Submitted by vignanv8 on Fri, 2013-01-18 08:09
I am trying to crunch the numbers needed to make a super(ultra) capacitor based EV commercially feasible.
Take for example the Model S:
1. For a battery with 85 kWh capacity, it can run a 2.1 ton car for 300 miles.
2. Assuming the specific energy of the Panasonic cells as around 240-260 Wh/kg, the battery weighs approx 700 lb (320 kg) excluding the battery management.
3. The best UCs (Graphene-based) achieved around 85 Wh/kg under laboratory conditions. At this rate, a 85 kWh source for Model-S weighs about 2100 lb (950kg) i.e. making the car 30 % heavier and affecting the range by say 80 miles.
4. As the UCs have high power density, the power electronics can be adjusted to maintain the same performance.
5. The UCs charge extremely fast. Hence, a nationwide network of superchargers can gain further momentum as charging can be dropped to a fraction of the current time. You need not have lunch everytime you charge, listening to a song would suffice :)
As specific energy doesn't seem to be much of a problem, benchmark for UCs must be based on volumetric energy density (Wh/L). What should be the vol. energy density for UCs to get adapted in EVs?
The above analysis has been simplified just to get an idea of the order of magnitude and not the exact values of such technologies. There has been significant improvements in mass production of Graphene and if it can replace silicon in semiconductors, the price would drop even further.