TYPE EDL
Electric Double Layer Supercapacitors
Lifetime
The minimum rated life at 85 ºC with 5.5 Vdc applied is 1000 hours with maximum permitted end-of-life
change of –30% capacitance and a 4 times increase in internal resistance.
Temperature Factor
To determine the effect of temperature on expected life of a supercapacitor, use the fact that expected
lifetime doubles for each 10 ºC that the operating temperature is reduced. As an illustration, at 85 ºC
and full voltage the rated lifetime is 1000 hours. So, at 40 ºC the expected lifetime would be multiplied
by 2
(85-40)/10
= 2
4.5
= 22.6 times. The Temperature Factor is 22.6, and for 1000-h, 85 °C rated life, the
expected 40 °C life would be 22600 hours.
Voltage Factor
The rate of change of capacitance decreases with decreasing applied voltage. The effect on life ex-
tension is roughly proportional to the voltage derating, e.g., 5 V applied to 5.5 V rated supercapacitors
extends the life 1.1 times.
Moisture Factor
Expected life of these supercapacitors is considerably shortened by operation in high humidity. The
applications discussed here assume that the relative humidity is no more that 50%.
Expected Life Example
So, for a 5.5 V supercapacitor at 40 °C charged to 5.V in less than 50% RH the expected life is
Expected Life = (Lifetime) (Temperature Factor) (Voltage Factor) (Moisture Factor)
= (1000 h) (22.6) (1.1) (1)
= 24800 hours
= 2.8 years
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