Apparatus consisting of a pressure plate unit, four springs of known spring constant and a micrometer measures the swelling and force exerted by the polymer membranes of alkaline electrochemical cells

Hennigan, T. J.

English

NASA Technical Reports Server

Neoprene Diaphragm 
Membrane- Electrode 
Assembly 
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April 1965
	
Brief 65-10087 
NASA TECH BRIEF I& 
Apparatus Measures Swelling of Membranes in Electrochemical Cells 
The problem: To measure with a high degree of 
accuracy the swelling characteristics of polymer 
membranes used as electrode separators in alkaline 
electrochemical cells. Existing testing methods are in-
capable of accurately measuring the amount of swell-
ing and the force exerted by the expanded membrane 
against the cell walls. These characteristics must be 
accurately controlled in order to ensure optimum cell 
operation. 
The solution: A measuring apparatus that includes 
four springs of known spring constant, a pressure-
plate unit, and a micrometer caliper head.
How it's done: A dry membrane-electrode as-
sembly is placed beneath the pressure plate in the 
apparatus and the micrometer is adjusted to obtain a 
zero reading of the thickness of the membrane-elec-
trode assembly and the spring compression. The com-
partment containing the assembly is then filled with 
the electrolyte solution and placed under vacuum (5" 
of Hg) to rid the assembly of entrapped air. When the 
system reaches equilibrium (after release of the 
vacuum), the micrometer reading gives a measure of 
the expansion or swelling of the membrane and the 
compression of the springs. The force exerted by the 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern-
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19650000086 2020-03-11T17:22:19+00:00Z
membrane assembly is computed from the micrometer 
readings and the value of the spring constant. 
Notes: 
I. This apparatus should be of value to designers 
of electrolytic cells or other devices where the 
swelling characteristics of membranes must be 
accurately controlled. 
2. Inquiries concerning this invention may be directed 
to:
Technology Utilization Officer 
Goddard Space Flight Center 
Greenbelt, Maryland, 20771 
Reference: 1365-1008[7
Patent status: NASA encourages the immediate 
commercial use of this invention. Inquiries about ob-
taining rights for its commercial use may be made to 
NASA, Code AGP, Washington, D.C., 20546. 
Source: Thomas J. l-Iennigan 
(GSFC-280) 
Brief 65-10087	 Category No. 01


Apparatus measures swelling of membranes in electrochemical cells

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