Quantifying EV Battery End-of-life Through Analysis of Travel Needs with Vehicle Powertrain Models
Journal of Power Sources (May 15, 2015, v282, p265-276; doi: 10.1016/j.jpowsour.2015.01.072)
[Green Car Congress] A new study by researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley shows quantitatively that EV batteries can continue to meet daily travel needs of drivers well beyond the 80% floor for remaining energy storage capacity that is commonly assumed. An open access paper on their work, which applied detailed physics-based models of EVs with data on how drivers use their cars, is published in the Journal of Power Sources.
The study also sheds light on a number of other factors concerning battery use and energy and power fade, including that even EV batteries with substantial energy capacity fade continue to provide sufficient buffer charge for unexpected trips with long distances; that enabling charging in more locations, even if only with 120 V wall outlets, prolongs the useful life of EV batteries; and that EVs meet performance requirements even down to 30% remaining power capacity.
Energy capacity fade impacts the range capabilities of EVs; power fade impacts the driving performance of EVs in terms of acceleration, gradeability, and maximum charging during regenerative braking or charging events. Put another way, that final finding illustrates that energy capacity fade is a more limiting factor governing retirement than power fade…