Integrated lithium micro batteries for highly miniaturized sensors

Highly miniaturized energy autarkic sensors require an energy storage which is small and can be integrated into the system. Lithium ion batteries are a favourite option since they show a superior energy density and pulse performance while self-discharge is very low. In particular they are used as buffer storage in energy harvesting devices. Starting with a description of the state of the art of secondary micro batteries an overview is given of the research directions towards integrated lithium micro batteries classified by the construction principles. The research on lithium micro batteries with coplanar electrode structure performed at Fraunhofer IZM is described in the main section of this paper. Capacity, discharge curves and rate retention as function of current is shown and compared with the international state of the art.