Electrical energy storages are essential for the reorganization of the energy system. In this field, we focus on the development of batteries and SuperCaps. The applications of batteries are numerous and range from compact mobile entertainment and communication devices, batteries for hybrid and electrical vehicles through to storages for renewables with MW/MWh capacities. The common development goal of these fields of applications is an ideally high energy and power density, which means short loading and unloading times. A reliable operation and a long durability are further features.
Redox-flow batteries are a pioneering technology for the energy storage with high outputs (megawatts). The stored energy is held in external tanks and can be converted in the conversion unit when needed. They offer the possibility of individually adjusting power (kW) and energy (kWh) of the application. The applications range from the storage of renewables from fluctuating renewable energy sources and the possible usage as almost continuously available energy storage in the grid through to the uninterruptible power supply.
Rechargeable lithium-ion batteries are increasingly used in all areas of daily life and also gain importance as stationary temporary energy storage.
Advantages of the lithium-ion battery include its low self-discharge rate, the fact that there is no considerable memory effect and its high energy density. Especially the electric mobility in form of e-cars or e-bikes makes use of the high energy density in order to achieve a long range. In addition to the development of materials, their processing and process engineering, battery management and monitoring as well as investigations into the security of these energy storages are also at the focus of the Fraunhofer Energy Alliance.
With their very high power density and related short retrieval and charging times, double-layer capacitors are an alternative or complement to battery technologies. Researchers at Fraunhofer are committed to improve these SuperCaps by using new materials and coating technologies.