Comparative Study of Equivalent Circuit Models Performance in Four Common Lithium-Ion Batteries: LFP, NMC, LMO, NCA

Manh-Kien Tran,Satyam Panchal,Michael Fowler,Anosh Mevawalla,Andre Dacosta

doi:10.3390/batteries7030051

Abstract

Lithium-ion (Li-ion) batteries are an important component of energy storage systems used in various applications such as electric vehicles and portable electronics. There are many chemistries of Li-ion battery, but LFP, NMC, LMO, and NCA are four commonly used types. In order for the battery applications to operate safely and effectively, battery modeling is very important. The equivalent circuit model (ECM) is a battery model often used in the battery management system (BMS) to monitor and control Li-ion batteries. In this study, experiments were performed to investigate the performance of three different ECMs (1RC, 2RC, and 1RC with hysteresis) on four Li-ion battery chemistries (LFP, NMC, LMO, and NCA). The results indicated that all three models are usable for the four types of Li-ion chemistries, with low errors. It was also found that the ECMs tend to perform better in dynamic current profiles compared to non-dynamic ones. Overall, the best-performed model for LFP and NCA was the 1RC with hysteresis ECM, while the most suited model for NMC and LMO was the 1RC ECM. The results from this study showed that different ECMs would be suited for different Li-ion battery chemistries, which should be an important factor to be considered in real-world battery and BMS applications.

Highlights

Over the past 10 years, the annual energy generation has increased over 73 million megawatts per hour, and renewable energy generation such as solar, wind, and tidal increased over 30 million megawatts per hour in Canada [1]
With changes to the materials used in anodes and cathodes such as spherical lithium iron phosphate cathodes and lithium-sulfur, Li-ion batteries can have higher power density, higher energy density, and lower costs than competing chemistries, allowing them to be used in applications formerly dominated by other battery types [7]
Two types of cycles were used in the validation experiments, a dynamic Urban Dynamometer Driving Schedule (UDDS) and a nondynamic discharge/rest/charge cycle, representing two different battery application types

Summary

Introduction

Over the past 10 years, the annual energy generation has increased over 73 million megawatts per hour, and renewable energy generation such as solar, wind, and tidal increased over 30 million megawatts per hour in Canada [1]. With changes to the materials used in anodes and cathodes such as spherical lithium iron phosphate cathodes and lithium-sulfur, Li-ion batteries can have higher power density, higher energy density, and lower costs than competing chemistries, allowing them to be used in applications formerly dominated by other battery types [7]. Li-ion batteries have a structured anode and cathode that houses lithium. With changes to the cathode materials on Li-ion batteries, the characteristics of energy density and cost effectiveness can be further improved [6,7]. When Goodenough et al demonstrated the lithium extraction and insertion stability into FePO4, an olivine structure, LFP solidified its position as the best candidate for phosphate-based cathodes [21]

Results

Discussion

Conclusion