Watts the Deal With Lithium-Ion Batteries?
source: http://www.edmunds.com/advice/alternativefuels/articles/122191/article.html
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Ten years ago, the idea of driving a mass-produced vehicle that could run on electricity seemed like science fiction, yet there are currently over a dozen gas-electric hybrid vehicles to choose from and more on the way. As climate change becomes an increasingly hot topic and our national addiction to oil appears in the news almost every day, alternative-fuel vehicles are entering the mainstream and electric power is leading the way.
Early electric vehicles (EVs) ran on lead acid batteries that were heavy and lacked sufficient power. As technology progressed, the industry moved to nickel metal hydride (NiMH) batteries that were much better suited to the task of propelling a vehicle. Today, with hybrid cars gaining ground and EVs just about to hit the market in earnest, a debate is under way as to whether lithium-ion batteries will (or should be) the next battery system to come into play. Although big names like Toyota and GM are racing to develop them, lithium-ion batteries have yet to be tested on the same mass scale as NiMH batteries. As such, they are not quite ready for prime time.
The Pros
"Lithium has so much potential to be less expensive and has such a higher energy density than other types of batteries that I think it's the future" says Greg Hanssen, CEO of Edrive Systems, a company that retrofits Prius hybrids, allowing them to be plugged in. The energy density — the amount of energy that can be stored within a given space — is one of the biggest selling points of lithium-ion technology. Lithium-ion batteries have an energy density almost twice that of the NiMH batteries currently being used in hybrid vehicles and about six times the energy density of lead acid batteries, the units found in most conventional cars and in GM's ill-fated EV1. Take a vehicle with a 1,500-pound NiMH battery pack and replace it with a 1,500-pound lithium-ion pack, and you'll be able to go roughly twice as far without adding any weight. Or, put in a battery half the size and achieve the same mileage. Either way, you win.
Another plus for lithium-ion batteries, Hanssen points out, is cost. "While lithium is still expensive, it is dropping and at the same time the cost of nickel is rising. Over time, lithium prices will come down to the point where [the batteries] are cheaper. In an industry where automakers will try to shave 20 cents off the cost of a door panel, the price of the battery system can make a huge difference."
On an environmental level, lithium-ions are a big step forward as well. "Since lithium is a lighter element it is less toxic and therefore has less of an impact on the environment," points out Wally Rippel, the principal power electronics engineer for Tesla Motors, makers of the lithium-ion battery-powered Tesla Roadster. Rippel adds that since there is value in lithium it's in the best interests of the battery manufacturers to recycle them. Built into the cost of the Tesla is the price of reclaiming the battery packs, to ensure they will be recycled.
The Cons
The primary concern regarding lithium-ion batteries is safety, fueled in part by the 2006 global recall of lithium-ion laptop batteries after a small number of them overheated or caught fire. Although overheating — or worse, fire — would be a concern to anyone driving a vehicle powered by a battery pack, Hanssen is quick to point out that "whenever you have a high concentration of energy in a very small package, the potential for that energy to react negatively is high," which is why battery packs are equipped with energy and heat sensors and computer safety nets so that the units will shut down should they become unstable.
"Any battery can blow up if treated improperly," he points out, adding that presently, people drive around sitting on top of canisters filled with highly flammable gasoline and think
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Early electric vehicles (EVs) ran on lead acid batteries that were heavy and lacked sufficient power. As technology progressed, the industry moved to nickel metal hydride (NiMH) batteries that were much better suited to the task of propelling a vehicle. Today, with hybrid cars gaining ground and EVs just about to hit the market in earnest, a debate is under way as to whether lithium-ion batteries will (or should be) the next battery system to come into play. Although big names like Toyota and GM are racing to develop them, lithium-ion batteries have yet to be tested on the same mass scale as NiMH batteries. As such, they are not quite ready for prime time.
The Pros
"Lithium has so much potential to be less expensive and has such a higher energy density than other types of batteries that I think it's the future" says Greg Hanssen, CEO of Edrive Systems, a company that retrofits Prius hybrids, allowing them to be plugged in. The energy density — the amount of energy that can be stored within a given space — is one of the biggest selling points of lithium-ion technology. Lithium-ion batteries have an energy density almost twice that of the NiMH batteries currently being used in hybrid vehicles and about six times the energy density of lead acid batteries, the units found in most conventional cars and in GM's ill-fated EV1. Take a vehicle with a 1,500-pound NiMH battery pack and replace it with a 1,500-pound lithium-ion pack, and you'll be able to go roughly twice as far without adding any weight. Or, put in a battery half the size and achieve the same mileage. Either way, you win.
Another plus for lithium-ion batteries, Hanssen points out, is cost. "While lithium is still expensive, it is dropping and at the same time the cost of nickel is rising. Over time, lithium prices will come down to the point where [the batteries] are cheaper. In an industry where automakers will try to shave 20 cents off the cost of a door panel, the price of the battery system can make a huge difference."
On an environmental level, lithium-ions are a big step forward as well. "Since lithium is a lighter element it is less toxic and therefore has less of an impact on the environment," points out Wally Rippel, the principal power electronics engineer for Tesla Motors, makers of the lithium-ion battery-powered Tesla Roadster. Rippel adds that since there is value in lithium it's in the best interests of the battery manufacturers to recycle them. Built into the cost of the Tesla is the price of reclaiming the battery packs, to ensure they will be recycled.
The Cons
The primary concern regarding lithium-ion batteries is safety, fueled in part by the 2006 global recall of lithium-ion laptop batteries after a small number of them overheated or caught fire. Although overheating — or worse, fire — would be a concern to anyone driving a vehicle powered by a battery pack, Hanssen is quick to point out that "whenever you have a high concentration of energy in a very small package, the potential for that energy to react negatively is high," which is why battery packs are equipped with energy and heat sensors and computer safety nets so that the units will shut down should they become unstable.
"Any battery can blow up if treated improperly," he points out, adding that presently, people drive around sitting on top of canisters filled with highly flammable gasoline and think
VISIT LINK FOR THE COMPLETE ARTICLE
