C. Hafner, T. Bernthaler, V. Knoblauch, G. Schneider
June 11, 2013
Lithium ion accumulators are widely used already in numerous electronic devices. However, a great deal of research will still be required as to their use as a reliable and efficient energy storage unit in the automotive industry. Their characterization using physical and electrochemical methods has made great progress and was published already. In contrast, the classical materialographic characterization of their microstructure by means of microscopy is applied only to a small extent nowadays. Access by the public to relevant results is scarcely possible. Properties like capacity and power as well as safety und stability also depend very much on the cell design (e. g. geometry, layer thicknesses) and microstructure (e. g. volume fraction, grain size) of the materials employed. A microstructure analysis by microscopy is intended to provide for a more profound comprehension of the connection between the basic parameters and function here. A challenge is posed by the preparation of a microsection to reveal a representative image of the microstructure without artefacts. The process of materialographic preparation and the potential of various microscopy techniques for visualizing and quantifying the cell components and ageing effects are presented here. The opportunities of characterizing the basic parameters specific to the cells furnishes new knowledge on the properties of battery materials and, hence, will be of great utility for future examinations and further developments of the lithium ion technology.