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Could Tesla’s electric-electric hybrid powertrain eliminate range anxiety?

Tesla Model S white

A Tesla hybrid? You bet. Except, a Tesla hybird would still be all-electric.

Tesla Motors is, if nothing else, a company that likes to be different.

The Model S defied all preconceived notions of what a car could be, and Tesla is keeping up the momentum with battery pack swapping and a goal of putting a self-driving car on sale in three years. Plus, CEO Elon Musk wants to build a human-size potato cannon.

That’s why it is not too surprising that Tesla has also patented a new type of battery, AutoBlogGreen reports. The patent for an “electric vehicle extended range hybrid battery pack system” was filed on December 8, 2010 and granted on June 25, 2013.

Yes, Tesla is talking about a hybrid powertrain but you won’t find any gasoline engines here.

The hybrid system described in the patent is actually electric-electric: it uses two types of batteries to, theoretically, give an electric car greater range. 

The Tesla hybrid would have the standard lithium-ion battery pack (other chemistry types could be substituted), controller, and electric motor of a regular EV. Here’s where it gets tricky. The all-electric hybrid would also have a second metal-air chemistry battery pack.

The lithium-ion pack would directly power the car, just as in today’s EVs and extended-range electrics, while the metal-air pack would be used primarily to charge the first battery pack. In this design, the metal-air pack would essentially take the place of a range-extending internal combustion engine.

A metal-air battery makes sense as a range-extender because it has high energy density – allowing it to hold more electricity- but a low power density.

If electric cars are ever going to become truly mainstream, battery technology will have to take a giant leap forward. The current trifecta of short range, long charging times, and high battery pack costs means EVs don’t make sense for average buyers. And it’s those average buyers that Tesla is targeting with its upcoming Model E.

The full electric-electric hybrid patent filing is available through the U.S. Patent Office. Read through it if you’ve got the time but make sure to have a cup of coffee ready, as it’s a bit dry.

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