Degradation of Commercial Lithium-Ion Cells as a Function of Chemistry and Cycling Conditions

Abstract

Energy storage systems with Li-ion batteries are increasingly deployed to maintain a robust and resilient grid and facilitate the integration of renewable energy resources. However, appropriate selection of cells for different applications is difficult due to limited public data comparing the most commonly used off-the-shelf Li-ion chemistries under the same operating conditions. This article details a multi-year cycling study of commercial LiFePO4 (LFP), LiNixCoyAl1−x−yO2 (NCA), and LiNixMnyCo1−x−yO2 (NMC) cells, varying the discharge rate, depth of discharge (DOD), and environment temperature. The capacity and discharge energy retention, as well as the round-trip efficiency, were compared. Even when operated within manufacturer specifications, the range of cycling conditions had a profound effect on cell degradation, with time to reach 80% capacity varying by thousands of hours and cycle counts among cells of each chemistry. The degradation of cells in this study was compared to that of similar cells in previous studies to identify universal trends and to provide a standard deviation for performance. All cycling files have been made publicly available at batteryarchive.org, a recently developed repository for visualization and comparison of battery data, to facilitate future experimental and modeling efforts.

ENPOLITE: Comparing Lithium-Ion Cells across Energy, Power, Lifetime, and Temperature

“…Additionally, the metrics for lifetime are not standardized, and conclusions about lifetime performance are generally dependent on the choice of metrics used (e.g., relative vs. absolute capacity or energy; see Figures 1b-1c). Furthermore, battery degradation is often nonlinear [8][9][10] ; therefore, using a single parameter from a linear fit (e.g., the slope) to represent nonlinear aging trends must be handled with care. Despite these challenges, standardized reporting and visualization of these parameters is still useful for both fundamental understanding and practical concerns such as cell selection.…”

Second Life Batteries Used in Energy Storage for Frequency Containment Reserve Service

“…Many studies have already dealt with the degradation principle of battery cells during operation. We based the lifespan estimation at the battery cells aging principles in storage on the knowledge from studies [42,44,45]. A look at the aging of the battery cell, which most authors agreed on, is the possibility of dividing the aging of the battery into two independent principles according to the following equation:…”

“…Concerning the function above, we decided to use the EFC discharge capacity retention methodology for NMC battery cells described by Yuliya Preger et al [44] to determine the cyclic degradation's final contribution to the overall capacity fade.…”

Battery Lifecycle Framework: A Flexible Repository and Visualization Tool for Battery Data from Materials Development to Field Implementation

“…The Battery Archive site was released in September 2020 and currently includes battery cycling data from the Center for Advanced Life Cycle Engineering (CALCE) 15,16 , the Hawaii Natural Energy Institute (HNEI) 17 , Oxford University (OX) 18,19 , and Sandia National Laboratories (SNL). 20 We are in the process of uploading data from Purdue University 21 , University College London (UCL) 22 , UC Berkeley (CAL) 23 , and NASA. 24 Various other datasets are in the pipeline.…”