Accession Number : AD0832025

Title :   DIODE CONTROL RESEARCH.

Descriptive Note : Quarterly technical progress rept. no. 7,

Corporate Author : MALLORY (P R) AND CO INC BURLINGTON MA LAB FOR PHYSICAL SCIENCE

Personal Author(s) : Ball, James V.

Report Date : MAR 1968

Pagination or Media Count : 34

Abstract : After having been operated for 50 consecutive 90-minute, 75 percent depth of discharge cycles at each of three test temperatures (0, 25 and 35C), the 12 Amp-hour stabistor-protected nickel-cadmium battery was placed on continuous cycling at 25C. The discharge time was 35 minutes for the 75 percent discharge and charge time was 55 minutes. When 780 continuous cycles had been successfully completed, cell reconditioning was required because of low cell discharge voltage. Thereafter, another 98 cycles were run. In all, the battery was cycled 1028 cycles. The effects of memory in reducing discharge voltage was minimized by overdischarging the cells (90 percent or more) once during each working day. A battery of three 25 Amp-hour silver-zinc cells protected by stabistors containing three junctions was found to operate satisfactorily over a range of 0 to 50C, in that the stabistors protected each cell individually from overcharge while allowing a substantially complete recharge. Depth of discharge was 75 percent of the 2C capacity (20AH) and cycle time was 120 minutes (35 minutes discharge and 85 minutes charge). Over 60 consecutive cycles were subsequently carried out at 25C, with charge control being provided solely by the stabistor circuitry. Degradation of cell capacity due (probably) to the great depth of discharge was the limiting factor in continuous cycling. A cell revers voltage limiting module for protection of a 5-cell battery at discharge currents to 40 Amps was fabricated and tested. It is designed to limit cell reverse voltage to 0.2 volts maximum. (Author)

Descriptors :   (*ALKALINE BATTERIES, PERFORMANCE(ENGINEERING)), STORAGE BATTERIES, SPACEBORNE, SEMICONDUCTOR DIODES, ELECTRIC DISCHARGES, STABILIZATION, NICKEL, CADMIUM, SILVER, ZINC, CURRENT REGULATORS, VOLTAGE REGULATORS, VOLTAGE.

Subject Categories : Electrochemical Energy Storage

Distribution Statement : APPROVED FOR PUBLIC RELEASE