The desire to move towards the rapid charging of lithium-ion batteries has motivated many researchers to understand the underpinning degradation mechanisms as a precursor for the design of novel models and control algorithms to help mitigate their occurrence. It is widely reported that lithium plating is a significant ageing mechanism that occurs when charging the battery at low temperatures, high C-rates and high state of charge (SOC). There are multiple efforts embracing the measurement of different parameters during charging, such as battery voltage and current, that may collectively provide critical information useful for the detection of lithium plating. Much of this research is focussed on the post-processing of such data after completion of charge to infer the onset of lithium plating. This study aims to extend recent work, by proposing a new method of lithium plating detection, based on an estimation of cell impedance. This approach is able to operate in real-time during charging and therefore transferable to the battery management system (BMS). Experimental results highlight that the proposed method is highly sensitive and capable of effectively detecting the onset of lithium plating in real-time, underpinning the design of future optimal charging strategies to minimise lithium plating.
This study develops two novel charging strategies for lithium-ion batteries, designed to prevent the onset of lithium plating when the cells are charged at low ambient temperatures. Commercially available 3.1 Ah 18650-type cells with NCA and graphite electrodes have been selected for this study. Experimental results highlight that for these cells, lithium plating can be detected when the cells are charged with a traditional constant-current constant-voltage (CC-CV) profile at an ambient temperature of 5 o C and a charge rate of 1C. The occurrence of lithium plating is known to lead to a considerable capacity reduction. To avoid the onset of lithium plating with minimum impact on the charge time, two optimal charging strategies are proposed. The first is based on detecting the onset of lithium plating through the online analysis of the voltage relaxation profile (VRP). The second is to manage the cell charging process to achieve a pre-defined rate of battery degradation per charge cycle. Experimental results highlight that the capacity fade of cells using the proposed charging strategies can be significantly reduced compared to when charged using the conventional CC-CV approach by 45% and 70% respectively while minimizing their impact on the charging speed.
Lithium plating significantly reduces the lifetime of lithium-ion batteries and may even pose a safety risk in the form of an internal short circuit, leading to catastrophic cell failure. Low temperatures, high charge currents and battery age are known to be contributing factors to increased lithium plating. To reduce or avoid battery ageing induced by lithium plating, a method for lithium plating detection is essential to help understand the favourable conditions under which battery charging is optimised. In this study, we present a concept to design an experiment-based approach to improve lithium plating detection sensitivity using the non-destructive voltage relaxation analysis method. Commercial NCA/graphite cells are employed for this study. Here, the reversible part of the plated lithium providing a unique cell voltage relaxation profile is used as a pseudo-measure to detect the onset of plating. This profile is observed while the cell is at rest as well as under a low C-rate discharge regime immediately after charging. It is found that the CV (Constant Voltage) phase cut-off current value significantly influences plating detection. To address this issue, a procedure to determine the optimal cut-off current in the CV phase of charging is introduced to improve the detection sensitivity. With the proposed method, plating detection chances are improved which will help in understanding the favourable conditions and developing plating control strategies. Furthermore, a correlation between lithium plating and Electrochemical Impedance Spectroscopy (EIS) measurements are utilized to demonstrate the influence of previous ageing conditions on lithium plating.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.