Edison-powered car

Battery Thomas Edison invented finding new life in cars

It turns out the battery chemistry Edison invented in the early 20th century could be the next step in getting us from point A to point B in electric vehicles.

Just after the turn of the 20th century, Thomas Edison, arguably one of the world's greatest inventors, came up with a battery design he believed would power America's transportation future. Nearly forgotten, that battery is getting a recharge thanks to research at Stanford University.

Called the Edison Battery, it's a well-vetted chemistry of nickel-iron and was an early progenitor of today's popular rechargeable Nickel-Metal Hydride (NiMH) batteries. Although the Edison Battery lost favor in the 1970s as other chemistries for vehicles came to the fore, scientists at Stanford have turned back to it and believe it could hold a key to taking electric vehicles to the next level.

Edison strongly believed in electric vehicles as transportation's future. He attempted to convince Henry Ford of this idea, describing gasoline engines as having "..that almost terrifying uncertain throb and whirr.." Battery technology at the time, even with Edison's design, was woefully inadequate to compete with combustion engines and quickly lost favor as gasoline and diesel became the dominant fuels for vehicles.

Batteries, however, didn't die and the Edison Battery continued to improve, finding life in other applications because of their unique properties. Properties that were replaced by what we now call capacitors and (today) super-capacitors. You see, the Edison Battery's primary advantage is not storage capacity - compared to chemistries now commonly in use, nickel-iron is woefully inadequate. It's advantage is charge and release time. It can be charged nearly as fast as a capacitor, but unlike capacitors, the Edison Battery can hold that charge for much longer.

In fact, the nickel-iron chemistry Edison invented is still in common use today in wind turbines, solar arrays, and other power production facilities that need a fast storage and release capability without the losses that capacitors have if they hold their power more than a few moments. Over time, Edison's original design has improved with new technology.

In Edison's original, the nickel-iron battery was a more or less random mixture of iron and nickel with conductive carbon. While the amounts of the substances could be controlled, how they came together was not. Now, using nanotechnology, the carbon can be made into honeycomb-like graphene sheets with the iron and nickel added in specific molecular shapes. This control means a much more dense battery, higher capacity and better conductivity (which means faster charging and release).

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The Anode has a flat, one atom thick sheet of graphene topped by iron, shaped spherically. The Cathode contains the graphene in a cylindrical shape (called a carbon nanotube) with the nickel added in layered, flat sheets atop it. This improves performance about 1,000 times over Edison's original design.

Further, the batteries are relatively cheap because all of these ingredients are readily available and easy to work with. The process is well-known and is actually used in many applications already, just not necessarily for automotive batteries.

What researchers at Stanford are presenting in the latest issue of Nature is the idea of coupling a small Edison Battery to a larger lithium-ion battery in a car like the Nissan Leaf. By combining them, researchers believe that shorter distances could be achieved on very fast charges (just a couple of minutes) while longer distances would be facilitated by the longer charge time required by li-ion.

For example, in a Leaf with roughly 70 miles of range, if 20 miles of that were stored in an Edison Battery and the rest in lithium, then quick charges when plugged in at a shopping center or convenience store - or even at a fueling station - could be made in three or four minutes, filling the battery with the 20 miles' range to let the driver get home - or just augment their range.

There are other implications for military applications, industrial uses, and more. Anything requiring fast charging and fast release but that needs a longer storage time than capacitors allow would benefit from a nickel-iron battery.