EVOLi2S

Motivation:

The current change in the production of electric energy creates new challenges in maintaining stability and reliability for the distribution network, which can be solved by a decentralised storage of excess energy. Meanwhile the currently used battery technologies like lithium-ion are near their limits especially with the increasing demand for power and lifetime in automobile applications. New concepts for the chemical or mechanical structure of batteries are needed to exceed these current limits and for example improve the range of electric cars significantly.

Project description:

Lithium-sulfur batteries are a promising candidate for high energy battery applications because of their significantly higher capacity in comparison to lithium-ion. However, the lithium-sulfur chemistry has new challenges. One of these challenges is the shuttle effect of sulfur-compounds dissolved in the electrolyte which causes a parasitic side reaction as well as a thickening of the electrolyte which leads to a fading of the capacity and the power of the battery. Another challenge is the dendritic growth of the lithium anode during multiple charge-discharge-cycles.

In EVOLi²S these challenges are addressed by different approaches. To fight the parasitic shuttle effect new electrolyte concepts as well as a new sulfur-based active material are tested to suppress a dissolution of sulfur in the electrolyte. Furthermore, a new module concept, the Open Cell Module (OCM), is developed and tested in EVOLi²S. The single Lithium-sulfur cells are plugged in the OCM-case containing a hydraulic media which applies a constant pressure to the cells during their lifetime, as well as cooling them. This constant pressure and temperature is able to reduce the uncontrolled dendritic growth of the lithium-anode as well as to improve the performance of the cells.

The target of the project is the development of prototype Lithium-sulfur battery-modules and the comparison to modules with classic lithium-ion chemistry in order to quantify and evaluate the advantages and possible disadvantages of the new approaches in the context of mobile and stationary use cases.

Contact:

Robin Moschner
r.moschner(at)tu-braunschweig.de