Powering GM's Electric Vehicles

Recent advances in battery chemistry and systems design could lead to working prototypes by year's end.

Published: 11-Jan-2007

General Motors (GM) recently announced that it is developing two types of plug-in hybrid vehicles, cars designed to run exclusively or almost exclusively on electricity for daily commutes. (See "GM's New Electric Vehicle" and "GM's Plug-In Hybrid.") But the announcements came with this caveat: the battery technology isn't ready, and production will have to wait. In reality, the battery technology is actually quite close to being ready.

Indeed, GM's vehicle chief engineer, Nick Zelenski, says that individual batteries are already good enough. "We've got enough data at the cell level to feel that the technology is there," he says. What remains to be done is packaging the cells into large battery packs and testing them in actual vehicles. This will be a challenge, Zelenski says, since there is a big difference between using "a single cell and multiplying them all together to get the energy levels that we need for this type of vehicle." But according to development contracts GM recently signed with two groups of companies, such battery packs will be ready for testing in vehicles by the end of this year.

Making batteries for vehicles, especially plug-in hybrids, is very challenging. For accelerating and climbing hills, the battery pack has to deliver enough power to supply the electricity demand of several houses at once. The energy storage capacity required to give a vehicle a 40-mile range would be enough to power a laptop in continuous use for weeks. Yet the space on board for such a battery pack is limited. "What we need is a very reliable and long-lived battery that has also got quite high energy density so we can find a place for it in the car," says Peter Savagian, director of hybrid power-train systems at GM.


Allocating significant money to produce a saleable hydrogen fuel cell car is likely to be a tough decision for GM. Larry Burns with image of Sequel fuel cell car behind him.

The dual-mode hybrid system will be available in a wide range of cars, trucks and S.U.V.'s made by the three companies, starting with the 2008 Chevrolet Tahoe that goes on sale in fall 2007.

The pollution-free technology holds the potential of zero emissions and a sustainable source of energy produced when hydrogen and oxygen are mixed.


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