ultra fast battery charging

by Bruce Mulliken, Green Energy News

For a century or so, drivers have become accustomed to reenergizing their cars in a few minutes. Whatever the vehicular technology of tomorrow turns out to be, drivers will want the same nearly instantaneous gratification.

If a new discovery from researchers at the Massachusetts Institute of Technology (MIT) pans out, a quick fill up in the not too distant future may mean filling up with electricity, not gas. There, researchers Byoungwoo Kang and Gerbrand Ceder have discovered that with some modification, lithium iron phosphate (LiFePO4) batteries can be recharged as quickly as it takes to fill a tank with gasoline – maybe even quicker. The batteries, too, will discharge quickly, adding an extra boost to motor power when needed.

Until this discovery, battery experts had always thought ions (charged particles) could move only so fast within a battery. They thought there was a kind of speed limit to ions which limited how fast the battery could charge or discharge. Slow movement of ions meant that long charging times were inevitable, something to be expected and planned for.

Kang, Ceder and team found something different.

In lithium batteries, ions move from one plate of a battery to the other, from anode to cathode and back depending on whether a battery is in a state of discharge (like while powering an electric car for instance) or a state of recharging. In lithium iron phosphate batteries Kang and Ceder found that those ions actually move very quickly while within the cathode material itself, but were slowed by entering and exiting the material in the first place.

By the wonders of computer simulation they noticed that the standard lithium iron phosphate material, used in some commercially available batteries, had a crystalline structure that created neat miniscule tunnels or pathways for the ions to travel quickly, but the ions had trouble finding the doorways to those tunnels thus moved sluggishly into and out of the cathode material.

They solved the problem by coating the cathode with a thin layer of lithium phosphate glass which created lots of nicely aligned doors for the ions to travel to and fro.

The result was a lithium iron phosphate battery that could charge and discharge in as little as nine seconds as compared with hours.

The researchers say the improvement to the lithium iron phosphate material is inexpensive and relatively few changes would be needed to the manufacturing process to make those batteries a reality.

How soon might the technology make it to the battery marketplace? Two to three years they say.

Further, Ceder says that lithium iron phosphate may not be the only battery chemistry that would benefit from improving ion flow within a battery’s cathode. With computer simulations other chemistries may have similar results. All this research will take time, of course.

For automotive transportation, the ability to recharge an electric vehicle as quickly as filling a tank of gas (or even quicker) would be a significant (read huge) breakthrough in clean transportation, as well as be extraordinarily disruptive to the oil industry – perhaps.

The downside of these ultra fast recharging batteries is that it may not be possible to charge them at home. “Filling” a battery with all the electricity needed to propel a car 200 miles or so would take electricity supplies more robust than found in homes or with currently available charging equipment. Cars and trucks would need to be “refilled” at specially designed, high-powered charging stations that could safely deliver large quantities electric current to a vehicle in a short amount of time.
March 15, 2009 – Vol.13 No.52

ULTRA FAST BATTERY CHARGING.
by Bruce Mulliken, Green Energy News

For a century or so, drivers have become accustomed to reenergizing their cars in a few minutes. Whatever the vehicular technology of tomorrow turns out to be, drivers will want the same nearly instantaneous gratification.

If a new discovery from researchers at the Massachusetts Institute of Technology (MIT) pans out, a quick fill up in the not too distant future may mean filling up with electricity, not gas. There, researchers Byoungwoo Kang and Gerbrand Ceder have discovered that with some modification, lithium iron phosphate (LiFePO4) batteries can be recharged as quickly as it takes to fill a tank with gasoline – maybe even quicker. The batteries, too, will discharge quickly, adding an extra boost to motor power when needed.

Until this discovery, battery experts had always thought ions (charged particles) could move only so fast within a battery. They thought there was a kind of speed limit to ions which limited how fast the battery could charge or discharge. Slow movement of ions meant that long charging times were inevitable, something to be expected and planned for.

Kang, Ceder and team found something different.

In lithium batteries, ions move from one plate of a battery to the other, from anode to cathode and back depending on whether a battery is in a state of discharge (like while powering an electric car for instance) or a state of recharging. In lithium iron phosphate batteries Kang and Ceder found that those ions actually move very quickly while within the cathode material itself, but were slowed by entering and exiting the material in the first place.

By the wonders of computer simulation they noticed that the standard lithium iron phosphate material, used in some commercially available batteries, had a crystalline structure that created neat miniscule tunnels or pathways for the ions to travel quickly, but the ions had trouble finding the doorways to those tunnels thus moved sluggishly into and out of the cathode material.

They solved the problem by coating the cathode with a thin layer of lithium phosphate glass which created lots of nicely aligned doors for the ions to travel to and fro.

The result was a lithium iron phosphate battery that could charge and discharge in as little as nine seconds as compared with hours.

The researchers say the improvement to the lithium iron phosphate material is inexpensive and relatively few changes would be needed to the manufacturing process to make those batteries a reality.

How soon might the technology make it to the battery marketplace? Two to three years they say.

Further, Ceder says that lithium iron phosphate may not be the only battery chemistry that would benefit from improving ion flow within a battery’s cathode. With computer simulations other chemistries may have similar results. All this research will take time, of course.

For automotive transportation, the ability to recharge an electric vehicle as quickly as filling a tank of gas (or even quicker) would be a significant (read huge) breakthrough in clean transportation, as well as be extraordinarily disruptive to the oil industry – perhaps.

The downside of these ultra fast recharging batteries is that it may not be possible to charge them at home. “Filling” a battery with all the electricity needed to propel a car 200 miles or so would take electricity supplies more robust than found in homes or with currently available charging equipment. Cars and trucks would need to be “refilled” at specially designed, high-powered charging stations that could safely deliver large quantities electric current to a vehicle in a short amount of time.

And who has the most experience in building a network safe vehicle refueling stations? The oil companies and their distributors, of course.

They might even like the idea of selling electricity. The oil companies are not just in the business of extracting, refining and distributing oil. They’re in the business of selling energy. They may not care what they’re selling as long as they’re selling something and profiting from it. Selling electricity might be easier than selling oil products.

As with all the technology that is still in the laboratory stage, there is the possibility that unforeseen development hurdles could pop up at any time. So, as the saying goes, only time will tell.

The new research is reported in the scientific journal Nature.
from : http://www.green-energy-news.com