique says much of Nissan’s indecision about the length of the Leaf’s lifecycle comes down to expected-but-not-guaranteed improvements in lithium-ion battery technology.

And even if future Li-ion breakthroughs are made in a laboratory, affordability may be a challenge, he says.

But such uncertainty isn’t stopping Nissan from planning for a day when car buyers will be able to choose the type of battery that fits their driving needs.

Someone with a shorter daily commute could opt for a Li-ion with a 100-mile (161-km) range, while those covering greater distances could select a more expensive 150-mile (241-km) battery, Dominique says.

“We want to do everything we can to increase range,” he says. “If we can get a new battery that’s more advanced into production during the life of (the) Leaf, we’re going to do it.”

The Leaf debuting in December can travel 100 miles on a single charge to its 90-kW Li-ion battery, Nissan claims.

Dominique says no structural revisions to the Leaf would be necessary to accommodate a longer-range battery, assuming future Li-ion range can be improved without increasing the battery pack size.

“You (would) offer the old battery at one cost and the new battery at a different cost,” he says. “We’re not going to redesign the vehicle. We can just add more energy to the same size cell pack.”

Earlier this week, Nissan and the state of Hawaii inked a pact to develop plans for deploying, operating and maintaining an EV charging infrastructure.

Hawaii is offering EV buyers a $4,500 tax credit. Including the federal tax credit of $7,500, a Leaf purchased in the state could cost as low as $20,780.