Calendar Aging Lifetime Model for NMC-based Lithium-ion Batteries Based on EIS Measurements

Lithium batteries are increasingly becoming the energy storage technology preferred for many applications. The interest for its use in applications that require a large storage capacity, such as the automotive industry or renewable energy, demands better prognostic and health monitoring procedures in order to prevent unforeseen failures because of the significant cost involved. This work focuses its study on the degradation of the batteries produced during idle-time, i.e. calendar aging. In this paper electrochemical impedance spectroscopy (EIS) is investigated as a tool of prognosis under several conditions of state of charge (SOC) and temperature. For the tests, 63 Ah Lithium-ion cells based on Nickel Manganese Cobalt oxide (NMC) cathode, were used. The batteries were tested during 12 months in climatic chambers and their capacity and impedance spectra were measured on a regular basis. The data set collected was analyzed in order to create a model capable of predicting the batteries’ state of health (SOH) according to the calendar aging conditions.