Ultracapacitors

1
Ultra-capacitors

• Gabe Chong
• Rob Erdesky
• Pat Gianelli
• Paul Stegner
• Chris Yorgey

2
Capacitors ? Batteries

• Batteries
• Store energy by converting between electrical and
  chemical energy
• Shelf life of a few years
• Not all are rechargeable
• Capacitors
• Store energy as an electric potential between two
  surfaces and a dielectric constant (ie. Aluminum)
• Rechargeable
• Long shelf life
• Miniscule amount of energy loss during shelf time

3
Solar Panel

• 12Volts- Nominal Output
• 16.9 Volts- Peak Voltage
• 120 Watts Peak Wattage
• 80 Watts on an average day
• P I V
• 120W 60 seconds 15 minutes 108000J
• 80W 60 sec 15 min 72,000

4
Maxwell PC2500 Ultracapacitors

• Capacitor Specs
• 2500 Farad Capacitance
• 2.5 Volt Operating Voltage
• Q C V
• 2500 2.5 6250 Coulombs of Charge
• U ½ C V2
• ½ 2500F 2.52 7812.5 Joules

5
Safety Concerns

• The ultra capacitors electrolyte
• Made of Tetraethyl Aluminum Tetrafluoroborate and
  Acetonitrile
• Acetonitrile is solvent and is not a hazard when
  contained properly
• Capacitors are hermetically sealed, therefore the
  chemicals will not escape
• Capacitors have the potential to shock
• To prevent, keep the capacitors in a discharged
  state when not in use

6
Our Array

• 10 ultra capacitors in total
• 5 in series yields 500F at 12.5V Nominal, Max at
  13.5V
• Two of these sets in parallel yielding 1000F
  system capacitance.
• When you place these in series, you can get 25V
  250F
• Total Storage 81,250 J

7
Charging/Discharging and Efficiency

• When we are charging at 1V, using 7A, we will
  only use 7W (P I V)
• Solution would have been a DC-DC converter
• Instead, we will start with some charge on the
  capacitors
• While capacitors are in parallel, the beginning
  charge will be 5V (1V on each capacitor)
• Energy storage
• U ½ C V2
• (½ 1000 12.52) (½ 1000 52) 65,625J
• Discharge can take up to 1 hr to go from full
  charge to zero.
• Preliminary tests show 85 efficiency

8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
Budget
12
Scalability

• Very high efficiency (our tests show 85)
• Very long long shelf life (500,000 cycles)
• No moving parts to deal with
• Simplistic Power management
• Currently very high cost (about 50 times that of
  a similar energy battery array)

13
(No Transcript)