Combined Thermo-Electrical Simulation Model for Large-scale Battery Electrical Storage Systems

The self-consumption of the peripheral equipment, especially the cooling system, of a large-scale battery electric storage systems (BESS) affects its overall efficiency. Simulation models can help estimating the efficiency in the design process, but existing models mostly focus on the electrical behavior of smaller storage systems not including peripheral equipment. Here, a model is developed that displays the electrical and thermal behavior of a large-scale BESS and includes its peripheral equipment. The model is validated with measurement data of an operating 1 MW system and it is shown that the model displays the electrical behavior with a relative deviation of 10 %; the thermal behavior with 27 %. Three parameters are varied investigating the impact of the cooling system on the efficiency: nominal thermal power, target temperature and temperature bandwidth of the cooling system. Decreasing the nominal power improves the overall efficiency, whereas varying the temperature bandwidth and target temperature has a minor effect.