Today we’re going to look at the vanadium redox battery, also known as the VRB or vanadium flow battery. It’s a rapidly improving type of rechargeable flow battery which employs vanadium ions in different oxidation states to store chemical potential energy. The battery involves energy stored in chemical form, in a liquid electrolyte (V2O5) contained in two separate tanks. The battery uses the ability of vanadium to exist in solution in four oxidation states, using this property to make a battery that has one electroactive element instead of two.
The Vanadium Energy Storage Battery
In many ways it is a superior technology to lithium-ion, which was designed with portability in mind and as such is not necessarily the best choice for larger scale energy storage.
- Long-scale duration (they can run for excess of 25 years)
- No self-discharge
- No Memory/Ghost effect (always runs at 100% discharge)
- Up to 1 year charge retention.
- Excellent scalability.
According to Wikipedia, second-generation batteries (utilising vanadium and bromine) could double the energy density whilst simultaneously increasing the temperature range in which the battery is operable.
Vanadium Vs. Lithium Ion
Vanadium flow batteries offer 100% capacity for a lifespan of up to 25 years. Lithium-ion degrades quite seriously (e.g. the Tesla Powerwall 2 guarantees at least 70% of the original capacity after 10 years or 37,800 kilowatt-hours).
They’re also safer than lithium-ion – the chemistry involved in VRBs is non-flammable and non-explosive (in contrast to lithium-ion – have a read about the exploding Samsung Note 7).
Vanadium won’t replace lithium-ion in any small applications, however – they are too big and heavy for any small items like mobile phones or laptops. In terms of storing solar power, their increased safety, 100% depth of discharge, and 100% capacity for up to 25 years means there are definitely some serious benefits over lithium-ion.
Vanadium Energy Storage Options
StorEn are planning on making their THERMASTABLE batteries available in late 2019 – targetting the US first and then other countries after that.
VSun Energy Pty Ltd offer the VRB energy storage system aka the Cellcube and the first battery has already been installed in Western Australia. According to the website, they are also in initial talks and have submitted proposals to other companies, with potential customers emerging from a range of backgrounds, including mining and exploration companies, the farming community and industrial sites.
Other manufacturers of VRBS include Schmid, UET, redT Energy and Rongke Power.
We’ll keep this page updated with more information about this new technology and what sort of applications we’re seeing it used in! Something will come along to usurp lithium-ion soon enough, both for small-scale and large-scale storage – the technology has been lagging for years and we’re excited to see what comes next.