Why isn't any electric car makers use flow batteries? Redox flow batteries, and to a lesser extent hybrid flow batteries, have the advantages of flexible layout (due to separation of the power and energy components), long cycle life (because there are no solid-solid phase transitions), quick response times, no need for "equalisation" charging (the over charging of a battery to ensure all cells have an equal charge) and no harmful emissions. Some types also offer easy state-of-charge determination (through voltage dependence on charge), low maintenance and tolerance to overcharge/ overdischarge. Flow batteries are normally considered for relatively large (1 kW·h – 10 MW·h) applications. Suitable for: Electric vehicles - Because flow batteries can be rapidly "recharged" by replacing the electrolyte, they can be used for applications where the vehicle needs to take on energy as fast as a combustion engined vehicle. Then any petrol station could have fill-refill-plug that changes the electrolyte, and you are "filled-up" in no time. And the "petrol station" could charge the electrolyte with a low power over longer time. Best sollution ever..