UnABESA – Universal connection of battery storage systems from electric vehicles for stationary applications

As part of the UnABESA collaborative project, an innovative system was developed that enables batteries from electric vehicles to be used as stationary energy storage systems without altering their cell architecture or electronics. This was achieved through the development of an intelligent, bidirectional coupling element which, as a ‘plug-and-play solution’, establishes the connection between the vehicle battery and a stationary inverter. The integrated DC-DC converter in the coupling element efficiently adjusts the battery voltage to the level required by the grid inverter, whilst complying with safety requirements and avoiding the use of costly grid transformers. This solution enables the flexible and cost-effective scaling of stationary storage systems for various applications, such as charging stations for electric vehicles, grid load reduction, increasing the self-consumption of solar power, or large-scale storage solutions in the balancing energy market. All partners involved in the project were able to contribute their extensive experience and research capabilities, ensuring the optimal integration of the necessary expertise and the successful commercialisation of the overall system.

Following the successful completion of the project, the prototype developed was used for further research and modified. A new control method for the single-stage AC-to-DC converter was developed, which enables flexible control of reactive power by utilising multiple modulation schemes. This method, validated by a 3 kW prototype, achieves a high efficiency of over 96.5 per cent and keeps output current distortion low. The exhibit on display shows the modified UnABESA converter.