A Modelica Library for Simulation of Electrical Energy Storage Coupled with Photovoltaic Systems

Battery energy storage systems (BESS) are one of the most common elements for energy storage. The usage of these systems in renewable energy and traction sectors is gaining wide interest. A BESS has a finite life-cycle, determined by many influencing factors. An electrical storage models offer the possibility to simulate the behavior of these systems and their aging. We developed an equation based model in the open source object-oriented modeling language Modelica. We considered physical phenomena and parameters such as charge/discharge rate, calendar and cycling ageing, battery cell’s internal resistance variations, temperature effects and self-discharge rate. The model has been validated with experimental data from our load management test site. By reducing the order of the model and eliminating discrete modelling functions, it is possible to use the library in combination with an optimal control framework. This enables to test multi-objective optimisation algorithms for BESS coupled with photovoltaic power generation and to estimate the system optimal sizing and control strategies.