Type EDL , Electric Double Layer Supercapacitors
Ultra High Capacitance, Small Case Size Options
Type EDL electric double layer supercapacitors offer extremely
high capacitance values (farads) in a variety of packaging options
that will satisfy, low profile, surface mount, through hole and high
density assembly requirements. The EDL is a cut above the standard
electrolytic capacitor in that it can act as a battery without having
to deal with the environmental or hazardous material issues that
batteries entail.
Highlights
- Unlimited charging and discharging capability
- Recycling is not necessary
- Long Life - 15 years
- Low ESR
- Will extend battery life up to 1.6 times
- First class performance with economy pricing
Specifications
Operating Temperature Range 25 C to +85 C
Rated Voltage Range 2.1 Vdc to 5.5 Vdc
Capacitance Range 0.022 F to 70 F
How To Select an Electric Double Layer Capacitor
Estimated Initial Backup Time Back-up time for Type EDL Electric Double Layer Supercapacitors decreas-
es with use and over time especially when the current is large or operat-
ing at high temperature. Be sure to specify extra back-up time initially to
allow for product changes.
Select the optimum supercapacitor according to applied The internal resistance of the supercapacitor prevents drawing high
current discharge currents. Select the supercapacitor capable of delivering the
peak current at switchover to back-up mode using the following table.
Maximum Operating (Discharge) Current
Series
0.1 F to 0.47 F to 3.3 F to 10 F to
0.047 F 0.33 F 1.5 F 4.7 F 50 F
SG, SD, NF 200 A 300 A 1 mA
F 200 A 300 A 300 A
EN 10 A
HW 300 mA 1 A
Back Up Time Example Back-up time is the time it takes for the applied voltage to decay to the
cut-off voltage set by the user after applying the applications maximum
voltage at application maximum temperature.
Example: An F Type EDL, P/N EDLF105B5R5C (Rated at 5.5 V, 1.0 F) is
charged to 5.0 Vdc. The circuit requirement is such that it must maintain a
memory circuit with a current drain of 10 A in an ambient temperature of
+40 C. The memory RTC cut-off voltage is 2.0 Vdc.
Using minimum capacitance, calculate the back-up time as
follows:
t = CV I = C[V0(iR)V1] (i+iL)
C = 1.0 F20% = 0.8 F, R=50 , V0=5 V, V1=2 V, i=10 A
Therefore,
t = 0.8 (50.00052) ((10+2) x10^6)= 55 hours
And thus the initial back-up time is 55 hours. After 1000 hours,
calculate the back-up time will drop to about 38 hours.
t: Back-up time (s)
C: Capacitance of Type EDL (F)
V : Applied voltage (V)
0
V : Cut-off voltage (V)
1
i: Current during back-up (A)
i : Leakage current (A)
L
R: Internal resistance () at 1 kHz
CDE Cornell Dubilier 1605 E. Rodney French Blvd. New Bedford, MA 02744 Phone: (508)996-8561 Fax: (508)996-3830 Type EDL , Electric Double Layer Supercapacitors
Ultra High Capacitance, Small Case Size Options
Life Design Type EDL supercapacitors have a useful lifetime that decreases with
increasing operating temperature, humidity, applied-voltage, current and
backup-time requirements.
Expected lifetime is the product of four factors:
Expected Life = (Lifetime)(Temperature Factor)(Voltage Factor)(Moisture
Factor)
Lifetime The minimum rated life at 85 C with 5.5 Vdc applied is 1000 hours with
maximum permitted end-of-life capacitance change of 30% and a 4
times increase in internal resistance.
Temperature Factor To determine the effect of temperature on expected life of a supercapaci -
tor, use the fact that expected lifetime doubles for each 10 C that the
operating temperature is reduced. As an illustration, at 85 C and full
voltage the rated lifetime is 1000 hours. So, at 40 C the expected lifetime
would be multiplied by 2(85-40)/10 = 2^4.5 = 22.6 times. The Tempera-
ture 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 extension 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 than 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
RoHS Compliant
Electric Double Layer Supercapacitor Construction
Current
Current
Activated
Collector Electrolyte
Separator Collector
Carbon
Resistor Resistor
Electric Double
to Charge to Move Ions
Layer Capacitor
CDE Cornell Dubilier 1605 E. Rodney French Blvd. New Bedford, MA 02744 Phone: (508)996-8561 Fax: (508)996-3830