5 Things You Need to Know About Lithium-Ion Batteries
By Jennifer Olvera
How Lithium-Ion Batteries Work in Cars
Batteries that use lithium move electrically charged atoms between their electrodes. When charging, the ions head in one direction and go the other way when they're discharging. There are many different chemical make-ups used for these batteries, the most common being ones that contain a positive electrode from cobalt or manganese oxide as well as a negative electrode from graphite. The ions then pass through a lithium-based polymer or gel. Automobiles, unlike household items, rapidly recharge and discharge batteries and are subject to wildly varying temperatures. This adds to the instability of the batteries and can lead to overheating.
Why Lithium-Ion Batteries are Appealing
Lighter, more compact, and more powerful than NiMH (nickel-metal-hydride) batteries, lithium-ion batteries also are high in energy density and power. Because the cells weigh less and don't take up as much space as those used in other hybrid systems, incorporating lithium-ion batteries into cars can help boost fuel efficiency. The end goal – although technology has a ways to go – is to produce highly efficient hybrid and electric cars with speedy acceleration, stamina, and an affordable price point.
There Are Concerns
Lithium-ion batteries are not a new technology. They can be found in everything from cell phones to camcorders, iPods, and laptops. However, they're seen as unstable when charged and, while uncommon, have been known to spontaneously short circuit and explode or burst into flames. So, carmakers and battery developers are looking into fail-safe options for obvious reasons. Another issue with lithium-ion batteries is that their ability to hold a charge declines after a period of time and may not last the life of a car, although this could also be an issue with other batteries, depending on how a car's "lifetime" is measured. Add that to the fact that, for now, they're considerably more expensive than NiMH batteries. As production and demand increases and technology improves, however, the cost of lithium-ion batteries is anticipated to drop.
Integrating the Batteries
In addition to finding a battery that's a fit for cars, it will be important that the end result syncs with the driving system of each model. So, that means manufacturers first have to get the battery chemistry right, address the issue of battery stability, build the cells, and incorporate them into the algorithms and software inherent in vehicles.
When to Expect Major Production
Because there still are significant hurdles to overcome, drivable versions of cars entirely powered by lithium-ion batteries are limited in number. There are numerous car companies that claim to be nearly ready to hit production lines, but more conservative estimates target 2010 or 2011 to be when these cars are readily available to the public.
Jennifer Olvera, a graduate of DePaul University in Chicago, has been writing professionally for over a decade. In addition to covering the "green scene" for publications such as Where Magazine and Crain's, she has become one of the preeminent dining, food, and entertainment writers in Chicago. She has regularly been published in Chicago Magazine, Chicago Sun-Times, Chicago Tribune, Zagat, Citysearch.com, and Gayot.com.
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