Li-Oxygen Versus Li-Ion Battery Systems: Chances and Challenges for Utilization in the Automotive Industry

Due to its ultra-high energy density Li-oxygen battery technology is one of the first-choice candidates for the realization of full electric vehicles capable of covering a driving range beyond 500 km [1].

The present contribution deals with the development of a full system for operating Li-oxygen technology in an automotive environment.

Electrochemical models based on the work of Doyle and Newman [2] as well as battery system requirements form the fundament for developing a suitable Li-oxygen cell design (i.e. simulation of reactant flow). The integration of the cells into a full battery system is elaborated in detail with special focus on the requirements of Li-oxygen technology [3]. For the Li-oxygen battery system an operation strategy is described. A discussion of range- and power capabilities as well as predictions for weight and volume of the full battery system for achieving a vehicle range beyond 500 km is presented. With the help of statistical methods safety aspects of Li-oxygen battery pack design are studied. In addition a comparison between conventional Li-ion technology and Li-oxygen technology on battery system level is drawn.

Our findings point out that both Li-oxygen and Li-ion technology feature mutually beneficial properties with respect to energy and power density and that a combined use of these technologies is highly recommendable for automotive applications.

[1]    Girishkumar et al, J. Phys. Chem. Lett. 1, (2010), p.2193-2203

[2]    J. Adams, M. Karulkar, J. Power Sources 199 (2012) 247-255

[3]    Traußnig et al, Poster Session, Kraftwerk Batterie  (2013)

Acknowledgement

The research leading to these results has received funding from the European Union’s Seventh Framework Program under EC-GA No. 265971 ‘LABOHR’.

The attached image shows a Li-oxygen pack design which is separated into three different areas (oxygen uptake area in yellow, cell assembly in blue and E/E unit in red -> see also integrated caption). The simulation on the upper right side of the image studies the impact of the reactant flow on cell chemistry, whereas the simulation on the lower right side of the image investigates the impact on system level.