Lithium-ion batteries degrade over time. There's no getting around this fact. GM is going out of its way to pamper the Volt's pack so as to guarantee up to 40 miles of pure electric range even at 10 years or 150,000 miles of driving. But what happens beyond that?

Most experts believe the Volt's battery will have anywhere from 50% to 75% of its original capacity after 10 years. Since 8kwh of energy are required to deliver 40 miles of driving, when the battery drops below 8 kwh of storage potential, the range should reduce.

GM's Director of Hybrids and EVs, Bob Kruse, predicts the Volt will continue to function successfully even after 10 years. "People will continue to use them well after that period of time," he says. "That’s the beauty of the Voltec system. As the battery begins to age it will eventually have less capacity but it still will provide some capacity and some amount of electric range."

Asked if the software and controls could dysfunction if there is less than 8kwh of energy left Kruse promises, "the software and the control system will be there to allow the customer to utilize what battery capacity if left."

I asked him about is whether the system will continue to operate within a 50% band of the now smaller total capacity.

"I'm not going to talk about that because it is highly prized intellectual property," said Kruse. "That whole notion of how you make this successful, how you use the battery, how you treat the battery, how you charge and discharge it is all central to our promise and how we do that and what we are going to do, as open as we are, I'm not interested in telling my competitors things that I don’t want them to know at this point in time."

I don't blame him.