One common problem with electric cars is there is a lack of charging stations to charge the cars on long drives. “After you run out of battery power, a small four-cylinder engine runs a generator to extend the range of the car for another 300 or 400 miles, and you can always just keep putting more gas into it to keep on going,” writes Evan Ackerman.

But what if it simply wasn’t an issue? What if the car could go 300 or 400 miles without a recharge? That would make it pretty difficult to argue against the electric car, so it’s exactly what Tesla Motors went ahead and did: it patented a battery that can allegedly keep a car running for 400 miles.

That it comes from Tesla isn’t surprising. The company’s long been cutting edge. It’s racing to build three self-driving cars in three years, and its Model S EV can have its entire battery pack swapped out in 90 seconds.

The science-y stuff: The battery would combine a lithium-ion and a metal-air battery pack, generally drawing power from the lithium-ion battery (that’s the makeup of most electronic batteries).

Metal-air batteries use oxygen as an electrode. As a result, they’re easier to charge but have a shorter lifespan when repeatedly charged. So you would choose which to use, and you’d likely be advised only to use the metal-air side when in dire need.

Via Dvice