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Here Are the Two Problem With EV’s

Posted by on | November 17, 2017 | Comments Off

There are two problems with electric vehicles.  Neither are unsolvable in the long-term, but neither are probably going to get solved in the next 5 years.

  1.  Energy Density.  15 gallons of gasoline weighs 90 pounds and takes up 2 cubic feet.  This will carry a 40 mpg car 600 miles.   The Tesla Model S  85kwh battery pack weighs 1200 pounds and will carry the car 265 miles (from this article the cells themselves occupy about 4 cubic feet if packed perfectly but in this video the whole pack looks much larger).  We can see that even with what Musk claims is twice the energy density of other batteries, the Tesla gets  0.22 miles per pound of fuel/battery while the regular car can get 6.7.  That is a difference in energy density of 30x.  Some of this is compensated for by heavy and bulky things the electric car does not need (e.g. coolant system) but it is still a major problem in car design.
  2. Charge Time.  In my mind this is perhaps the single barrier that could, if solved, make electric cars ubiquitous.  People complain about electric car range, but really EV range is not that much shorter than the range of traditional cars on a tank of gas.  The problem is that it is MUCH faster to refill a tank of gas than it is to refill a battery with a full charge.    Traditionally it takes all night to charge an electric car, but 2 minutes at the pump to “charge” a gasoline engine.   The fastest current charging claim is Tesla’s, which claims that the supercharger sites they have built on many US interstate routes sites will charge 170 miles of range in 30 minutes, or 5.7 miles per minute.   A traditional car (the same one used in point 1) can add 600 miles of range in 2 minutes, or 300 miles per minute, or 52 times faster than the electric car.  This is the real reason EV range is an issue for folks.

Interestingly, Fisker (which failed in its first foray in to electric cars) claims to have a solid state battery technology that gets at both these issues, particularly #2

“Fisker’s solid-state batteries will feature three-dimensional electrodes with 2.5 times the energy density of lithium-ion batteries. Fisker claims that this technology will enable ranges of more than 500 miles on a single charge and charging times as low as one minute—faster than filling up a gas tank.”

Forget all the other issues.  If they can really deliver on the last part, we will all be driving electric vehicles in 20 years.  However, having seen versions of this same article for literally 30 years about someone or other’s promised breakthrough in battery technology that never really lived up to the hype, I will wait and see.

 Here Are the Two Problem With EVs  Here Are the Two Problem With EVs  Here Are the Two Problem With EVs

 Here Are the Two Problem With EVs

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