Electrolyte film breakers made from polytetrafluoroethylene are installed in the reactant and water vapor removal outlets of each cell and sealed by elastomers. Use of these devices in the water vapor removal cavity outlets prevents loss of KOH solution through film migration during water removal

Hess, P. D.

English

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May 1970	 Brief 70-10277 
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NASA TECH. BRIEF 
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 Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division. NASA, Code UT, Washington, D.C. 20546. 
Film Breakers Prevent Migration of Aqueous

Potassium Hydroxide in Fuel Cells
Film Breaker 
Electrolyte film breakers have been used in -fuel 
cell outlets to minimize purge blockage and loss of 
electrolyte. Migration of electrolyte into the reactant 
and water vapor removal outlets of fuel cell plates 
occaionally causes blockage of outlets because of 
the electrolytic corrosion. Degradation in cell per-
formance occurs when .
 the cells cannot be adequately 
purged of accumulated. reaction products following 
blockage of the reactant outlets. The direct loss of 
electrolyte could lead to decrease in life as well as 
performance.
The electrolyte film breakers are small-
 "spool like" 
devices made from polytetrafluoroethylene (TFE). 
They are installed in the reactant and water vapor re-
moval outlets of each cell and sealed by elastomers. 
Use of these devices in the water vapor rejnoval cavity 
outlets prevents loss of KOH solution through film 
migration during water removal. Gas flow in the re-
strictor is achieved through the bore and a small 
orifice (typically .040 - .060 in. in diameter) in 
the side. The restrictors produce a discontinuity in 
KOH—H 2 0 films because of the non-wetting proper-
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19700000266 2020-03-17T00:18:35+00:00Z
ties of TFE and the reduced cross section. This innova-
tion may be used in any gaseous-reactant fuel cell. 
Note: 
This Tech Brief is complete in itself. No additional 
information is available.
Patent status: 
No patent action is contemplated by NASA. 
Source: Paul P. Hess of 
Allis-Chalmers Manufacturing Co. 
under contract to 
Manned Spacecraft Center 
(MSC-13174)
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Brief 70-10277	 Category 01


Film breakers prevent migration of aqueous potassium hydroxide in fuel cells

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