Dominik Schulte

Nafion Hybrid Membranes for Use in Redox Flow Batteries

The membrane is the key component of a redox flow system, as it has to avoid cross-contamination of the ions of the active material as well as to permit high proton conductivity. A membrane with drastically reduced cross-contamination ability would overcome the main problem of several redox couples and, in consequence, a wider variety of redox couples would potentially allow redox flow systems with higher energy densities or lower material costs. This work deals with modifications of Nafion membranes to decrease the cross-contamination ability without affecting the proton conductivity. Several in situ gel reactions were used for modification of the membranes. Cross-contamination has been reduced in this work by a factor of 2 compared to previous works by Xi et al. [J. Power Sources, 166, 531 (2007)] and Teng et al. [J. Power Sources, 189, 1240 (2009)].

Adaptive battery steering and management system for the optimized operation of stationary battery energy storage systems in multi-use applications

In stable electrical networks, such as the German one, the service of uninterruptible power supply (UPS) systems is only rarely called. Consequently the battery lifetime in this application is mostly restricted by calendar aging. The concept of multi-use describes here the delivery of additional services with a UPS during stable grid operation. The overall goal is to allocate the battery capacity and power according to the current state of health (SoH). Therefore, the Battery Steering and Management System (BSMS) was designed to allow for an optimal operation strategy over the full lifetime of a battery energy storage system (BESS). The BSMS combines a diagnostic unit with a management system that withholds an electrical and an aging model. The system is conceptualized to secure short term functionality as well as to predict long-term behavior and allow for operation planning. Over the lifetime of the battery the operation recommendation will adapt according to the batterys current status and its history. In addition, the paper presents briefly the basic concept of multi-use applications and the currently attractive markets for further services by a UPS.