Thin coating of high-temperature epoxy resin provides necessary electrical insulation, as well as good thermal conductivity between battery cells. Insulation increases efficiency of nickel-cadmium battery, as it would any multicell battery assembly in which cell-to-cell thermal balance is critical

Doyle, H. M.

English

NASA Technical Reports Server

August 1973	 B73-10237 
NASA TECH BRIEF 
Langley Research 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. 
Battery Cell Thermal-Conductive Coating Increases Efficiency 
A)
Applying a thin coating of high-temperature epoxy 
resin (containing an aluminum-oxide tiller) to battery 
cells provides the necessary electrical insulation, as 
well as good thermal conductivity between the cells. 
This insulation increases the efficiency of a nickel-
cadmium battery, as it would any multicell battery 
assembly in which cell-to-cell thermal balance is critical. 
With this thermally conductive coating, the efficiency 
of the battery was 23% greater than with the best al-
ternative method tested. This improvement was obtained 
even though the primary heat transfer surface was the 
cell base, which was heat sunk to a plate in the center of 
the battery. A battery designed for more uniform heat 
rejection over the cell surfaces should have much 
greater thermal efficiency. 
To prepare battery cells using this method, a thin 
0.05- to 0.76-mm (2- to 3-mil) film of high-temperature, 
aluminum-oxide-filled epoxy resin is applied to each 
cell, to provide the electrical resistance required to 
prevent shorting and to provide a thermally conductive 
path between cells to reduce the temperature difference 
to 0.6° C (1° F). 
The resin used (Stycast 2850FT or equivalent) has a 
thermal conductance of 14 watt-cm/m 2 -K (10 BTU-in./ 
ft2 -hr-017) and an electrical resistance of 1014 ohm-cm. 
The coating is applied by dipping each cell into the 
solution that has been heated to 66° C (150° F). The
cells are rotated, to maintain a uniform coating thick-
ness, until gel is achieved. Then they are cured for four 
hours at 74° C (165° F) and for two hours at 100° C 
(212° F). 
Note: 
No further documentation is available. Specific ques-
tions, however, may be directed to: 
Technology Utilization Officer 
Langley Research Center 
Mail Stop 139-A 
Hampton, Virginia 23665 
Reference: B73-10237 
Patent status: 
Inquiries concerning rights for the commercial use of 
this invention should be addressed to: 
Patent Counsel 
Langley Research Center 
Code 456 
Hampton, Virginia 23665 
Source: H. M. Doyle of
Martin Marietta Corp.
under contract to
Langley Research Center 
(LAR- 10963) 
Category 01, 08 
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.
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Battery cell thermal-conductive coating increases efficiency

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