Eight heaters are included in 14-cell package to provide 14-Vdc. Each heater is 11-ohm self-adhesive strip placed across broad face of each pair of cells. They are installed before cells are wired. Heaters are in series and are connected through pair of redundant thermostats

Jackson, T. P.

Webster, W. H., Jr.

English

NASA Technical Reports Server

Solar 
Array 
10 Ampere-Hour 
Silver-Cadmium
Cell
(14 Used) 
•
May 1975	
.	 B75-10071 
•	 NASA TECH BRIEF 
Goddard Space Flight Center 	
£ 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Heater Improves Cold-Temperature Capacity of Silver-Cadmium Batteries 
.
The problem: 
Silver-cadmium batteries have significant capacity 
losses at cold temperatures. For example, a battery 
which delivers 11.2 ampere-hours at a temperature of 
200 C will yield only 6.0 ampere-hours at -10° C, 
resulting in a 46-percent loss in capacity. 
The solution: 
A 9-watt heater included as an integral part of the 
battery keeps the battery temperature at 200 C when 
the ambient is at -10° C.
How it's done: 
A multicell battery with heaters is shown in the 
figure. The 14-cell package is designed to provide 
14-Vdc and includes eight heaters (not all the heaters 
are shown). Each heater is an 11-ohm self-adhesive 
strip placed across the broad face of each pair of cells. 
They are installed before the cells are wired. The 
heaters are in series and are connected through a pair 
of redundant thermostats. 
Heater
(11 Ohms Each) 
0  OO14EH 
32G}O13Q
Integral Battery Heater Design
(continued overleaf) 
This document was prepared under the sponsorship of the National
	
Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	
information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19750000071 2020-03-19T20:04:41+00:00Z
The thermostats are designed to open when the 
battery temperature reaches 15 ±2° C. The most 
common failure is for the thermostats to remain open, 
in which case the batteries will not overheat. If the 
thermostats fail and remain closed, the heaters can be 
shut off by remote control to prevent battery damage. 
The total heater output is 9 watts and the entire heater 
system is powered by a separate solar-cell array. A 
3-mm (1/8-in.) Teflon layer, or equivalent, serves as 
thermal insulation to isolate the battery package from 
its surroundings.
Note: 
No further documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Goddard Space Flight Center 
Code 704.1 
Greenbelt, Maryland 20771 
Reference: B75-10071 
Patent status: 
NASA has decided not to apply for a patent. 
Source: William H. Webster, Jr.,

and Tazewell P. Jackson

Goddard Space Flight Center
(GSC-11913)
. 
. 
Category: 01 (Electronics - Components 
B75-10071	 and Circuitry)


Heater improves cold-temperature capacity of silver-cadmium batteries

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