One of the most pressing issues many people have with all electric vehicles is the long charge time needed to reach maximum range. Some can take as long as 8 hours to go from completely depleted to a 100% charge, which a large portion of consumers find too long. Now, engineers from the Massachusetts Institute of Technology may have found a solution to this long-standing problem and, in doing so, launched a new era for battery technology.
Electron Micrograph of New Material
Our current Lithium Ion batteries are great for storing large amounts of energy. However, when it comes to charging and discharging, they take quite a long time, making them ideal for devices we want to last a while without any external power source. The perfect example of this can be seen in our current battery electric vehicles. "They have a lot of energy, so you can drive at 55 mph for a long time, but the power is low. You can't accelerate quickly," said Gerbrand Ceder, professor of Materials Science and Engineering at MIT.
To solve this problem, the team began studying how the ions move across the materials and therefore, how they store and release energy. What they discovered, was they the limiting factor was not the ions themselves, but rather the material being used as a transport medium. The ions will move very quickly across the medium, but only when they are near one of the tunnels located on the surface of the material. If the ion is not close to one of these tunnels, it will move very slowly along the surface till it finds one.
To combat this, the engineers began experimenting with Lithium Iron Phosphate, a common material used in battery assembly. After a little research, a new surface structure that allowed the ions to move along the exterior of the material very rapidly was developed. Once the ion finds a nearby tunnel, it will instantly be diverted into the tunnel and travel across the material.
Using the new technology, Cedar and Byoungwoo Kang, a graduate student in the materials science and engineering program, were able to build a small battery capable of charging and discharging in as little as 10 seconds. A similarly sized battery made of unprocessed material averages about 6 minutes for the same charge/discharge cycle.
Another interesting discovery was the reduction in "battery memory" when using the new material. If a battery is not allowed to fully discharge between recharging cycles, after a while it will no longer hold what used to be a full charge. This is most prevalent in laptop computers, digital cameras and many portable music devices.
The technology opens new doors for many different commercial applications. Cellular telephone batteries could become smaller and therefore lighter, as could pretty much anything that relies on a rechargeable battery. Hybrids that rely on batteries for storage could be charged literally in a matter of minutes, rather than overnight.
The new materials could also lead to large scale changes to the way we accomplish many of our jobs. Being able to provide a large amount of power in a short period of time could lead to applications in heavy machinery and manufacturing. The new batteries could also usher in a new era for racing enthusiasts.
There are already several teams out there that are strictly using battery electric vehicles to tear up the pavement. Even Formula-1 has accepted electric power, using it as a means to boost acceleration during overtaking and when coming out of corners.
The technology has already been leased to two companies, with many others surely on the way.
MIT , Boston Globe