Page 127 - Battery Reference Book

Nickel-cadmium secondary batteries 4/11

Table 4.8 Comparison of sealed lead-a,cid and nickel-cadmium batteries
Property Lead-acid (DlrJit) Nickel-cadmium

Capacity range A300 series, standby operation Mass cells, lOmAh to 23 Ah: sinter cells
1-9.5 Ah; A200 series, high cyclic 100 mA h to 15 Ah
applications 1-36 Ah
Cell voltage 2.1 v 1.25V
Number of cells/l2 V battery 6 10
Case material Plastics Nickel-plated steel
Stability of case dimensions Do not change Button cells increase by up to 3%
during charging
Stabilization of electrolyte With gelled acid -
Gassing Practically no escape of gas Practically no escape of gas
Cell closure Self-closing safety valve Plastics seal or self-closing or non-resealing
safety vent
Energy density The same order of magnitude for Dryfit, nickel-cadmium button cells, sintered
cylindrical cells and sinter cells in plastics cases. Rectangular nickel-cadmium mass
and sinter cells in steel cases exhibit lower energy densities
Current-dependent capacities Average Button cells, average; sintered cylindrical
cells, above average; rectangular sinter cells,
below average
Allowable continuous current- Very good Sinter cells, goodhery good; mass cells, poor
carrying capacity
Self-discharge Very low Mass cells, slightly higher than Dryfit; sinter
cells, exceptionally high
Series connections Permitted Not allowed for small capacities, not
recommended for high capacities
Parallel connections Permitted Permitted
Storage life when discharged Weeks to over 1 year depending Weeks to over 1 year depending on
on temperature temperature
Charging temperature range -30 to t50"C Mass cells, 0 to 45°C; sinter cells, -30 to
f50"C
Discharge temperature range -45 to f50"C Mass cells, -20 to f45"C; sinter cells, -40
to +50"C
Rapid charging temperature -30 to +50°C Not recommended for mass cells; sinter cells,
range -30 to +50"C
Charging methods Voltage limited Current limited
Charging time No time limit Above 1x0 dependent on current
Shortest charging time 1 h approx. Mass cells, 3 h with supplement voltage
control; sinter cells, 15 min for part charge
with voltage and temperature control
Chargers Require voltage stabilization Mass and sinter cells, no stabilization
required for cyclic operation
Quick charge units-trickle Normal, but with higher Mass cells, permitted only up to 0.1 120; sinter
charge performance. Constant cells constant but adequate current limit
Cyclic service life Up to 500 deep discharge cycles Mass cells, approx. 300 shallow discharge
and 1000 shallow discharge cycles cycles; sinter cells, 500- 1000 deep discharge
cycles or up to 15 000 shallow discharge
cycles
Service life under trickle charge 5 years approx. Mass cells, 4-5 years at small current up to
0.1 Ilo; sinter cells, approximately 10 years