Improvements in Storage Batteries.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Storage Batteries.
I, EDWARD PRESTON USHER of Grafton, Worcester County State of Massa-
chusetts, United States of America, Lawyer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
My invention relates to the construction of the cell of a secondary battery, and its
main features may be applied to a cell made up of any of the conventional types
of plates, the object being to ensure against danger of short-circuiting, and to
firmly unite the plates and their separators at bottom.
The especial feature of novelty in my method and apparatus is the sealing of the
several plates and interposed separators at and near their lower edges so as to hold
the parts in the proper relation and prevent the contact with the negative plate of
any of the active material which may crumble from the positive plate. This
sealing is effected by erecting the plates and separators in a shallow body of gum
or the like while in a hot and liquid state, and allowing it to cool and harden
around and among the parts, or by applying plastic strips which harden and adhere
to the edges of the plates and separators near the bottom. I prefer to combine
both these means of sealing the parts.
I employ separator plates of kiln-dried wood, and apply them directly to the
face of the positive plates, while I maintain an open space between the separators
and the several negative plates, so as to ensure a free circulation.
In the drawing
Figure 1 is an edge view, partly in vertical section through a battery cell sealed
according to my invention.
Fig. 2 is a like view in a plane at a right angle to that of Figure 1.
In carrying out my invention, I place two or more rubber bands A, around each
of the negative plates B. In practice I have found four bands preferable. Close
to the positive plate C, and on each side of it I place a thin kiln-dried wooden
separator plate.
Upon assembling the plates the rubber bands which encircle the negative plate
against the adjacent separator plate, leaving however between the wooden plate
and the negative a clear open space corresponding in size to the thickness of the
rubber band employed. Any other article equivalent in effect to the rubber band
could of course be used.
In lieu of this construction, I sometimes surround the positive plate and the two
separator plates in contact with it, with the rubber bands or other binders, thus
giving, between said separators and the negative plate, the open space desired for
free circulation.
I then prepare a substance made of beeswax, pitch sulphur tallow and rosin, or
their equivalents, which compound when heated, flows as an oil or liquid gum, and
when cold is hard and tough and slightly flexible. The above mentioned substance
is preferably composed of two parts each of beeswax pitch and rosin, and one part
each of sulphur and tallow, all thoroughly mixed and commingled and applied
while very hot. These proportions may be somewhat varied if desired.
Into a shallow mold or pan E filled with this oil while hot, I place the assembled
plates and allow the oil to cool and harden. This filling of the pan I regulate so
that the substance F. shall rise about one-half inch from the bottom of each plate.
A sheet or strip G. of this same substance, or of a suitable material coated there-
with, is prepared and applied when warm and somewhat plastic to the edges of the
separators and plates forming the cell, at the bottom, so as to cover such edges to
the height of one inch or more.

page_text: It will be seen that flotation of the separators is entirely overcome by the bottom
sealing described or by the edge-strips applied to the several plates and separators,
and hence that short-circuiting cannot arise from any crumbling of the active
material, and the cell will be far firmer than has been possible heretofore.
It will also be apparent that the lower edges only of the plates and separators
are imbedded in the gummy compound, and that such compound being placed
within the mold or pan E, will not adhere to the enclosing jar, and hence will not
involve destroying the jar when the plates are removed.
I am aware that wooden separator plates have been proposed but 1 believe that
no commercial use has ever been made of cells fitted with them, and that no
distinction has been recognised in the essential condition of the work.
if
I have discovered that if green wood be used the internal resistance of the cell
is increased in a very marked degree, while the kiln-dried wood does not seem to
injuriously affect the use of the cell to any appreciable extent. Furthermore
the wooden separator be placed in close contact with both negative and positive
plates the liquid cannot circulate freely and the efficiency of the cell is impaired.
As the negative plate undergoes no deterioration the open space left as have
described above does not endanger an accumulation of the active material at the
bottom of the cell, while it gives the free circulation so essential to successful use.
The sealing of the bottom and sides of the cell as described prevents short-
circuiting by reason of any deposit that might be made from the positive plates,
while the use of the separators tends to reduce this deposit to a minimum. The
separator plates also prevent all short-circuiting arising from buckling or analogous
difficulties.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manuer the same is to be performed, I declare that what I
claim is ;-
:-
First In combination with the plates of a secondary cell, two wooden separator
plates applied closely on each side of each positive plate, two or more rubber
bands or their equivalent interposed between each negative plate and the adjacent
separator, leaving an open space on each side of said negative plate, substantially
as described.
Second-A battery cell composed of alternate positive and negative plates
with interposed separator plates, in combination with a sealing substance or com-
pound, in which the lower edge only of said plates are embedded, such substance
or compound not adhering to the jar, substantially as set forth.
Third A battery cell composed of alternate positive and negative plates and
interposed separator plates, in combination with sealing strips applied to the
vertical edges of the several plates along the lower portion thereof substantially
as set forth.
4
Fourth-The described method of sealing and uniting the several plates and
interposed separators of a battery consisting in erecting such plates and separators
in a shallow mass of hot viscous gum and allowing said gum to cool and harden
around the base of the plates and separators, and finally applying a strip of
similar material to the lower vertical edges of said parts, substantially as set
forth.
Dated this Dixteenth day of August 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.

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