A modular energy storage for integration in the power grid is to be developed. Especially in combination with renewable energies, such energy storages can improve stability and reliability of the power grid.

The project’s objective is to optimize the lifetime of battery modules integrated in a power inverter. This is achieved by a modular approach, which allows every module to be charged or discharged individually, depending on its state. Therefore, the system can possibly also be a second use application for used batteries.

For the project, suitable lithium-ion batteries are selected and integrated in the structure of a modular multi-level converter (MMC). The MMC-structure ensures good grid performance. Additionally, direct current sources and storages, such as photovoltaic, can be connected to the grid using the inverter. To optimize the lifetime of the battery modules, novel modeling approaches are used. With this, different types of batteries are planned to be usable in the MMC. Maximum lifetime is achieved by optimized power allocation. For example, the State-of-Health (SoH) could be used in this strategy. Furthermore, the optimized operation makes it possible to reduce the total capacity and therefore cheaper systems with the same properties can be realized. The developed system is to be evaluated as a demonstrator in the PHiL-Laboratory of the Energy Lab 2.0.

2.3 mio. €

link to datasheet