Redox-Flow: Rechargeable batteries with external tank
Redox-flow batteries are of particular interest in stationary energy storage applications. Due to the storage of energy in an external tank, the performance of the battery can be scaled independently of capacity. In addition, the redox-flow batteries are very efficient and potentially last longer than standard rechargeable batteries.
The Fraunhofer Institute for Chemical Technology ICT is involved with the development of redox-flow batteries based on zinc-bromine and hydrogen-bromine. In the context of the “RedoxWind” project, a large-scale redox-flow storage unit was built with 2 MW and up to 20 MWh, coupled with a 2 MW wind turbine in order to store renewable wind energy. In this application center, we are researching the battery periphery and infrastructure for connecting this type of storage unit to the power grid.
“InTeLekt” – Electric cars can never be reliable without power electronics
In an electric vehicle, the power electronic components control the power supply of the battery, the drive unit and the onboard electronics. As such, they are subject to significant mechanical and electrical stresses during day-to-day use in electric vehicles. These can limit the reliability and lifespan of components. That’s why the partners involved in the “InTeLekt” project are working to develop a new, integrated check and test environment for power electronics, with a view to making them both safer and more reliable. To do so, a new simulation environment is being developed, which will mean that the reliability and lifespan of power modules can be evaluated more rapidly. The Fraunhofer Institute for Structural Durability and System Reliability LBF is playing a major part in this project.
“MiBZ” – Intelligent cells for electromobility and stationary storage
As well as electromobility, stationary energy storage is increasingly gaining in importance to guarantee supply security. An interesting approach for a longer useful lifespan for batteries is so-called “second use”. After five years, batteries designed for electromobility no longer offer the energy density needed, but they are still nowhere near being out of order and can normally continue to be used for other applications such as in stationary energy storage. For this kind of purpose the batteries do not require very high energy density. What is much more crucial is that they are still reliable and can safely function for many more years. To research this application concept, the “MiBZ” project looks at the integration of electronics and sensors into the battery cells and the battery systems in order to develop multi-functional, intelligent lithium-ion batteries. This means that the batteries can be continuously monitored, the state of their cells determined, and high levels of safety guaranteed. The Fraunhofer Institute for Integrated Systems and Device Technology IISB is a Partner in this project.
Fraunhofer IISB, Energy Electronics