Lifetime Estimation of the Nanophosphate LiFePO4/C Battery Chemistry Used in Fully Electric Vehicles

There are currently many different lithium ion (Li-ion) chemistries available on the market, and several new players are in the research and development process; however, none of them is superior to the other chemistries in all aspects. Relatively low price, long cycle and calendar lifetime, and intrinsic safety of the nanophosphate LiFePO4/C Li-ion chemistry make it possible to consider this chemistry for electric vehicle (EV) applications. This paper investigates the lifetime of the nanophosphate LiFePO4/C battery chemistry when it is used for full electrical vehicles. The investigation is performed considering a semiempirical calendar and cycle lifetime model, which was developed based on extended accelerated lifetime tests. Both capacity and power capability degradations during calendar and cycle life aging are considered and quantified. Finally, the developed battery cell lifetime model is used to study the capacity and power capability degradation behavior of the tested nanophosphate LiFePO4/C battery for two EV operational scenarios.