ISBN 9783843933667

978-3-8439-3366-7, Reihe Verfahrenstechnik

Stefan Jaiser
Film Formation of Lithium-Ion Battery Electrodes during Drying - The Interrelation of Process, Microstructure and Properties

267 Seiten, Dissertation Karlsruher Institut für Technologie (2017), Softcover, A5

Zusammenfassung / Abstract

Lithium-ion batteries add to our daily life by powering consumer electronics or power tools, by storing renewables or by fueling electric vehicles (EVs). Especially traction batteries for use in EVs face high levels of demand with regard to energy density, lifetime, safety or costs. Besides research on innovative materials, the profound understanding of manufacturing processes and, as a consequence, their further improvement is a key direction for advancing the current state of the art.

This work focuses in detail on the drying process of lithium-ion battery electrodes, which has a strong impact on electrode properties. Constituting more than mere solvent evaporation from a coated wet film, the drying step comprises processes, such as wet film shrinkage, consolidation of the active material particles, pore drainage and migration of functional additives throughout the complex microstructure. In short, the drying process decisively determines electrode quality.

This work illuminates the drying process from different angles, employing established experimental approaches, such as laser triangulation, scanning electron microscopy and energy-dispersive x-ray spectroscopy of vitrified electrode cross sections under cryogenic conditions, as well as a number of new methods comprising in-situ analysis of the liquid phase through fluorescence emission or the development of Property Development Curves (PDCs). The results are solidified in a detailed film formation process of lithium-ion battery electrodes that provides a multitude of starting points for process optimization.