Leading The Charge To Make Better Electric Cars
Filed by KOSU News in Science.
June 8, 2011
When the automobile first emerged at the end of the 19th century, there were two types of cars on the road: gasoline-powered cars and electric cars. And at first, it was unclear which type would attract more drivers.
“Electric cars had some early advantages,” says science writer Seth Fletcher. “Gas cars were loud and dirty and nasty, and they had to be started with a hand-crank, which could sometimes backfire and break your arm. And electric cars were clean and quiet and civilized and they worked well in the city.”
But the gasoline-powered car slowly improved. And once people started driving longer distances, it quickly won the battle of the roadways.
“If you were out in the country and you ran out of charge [with an electric car], you were stuck,” Fletcher says. “If you were driving a gas car, you could stop and get a tin of gasoline from the general store and fill up in a matter of minutes. That [recharging] problem has actually plagued the electric car ever since. If you want to take electricity on the road with you, you have to have a way to store it. And we’ve always needed better batteries.”
Fletcher traces the battle to create a better, long-lasting battery in Bottled Lightning: Superbatteries, Electric Cars and the New Lithium Economy. Fletcher tells Fresh Air’s Dave Davies that lithium, the material of choice for battery manufacturers, has the potential to transform the automotive industry, power grids and the environment.
Building A Better Battery
But first, engineers must figure out how to create long-lasting, safe and lightweight batteries that don’t need frequent recharging — a task that is easier said than done. One of the benefits of a gas tank, Fletcher says, is that liquid hydrocarbon fuels, like gasoline, can be easily stored. But electrons must be stored in a chemical system — the battery — and are part of a highly controlled chemical reaction.
“The key challenge here is to come up with something that will store as much energy as possible, that’s really safe and that will last a really long time,” Fletcher says. “That has led the major automakers to work with battery makers to find alternative chemistries. There are a bunch of different ways to mix the chemistry to make the various kinds of lithium-ion batteries, but in almost all cases, you’re giving something up. You can make it safer, but you’re giving up a little bit of energy. You can have more energy, but you’re giving up some power. So finding that balance is something that carmakers and scientists are still struggling with, and I don’t know if there’s any single answer yet.”
Currently, electric cars on the market can be recharged overnight and can travel anywhere between 40 and 100 miles per charge, depending on the manufacturer. But they are still more expensive than comparable gasoline counterparts. That’s likely to change, Fletcher says, as technology improves.
“The problem right now is that batteries are built in such small quantities [because] it’s such a new thing,” he says. “There are billions of lithium ion laptop cells and cellphone cells built every year. But the batteries that go into these cars are so new that they’re still expensive. The next step is to scale them up, [and] the prices will come down.”
Expanding Charge Capacity
Engineers are also working to increase the charge capacity of batteries so that they will be able to store as much energy as gasoline — meaning cars powered by lithium batteries would be able to travel the same distance as their gasoline-powered counterparts without needing to be recharged.
One concept? A lithium air battery that is powered by a reaction between lithium and oxygen. It has an incredibly high charge capacity and could theoretically store as much energy as gasoline.
“There are a lot of people working on [the lithium air battery] and they will warn you that we don’t even know what showstoppers there might be,” Fletcher says. “It’s at least two decades away. If you talk to the people who are working on this, it’s their dream. This ultimate goal of the battery researcher is to match the energy density of gasoline, and lithium air offers one possible way forward toward that.” [Copyright 2011 National Public Radio]