Sealed electric storage battery with gas manifold interconnecting each cel

Wylie, G. M.

English

NASA Technical Reports Server

SEALPID BATTERY GAS MANIFOLD CONSTR 
Filed April 20, 1964 
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total volume of about 2100 cc. to accommodate gases 
generated during the operation of the battery. 
One of the problems encountered when using such a 
gas manifold is the possibility that an electrolyte path can 
develop between the cells and thus cause short circuiting 
of the battery. In accordance with this invention, this 
problem has been overcome by providing a tortuous path 
in the gas manifold whereby a fluid must travel substan- 
tially the longest possible path to get from one cell to 
]LO another. The tortuous path comprises a series of com- 
The invention described herein was made in the per- partments, partitions and tubes which are arranged in a 
formance of work under a NASA contract and is subject non-aligned manner so as to make it very diEcult for 
to the provisions of Section 305 of the National Aero- electrolyte to form a path between cells. 
nautics and Space Act of 1958, Public Law 85-568 (72 An additional feature of this invention is that each cell 
Stat. 435; 42 U.S.C. 2457). 15 has access to the space enclosed by the manifold through 
This invention relates to a novel sealed battery gas a stand-pipe which projects into each cell. The stand-pipe 
manifold construction. In particular, the invention re- extending into each cell insures that the electrolyte-free 
lates to a sealed battery which has a gas manifold inter- volume at the top of each cell will be available to accom- 
connecting all of the cells of the battery to provide addi- modate gases generated during the charging and discharg- 
tional volume within the sealed battery for receiving gases 20 ing of the battery, regardless of where the free electrolyte 
which are evolved during operation of the battery, and moves. The stand-pipe mmprhes a hollow tube which is 
the gas manifold is designed in such a manner that the tapered at the end near the electrolyte, with a small bore 
development of an electrol9e path between cells is sub- hole in the tapered end giving access to the space en- 
stantially prevented. closed by the manifold. For additional protection against 
Sealed storage batteries and the problems associated 26 electrolyte creepage, the stand-pipe may be filled With a 
therewith are well known in the electric storage battery porous, absorbent material such as a cellulosic sponge. 
industry. One of the principal problems is the evolution A more detailed description of a preferred embodiment 
of gases during operation of a sealed battery, particularly of this invention may be obtained by referring to the 
upon overcharging and overdischarging. Since the battery drawings, in which FIGURE 1 is a top plan view of a 4- 
is sealed, the evolution of an excessive amount of gas can 30 cell sealed battery having a tortuous path gas manifold. 
result in an explosion of the battery container. As shown in FIGURE 1, a battery container 10 is fitted 
It is an object of this invention to provide a sealed at its top with a gas manifold top piece, generally desig- 
battery having a gas manifold interconnecting all of the nated as 11. The gas manifold, which may be a molded, 
aells of the battery in such a manner that. there is a much electrolyte-resistant, plastic piece, has a beveled edge 12 
larger volume to accommodate gases which are evolved 35 and comprises a series of compartments 13, partitions 
during the operation of the battery. 14 and 65 and tubes 16. The edge 12 is beveled in order 
Whereas the gas manifold does provide additional gas to accommodate a cement fitlet. The partitions 14 also 
space within the battery container to receive evolved extend below the gas manifold and function as intercell 
gases, it also makes it possible to form an electrolyte path partitions in cooperation with the intercell partitions in 
between cells which could short circuit the battery. This 40 the container with which they are aligned. One of the 
problem often occurs in batteries dhich are inverted dur- principal features of this invention is that the tubes B 
ing their operation, such as those used on airplanes and which interconnect the compartments 13 through the par- 
missiles. It is particularly prevalent in missile and space- titions 14 and %§ are arranged in a non-aligned manner 
craft batteries for they are required to operate under con- SO as to form a tortuous path interconnecting the cells 
ditions in which the force of gravity is zero. 45 A, B C and D. This requires every fluid to travel the 
It is another object of this invention to provide a sealed tortuous path in order to pass from one cell to another, 
battery having a gas manifold interconnecting all of the which renders the formation of electrolyte paths between 
cells of the battery which has a tortuous path that must be cells extremely difficult. 
traveled by any fluid passing from one cell to another. Other conventional items which are illustrated in FIG- 
A further object of the invention is to provide a sealed 60 URE 1, are the cell terminals 17 and the intercell elec- 
battery having a gas manifold interconnecting all of the trical connectors 18. The holes 19 which communicate 
cells of the battery and which has a stand-pipe extending,( with the housing 29 are used to fill the housing 29 with 
into each cell so as to insure that each cell will have a6 an electrolyte-resistant, sealing composition such as an 
certain amount of electrolyte-free space, each of said b epoxy resin sealant. This prevents erectrolyte from ieak- 
stand-pipes having a tapered end near the electrolyte with- , 5 ing around the electrode lug wires 28. 
