Accession Number : AD0433871

Title :   LOW TEMPERATURE OPERATION OF BATTERIES.

Descriptive Note : Quarterly progress rept. no. 5, 15 Sep-14 Dec 63,

Corporate Author : LITTLE (ARTHUR D) INC CAMBRIDGE MA

Personal Author(s) : Horne, R. A. ; Richardson, D. L.

Report Date : 14 DEC 1963

Pagination or Media Count : 32

Abstract : Common Leclanche cells can deliver currents in the hundred microamp range even at very low temperature (-55 F). Measurements of the thermal masses of batteries indicate that they can be approximated by the thermal masses of their constituent cells. Inclusion of a term for the insulating effect of the air space between a battery and its insulation has improved the prediction of battery cool-down rates; however, the agreement between predicted and observed cooldown rates for multi-cell batteries with internal air spaces and/or sealing material is still poor. The advantage in weight capacity (watt-hr per unit weight relationship) of an insulated battery to be gained by increased thickness of insulation begins to level off at about 0.6 in. for expanded polystyrene. Analysis shows that for a given insulation there is a maximum attainable fraction of the +70 F volume capacity (watt-hr per unit volume relationship). For short missions this maximum is approached by thin insulation and for long missions by thick insulation. The effect of initial battery and ambient temperatures on weight capacity has been examined. The attainable fraction of the +70 F weight capacity increases rapidly with increasing battery thermal mass but tends to level off at higher masses. The effect of the thermal conductivity of the insulation on the weight capacity has also been examined. (Author)

Descriptors :   *BATTERY COMPONENTS, *PRIMARY BATTERIES, *LOW TEMPERATURE BATTERIES, PERFORMANCE(ENGINEERING), DRY BATTERIES, MAGNESIUM, SPECIFIC HEAT, THERMAL INSULATION, LOW TEMPERATURE.

Distribution Statement : APPROVED FOR PUBLIC RELEASE