"Range anxiety may be an over-stated concern” finds US study
Carried out by scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), the study debunks the theory that EV batteries will be retired after the battery has lost 20% of its energy storage or power delivery capability.
In fact, the study, which was carried out on real-world driving patterns, found that at such levels batteries can still meet the daily travel needs of more than 85% of US drivers.
Samveg Saxena, who leads a vehicle powertrain research programme at Berkeley Lab, and his research team also analyzed battery power fade and found that even after substantial loss in battery power capabilities performance requirements are still met.
Saxena commented: “We have found that only a small fraction of drivers will no longer be able to meet their daily driving needs after having lost 20% of their battery’s energy storage capabilities. It is important to remember that the vast majority of people don’t drive more than 40 miles per day on most days, and so they have plenty of reserve available to accommodate their normal daily trips even if they lose substantial amounts of battery capacity due to degradation.”
The Berkeley Lab scientists also analyzed power capacity fade and found that power fade for the chosen vehicle does not have a significant impact on an EV’s performance, and that a battery’s retirement will be driven by energy capacity fade rather than by power fade.
The researchers concluded that batteries can “satisfy daily mobility requirements for the full lifetime of an electric vehicle”.
“In sum, we can lose a lot of storage and power capability in a vehicle like a Leaf and still meet the needs of drivers,” Saxena said.
Future work will involve providing personalised EV information for drivers, which takes into account an individual’s driving behaviour.