Maintenance-Free Silver-Cadmium Batteries for Aircraft Emergency Applications.
Technical rept. no. 8 (Final), Jun 65-Aug 69,
YARDNEY ELECTRIC CORP NEW YORK
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An emergency battery and a power conditioning system are described for use in connection with an aircraft electrical system. A 20-cell silver-cadmium battery with a nominal capacity of 22Ah at the 1 hour rate is described. It is charged from an aircraft bus which may be held by the aircrafts generators and voltage controllers at any voltage between 24 and 32. Each cell contains a platinum-catalyzed third electrode connected through a 5-ohm resistor to the cadmium negative of that cell. The third electrode recombines oxygen produced at the silver electrode at the end of charge. The power conditioner scans the cells and uses the magnitudes of the signals developed across the 5-ohm resistors by the recombination current to determine when to terminate and to reinstitute charging. In combination with the recombination electrode the system thereby avoids the development of excessive pressure in any cell. The system is capable of discharging at 320 amps for 1 min. to aid in engine starting and can reinsert up to 70 of nominal capacity in 20 minutes. Thermostatically controlled heaters eliminate the effect of low temperature on performance. The battery serves as a heat sink for the power conditioner. Author
- Electrochemical Energy Storage