Design and construction of a test bench to characterize the charging and discharging behaviour

Battery energy storage systems are able to compensate volatile energy sources, such as wind and solar energy. One system topology for medium voltage grids uses high voltage batteries. This yields in an improvement of the overall system efficiency. High voltage batteries may be advantageous for future DC-grids as well. However, as there is little expert knowledge about series connected batteries up to several kV, this makes investigations of the charging and discharging behaviour of such systems necessary. For this purpose, a test bench for high voltage storage systems is built to analyse these processes for different battery technologies. A special safety infrastructure for the test bench must be developed due to the high voltage and the storable energy of approximately 120 kWh. This paper presents the layout of the test bench with all components, the safety requirements with the resultant safety circuit and the aim of the investigations to be performed with the test bench.