Nonmagnetic hermetically sealed battery case made of epoxy resin and woven glass tape for use with electrochemical cells in spacecraf

Hennigan, T. J.

English

NASA Technical Reports Server

REPLY TO 
ATTN OF: GP 
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
WASHINGTON. D.C. 20546 
October 15, 1970 
~ ~ ~ / ~ c i e n t i f i c  & Technical Information Divis ion 
At tent ion:  M i s s  Winnie M. Morgan 
FROM : ~ ~ / ~ f f i c e  of A s s i s t a n t  General 
Counsel f o r  Pa ten t  Matters  
SUBJECT: Announcement of NASA-Owned 
U.S. P a t e n t s  i n  STAR 
I n  accordance wi th  t h e  procedures contained i n  t h e  Code GP 
t o  Code US1 memorandum on t h i s  s u b j e c t ,  dated June 8, 1970, 
t h e  a t tached NASA-owned U.S, p a t e n t  i s  being forwarded f o r  
a b s t r a c t i n g  and announcement i n  NASA STAR. 
The following information i s  provided: 
U.S. Pa ten t  N o ,  
Corporate Source : Goddard Space F l i g h t  Center 
Supplementary 
Corporate Source . 
NASA Pa ten t  C a s e  No.: XGS-00886 
Gayle Parker 
Enclosure: 
Copy of Pa tent  
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0 
N71- 1 1 0 5 3  
(ACCESSION NUMBER) (THRU) 
5 
P J A  (CODET z 
-
(NASA CR OR TMX OR AD NUMBER) (CATEGORY) i 
https://ntrs.nasa.gov/search.jsp?R=19710001578 2020-03-17T02:33:52+00:00Z
Nov. 1, 1966 T. J. HENNIGAN 
,, - - NON-MAGNE+IC BATTERY 'CASE 
-.. 
Filed Oct.  29. 1963 
INVENTOR 
THOMAS J. HENNIGAN 
Yfl&-- 
U% 
ATTORNEYS 
United States Patent 0% 3,282,739 ce Patented Nov. 1. 1966 
3,%82,"139 
NOH-MAGNE"P'PC BAmEBY C M E  
Thomas 3. Wennigan, Chilllum Terrace, Md., assignor to 
the United States of America as represented by the Ad- 
n~inisfrator of the National Aeronautics and Space Ad. 
ministration 
Filed Qct. 29.1963. Ser. No. 319.894 
FIGURE: 2 is a sectional side view of the cell of FIG- 
URE I with t h  terminals and spiralled wires thereof en- 
capsulated in epoxy resin; 
FIGURE 3 is a side view of the cell of FIGURE 2 hav- 
ing epoxy resin impregnated woven glass tape wound 
around it in one direction; 
FIGURE 4 is a bottom view of the cell of FIGURE 3 
12 ~ l a & s .  (61,136-132) 7 -  - having the epoxy resin impregnated woven glass tape 
wound around it in two directions; 
The invention described herein may be manufactured 10 FIGURE 5 is a front view of the cell of FIGURE 1 
and used by or  for the government of the United States having epoxy resin impregnated woven glass tape formed 
of America for governmental purposes without the pay- thereon in a U-shaped configuration; 
ment of any royalties thereon or  therefor, FIGURE 6 is a top view of the cell of FIGURE 1 hav- 
The present invention relates to  a non-magnetic battery ing the epoxy resin impregnated woven glass tape enclm- 
case, and more particularly, to a non-magnetic battery 16 ing all but the top surface of the cell; 
case formed of a non-magnetic woven glass tape material FIGURE 7 is a front view showing a plurality of cells 
impregnated with an epoxy resin. formed in a compact unit by epoxy resin impregnated 
Since magnetic materials would have an adverse effect woven glass tape covering portions thereof; and 
on many experiments being conducted on space vehicles FIGURE 8 is a top view showing a plurality of cells 
and satellites, i t  is essential that electrochemical cells, 20 having all extremities except their supper surfaces covered 
such as nickel-cadmium, silver-cadmium, or silver-zinc, by layers of epoxy resin impregnated woven glass tape. 
