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Laser-acoustic material characterization of foil coatings for lithium-ion battery technology

: Macher, F.; Windisch, T.

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Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren -IZFP-, Institutsteil Dresden:
7th International Workshop NDT in Progress. Online Proceedings : NDT of Lightweight Materials. Dresden, Germany, November 7 - 8, 2013
Online im WWW, 2013
2 pp.
International Workshop "NDT in Progress" <7, 2013, Dresden>
Conference Paper, Electronic Publication
Fraunhofer IZFP ()

The use of portable electronic devices like smartphones and tablets has become an indispensable part of life. Finally new developments are always based on the availability of efficient and compact storage technologies. This market is currently dominated by lithium-ion cells. In addition, the lithium-ion technology is the most promising system for high-energy batteries, which form the foundation for electric mobility. The special challenges for that are presently in optimization of large-sized cells with the highest possible energy density combined with maximum security, reliability and reasonable costs. To meet these requirements, intensive research on new materials, improved cell design, efficient production technologies and processes for quality assurance are aimed. Promising research subjects are the active materials, which are continuously developed in terms of the combination of materials, their mixing ratio and their production. Several studies of electrode foils, based on active material, show that electrochemical properties, such as the transport of ions, or the specific capacitance, can be improved with adjustment of porosity of the coating. With the porosity as a variable target in the manufacturing process, for manufacturers it is important to find an optimum of performance, durability and safety of their cells. This requires a quantification of their material properties and an establishment of suitable test methods for process control. For economic and production-related reasons, only non-destructive and contactless technologies come into question. Under these tasks the laser-induced thermo-elastic excitation of acoustic waves is especially suitable. The laser-acoustic method allows a further characterization ofmaterials based on ultrasonic measurement principles. By using the laser vibrometry the signals from specimens are also detected contactless. Through the comparative measurement of different sound attenuation a correlation between acoustic signal