Technological Rough Diamonds

Despite decades of research, the enormous potential of flow cell technology still has to be realized.

What many do not know is that flow cell technology has been undergoing research since the 1950s and has been, to some extent, commercialised with varying degrees of success. For the most part, flow cells the size of freight containers serve as storage batteries for solar or wind energy systems. Nonetheless, due to their specific technological benefits, flow batteries are among the most promising energy storage media of the future.

The advantage of the flow cell is the physical separation of energy storage and conversion, which, in other battery systems, occurs in the same place. Thanks to their external energy storage, flow cells can be scaled to suit requirements. Further benefits of the flow cell relative to conventional batteries such as lithium-ion or nickel-metal hydride batteries are their lack of sensitivity to total discharge, their high cycle tolerance due to the absence of the memory effect, and extremely low self-discharge.

Previously, flow cells were not considered suitable for use in electric vehicle drives because of their energy density. The technology's potential went unrecognised.

"For some people, the stone in their hand is simply a stone. Others, however, see it as a rough diamond that must be ground and polished to unveil its full brilliance. The same can be said for research - you must be able to recognise the quality of a research method in order to be able to guide it to a successful outcome," says Nunzio La Vecchia, Chief Technology Officer of nanoFlowcell AG. "Flow cell technology is a particular case-in-point where many people still think that all they have in their hand is a stone. Now, I ask you, does nanoFlowcell® look like a stone? It's clear to me that the full extent of the flow cell's potential is only very slowly being recognised by both academia and industry."

Diagram of the flow cell system in the QUANT FE (Image: nanoFlowcell AG)

No electromobility without the flow cell

In their latest study entitled "Global Flow Battery Market 2016-2020" (>) analysts from TechNavio - Infiniti Research Ltd. forecast that flow cells (redox flow batteries) will be the most significant energy storage medium of the future - particularly and specifically in electric vehicles, too.

Commercial providers and university research projects are currently concentrating largely on stationary application options for flow cell technology, primarily in their use in the field of grid energy storage, such as storage solutions for solar and wind farms used to charge lithium-ion batteries in electric vehicles. The redundancy of this approach is clearly demonstrated by the present status of flow cell research in the area of electromobility.

Research into flow cell technologies for mobile use in electric vehicles is currently being conducted by GE Global Research in cooperation with the Lawrence Berkeley National Laboratory (>), while the Illinois Institute of Technology is working with the Argonne National Lab (>). Ifbattery has announced a working flow battery suitable for hybrid and electric vehicles (>). Projects are also underway at the Fraunhofer Institute for Chemical Technology (>) and, of course, nanoFlowcell AG.

RC vehicle model with redox flow cell drive from the Frauenhofer Institute (Image: Frauenhofer Institute)

While the Fraunhofer Institute for Chemical Technology is initially only demonstrating the use of redox flow cell batteries in a model car (>),GE Global Research is going further and stating a range of 400 kilometres for its jointly developed flow cell drive (>) and reckons with cost savings of up to 75 percent compared with current electric drives (>).  All that is is known so far is that GE's flow cell works with inorganic chemicals in a water-based fluid. The Illinois Institute of Technology and the Argonne National Laboratory anticipate a range of 800 kilometres from their "Nanoelectrofuels" flow cell drive, with a calculated energy density of 600 Wh/kg. The final results of the study are expected in December 2016. (>)  and (PDF)

QUANTiNO on test drive (Image: nanoFlowcell AG)

nanoFlowcell AG is already so far advanced in the development of flow cell technology that it has been able to convince even electro-doubters with its nanoFlowcell® technology in road-legal electric vehicles like the QUANT FE and QUANTiNO - impressive speeds, a range of more than 1,000 kilometres, non-toxic and 100-percent environmentally friendly. Cumbersome, li-ion-based electromobility can soon be a thing of the past.

Research history

The foundations of flow cell technology were laid back in the 1950s by Walther Kangro at the Technische Universität Braunschweig. NASA then took up further development of the technology in the 1970s. The first commercial flow cell was the vanadium flow cell developed and patented in 1996 by Maria Skyllas-Kazacos at the University of New South Wales (Australia), which was subsequently developed into the vanadium-bromide flow cell (>). Due to their low energy density, these flow cells are currently used only as a storage medium for solar and wind power facilities.

Redox flow batteries are used by Sumitomo Electric in solar power installations as multi-megawatt energy storage media and converters. (Image: Sumitomo Electric)

The present-day highlights in flow cell research are the flow cell presented in 2014 by Harvard University based on water-soluble, organic quinones, which function without the use of rare and thus comparatively expensive substances (>), and the polymer-based redox flow battery presented in 2015 by Jena University. It likewise uses an aqueous saline solution instead of acids, which means it, too, is able to steer clear of toxic and expensive metals. However, due to their energy densities, both are conceived purely as energy storage media for large wind and solar power installations. (>)

In 2014, nanoFlowcell AG was the first company worldwide to present a fully functioning electric vehicle with flow cell drive, and is working continuously on the improvement of its namesake, the nanoFlowcell® drive, and the adaptation of flow cell technology for other areas of mobility. (>)

Flow cell quo vadis?

Our overview of current research locations for flow cell technology is far from exhaustive. The number of research projects in this field has multiplied since governments began making available billions in funding for research and development of alternative energy storage solutions. On closer examination, however, many of these projects look more like Potemkin villages, as there is a distinct lack of substantial ideas. Other projects are running in parallel, and yet are not linked or networked with one another. Efficiency and effectiveness suffers, as demonstrated by the meagre results arising from university research, despite the research billions invested over the last decades. nanoFlowcell AG is very strongly in favour of integrating and networking flow cell research activities. The company has presented the world's first research and development centre for flow cell technology under the name of QUANT City. (>)

Over the next few years, the company wants to establish a unique, international and interdisciplinary centre in Switzerland for the research and development of flow cell technology and the testing of new application options for nanoFlowcell®. At nanoFlowcell AG, the future of the flow cell has already begun.