used therein have cases of non-magnetic materials. Referring to the drawings, there is shown in FIGURES 
Prior to the present invention non-magnetic cases for 1 and 2 a battery cell 21 encased within a plastic housing 
electrochemical cells were formed by the cells being en- 22 and containing electrolyte 15, positive electrodes 16, 
capsulated in an epoxy resin or from welded stainless steel. 25 negative electrodes 17, and separators 18 separating the 
These cells had a disadvantage of not being capable of positive and negative electrodes. Terminals 23, affixed 
withstanding too much internal pressure before they to and forming a part of battery cell 21, are coupled by 
would leak electrolyte, bulge, or burst. To  prevent the an internal coupling member 19 to the positive or nega- 
bulging that occurred during the operation of the electro- tive electrodes depending on whether they are to behave 
chemical cells housed within a welded stainless steel case, 30 as a positive or negative terminal of the battery cell. A 
it was necessary to use clamps such as end plates and tie aolid terminal enamelled copper wire 24 is spiralled about 
bolts. The welded stainless steel case, additionally, tended each terminal 23 and connected thereto by nut 20. Both 
to possess magnetic properties due to the welding process. terminals 23 and the spiralled portion of terminal wires 
The invention as will be described hereinafter has the 24 are encapsulated in epoxy resin 25, as shown in FIG- 
advantage of being able to provide a n  inexpensive her- 35 URE 2. The epoxy having been poured into a mold 
metically seated case for an electrochemical system which formed about terminals 23 and allowed to harden. By 
will withstand a moderately high internal pressure and at spiralling terminal wires 24, a long tortuous path is pro- 
the same time retain the non-magnetic properties desired. vided for any electrolyte leakag~. Additionally, this wire 
Whereas cells encapsulated in a n  epoxy resin alone have is solid, rather than stranded, so that leakage paths be- 
a bursting pressure of less than 150 pounds per square 40 tween the strands are eliminated. 
inch, cells, of the same size, encased, as will be described As shown in FIGURE 3, a plurality of layers, for ex- 
herein, are able to take a pressure greater than 300 pounds ample, three, of epoxy resin impregnated woven glass 
per square inch before there is any failure therein, i.e., tape 26, formed from woven glass tape having been 
the new casing is capable of withstanding about twice as coated with epoxy resin, are wound around the front face, 
much internal pressure as can conventional epoxy resin 4 j  base, and back face of plastic housing 22 and over the 
cases and would, accordingly, have a prolonged life. In top of epoxy resin 25 covering terminals 23. Tape 26, 
addition, it is possible for the casing of the instant inven- before being impregnated with epoxy resin, is chosen to 
tion to  achieve a weight saving of approximatc:ly 20 per- have a width substantially the same as the width of front 
cent over conventional oasings. Furthermore, no clamp- face of plastic housing 22 so that, when it is impregnated 
ing is required as with many metal cases; there is no prob- 50 with epoxy resin and wound around plastic housing, it 
lem of any corrosive action due to the electrolyte; and will cover completely the surface it encases. 
the cell has the advantage of being more immune and re- To  complete the casing and cover the two end surfaces 
sistant to shuck. of the plastic housing 22, another piece of epoxy resin 
Not only does the case of the instant invention possess impregnated woven glass tape 27, having a width sub- 
the advantages enumerated above, but at the same time, 55 stantially the height of a plastic housing 22 and epoxy 
the leak rate test has indicated its leak rate to be of the resin 25 plus the thickness of the layers of tapc 26 already 
order of 10-7 cc. of helium per second (STP) which wound around plastic housing 22, is wound around the 
compares favorably with the prior art cell cases. two end surfaces and the back and front faces to form 
The above advantages are attained by using solid a plurality of layers thereon. FIGURE 4 shows the rela- 
spiralled wires for terminal leads; encapsulating the cell tionship of layers of tape 26 Lo the layers of tape 29, 
terminals and spiralled wires attached thereto in and, in particular, depicts there being three layers of each 
resin and wrapping epoxy resin impregnated woven glass of the tapes used to form the casing for battery cell 21, 
tape, i.e., woven glass tape which is saturated with epoxy The epoxy resin impregnated woven glass tape, after 
resin upon being coated therewith, arovnd the plastick9n- encasing bdtery in nlanner described above, 
cased cell to form a laminated casing therefor. 65 is allowed to harden to form a rigid structure about the 
The exact nature of this invention, as well as other ob- 
jects and advantages thereof, will be readily apparent battery cell. An even better packaging of the casing is 
from of the following specification relating obtained by clamping members On sides 
to the annexed drawings in which: of the wrapped battery cell immediately after the tape is 
FIGURE 1 is a front of a cell before it is en- wrapped therearound and before hardening thereof oc- 
cased and wherein the terminals thereof have connected curs, and solidifying the casing formed from tapes 26 
thereto solid spiralled terminal wires; and 27. 
