29-11-2012, 05:27 PM
ULTRACAPACITORS
ULTRACAPACITORS.pptx (Size: 1.27 MB / Downloads: 86)
What is Ultracapacitor..
Ultracapacitors are a type of capacitor with remarkably high power and energy density
It was first developed by General Electric in 1957.
Ultracapacitors' first general use was as low-power, low-energy, long-life back-up power sources for consumer electronics such as VCRs.
Working of a normal capacitor
Energy stored by the removal of electrons from one metal plate and depositing on another
This charge separation creates a potential between the plates
The total energy stored increases with both the amount of charge stored and the potential between the plates
High Current
Equalent series resistance in ultracapacitor is low, so it can be charged with a very high current
Charging and discharging can be done with the same rated current
The energy storage capacity is nearly constant under different rates of charging
ADVANTAGES
High pulse-power
compatibility
Performance in low temperature
Charge discharge cycles
Can be easily configured
No moving parts
State of charge can be easily determined
Improved safety with low toxicity of materials
Self discharge rate
DISADVANTAGES
A disadvantage of an ultracapacitor is that currently they store a smaller amount of energy than a battery does.
The amount of energy stored per unit weight is generally lower than that of an electrochemical battery
High self-discharge – the rate is considerably higher than that of an electrochemical battery.
Low maximum voltage – serial connections are needed to obtain higher voltages, and voltage balancing is required.