To follow up on GM’s announcement on January 7th of a series hybrid car, the “Volt,” today I spoke with Jon Lauckner, GM’s vice president of Global Program Management.
Since the series hybrid, which has at most a two-speed transmission, with only the electric motor connected to the drive train, is simpler to engineer compared to the parallel hybrid, we wanted to know what took so long. Lauckner explained that GM is waiting for a lithium ion battery.
|The Chevy “Volt” Flexfuel Electric Car
Photo: General Motors
Apparently, in order to have a car that can run exclusively on batteries for a reasonable duty cycle – 40 miles – GM was reluctant to go with the nickel metal hydride (NMH) solution used in parallel hybrids.
This makes sense insofar as the parallel hybrids, unless they’re “strong” hybrids, will not use their batteries exclusively for nearly such a sustained period – in a parallel hybrid the gasoline engine is always turning on, sometimes to add power to the drivetrain, sometimes to recharge the battery pack.
One can still argue that NMH batteries, which are more or less a proven technology, could be used to produce a series hybrid, just one with, say, a battery-only range of 30 miles instead of 40, with a little more drag on the car from the increased weight. But this may be beside the point.
Lauckner pointed out, probably not for the first time, that GM is not intending to produce a few hundred of these cars. GM is looking for a car design they can immediately produce by the tens of thousands, and eventually by the millions. There simply aren’t the factories yet to produce this volume of batteries, not NMH or Lithium Ion.
Lauckner, after reminding me that he is not a battery expert, made a point we’d never heard before. He said lithium ion batteries show potential to be far more economically scalable compared to NMH. He also said lithium ion batteries show better durability potential compared to NMH batteries. Since lithium ion batteries have superior energy density, this is a very encouraging bit of data. GM’s goal for their battery packs is 4,000 cycles – equivalent to ten years of use.
So when will the GM Volt and similar series hybrids – or flexfuel electric vehicles – be on the road by the millions? Don’t point the finger at GM. Instead look to the battery manufacturers. We need automotive scale battery plants and all the related infrastructure. Something far, far easier to envision than a whole hydrogen production, storage and distribution infrastructure, but nonetheless not something that will happen overnight.