A Method for Monitoring State-of-Charge of Lithium-Ion Cells Using Multi-Sine Signal Excitation

In this paper, a method for monitoring SoC of a lithium-ion battery cell through continuous impedance measurement during cell operation is introduced. A multi-sine signal is applied to the cell operating current, and the cell SoH and SoC can be simultaneously monitored via impedance at each frequency. Unlike existing studies in which cell impedance measurement is performed ex situ through EIS equipment, cell state estimation is performed in situ. The measured impedance takes into account cell temperature and cell SoH, enabling accurate SoC estimation. The measurement system configured for the experiment and considerations for the selection of measurement parameters are described, and the accuracy of cell SoC estimation is presented.

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Understanding the electrochemical reaction mechanism of VS2 nanosheets in lithium-ion cells by multiple in situ and ex situ x-ray spectroscopy

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/aadde7 ◽

2018 ◽

Vol 51 (49) ◽

pp. 494001 ◽

Cited By ~ 5

Author(s):

Liang Zhang ◽

Dan Sun ◽

Qiulong Wei ◽

Huanxin Ju ◽

Jun Feng ◽

...

Keyword(s):

Reaction Mechanism ◽

Electrochemical Reaction ◽

Lithium Ion ◽

Ex Situ ◽

X Ray ◽

Lithium Ion Cells

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Atomic Layer Deposition of LiF and Lithium Ion Conducting (AlF3)(LiF)x Alloys Using Trimethylaluminum, Lithium Hexamethyldisilazide and Hydrogen Fluoride

10.26434/chemrxiv.5459653 ◽

2017 ◽

Author(s):

Younghee Lee ◽

Daniela M. Piper ◽

Andrew S. Cavanagh ◽

Matthias J. Young ◽

Se-Hee Lee ◽

...

Keyword(s):

Lithium Ion ◽

Atomic Layer ◽

Mass Gain ◽

Alloy Film ◽

Ex Situ ◽

X Ray ◽

Layer Deposition ◽

Ion Conducting ◽

Good Agreement

<div>Atomic layer deposition (ALD) of LiF and lithium ion conducting (AlF3)(LiF)x alloys was developed using trimethylaluminum, lithium hexamethyldisilazide (LiHMDS) and hydrogen fluoride derived from HF-pyridine solution. ALD of LiF was studied using in situ quartz crystal microbalance (QCM) and in situ quadrupole mass spectrometer (QMS) at reaction temperatures between 125°C and 250°C. A mass gain per cycle of 12 ng/(cm2 cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH3)3 as a reaction byproduct instead of HMDS at 150°C. LiF ALD showed self-limiting behavior. Ex situ measurements using X-ray reflectivity (XRR) and spectroscopic ellipsometry (SE) showed a growth rate of 0.5-0.6 Å/cycle, in good agreement with the in situ QCM measurements.</div><div>ALD of lithium ion conducting (AlF3)(LiF)x alloys was also demonstrated using in situ QCM and in situ QMS at reaction temperatures at 150°C A mass gain per sequence of 22 ng/(cm2 cycle) was obtained from QCM measurements at 150°C. Ex situ measurements using XRR and SE showed a linear growth rate of 0.9 Å/sequence, in good agreement with the in situ QCM measurements. Stoichiometry between AlF3 and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF3)(LiF)x alloy consists of aluminum, lithium and fluorine. Carbon, oxygen, and nitrogen impurities were both below the detection limit of XPS. Grazing incidence X-ray diffraction (GIXRD) observed that LiF and (AlF3)(LiF)x alloy film have crystalline structures. Inductively coupled plasma mass spectrometry (ICP-MS) and ionic chromatography revealed atomic ratio of Li:F=1:1.1 and Al:Li:F=1:2.7: 5.4 for (AlF3)(LiF)x alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF3)(LiF)x alloy film was measured as σ = 7.5 × 10-6 S/cm.</div>

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Impact of Relaxation Time on Electrochemical Impedance Spectroscopy Characterization of the Most Common Lithium Battery Technologies—Experimental Study and Chemistry-Neutral Modeling

World Electric Vehicle Journal ◽

10.3390/wevj12020077 ◽

2021 ◽

Vol 12 (2) ◽

pp. 77

Author(s):

Md Sazzad Hosen ◽

Rahul Gopalakrishnan ◽

Theodoros Kalogiannis ◽

Joris Jaguemont ◽

Joeri Van Mierlo ◽

...

