Can't be used for car batteries, but, still a very promising energy storage system.
http://www.mining.com/rocketing-vanadium-price-primed-elon-musk-moment/?utm_source=digest-en-mining-180930&utm_medium=email&utm_campaign=digest
https://www.forbes.com/sites/jamesconca/2016/12/13/vanadium-flow-batteries-the-energy-storage-breakthrough-weve-needed/#18a139be5bde
"Vanadium flow batteries have lifespans of over 20 years without capacity loss, are non-flammable and can operate at any temperature. Another advantage over lithium ion is that this type of battery can be charged and discharged simultaneously making it highly suitable for large-scale storage from renewable sources such as solar and wind when connected to an electricity grid. Main downside is low energy density which means comparatively large installations needed."
James
http://www.mining.com/rocketing-vanadium-price-primed-elon-musk-moment/?utm_source=digest-en-mining-180930&utm_medium=email&utm_campaign=digest
https://www.forbes.com/sites/jamesconca/2016/12/13/vanadium-flow-batteries-the-energy-storage-breakthrough-weve-needed/#18a139be5bde
"Vanadium flow batteries have lifespans of over 20 years without capacity loss, are non-flammable and can operate at any temperature. Another advantage over lithium ion is that this type of battery can be charged and discharged simultaneously making it highly suitable for large-scale storage from renewable sources such as solar and wind when connected to an electricity grid. Main downside is low energy density which means comparatively large installations needed."
James