>> > According to the site, the current issue is energy density - at >> > 25kW/kg. They have some research that gets to 35kW/kg, but expect that >> > they would need to get to 50kW/kg to be viable for consumer EVs. >> >> If you mean 25 Kilowatt hours per kilogram (kWh/kg) specific energy, that
>> would be a sensational figure! Or perhaps you really do mean kW/kg -- a >> measure of specific POWER -- also extraordinarily high, as typical golf car >> batteries can comfortably deliver around 100 W/kg (not kW). >> >> State of the art in lead acid is around 35watt hours (NOT KILO-watt hours) >> per kg, nicad 55 is Wh/kg. Some advanced chemistries run 80+ Wh/kg. There >> is NOTHING I know of in the kilowatt hours per kg, except maybe some liquid >> fuels. >> >> Not to bash this poster or anyone else, but what's going on here is some >> plain vanilla carelessness in nomenclature. > >Considering I have next to zero knowledge of batteries, I wouldn't >assume to know anything about the terms for energy density, so I copied >that from the University's research page. So if the terms are >incorrect, then the people inventing the technology are wrong. So it >was NOT due to carelessness in posting to this list. Sorry to blow up >your soapbox. David's soap box is in no danger. You DID get the units wrong when you copied it. The website clearly states Wh/kg not kW/kg as you posted. "In the all-vanadium redox flow cell, the present energy density is 25 Wh/kg, this being based on a maximum vanadium ion concentration of 2 M or less for wide temperature range operation. " "More recent studies at UNSW has shown that vanadium concentrations of up to 3M can be achieved with addition of precipitation inhibitors that can stabilise supersaturated vanadium solutions. This allows the energy density to be increased to around 35 Wh/kg. "
