1. TO MEET AUTOMOTIVE POWER NEEDS
ULTRACAPACITORS
TO MEET AUTOMOTIVE POWER NEEDS

2. Traditional capacitors
Two electrodes, or plates separated by a dielectric
Capacitor’s energy stored in electric field

3. CONSTRUCTION Double-layer technology
Electrodes: Activated carbon (carbon cloth, carbon black, particulate from SiC )
Electrolyte: KOH, organic solutions, sulfuric acid

4. Limitations of Activated Carbon
Non uniform porosity:
Multiple time constant
Much of the surface area is not utilized
Limited ion mobility
Limited conductivity due to amorphous nature of activated carbon
Bonding limitation due to
Electrode junction has high resistance

5. Carbon Nanotube Enhanced Ultracapacitor

6. Electrode structure of vetrically aligned carbon nanotubes
* Paintbrush structure
High tube density:10 * *13 CNT/cm
Tube spacing: n
Tube diameter: 2 -5 n
Tubes length: μm

7. FEATURES
Energy storage device with excellent power capabilities ,high reliability
Long life -1 million charging cycles
High capacitance –about 3000F
No chemical reaction
Improved safety
Enhance efficiency
Optimize system size and cost

8. Battery problems in hybrid vehicles
Primary power system – continuous demand
Secondary power system-- peak power demand
Batteries have difficulty functioning in cold weather
Limited life cycle results in replacements
Limited in their ability to capture and provide bursts of high power
Hence less efficient

9. ADVANTAGES OVER BATTERIES
Function well in cold weather, down to –40C, batteries do not operate well below 0C
Long lifetime -1 million cycles , maintenance free
more efficient than batteries( 84-95% ), batteries (70 %)
Environmentally friendly (No heavy metals)
Up to ten times the power of batteries to boost the acceleration of a vehicle.

11. Some comparisons

12. OTHER APPLICATIONS
Regenerative braking systems for hybrid vehicles and electric rail
Battery free backup power systems
Provide backup power for the memory used in microcomputers and cell phone
Distributed power for vehicle systems
Electric power grid
Wind power and solar power

13. Air-conditioning
Provide safety when a car has electrically actuated brakes or door locks and the wiring fails because of a defect or an accident
Power lock

14. THANK YOU
QUESTIONS ?