Samenvatting

Li4Ti5O12 (LTO) has been proposed as a promising candidate to replace the market-dominating carbon-based anodes (graphite and amorphous carbon) due to its excellent cycling stability and safety concerns [1]. It works at a flat potential plateau at around 1.5 V vs. Li/Li+, and theoretically, it does not experience the formation of passivation layers with high impedance, the so-called “solid electrolyte interphase” (SEI) [2]. Therefore LTO-based batteries show a different degradation scenario which is investigated in this work.
A comprehensive aging study of Li4Ti5O12 /Li(NiCoAl)O2 (LTO/NCA) lithium ion batteries is carried out with a set of commercial pouch cells (5 Ah). These batteries were optimized for Hybrid Electrical Vehicles (HEVs) application. It has been proved that the aging behavior is directly related to the battery test condition so that a delicate test matrix has been fixed [3]. It includes both cycling aging and calendar aging. The cycling aging mainly investigates the influences of ambient cycling temperature, charge/discharge current rate and depth of discharge. The calendar aging focuses on two factors, state of charge (SOC) and ambient temperature. Additionally, the matrix includes several intermediate aging state batteries which provide information about the evolution of the degradation phenomena.
Aged batteries are post-mortem analyzed by multiple techniques to have a deeper insight into the origin of the aging phenomena. Electrochemical impedance spectroscopy (EIS) is one of the main tool for characterization. In this work, EIS is performed using the in-house developed Odd Random Phase EIS (ORP-EIS) [4]. Reliable impedance modelling has been performed to quantitatively address the origin of the rising impedance. Moreover, multiple surface analysis techniques are applied. Scanning electron microscopy (SEM) is used to demonstrate the morphology changes of the electrodes. The changes of the electrode composition is preliminary determined by Energy dispersive X-ray (EDX).
In this work, by coupling variable aging conditions and post-mortem analysis, the main aging processes of LTO/NCA battery are addressed and quantified. Especially, the strategy of using commercial batteries provides insights into the real-life HEVs application. The interpreted results will be served as input parameters for the development of a physics-based aging model, applied for the accurate battery lifetime prediction.

[1] Omar, Noshin, Mohamed Daowd, Peter van den Bossche, Omar Hegazy, Jelle Smekens, Thierry Coosemans, and Joeri van Mierlo. "Rechargeable energy storage systems for plug-in hybrid electric
[2] Scrosati, Bruno, and Jürgen Garche. "Lithium batteries: Status, prospects and future." Journal of Power Sources 195, no. 9 (2010): 2419-2430.
[3] Vetter, J., P. Novák, M. R. Wagner, C. Veit, K-C. Möller, J. O. Besenhard, M. Winter, M. Wohlfahrt-Mehrens, C. Vogler, and A. Hammouche. "Ageing mechanisms in lithium-ion batteries." Journal of power sources 147, no. 1 (2005): 269-281.
[4] Van Ingelgem, Yves, Els Tourwé, Orlin Blajiev, Rik Pintelon, and Annick Hubin. "Advantages of odd random phase multisine electrochemical impedance measurements." Electroanalysis 21, no. 6 (2009): 730-739.
Originele taal-2English
StatusUnpublished - 21 aug 2016
Evenement67th Annual Meeting of the International Society of Electrochemistry - The Hague, Netherlands
Duur: 21 aug 201624 aug 2016
http://annual67.ise-online.org

Conference

Conference67th Annual Meeting of the International Society of Electrochemistry
Verkorte titelISE67
LandNetherlands
StadThe Hague
Periode21/08/1624/08/16
Internet adres

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