Response From: National Renewable Energy Laboratory (NREL)
Question: What information is available on electric vehicle (EV) battery degradation due to different charging speeds?
First, for general information on the expected life cycle of an EV battery, please refer to the Department of Energy’s At A Glance: Electric-Drive Vehicles fact sheet (https://afdc.energy.gov/files/u/publication/electric-drive_vehicles.pdf). Specifically, see the maintenance section for information on battery life:
“Electrical systems (battery, motor, and associated electronics) require minimal scheduled maintenance. A manufacturer’s warranty of a battery typically covers 8 years/100,000 miles. Expected battery lifetime is 12–15 years under normal operating conditions.”
Next, it is our understanding that while EV batteries may degrade faster with the use of direct current (DC) fast charging compared to the use of Level 2 charging, the difference is minimal.
This study compared four new 2012 Nissan Leaf EVs, two of which were charged exclusively by Level 2 chargers and two of which were charged exclusively by DC fast chargers. The conclusion of the report states the following:
“A greater loss in battery capacity was observed for the fast-charged vehicles, though the difference compared to the level two charged vehicles was small in comparison to the overall capacity loss. The vehicle operation was, as intended, verified to be very similar between test groups, and the largest difference in conditions noted was battery temperature during charging. Hotter ambient temperatures appear to have accelerated capacity loss for all of the vehicles in the study, though the exact relationship remains to be seen.”
Further, a 2020 Geotab study of 6,300 EVs showed similar results to the above INL report (https://www.geotab.com/press-release/ev-battery-degradation-tool/):
“The use of DC fast chargers appears to speed up the process of degradation but there is not much difference in battery health based on frequent use of Level 1 versus Level 2 charging.”
Lastly, in 2023, Recurrent studied the battery management systems of 12,500 Tesla vehicles in the US and found that there was no significant difference in range degradation or battery damage when relying on fast charging versus level 2 or 1 charging. You may refer to the Recurrent article Full Speed Ahead: EV Study Reveals Impacts of Fast Charging (https://www.recurrentauto.com/research/impacts-of-fast-charging) more information on their results.
Battery Degradation Tools
NREL’s Battery Lifetime Analysis and Simulation Tool (BLAST) Suite (https://www.nrel.gov/transportation/blast.html) combines NREL’s battery degradation modeling with electrical and thermal performance models in order to assess battery lifespan and performance for behind-the-meter, vehicle, and stationary applications. BLAST tools incorporate realistic lab-based drive-cycles or simulated real-world driving patterns to anticipate EV battery lifetimes. In particular, BLAST-Lite (https://github.com/NREL/BLAST-Lite), which is available online, provides a library of battery lifetime and degradation models for various commercial lithium-ion batteries from recent years.
Further, Geotab offers a tool from 2020 comparing battery degradation of different EV models (https://www.geotab.com/blog/ev-battery-health/). Please note that we cannot verify the accuracy of nongovernmental resources. You may filter by model, model year, or add multiple models to compare the vehicles’ estimated battery degradation. This tool was developed from the study of 6,300 fleet and consumer EVs referenced above.
