It's not clear yet what the management shake-ups at General Motors this week, which sent the CEO, Fritz Henderson, packing and shuffled around senior management, will mean for the Chevrolet Volt, the much hyped electric vehicle (with a gas engine for added range) due out next year.

Fans of the Volt--which is also called a plug-in hybrid--have been nervous about its fate ever since an Obama administration commissioned report in March said the vehicle isn't likely to be an economic success. The car is likely to be too expensive, it said, which is due to its large battery pack. Fans have got more reason to worry now that the man the federal government appointed as chairman of GM, Edward Whitacre, is taking over as CEO. Although he says he's taken the position temporarily, his move puts him in a better position to influence day to day operations and decisions about products. That could hurt the Volt if he agrees with the government report.

Since last March, when the government bought a 61 percent share of the company, GM executives have repeatedly said the Volt program will continue, and that the car will come out on time. This week, after Henderson got the axe, it stuck to that story at the L.A. auto show, with vice chairman Robert Lutz highlighting progress on the Volt in a keynote speech. But since then Whitacre has started to make major changes to GM management. It's unclear what the company will look like when the dust settles.

Electric vehicles can take hours to recharge, making cross-country road trips a challenge. But researchers at the Fraunhofer Institute for Chemical Technology in Germany say they've got a potential solution: flow batteries.

This type of battery uses two electrolytes rather than the solid electrodes used in lithium ion batteries. Recharging them is as fast as pumping out depleted electrolytes and replacing them with fresh ones--it wouldn't take longer than refilling a gas tank. One of the problems with flow batteries, though, has been that they only store about a quarter of the energy as lithium ion batteries--you'd have to recharge a lot, making them impractical. The Fraunhofer researchers say they've improved the energy storage to match lithium ion batteries--still not as good as with gasoline, but a great improvement. Some lithium ion EVs get over 200 miles on a charge.

But here's the catch: one of the reasons hydrogen fuel cell vehicles have come under fire recently is that you need to install a large infrastructure for distributing and dispensing hydrogen. A flow battery system would have a similar problem. You'd need to install special refueling stations where the spend electrolytes can be recharged and dispensed.

Last week Nissan showed off the battery and drivetrain platform for its upcoming electric vehicle. Now it's revealed the car itself--the Leaf.

This zero-emissions vehicle, which has a range of 100 miles on a charge, will go on sale next year in Japan, the United States, and Europe. It will be powered by a lithium manganese battery developed in a joint venture between Nissan and NEC. Manganese-based lithium ion batteries are popular with automakers (GM plans to use one in the Volt) because they're more stable than the cobalt oxide batteries commonly used in laptops and other portable electronics.

Nissan is taking a markedly different strategy than companies such as Toyota, GM, and Chrysler, which have emphasized hybrid vehicles that can run on both electricity and gasoline. Even the Volt, which GM is describing as an electric vehicle, has an onboard gasoline generator that kicks in after 40 miles of driving to recharge its battery. Because gasoline stores orders of magnitude more energy than batteries, such vehicles can have longer range than pure battery electric vehicles like Nissan's Leaf. What's more, fuel tanks can be refilled much faster than batteries can be recharged, at least without special electrical connections, making long-distance road trips easier. (Electric vehicle enthusiasts like to brag about cross-country trips, but these require careful planning--it's good to find RV parks equipped with 220-volt outlets--and a willingness to take frequent breaks while the car charges.)

Nissan has been working with a company called Better Place on a strategy for extending the range of EVs. The idea is to build battery swap stations along major highways. Drive in and a simple robot takes out your car's depleted battery and inserts a charged one, and you're quickly on your way again. Nissan demonstrated one version of a swap station in May.

But it wasn't immediately clear whether the Leaf would be compatible with swap stations. A spokesperson for Nissan said that the company doesn't plan to use a swap strategy in the United States, but she expects the Leaf could be used with swap stations in other countries. She said she'd get back to me to confirm. (If she does, I'll add that here.)

Many EV supporters say it doesn't make sense to buy a car with a gasoline engine and fuel tank as well as an electric motor and battery pack. After all, most of the time either one or the other is just dead weight, sitting there unused. They say, if you commute less than 80 miles each day, buy an EV. Then, for those relatively rare occasions when a longer range is required, rent a car. Or use the EV as a second vehicle.

But one of the most expensive parts of an EV is the battery, and most people actually commute less than 40 miles a day. If you can make do with a battery pack half the size, you could save money, even with the added cost of a gasoline generator. So either strategy--pure EV or hybrid--could make sense.