As EV battery prices fall, is greater range or lower cost more important?
The cost of lithium-ion batteries has fallen significantly in a short time and will continue to drop as the market for advanced electric vehicle batteries grows. The improvements pose a critical question to automakers: how much range is enough? About what we have now, according to a recent study. A researcher for the Oak Ridge National Laboratory, Zhenhong Lin, concluded as much in his paper Optimizing and Diversifying Electric Vehicle Driving Range for US Drivers, published in Transportation Science (via Charged EVs).
What the study found
The study closely examined 36,664 sample drivers for things like driving habits and charging infrastructure availability, concluding that for most people the current status quo of sub-100 mile range is adequate.
Lin proposed a way to optimize desired driving range by converting range limitation to a ‘cost’ to measure range anxiety and minimizing the sum of battery, electricity, and range limitation costs.
“The quantitative results strongly suggest that ranges of less than 100 miles are likely to be more popular in the BEV market for a long period of time,” according to the author. As long as battery pack costs remain above $100/kWh, which will be the case for a while, it mathematically makes the most sense to drive down vehicle costs through battery cost reductions rather than use those advancements to improve range.
Why we disagree
No study is perfect, and this one is no exception. Whether or not a sub-100 mile range is actually feasible for these (or any) drivers, what matters is that the driver thinks it is feasible. Perception trumps reality when it comes to range anxiety, at least for the time being.
Though there is certainly a place for electric vehicles like the Nissan LEAF and its current 84-mile range, psychological barriers and the need for longer trips means that electric vehicles must diversify their offerings to include longer-range options.
Though the mathematically optimal range for the typical electric vehicle may be below 100 miles, humans rarely rely on cold logic when purchasing a vehicle. If they did, we would have a whole lot more Honda Fits out there. Even if 85 miles is more than enough for daily trips, its limitations without ubiquitous and reliable charging infrastructure relegate it to second-car status for all but the most dedicated.
Public charging infrastructure is headed in the right direction, but it has a long way to go. And even with DC fast chargers everywhere, it still wouldn’t make much sense to take a LEAF on a day trip that requires more than one fill-up, which largely rules out round-trip journeys longer than 150 miles (with the exceptions of a few adventures like this one taken by dedicated EV owners).
There is a tentative consensus that 120 miles is the threshold for electric vehicles to be considered practical for all but long road trips, which would still be possible with some inconvenience. Most automakers who are serious about the game are targeting 200 miles of range, most notably Tesla and GM.
The optimal solution?
Tesla was on to something when it chose to offer Model S with a choice of battery pack size. Nissan will likely give the next-generation LEAF several battery pack options, up to perhaps 150 miles of range.
Which brings me to my solution to the question of more range or less cost: offer both! Let the consumer decide if he prefers the cheaper, 85-mile version of the Nissan LEAF or the more expensive version with an extra 50 miles of range. As battery costs fall, the driver should be able to choose how he wants that cost reduction to manifest itself.
If the LEAF is offered with multiple pack sizes, and the 2016 Volt (as has been speculated) arrives with a cheaper version capable of less electric range, we will find out soon enough what most customers prefer.
Focusing battery developments on lowering the cost of the vehicle without improving range means eliminating a huge segment of the market that may want an EV as their primary vehicle but still need to drive it long distances on occasion. Studies like this one are useful, but ultimately there is no one right answer to how much range an electric vehicle ‘should’ have.