We’re going to turn into a battery blog if this keeps up. But the next generation of electrical storage devices is what will enable two very clean, transformative technologies to change the world – photovoltaic cells and electric cars. In the race between batteries, ultra-capacitors, and hydrogen fuel cell systems, my money is on the batteries.
On our recent post covering the Tango T600 Battery Powered Car, the 18th commenter pointed us towards vanadium batteries. The first thing you think about when you learn of these batteries, only patented in 1986 and based on concepts only about 30 years old, is “of course!”
These are batteries that can be recharged the way you might fill your gasoline tank – that is, the electrolytic material which carries the electrical charge is a liquid that, once discharged, can be quickly removed from the battery and replaced with liquid that has been recharged. This means that stationary systems can charge replacement liquid and a mobile battery can be recharged the same way you’d pump gasoline – within minutes.
Before we get too excited about the potential for these batteries to power electric cars, however, consider their energy density. The best lithium ion batteries we’ve got have an energy density of maybe 300 watts per kilogram. The vanadium batteries have an energy density of maybe 80 watts per kilogram (see discussion on Geocities), which is good enough for stationary sources, but not for vehicles.
On the other hand, these batteries may be relatively inexpensive and long-lived, good for stationary electrical storage systems, such as in a home or commercial building with photovoltaics. Apparently the costs for vanadium batteries could drop as low as $300-$600 per kilowatt-hour of storage. This is pretty inexpensive, considering the average home would generally not require more than 5-10 kilowatt-hours of energy per night, if that, and could recharge during the day. There is an excellent website called “The Energy Blog” with a post entitled “Vanadium Redox Flow Batteries” that cites these figures.
Don’t go out and throw away your stock in lithium ion and nickel metal hydride battery developers just yet, though. While vanadium batteries appear to be far less problematic than fuel cells, they are complex devices, and there are still a lot of unanswered questions. But the scalability of these storage devices suggests they could be used in very large scale electric utility applications, where other battery alternatives are unlikely. They may find a niche, and bear watching.
Companies involved in vanadium batteries include VFuel Pty Ltd (Australia), Pinnacle VRB Limited (Australia), Cellennium Company Limited (Thailand), and RE Fuel (UK).