Presentation Master Theses BFH Energy storage research centre 2020

The requirements for modern power grids are constantly changing due to the ongoing changes resulting from decentralized feed-in, storage and flexible consumers. These changes must be quantified in order to ensure an efficient  planning in the distribution grid. In this thesis a load profile tool was developed. It generates future power profiles in the power grid based on the energy perspectives 2050. The prosumer profiles can be used for power flow calculations in the planning of distribution grids in order to ensure a high quality of electrical power supply in the future.

In order to facilitate the monitoring and comparison of voltage quality in electrical grids, an index has been developed which combines all voltage quality parameters into a single representative and stable value. Based on two measurement campaigns, a regression model was developed which allows an extrapolation of the index to different grid nodes. This should help the distribution system operators to consider feedback effects from devices and installations in planning and operation and to prevent disturbances in the grid.

Within the framework of a real implementation project, the degradation process of an electrochemical storage system was evaluated using different control strategies. Through this analysis, the optimal configuration of the battery could be identified in order to extend its service life while minimising the necessary investments.

In today's EV batteries, the state of charge is usually estimated using equivalent circuit models. Unfortunately, they lack the representation of electrochemical states necessary for degradation minimization strategies. Enhanced physics-based battery models are introduced that are capable to simulate aging relevant properties. Based on a sensitivity analysis, the most crucial parameters of a commercial Li-ion cell are measured and optimized, resulting in an excellent cross-validation for realistic driving cycles.

Simulations are an important tool for the research and development of new battery designs. Several software packages for such calculations are available on the market, such as COMSOL's "Batteries & Fuel Cells Module". The vast majority of these packages are proprietary and licenses must be purchased to use them. In this thesis a tool for the simulation of batteries based on the freely available software package "FEniCS" was developed.