Argonne: EVs may be almost as energy-dense as gasoline vehicles by 2045

Nissan Leaf Chevy Volt

Hydrocarbon fuels have energy densities that are at least 100 times greater than that of current lithium-ion batteries. Even with projected improvements in battery technology as far out as 2045, batteries are still expected to be significantly less energy-dense than gasoline.

However, the energy density of the actual storage medium may not be the best measure to use when comparing conventional vehicles and BEVs. An analysis by a team at Argonne National Laboratory (ANL) has found that by 2045, some configurations of battery electric vehicles (BEVs) could become almost as energy-dense as legacy vehicles, if the efficiency of the powertrain as a whole is considered.

In “Comparing the Powertrain Energy Densities of Electric and Gasoline Vehicles,” presented at the recent 2016 SAE World Congress, Ram Vijayagopal and colleagues explain that making such a comparison requires assessing the efficiency of the conversion of the stored energy to useful mechanical energy to propel the vehicle.

The team compared three mid-size passenger cars: a gas car that can run 300 miles on a tank; a BEV with a range of 100 miles, comparable to many current models; and a BEV with a range of 300 miles to match the range of the gas vehicle.

They modeled, in five-year increments, projected changes in vehicle weight reduction, battery technologies, powertrain components, power and energy requirements, and powertrain energy and power densities.

They then calculated the “Ratio of the Powertrain Energy Density” of the gasoline vehicle to the BEV.

They found that current gas-powered vehicles require about 10 times more energy input per kg of vehicle powertrain mass, compared to BEVs. They predicted a significant decrease in energy consumed by the gas vehicle, thanks to innovations such as start-stop systems. However, even with projected improvements, gas vehicles in 2045 will still need almost twice as much energy input per kg compared to the 300-mile BEV.

On the other hand, although the BEV is more efficient, its greater mass results in spending more energy at the wheel per kg of the vehicle powertrain mass. This should improve as battery weight is reduced, and other components become more efficient.

“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,” write Vijayagopal and his team.


Source: Argonne National Laboratory via Green Car Congress

  • William

    Kind of a silly metric, IMHO — abstract and academic. EVs already are much cheaper per mile, vastly less polluting, and should achieve range parity long before 2045.

    • Michael B

      Yes, one would hope that the DOE would understand AGW and LCA of EOD as well as they do LCDs and ICEs of OEMs,

  • brian_gilbert

    I think supercaps will become more costeffective in which case a vehcle can recharge by stopping for only a few seconds.

  • Electric Bill

    As battery energy density increases, a whole new market will emerge that is entirely under the radar presently– electric passenger aircraft, such as the electric planes Airbus and some other smaller companies are working on.

    Electric planes enjoy many significant advantages– such as being nearly silent, making them far more desirable to residents near airport. Fuel – powered aircraft can be heard a dozen miles away, but EV planes are whisper quiet– all you hear is the WHISH of the propeller blades, which is undetectable more than a hundred feet or so from the plane once airborne.

    ICE plane crashes, although very rare, are often due to contaminated fuel ot engine failure, which would not be an issue with EV aircraft. Electric motors are far more reliable than reciprocsting engines used in general aviation and which need to be disassembled and checked for wear and signs of failure every few hundred hours of flight which adds significantly to the operating budget of aircraft. By comparison, even small EV aircraft can have multiple smaller electric motors for propulsion which not only increase the plane’s reliability, but also decrease its noise levels. Air-cooled, AC electric motors are so much more reliable than reciprocating engines that they would be nearly maintenance free by comparison, and what little maintenance they might require could be done in minutes rather than dozens of hours, reducing overall costs significantly.

    Battery packs can also be redundant, further adding to plane reliability, and have no such similar problem as “fuel contamination” to deal with.

    Jet aircraft have the problem of turbine damage due to bird strikes and other airborne debris sucked into engines. Again, there is no equivalent problem with EV aircraft.

    Fueled aircraft cannot generate their own propellant in flight, but by comparison, an EV aircraft’s entire exterior can be covered with thin, light, flexible solar panels that can harvest sunlight during flight to help recharge the batteries and extend flight time. Since aircraft are exposed to light, from, all directions, even on the lower surfaces of their wings and elevators, there is, great potential for increasing a plane’s range during daylight hours.

    Fuel-powered aircraft can explode during crash landings; passengers often survive such crashes only to burn to death afterward. , EV aircraft would have no such problems.

    Electric aircraft are presently an exciting, untapped market which, once initiated, would help to reduce airborne pollution, reduce our dependence on fossil fuels, reduce flight costs dramatically, and increase flight safety as well.

    • Mark Roest

      Great write-up!

      I think we will see medium range electric aircraft within 4 to 6 years.