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A Post-Mortem Study of Stacked 16 Ah Graphite//LiFePO₄ Pouch Cells Cycled at 5 °C

Moretti, Arianna; Carvalho, Diogo Vieira; Ehteshami, Niloofar; Paillard, Elie; Porcher, Willy; Brun-Buisson, David; Ducros, Jean-Baptiste; de Meatza, Iratxe; Eguia-Barrio, Aitor; Trad, Khiem; Passerini, Stefano

Abstract:
Herein, the post-mortem study on 16 Ah graphite//LiFePO4 pouch cells is reported. Aiming to understand their failure mechanism, taking place when cycling at low temperature, the analysis of the cell components taken from different portions of the stacks and from different positions in the electrodes, is performed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS). Also, the recovered electrodes are used to reassemble half-cells for further cycle tests. The combination of the several techniques detects an inhomogeneous ageing of the electrodes along the stack and from the center to the edge of the electrode, most probably due to differences in the pressure experienced by the electrodes. Interestingly, XPS reveals that more electrolyte decomposition took place at the edge of the electrodes and at the outer part of the cell stack independently of the ageing conditions. Finally, the use of high cycling currents buffers the low temperature detrimental effects, resulting in longer cycle life and less inhomogeneities.

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Verlagsausgabe §
DOI: 10.5445/IR/1000094541
Veröffentlicht am 14.05.2019
Originalveröffentlichung
DOI: 10.3390/batteries5020045
Coverbild
Zugehörige Institution(en) am KIT Helmholtz-Institut Ulm (HIU)
Publikationstyp Zeitschriftenaufsatz
Jahr 2019
Sprache Englisch
Identifikator ISSN: 2313-0105
KITopen-ID: 1000094541
HGF-Programm 37.01.01 (POF III, LK 01)
Erschienen in Batteries
Band 5
Heft 2
Seiten Article: 45
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Vorab online veröffentlicht am 07.05.2019
Schlagworte lithium-ion; batteries; ageing; post-mortem analysis
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