in each cell. Another feature of this invention is the stand-pipes 
Other objects and advantages of this invention will be which are inserted into the gas manifold and cement 
apparent to those skilled in the art, particularly in view hto place. A stand-pipe is clearly illustrated in FIGURE 
of the drawings in which: 2. There is a stand-pipe projecting into each cell of the 
FIGURE 1 is a top plan view of a 4-cell battery having 50 battery. The stand-pipe is a hollow tube which has B 
a tortuous path gas manifold in accordance with this in- tapered end 21 near the electrolyte with a small bore hole 
vention; and 22, e.g. 0.015 mch in diameter, to permit gases which are 
FIGURE 2 is a sectbn taken on line of FIG- evolved to escape into the gas manifold, The s td -p ipe  
URE 1. may be filled with a porous, absorbent material 23 
It has been discovered that a sealed storage battery 65 further impede electrolyte creepage. A plastic strip 
having a plurality of cells can be provided with a gas is cemented onto the top of the stand-pipe to hold 
manifold interconnecting all of the cells which gives in- absorbent material in place. It is known that in the ab- 
creased protection against the danger of explosion due to sence of the force of gravity, the tendency of a wetting 
accumulated gases. A standard type of alkaline cell has liquid is to move toward the apex of a cons. Therefore, 
a volume of 75 cc. for gas expansion. It was found that 70 batteries which are to be used on missiles should be 
when 14 of these cells were connected and provided with equipped with stand-pipes having tapered 
a gas manifold interconnecting all 14 cells, there' was a electrolyte passing through the opening 
Filed Apr. 20, B 364, Sera No. 360, 
3 
stopped by surface tension forces from moving away i'rom 
the apex of the opening in the stand-pipe. In addition it 
should be noted that the stand-pipe extends a substantial 
distance into the cell and thereby maintains an electrolyte- 
free space to accommodate gases generated when the bat- 
tery is charged and discharged. 
FIGURE 2 also illustrates several other features of the 
sealed batterys The gas manifold has a top piece 29 
which is cemented into place after the stand-pipes are 
inserted and cemented to the gas manifold. Prior to 
cementing the gas manifold into the top of the battery 
container, the electrodes 2 and the separators 27 
placed into the container. The electrode lug wires 
Id. Then a cementitious seal- 
be poured into the housing 
the electrode wires. Prior to 
cementing the gas manifold into place and after wires 28 
rolyte may be added to each cell 
into which the stand-pipes are later 
cemented. 
In addition to the above-mentioned advantages of this 
invention, the tortuous path gas manifold construction 
provides a means for gases which might be evolved in a 
weak cell to travel to a stronger cell and be recombined 
with the electrodes in the stronger cell. In other words, 
this invention provides both a larger gas expansion 
volume and also a means for consuming gases produced 
in one or more weak cells. Still another advantage is 
that the intercell walls can be made thinner and lighter 
since no differential pressure can develop between cells. 
The tortuous path gas manifold construction of this in- 
vention is applicable to all types of sealed cells, including 
cells using either acid or alkaline electrolyte. The inven- 
tion is particularly applicable to alkaline cells having 
silver-zinc, silver-cadmium or nickel-cadmium electrodes. 
Having completely described this invention, what is 
claimed is: . In a sealed electric storage battery having a plurality 
of cells containing a liquid electrolyte, the improvement 
which comprises a tortuous path gas manifold top piece 
5 
PO 
15 
20 
25 
30 
35 
40 
displaced from and intercon cting all of the cells of the 
battery, said gas manifold top piece comprising a series of 
compartments defining a volume which is substantially 
free of electrolyte, partitions and tubes, the tubes which 
interconnect the compartments through the partitions be- 
ing arranged in a non-aligned manner so as to form a tor- 
tuous path interconnecting the cells. 
2. An article in accordance with claim 1 in which each 
cell bas access to the gas manifold by means of stand-pipes 
which are firmly attached to the gas manifold piece and 
project into each cell of the battery. 
3. An article in accordance with claim 
stand-pipe comprises a hollow tube havin 
near the e1ect;olyte in each cell with a small bore hole in 
the apex of said tapered end through which gases evolved 
lyte, the improvement comprising in combination: a gas 
manifold comprising a partitioned fluid conduit having a 
plurality of partitions, means mounting said conduit ad- 
jacent the cells of the storage battery, means defining a 
plurality of fluid-conducting orifices arranged in spaced 
alignment along the conduit and extending from the con- 
duit to the cells in a manner such that a flow of fluid 
may be established between the cells along a tortuous path 
extending between the orifice through the partitions of the 
partitioned conduit, and means disposed along the tor- 
tuous path adapted to impede passage of the liquid elec- 
trolyte therealong, whereby those gases generated in the 
cells during the operation of the battery may be readily 
exchanged between the cells while electrolyte flow is sig- 
nificantly impeded. 
eferences Cited by the Examiner 
UNITED STATES PATENTS 
2,662,108 1211953 Coates -- ____-_ 136-177.21 X 
WINSTON A. DOUGLAS, Primary Examiner. 
D. L. WALTQN, Assistant Examiner. 


Sealed battery gas manifold construction Patent

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