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Our Technology

The vanadium flow battery technology is a rechargeable flow battery technology that stores energy using the ability of vanadium to exist in solution in four different oxidation states. This property of vanadium allows it to produce batteries with just one electroactive element instead of two with the elimination of metal cross-contamination.

The current design was patented in 1986 by the University of New South Wales in Australia, although recognition must be given to the work of other researchers such as P.A. Pissoort in the 30s and NASA researchers A. Pelligri and P.M. Spaziante in the 70s.

The first known commercial example of the all-vanadium flow battery was by Dr. Maria Skyllas-Kazacos and her team at the University of New South Wales in the 80s.

See Our Technology In Action

A Foreseeable Technology With Demonstrated Fundamentals!

100% Capacity, Forever

Vanadium flow batteries can discharge fully at 100% without decaying and losing capacity, unlike lithium batteries. This means that 100% of the initial capacity will be available through the batteries’ lifetime. This is crucial when matching the daily demands with generation. Your battery installation will not need oversizing and additional costs to compensate from the capacity lost over time. 

Durability > 25 Years

Vanadium flow batteries have a duration in excess of 25 years without degradation of the battery with low annual maintenance.  Thanks to StorEn’s IP, annual maintenance is now on-demand, as opposed to scheduled. The StorEn Battery Management System will tell us when maintenance is required. The vanadium electrolyte can be reused, thus no mining of fresh vanadium is required to replace the battery.


Because of the absence of loss of capacity, their ability to discharge fully (100% DoD), their longer lifetime, the declining cost/kWh for longer durations and the easiest end-of-life processing (lithium bears high disposal costs), the LCOE of vanadium batteries is much lower than lithium. The vanadium electrolyte retains its value at end-of life.

Open For Technology Improvements

While lithium batteries are already manufactured in several million units, vanadium flow batteries are at the beginning of their development cycle. Performance improvements are foreseeable with further technology advancements and new components are being developed, such as new membranes. Cost reductions are at the horizon as economies of scale will kick in coming from higher performance, volume manufacturing of batteries and components.


Positively Charged Electrolyte Tank

In the uncharged state, the positive electrolyte circuit contains vanadium ions with an oxidation state +4. Once, energy is supplied to be stored, the electrolyte oxidizes moving to an oxidation state +5. At full charge, the electrolyte will be completely shifted to vanadium +5. 

Negatively charged electrolyte

In the uncharged state, the negative electrolyte circuit contains vanadium ions with an oxidation level of +3. Once energy is supplied to be stored, the electrolyte reduces changing to the oxidation state +2.  At full charge, the electrolyte will be completely shifted to vanadium +2.

Battery Stack

This is the core of a vanadium flow battery, where the ion exchange takes place during charging and discharging. An ion-permeable membrane is used to separate the electrolyte flows, while allowing the ions to cross the membrane to complete the electric circuit.

A redox reaction converts electricity into chemical energy.


Pumping System

Each electrolyte circuit, positive and negative, has an individual pumping system. Each circuit feeds electrolyte to the relevant half battery cells.

The Safe Alternative To Lithium

Operational safety is a key indicator in energy storage. When compared to lithium, the vanadium flow technology offers decisive safety advantages.


The electrolyte of a vanadium flow battery is water-based. Therefore, its electrolyte is non-flammable as it contains a predominant share of water. 

Vanadium flow batteries therefore are 100% non-flammable!


As the electrolyte of a vanadium flow battery is water-based, explosion is also not an option.  Thus, vanadium flow batteries  deliver the highest level of safety amongst all battery technology.

Vanadium flow batteries therefore are 100% non-explosive!

100% Flexibility

Vanadium flow batteries are non-flammable and non-explosive. In addition to that, they operate at low temperatures, a few degrees above ambient temperature. They can be installed indoor, as well as outdoor. 

Vanadium flow batteries therefore deliver 100% flexibility of installation!

Our Propriety Innovation

Vanadium Flow Batteries have been around for some time and enjoy some strong fundamentals, demonstrated by a number of installations in several countries worldwide.

At StorEn, we believe that the technology offers still massive room for technological advancement and improvement.

​Our R&D activities benefit from years of experience in PEM Fuel Cells of our Technology Team and the technological cross-transfer that originates from that experience.


StorEn filed four International PCT patents claiming priority from the existing US provisional patents.


At the end of 2019, we have filed to extend our PCT patent applications to major regions and countries, such as the US, European Union, Canada, Brazil, Colombia, Chile, India, China, Japan, Korea, Indonesia, Thailand, Australia, several African countries and Eurasia.  


Our batteries deliver the highest power density today at the lowest cost/cycle, well below the one of lithium batteries.


The modularity of our design allows us to extend runtime to 10 hours and beyond, with the highest flexibility in terms of power and energy required by each installation. 


In addition to energy storage application, the ability of our batteries to deliver energy in milliseconds makes ideal also for power back-up installations for your home, as well as telecom towers and data centers.


Enhanced Performance

StorEn creative efforts focus on increasing performance, namely power density of the battery stack, well above current State-of-Art. 


Our extensive research in the fluid dynamic of the stack led us to develop MULTIGRIDS™, our patent-pending innovative flow design. This system allows reducing by over 50% the cost of the power side of the battery, at the same time preserving the reliability and duration of the stack by operating at lower pressure.


Install Anywhere

Our THERMASTABLE™ geothermal design enables the outdoor installation in location with harsh temperatures. Our patented design is ideal for the Africa, as well as for the Alaskan ice.  THERMASTABLE™ will also deliver increased round-trip efficiency and resilience against natural disasters and vandalism.


Virtually Maintenance-Free

Total Cost of Ownership (TCO) of the batteries add the cost of purchasing the device and the costs of servicing and maintaining the batteries. We focused our R&D on delivering the lowest TCO possible with a battery design that is virtually maintenance-free, eliminating scheduled service inspections while delivering improved reliability. Our RESAFE™ and EQUILEVELS™ technologies achieve just that. Furthermore, our Battery Management System will tell us when maintenance is required.

Smallest Size

Our research on the formulation of the electrolyte allowed increasing its molarity. Attention was also paid to the engineering of the battery and the integration of its components to reduce the total volume of the battery. This led to 30% decrease in the size of the battery compared to designs with similar energy. This work is critical to expand the range of applications to those that are volume-critical.