Will lithium-ion batteries power cars?

Remember when laptops were bursting into flame in 2006? It was the lithium-ion battery.

Random explosions from overheating weren't a widespread problem, but nevertheless, lithium-ion battery manufacturer Sony, which came out with the first commercialized Li-ion battery in 1991, had to recall more than 6 million computers because of it [source: Lamb].

In the couple of years since then, the Li-ion battery hasn't completely recovered its reputation for safety. Now you can see why putting it inside of a car makes some people a little antsy.

Why is there a chance for explosion? Li-ion batteries work by separating its positive and negative sides by a thin layer, called an electrolyte. The electrolyte is perforated to allow the lithium ions to pass through from one side of the chamber to the other, thus generating a current. Tiny bits of metal that result from the manufacturing process can potentially get stuck in those perforations, preventing the ions from freely flowing. Pressure and heat can then build up, causing an explosion. Also, allowing the ions to move too quickly can lead to overheating as well.

So how does the all-electric Tesla Roadster manage to pack 6,831 Li-ion batteries under its hood without risking a major blow-up? The Tesla's energy storage system that propels the car is equipped with a cooling system, which ensures the batteries don't overheat. It also regulates the speed of the flow of ions to keep them from re-charging or draining too quickly.

Since car companies and scientists realize the broad potential of Li-ion batteries, they have poured time and money into finding ways to reduce any safety hazards. For instance, nanotechnology, the study of atoms and nanostructures, may be able to prevent those dangerous explosions. New nanomaterials, such as nanophosphate, aren't prone to shorting out like graphite, the traditional Li-ion electrolyte [source: Peter].

And speaking of time and money, before Li-ion batteries make their grand entrance into the consumer automotive world, they need to be cheaper and longer-lasting. Learn why and how on the next page.

The Tesla Roadster can go the equivalent of 256 miles per gallon. Just plug it in overnight, and you can go up to 250 miles (402 kilometers) without stopping by the gas station. But there's a catch -- a 2009 model retails for more than $100,000.

Part of that hefty price is the sleek, sports car design and amenities and the power to go from zero to 60 miles per hour in under four seconds -- an acceleration that ranks among the best-performing gasoline sports cars. But that power doesn't come cheap. In fact, Li-ion batteries are around four to five times more expensive than nickel-metal-hydride­ ones [source: Popely]. Since the car-capable packs can cost between $10,000 and $15,000 each, finding a cheaper alternative will be a major hurdle for car companies that want to market them [source: Popely].

There's also an issue with the battery life. Like the AA batteries that you put into your TV remote control, Li-ion batteries eventually die. Even if you aren't using them, they'll begin to degrade as soon as they're made. You can recharge them, but only a limited amount of times. It's like trying to fill up a pitcher of water that has a tiny hole that grows bigger and bigger with each use.

We measure battery longevity in cycle lives, or the number of times that you can run it down, charge it up and use it again. With Li-ion batteries, starting from a 100 percent fully-recharged battery will give you a longer individual cycle life, but will reduce the total number of cycles you'll get from it. For that reason, the Tesla Roadster doesn't allow you to re-charge more than 95 percent of the original power or let it drain down to less than 2 percent [source: Eberhard and Straubel]. Also, the company projects the battery pack to last 100,000 miles, or five years. At that point, you would have to replace the battery.

As with the safety issue, researchers are looking for a longer-lasting Lithium alternative. And once again, nanotechnology seems to be leading the pack of potential solutions. One company, Altair Nanotechnologies announced in 2006 that it had found a new material that would far outlast Li-ion batteries and recharge faster for the same price, called lithium titanate [source: Bullis]. Canadian car company Phoenix Motorcars is using lithium titanate batteries in its line of electric cars that have a 100-plus mile range.

Toshiba has also come out with a fast-charging Li-ion battery initially for bicycles and construction vehicles that it eventually wants to test in cars [source: MSNBC]. In June 2008, Toyota also publicized plans to join forces with the company that produces its current hybrid batteries to develop Li-ion batteries by 2009 [source: Kim].

With so much energy going into Li-ion battery development, there's a strong possibility that they could be fueling our cars in the near future. For more information about tomorrow's cars and related information, visit the links on the next page.

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