The Redox Flow Battery for Grid-Level Energy Storage*

4:30 pm on March 3, 2015 in ME 2054

Dr. Matthew M. Mench

Head, Department of Mechanical, Aerospace, and Biomedical Engineering

Professor and Condra Chair of Excellence

The University of Tennessee, Knoxville

Abstract:

With the chosen, and in some cases mandated, integration of renewable energy technologies world-wide, there are growing advantages to creating an energy storage component to the electrical grid. The locally unpredictable nature of renewable wind and solar output does not often meet time-dependent load requirements, resulting in a need to augment the renewable power input with a baseline of traditional power sources and lost potential. The integration of energy storage capacity to the grid enables a more efficient capture and use of renewable resources, and also reduces the need to match power generation capacity with peak load requirements. Additionally, the mismatch between daytime and nighttime power requirements results in an arbitrage opportunity, which can help the financial case for the addition of a storage infrastructure. Thus, there is a huge potential for peak shaving and efficiency gains with the addition of energy storage. The capacity of such systems, however, must be massive. To date, few technologies have shown the potential to handle the required loads and be geographically deployable.

One potential disruptive technology for grid-level energy storage is the redox flow battery. In the redox flow battery, power and storage capacity are decoupled, providing the advantage of high conformability to local needs. Unlike hydro and compressed air storage systems, the redox flow battery is also geographically independent and massively deployable. One of the most promising chemistries of the redox flow battery is the all-vanadium system, which relies on vanadium in an acid solution at different oxidation states at both electrodes. As a result, the potential impact of species crossover through the separator is minimized and rebalancing can recover lost capacity. However, the cost of vanadium in these systems is high for conventional systems. Work at the University of Tennessee has shown an increase in the operating current density of the all-vanadium system by over an order of magnitude compared to conventional systems presently in service. This achievement enables a tremendous reduction in cost of the power plant and brings the vanadium chemistry and its variants closer to a practical reality. To achieve this advance, a full array of diagnostics and modeling efforts applicable to a wide variety of potential battery chemistries are being deployed and will also be discussed.

Bio:

Matthew Mench is the Department Head of Mechanical, Aerospace and Biomedical Engineering at the University of Tennessee. He is also Professor and Condra Chair of Excellence in Mechanical Engineering, with joint appointments at Oak Ridge National Laboratory (ORNL) and in Chemical Engineering. He has published over 100 peer reviewed publications, numerous book chapters, has multiple patents granted or under review, and authored the textbook entitled Fuel Cell Engines. He was recognized as a 2014 Highly Cited Researcher (HCR), ranking among the top 1% most cited researchers over the past decade in the field of engineering. Dr. Mench is an ASME Fellow, and also serves as the Executive Vice President of the International Association for Hydrogen Energy, and as an Associate Editor Emeritus for the International Journal of Hydrogen Energy. He was awarded a National Science Foundation Early Career Development Award in 2006, and was a recipient of the Penn State Engineering Society Premier Teaching Award in 2009 and University of Tennessee Research Fellow Award in 2013. His research interests span multi-phase transport phenomena, degradation, dynamics, advanced diagnostics, sensors, and modeling of electrochemical power conversion and storage systems including polymer electrolyte fuel cells and flow batteries.

* KENNINGER SEMINAR, School of Mechanical Engineering