Impact of battery ageing on e-mobility energy efficiency

Abstract

Abstract-This paper focuses on energy efficiency degradation of two lithium-ion technologies, NMC (Nickel Manganese Cobalt) and LFP (Lithium Iron Phosphate), under accelerated calendar ageing tests. Results reveal the importance of considering battery ageing in the design phase of electric vehicles, not only for capacity but also for energy efficiency reasons.

On the Efficiency of LFP Lithium-ion Batteries

“…Another interesting result is that efficiency is generally quite constant in medium DoD levels and it rapidly decreases with extreme values (full charge or full discharge). This result is quite characteristic of LFP cells and differs from that obtained in NMC (Nickel Manganese Cobalt) cells [8], where efficiency is continuously decreasing with DoD.…”

“…In some previous works, we showed that the energy efficiency is modified by cell aging and that it would be important to consider not only the efficiency of fresh batteries but also the efficiency of aged batteries when comparing two technologies [8]. The degradation of the efficiency could be linked with the fade of capacity [9].…”

Modeling and Analysis on Efficiency Degradation of Lithium-ion Batteries

“…A study has also been conducted on the energy efficiency of electric vehicles [16]. The optimal battery SOC range for battery vehicles has been estimated by analyzing the relationship between battery energy efficiency and battery SOC range [17]. There has also been discussion of the energy efficiency of NiMH batteries as they are applied to grid frequency control at various discharge currents [18].…”