Long-Term Self-Discharge Measurements and Modelling for Various Cell Types and Cell Potentials
- Self-discharge of lithium-ion cells leads to voltage decay over time. In this work, the self-discharge was measured at 30 °C for three cell types at various voltage levels for about 150 days in a constant voltage mode determining the current at a high precision (float current). All cells exhibit a transient part leading to a steady-state, which is no longer influenced by reversible effects. To study the effect of the check-ups on the steady-state float current, the cells, interrupted and not interrupted by check-ups, were compared. The results indicate that both the transient processes and steady-state currents are highly reproducible. In the first period of the float current, the polarization dominates the measured current, followed by the anode overhang effect dominating the process for a period of 5–30 days. After the decline of both processes, a mostly constant steady-state in the order of µA is observed. The check-up interruption generally shows no apparent effect on the reached steady-state and results only in an extendedSelf-discharge of lithium-ion cells leads to voltage decay over time. In this work, the self-discharge was measured at 30 °C for three cell types at various voltage levels for about 150 days in a constant voltage mode determining the current at a high precision (float current). All cells exhibit a transient part leading to a steady-state, which is no longer influenced by reversible effects. To study the effect of the check-ups on the steady-state float current, the cells, interrupted and not interrupted by check-ups, were compared. The results indicate that both the transient processes and steady-state currents are highly reproducible. In the first period of the float current, the polarization dominates the measured current, followed by the anode overhang effect dominating the process for a period of 5–30 days. After the decline of both processes, a mostly constant steady-state in the order of µA is observed. The check-up interruption generally shows no apparent effect on the reached steady-state and results only in an extended settling time. A model to simulate the transient process and steady-state of float currents was developed. The model shows a high accuracy in reproducing the results and identifying the time needed to reach the steady-state.…
Author: | Mohamed AzzamORCiD, Moritz EhrensbergerORCiD, Reinhard Scheuer, Christian EndischORCiD, Meinert LewerenzORCiD |
---|---|
Language: | English |
Document Type: | Article |
Year of first Publication: | 2023 |
published in (English): | Energies |
Publisher: | MDPI |
Place of publication: | Basel |
ISSN: | 1996-1073 |
Volume: | 16 |
Issue: | 9 |
Pages: | 19 |
Article Number: | 3889 |
Review: | peer-review |
Open Access: | ja |
Version: | published |
Tag: | 18650; LFP; NCA; NMC; anode overhang; filtering; float current analysis; graphite; modelling; potentiostatic hold; self-discharge rate |
URN: | urn:nbn:de:bvb:573-36693 |
Related Identifier: | https://doi.org/10.3390/en16093889 |
Faculties / Institutes / Organizations: | Fakultät Elektro- und Informationstechnik |
Institut für Innovative Mobilität (IIMo) | |
Licence (German): | ![]() |
Release Date: | 2023/05/05 |