9,882,730 
3 4 
11 has been found that srrccessful cell casings have been netic expanded metals, such as stainless steel, copper, or 
built with both the epoxy resin 25 acd the epoxy impreg- silver c a ~ ?  be rased as the reinforcing tape in place of 
nating the fiber glass woven xnateriat being Shell Chemical the woven glass. The method of potting and wrapping 
Company EPON 834 or EPON 828 epoxy resins having would be similar. 
a catalyst of diethylenetriamine (DTA). The EPON 834 6 The foregoing disclosure relates to preferred embodi- 
and EPON 828 resins can be properly identified by data ments of the invention, Numerous modifications or al- 
sheets furnished by the Shell Chemical Company Division terations may be made therein without departing from the 
of the Shell Oil Company. EPON 828 resin is described spirit and scope of the invention set forth in the appended 
in Data Sheet SC:6C!-146R dated July 1962, and EPON claims. 
834 resin is described in Products Specifications SC:60- 10 What is claimed is: 
148 dated November 1960. 1. An electrochemical device including an outer hous- 
Another embodiment of the invention is shown in FIG- ing having terminals affixed thereto and containing there- 
URES 5 and 6. FIGURE 5 shows the epoxy resin im- in an electrolyte, positive and negative electrodes and 
pregnated woven glass tape 26 cut as strips and formed separators positioned between said positive and negative 
in a substantially U-shaped manner about the front face, 15 electrodes, the improvement comprising: a n  epoxy resin 
base and rear face of plastic housing 22; and FIGURE 6 impregnated woven glass tape formed about said hous- 
illustrates the layers of tape 27 as well as the layers of ing. 
tape 26, with tape 27 wrapped around the two end sur- 2. An electrochemical device having an outer housing 
faces of the battery cell and over tape 26 on the front and including a front face, a rear face, end surfaces, a base 
rear faces of plastic housing 22. As already described 20 and a top; terminals affixed to said top; and containing 
in connection with the earlier described embodiment of therein an electrolyte, positive and negative electrodes 
the invention, the width of the tape s:rips are cut to con- and separators positioned between said positive and neg- 
form with the shape of plastic housing 22. The casing ative electrodes, the improvement comprising: terminal 
and sealing of battery cell 21  is completed by epoxy resin wires equal in number to the number of said terminals, 
25 being poured over terminals 23. 25 each having a portion thereof spiralled about the ter- 
The epoxy resin impregnated woven glass tape, itself, minal with which it is associated and an epoxy resin coat- 
can be used to form the mold for the epoxy resin which ed flexible tape formed about said housing. 
is to be used to seal cell terminals 23. This can be ac- 3. The electrochemical device of claim 2 wherein said 
complished by extending the tape 26 higher than the edges epoxy resin coated flexible tape comprises: first layers 
of the front and rear faces of plastic housing 22 and 30 thereof formed about said base, said front face and said 
choosing the width of tape 27 so that it is wider than the rear face and extending above said top from said front 
height of plastic housing 22 and wrapping it so a portion face and said rear face; and second layers thereof formed 
thereof extends above the top thereof. The tapes 26 about said end surfaces and the top layer of said first 
and 27 then form a cavity 32 which houses the terminal, layers of said tape positioned on said front face and said 
extends over the top thereof, and acts as the form for 35 rear face, said second layers having a portion thereof 
the epoxy resin. extending above said top of said housing. 
Should it be desired to form a compact battery 3 1  of 4. The electrochemical device of claim 3 further in- 
the number of battery cells 21, the battery cells can be cluding: epoxy resin encapsulating said terminals and 
placed together side by side in a manner shown in FIG- said spiralled portions of said terminal wires attached 
URES 7 and 8 and be encased in the epoxy resin impreg- 40 thereto and being contained by the portions of said first 
nated woven glass tape in the same manner as described layers and said second layers extending above said top 
for encasing a single battery cell. This compact battery of said housing. 
can be formed of cells which have or have not already 5. The electrochemical device of claim 2 further in- 
been previously encased in the manner described here- cluding epoxy resin encapsulating said terminals and said 
inabove. 45 portions of said terminal wires spiralled about said ter- 
In FIGURE 7 compact battery 31, formed of a plu- minals and forming with said housing a unitized struc- 
rality of battery cells 21, is encased in the same manner ture. 
