Journal of Power Sources · 2015 · 354 citations · 24 references
EngineeringAutomotive EngineeringElectrical EngineeringElectric Vehicle TechnologyTransportTransportationCharging SystemsElectric Vehicle SimulationEnergy StorageState Of Charge ManagementSustainable TransportSustainable TransportationBattery DegradationBattery Degradation AnalysisBattery Degradation ModelingCapacity FadePerformance RequirementsRetirementStorage CapacityVehicle Energy Consumption
Electric vehicles promise clean, efficient transport, yet range anxiety and battery degradation limit adoption, and the prevailing 70–80 % capacity end‑of‑life definition lacks empirical support. The study proposes that battery retirement be defined by the point at which batteries fail to meet a driver’s daily travel needs. Using physics‑based EV models and real driving data, the authors demonstrate that batteries remain functional for daily and unexpected trips well beyond 80 % capacity fade, that wider charging availability extends useful life, that performance is adequate even at 30 % power capacity, and that the 70–80 % retirement threshold is inaccurate, providing a new metric to estimate retireable battery fractions.
Electric vehicles enable clean and efficient transportation, however concerns about range anxiety and battery degradation hinder EV adoption. The common definition for battery end-of-life is when 70–80% of original energy capacity remains, however little analysis is available to support this retirement threshold. By applying detailed physics-based models of EVs with data on how drivers use their cars, we show that EV batteries continue to meet daily travel needs of drivers well beyond capacity fade of 80% remaining energy storage capacity. Further, we show that EV batteries with substantial energy capacity fade continue to provide sufficient buffer charge for unexpected trips with long distances. We show that enabling charging in more locations, even if only with 120 V wall outlets, prolongs useful life of EV batteries. Battery power fade is also examined and we show EVs meet performance requirements even down to 30% remaining power capacity. Our findings show that defining battery retirement at 70–80% remaining capacity is inaccurate. Battery retirement should instead be governed by when batteries no longer satisfy daily travel needs of a driver. Using this alternative retirement metric, we present results on the fraction of EV batteries that may be retired with different levels of energy capacity fade.
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