Metallic lithium batteries could potentially provide higher energy and power densities than standard lithium-ion batteries for electromobility and storage – but not enough is known about the processes that detract from their safety and performance. Now, through the “metaLIT” project, the Fraunhofer Institute for Energy Economics and Energy System Technology (IEE) is developing mathematical models to simulate the electrochemical and physical processes that cause them to malfunction.

It is well-known that the formation of needle-like lithium dendrites results in short-circuiting when they penetrate the electrode separator – thereby presenting a safety risk. Futhermore, the lithium deposits a protective layer on the electrode (called a Solid Electrolyte Interphase or SEI) that breaks due to mechanical stress when discharging, then subsequently reforms, and so on, thereby reducing the cell’s performance over time.

Working together with the research institute Edelmetalle + Metallchemie (fem), the IEE has developed a special battery management system (BMS) to counteract these effects. The BMS uses algorithms that infer the battery’s condition from a wide range of variables including voltage, temperatures, current, as well as different load and environmental conditions. The digital models serve as battery emulators in the hardware-in-the-loop test beds, thus reducing the need for time-consuming and expensive physical experimentation.

"The market potential of 'Beyond Lithium Ion' batteries is enormous, because with a theoretically higher energy and power density, electric cars get more range," explains Lars Pescara, research associate at Fraunhofer IEE, in a press release. "With our modelling, we support battery manufacturers and automotive suppliers in bringing this potential to the road."

MetaLIT is funded until September 2022 by the Federal Ministry for Economic Affairs and Energy (BMWi).