Battery Energy Density Same As Gasoline By 2045


Argonne National Laboratory says the energy density of battery powered vehicles will not be the same as gasoline powered vehicles until some time in the far distant future. Right now the lab people say, gasoline is 100 times more energy dense than a battery. That means you would need 100 lbs of battery to go as far as 1 lb of gasoline can take you. If that’s true, how are we ever going to get to parity between electric and gas powered cars?

battery electric car

There is one other critical factor to consider. Electric powertrains are far more efficient than powertrains powered by gasoline. In fact, in many cases, less than 20% of the energy contained in a gallon of gas actually gets converted to forward motion. The latest Toyota Prius has an internal combustion engine that is 40% efficient, but it stands at the top of the heap when it comes to engines.

Even assuming a gas engine is as efficient as the Toyota, it still has to transmit the power it makes through a complex set of gears in a transmission and a differential. By the time power gets to the wheels that do the actual driving, it has suffered significantly more mechanical losses. By contrast, an electric powertrain can be more than 90% efficient. That advantage tilts things in favor of electric cars.

Argonne Lab says in its latest report that just looking at the gas tank and battery is an “incomplete analysis,” which “ignores the impact of powertrain efficiency and mass of the powertrain itself. “When we compare the potential of battery electric vehicles (BEVs) as an alternative for conventional vehicles, it is important to include the energy in the fuel and their storage as well as the eventual conversion to mechanical energy.”

Weighing all the factors and adjusting for the differences between powertrain efficiency, Argonne Lab concludes that when it comes to driving a distance of 300 miles, gasoline and electric drivetrains will be equal to each other in about 30 years. “By 2045, BEV 300s will be comparable to conventional vehicles in terms of the energy spent at the wheel per kg of the powertrain mass.”

The Argonne Lab report does not consider price in its calculations. What it shows is that if we base the changeover from fossil fuels to electricity solely on energy density comparisons, it will come far too late for the environment. The key to keeping fossil fuels in the ground is to remove the enormous direct and indirect subsidies they enjoy and make their market price consistent with their total cost to society.

Source: AutoBlog  Photo credit: Audi

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I have been a car nut since the days when Rob Walker and Henry N. Manney, III graced the pages of Road & Track. Today, I use my trusty Miata for TSD rallies and occasional track days at Lime Rock and Watkins Glen. If it moves on wheels, I'm interested in it. Please follow me on Google + and Twitter.
  • Atanas

    Tesla/Panasonic cells now has 260Wh/kg(2.2lbs), 156Wh/kg of the battery pack. EV has 90% efficiency. We heard about other batteries with higher energy density but with shorter life cycle.
    Gasoline has 12000Wh/kg but car without start-stop system has around 18% efficiency(lower in city and higher on highway) or about 2200Wh/kg(1650Wh/liter) used energy. With 26-28% max efficiency on highway used energy per liter is 2350Wh.
    Model S 85D or P90D 270miles range has the same weight like car AWD with same size & 500+hp. Tesla cars could be lighter but not so safe.

    • Mike Dill

      Elon has stated that 400Wh/kg is sufficient to get mid range electric planes to happen. It will be interesting to see how long it takes to get there.

  • Marcel

    Is this density metric relevant when we practically have EVs with 600 km range and weight that’s manageable? (would rather have a heavier car than a lighter one, just personal preference) I suspect the cheaper EVs like Model 3 will also have that kind of range in the 2020s or sooner. Much greater efficiency and super low emissions (or zero on clean electricity) are more important in my opinion. Also TCO…

    • Steve Hanley

      It may not be especially relevant, Marcel. But research labs gotta research stuff and writers gotta write stuff! ; – ) Let’s put this in the “mildly interesting” category.

  • Michael G

    Transportation accounts for about 32% of GHG emissions. Of that about 18% is from passenger vehicles and 14% is from trucks, ships, planes, etc.

    For cars/SUVs, since they are mostly air even with 4-5 passengers, this is irrelevant, even though projections that far out into the future are *pure conjecture*. It is especially so when the ICE itself is so heavy.

    It is for the 40% of oil-based GHGs emitted by long-distance trucks, planes, ships, and military equipment that energy density really matters. We need to get those to be as close to carbon neutral as possible, and the only that comes to mind is synthetic bio-fuels.

    Al-air batteries get close to petroleum densities but they are proving incredibly hard to get to emulate the capabilities of Li-ion.

    • Steve Hanley

      All excellent points. I agree that cleaning up diesel emissions from heavy duty trucks is of primary importance. And ocean going vessels as well.

  • Chris Overholt

    I think they will be eating their words in 10 years max. Electricity itself doesnt occupy a set volume like gas. The same amount of size and weight to drive a car 300 miles will shrink dramatically as we find more efficient ways to store it. Think of how much data can now be stored on a micro SD card. I have a 64 GB one in this phone. Batteries will follow the same trajectory. The momentum is already heading in thst direction.

    • Steve Hanley

      I agree. I feel that pronouncements like the one from Argonne are similar to the words attributed to the head of the US Patent Office on New Year’s Eve, 1899, when he is alleged to have said, “Everything that can be invented has now been invented.”

      Those of us who follow this stuff wish the changes would happen sooner. The global environment NEEDS for these changes to happen sooner. But the truth is that 30 years is usually the time frame for major new technology to mature and become widespread.

      Our grandchildren will look upon today’s batteries the way we do the gigantic computers that filled entire rooms in the 60’s. They were thought of as miracles of technology then, but today we hold that much computing power or more in the palm of our hand.

      • Chris Overholt

        Steve, thanks for the reply. Note that in this case, the technology isnt new. Its been around for 100 years and of course the latest versions (lithiun ion batteries) habe been around for 20+ years.

        All we are waiting for is a Steve Jobs to come along and repackage it. Elon seems to be that guy, but there may be more on the way. Just like the music industry changed rapidly (using an overused example) we are about to have a rapid change tp our cars.

  • kevin mccune

    I wouldnt put a whole lot of credence on the relevance of this ,if we find some of the stuff coming down the pike as acceptable ,then competition will up the ante so to speak ,even at this stage of development,there are so many advantages to having certain things powered by electricity,what interests me is the coming E-trucks with AWD.