Second-life lithium-ion battery aging dataset based on grid storage cycling

Abstract

This paper describes an experimental dataset of used lithium-ion battery cells cycled on grid storage synthetic duty cycles to study their feasibility for second-life applications. Data were collected at the Stanford Energy Control Laboratory at Stanford University, CA, USA. The ten INR21700-M50T battery cells with graphite/silicon anode and Nickel-Manganese-Cobalt (NMC) cathode had been previously tested over a period of 23 months according to the Urban Dynamometer Driving Schedule (UDDS) discharge driving profile. In this paper, six out of these ten cells are tested for a period of 24 months. The aging campaign is a combination of calendar aging and cycling. The cycling portion is designed to replicate real-world usage patterns based on synthetic duty cycles for residential and commercial grid energy storage systems (ESS). Battery cycling alternates between 20 °C and 35 °C to simulate seasonal temperature variations encountered in grid applications. The calendar aging, on the other hand, occurs at room temperature. Periodic assessments of battery degradation during second-life testing are accomplished via Reference Performance Tests for second-life (RPT S) comprising of a combined capacity and pulse power test, and Electrochemical Impedance Spectroscopy (EIS) at three state-of-charge (SOC) values. The data set captures the combined effects of cycling-induced stress and long-term storage.