as depicted in FIGURE 6 for a single battery cell. The 6. The electrochemical device of claim 5 wherein said 
plurality of battery cells 21  are placed together with the epoxy resin coated flexible tape comprises: first layers 
rear face of one cell resting against the front face of an 50 thereof wrapped around said front face, said haw, said 
adjacent cell and with tape 26 formed as layers extending rear face and said epoxy resin encapsulating said ter- 
from above the front face of one extreme cell along the minals; and second layers thereof wrapped round said 
face thereof, down along the bases of all the cells and end surfaces, and the top layer of said first layers of said 
then up again along the rear face of the other extreme tape positioned on said front face and said rear face. 
cell and slightly above it. 65 7. In the electrochemical device of clain~ 6, the tape 
As already described in connection with FIGURE 6 forming said first layers being of a width substantially 
tape 27 in FIGURE 8 is chosen to have a width greater equal to the width of said front face and the tape form- 
than the height of the battery cells 21 forming the com- ing said second layers being of a width substantially equal 
pact battery so that when it is wrapped around all the end to the height of said front face plus the height of said 
surface of the individual cells and tape 26, on the front 60 epoxy resin encapsulating §aid terminals. 
and rear surfaces of the two extreme cells, respectively, it 8. In a battery structure wherein said battery has a 
forms, in conjunction with the extremities (extended par- front face, a rear face, end surfaces, a base and a lop, the 
riOns in 71 of lape a cavity '' into Improvement comprising a casing having: first layers of 
which epoxy resin is poured to colnplete the battery casing epoxy resin impregnated ~ ~ ~ i b l ~  formed said 
assembly and sealing after the terminal wires and interell 66 front face, said base, said rear face and mid top 
said 
comectors (not show)  m connected to the t e r ~ n a l s  
rhereot battery; and second layers of epaxy resin impregnated 
already ctescnbed above in conneee~on Flexible t a p  formed about said end surfaces of said bat- 
battery cell, tile epoxy resin hpregnated woven glass tery and fop layer of said first layers of said tape: ~ s i -  
tape casing structure for the compact battery can harden 70 lioned On said front face and said rear face of said bat- 
by itself or he encased in a mold until the casing is fomed tew- 
as a solid structure, the mold to be removed after the 9. In the battefy structure of claim 8, the tape form- 
hardening occurs. ing said first layers being of a width substantially equal 
While the casings for the e l l s  are describd as being to the width of said front face; the tape forming said sec- 
of epoxy resin impregnated woven glass tape, non-mag- 75 ond layers being of a width substantially equal to the 
3,282,759 
5 6 
height of said front face; and said first and second layers cells and the bases of all said plurality of battery cells 
of epoxy resin impregnated flextble tape being epoxy and extending above the lops of said pl~iratliy of battery 
resin impregnated woven glass. cells from said front face and said rear face, res~ectively, 
10. A casing for a multicell electrochemical structure of said two extreme battery cells; and second layers 
comprising: a plurality of battery cells positioned side by 5 thereof wrappcd around the end surfaces of said plural- 
side with the front face of each cell resting against the ity of battery cells and the top layer of said first layers of 
rear face of an adjacent cell; and epoxy resin impreg- said tape posltloned on said froilt face alld said rear 
nated woven glass lape said plurality of face, respectively, of said two extreme battery cells, said 
battery cells with first layers there~f  wrapped around the second layers extending above the tops of said plurality front face and the rear face, reppectively, of the two of said battery cells. 
extreme battery cells forming said plurality of battery 12. The electrochemical structure of claim 11 further ' 
cells and the tops and the bases of all of said plurality of 
battery cells; and second layers thereof wrapped around including epoxy resin contained by the portions of said 
the end surfaces of all said plurality of battery cells and first layers and said second layers extending above said 
the top layer of said first layers of said tape positioned 15 tops mid plurality said battery 
on said front face and said rear face, respectively, of said 
two extreme battery cells. References Cited by the Examiner 
11. A casing for a multicell electrochemical structure UNITED STATES PATENTS 
comprising: a plurality of battery cells positioned side by 912,946 2/1909 Eastman. 
side with the front face of each cell resting against the 20 2,645,676 7/1953 Emeriat --------- 136-132 X 
rear face of an adjacent cell; and epoxy resin impreg- 
nated woven glass tape formed about said plurality of WINSTON A. DOUGLAS, Pritnary Exntnir~er. 
battery cells with first-layers thereof wrapped-around the ALLEN B. CURTIS, Exmniner. front face and the rear face, resvectivelv, of the two 
extreme battery cells formin$ said pluraiity of battery 25 D. L. WALTON, Assistant Examiner. 


Non-magnetic battery case Patent

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