Keyword(s):

Relaxation Time ◽

Electrochemical Impedance Spectroscopy ◽

Impedance Spectroscopy ◽

Electrochemical Impedance ◽

Impedance Measurement ◽

Nonlinear Behavior ◽

Lithium Ion ◽

Health Condition ◽

Battery Cell ◽

Rest Time

In electrified vehicle applications, understanding the battery characteristics is of great importance as it is the state-of-art principal energy source. The key battery parameters can be identified by one of the robust and nondestructive characterization techniques, such as electrochemical impedance spectroscopy (EIS). However, relaxing the battery cell before performing the EIS method is crucial for the characterization results to be standardized. In this study, the three most common and commercially available lithium-ion technologies (NMC/graphite, LFP/graphite, NCA/LTO) are investigated at 15–45 °C temperature, in the range of 20–80% state of charge (SoC) and in fresh and aged state of health (SoH) conditions. The analysis shows that the duration of the relaxation time before impedance measurement has an impact on the battery’s nonlinear behavior. A rest time of 2 h can be proposed, irrespective of battery health condition, considering neutral technology-based impedance measurement. An impedance growth in ohmic and charge transfer characteristics was found, due to aging, and the effect of rest periods was also analyzed from an electrochemical standpoint. This experimental data was fitted to develop an empirical model, which can predict the nonlinear dynamics of lithium technologies with a 4–8% relative error for longer rest time.

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Understanding Volume Change in Lithium-Ion Cells during Charging and Discharging Using In Situ Measurements

Journal of The Electrochemical Society ◽

10.1149/1.2386933 ◽

2007 ◽

Vol 154 (1) ◽

pp. A14 ◽

Cited By ~ 56

Author(s):

Xianming Wang ◽

Yoshitsugu Sone ◽

Go Segami ◽

Hitoshi Naito ◽

Chisa Yamada ◽

...

Keyword(s):

Volume Change ◽

Lithium Ion ◽

In Situ Measurements ◽

Lithium Ion Cells

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In Situ and Ex Situ diagnostics of ALD-Ultrathin Lithium-Ion Films

ECS Meeting Abstracts ◽

10.1149/ma2021-0229890mtgabs ◽

2021 ◽

Vol MA2021-02 (29) ◽

pp. 890-890

Author(s):

Messaoud Bedjaoui ◽

Sylvain Poulet

Keyword(s):

Lithium Ion ◽

Ex Situ

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A Combined Experimental and Theoretical Study of Lithiation Mechanism in ZnFe2O4 Anode Materials

MRS Advances ◽

10.1557/adv.2018.305 ◽

2018 ◽

Vol 3 (14) ◽

pp. 773-778 ◽

Cited By ~ 4

Author(s):

Lei Wang ◽

Alison McCarthy ◽

Kenneth J. Takeuchi ◽

Esther S. Takeuchi ◽

Amy C. Marschilok

Keyword(s):

Early Stage ◽

Deep Understanding ◽

Lithium Ion ◽

Oxidation Products ◽

Ex Situ ◽

Theoretical Modelling ◽

X Ray Diffraction ◽

X Ray ◽

X Ray Absorption

ABSTRACTZnFe2O4 (ZFO) represents a promising anode material for lithium ion batteries, but there is still a lack of deep understanding of the fundamental reduction mechanism associated with this material. In this paper, the complete visualization of reduction/oxidation products irrespective of their crystallinity was achieved experimentally through a compilation of in situ X-ray diffraction, synchrotron based powder diffraction, and ex-situ X-ray absorption fine structure data. Complementary theoretical modelling study further shed light upon the fundamental understanding of the lithiation mechanism, especially at the early stage from ZnFe2O4 up to LixZnFe2O4 (x = 2).

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