Improvements in Secondary Batteries.
Year: 1890

page_text: Date of Application, 1st July, 1890-Accepted, 9th Aug., 1890
COMPLETE SPECIFICATION.
Improvements in Secondary Batteries.
I, THEODORE MARSHALL FOOTE, of Boston in the County of Suffolk, and State of
Massachusetts United States of America, Electrician 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 :-
As storage batteries are generally constructed the metallic oxides which are acted
upon by the current in charging the battery are applied as a coating in the form of
a paste to the surface of a metallic plate for which lead has been used as the most
suitable material, while the oxides which are used are those oxides of lead which are
commonly known as litharge and as minium.
In order to secure the proper adherence of this coating to the lead plates, various
devices have been adopted, as for example, the formation in the plate of perforation
in which the oxide is packed, the construction of the plate in the form of a grid,
in the interstices of which the oxide is compressed, and the use of corrugated plates.
Storage batteries made in this manner have been extensively manufactured and used,
and have been adopted in the various departments of electric engineering to such an
extent as to demonstrate that if they can be constructed so as to be durable and
reliable, they have an important field of usefulness, but it has been found by experience
that it is impossible to prevent fragments of the coating from becoming detached
from the plates and injuring the cell by falling between adjacent plates and
establishing a short circuit, and also, that the cells are liable to become short circuited
by the bending outwards or "buckling" of the plates whereby adjacent plates are
brought into contact.
It has also been noticed that when the cells are used in vehicles or in railroad
cars, the jolting to which the cells are subjected causes fragments of the coating to
become detached from the plates and to fall between adjacent plates.
For these reasons the life of a storage battery is liable to be impaired and the
battery is rendered unreliable and uncertain in action so that these batteries have
failed to realize the expectations of their inventors and manufacturers.
Moreover the method of constructing the plates which has been found necessary in
order to secure the proper adherence of the oxides of lead increases the cost of the
battery much above the cost of the materials used.
It is the object of my invention to obtain a storage battery which will be free
from the defects before stated and the cost of which will not much exceed the cost
of the materials used, thus rendering the battery reliable, increasing the life and
reducing its first cost, and to this end, the invention consists, in a storage battery
whose electrodes are formed of tubes or cells of metal filled with a powder composed
of the oxide which is acted upon by the charging current and which tubes are
provided with perforations in their sides through which the electrolytic solution finds
access to the powder in the tube, and which perforations have an internal burr
around them on the inside of the tube whereby the powder is held in position and
prevented from escaping from the tube.
In order to obtain a surface for the electrode of the desired extent, a series of
these tubes are connected together, side by side, and this can be accomplished by
folding a tube upon itself several times, by forming a tube into a scroll, or flat helix,
or by connecting a series of these tubes at their top and bottom or at both top and
bottom by a cross tube.
The accompanying drawing shows various forms of electrodes constructed in this
manner and a storage battery made up of one forin of these electrodes.
In this drawing Fig. 1 shows one form of electrode.
Fig. 2 is a sectional view of a cell of a storage battery having electrodes of this
form.

page_text: is another sectional view of this cell.
Fig. 4 is a plan view of the cell; and
Figs. 5, 6, and 7 shows various forms of electrodes embodying my invention.
In these several figures the same letters refer to the same parts.
Referring to the drawing, A is the electrode. This is formed from a tube of lead
which is filled with litharge or minium in the form of a powder. Litharge being
preferably used for the positive electrode and minium for the negative electrode.
066
This tube is then folded so that what is in effect a plate is formed which comprises
a series of vertical and adjacent compartments or cells. In order to bring these
compartments near together, it is preferable to compress or flatten the tube. The
adjacent sections are united by burning at two points, B, B, one at the top of each
section and the other at the bottom of the same. The sections are united at these
points, only, in order that the sections may be independent of each other and any
buckling" or bending outwards which may be caused by the effect on the contents
of the compartments of charging or discharging the cell may be limited to each
section and therefore much reduce the possibility of this "buckling" of the electrode
from being sufficient to cause the contact of adjacent electrodes as would be more
likely to be the case if the sections were united together throughout their whole
length. I regard this as an important feature of my invention. It is obvious that
it is not necessary for the action of the electrode that these sections should be united
but it is preferable that this should be the case.
After the tube is filled, and preferably after it is compressed, a series of perfora-
tions, a, are made on the sides of the tube, from each side inwards, by a punch
operating so as to form a "burr" or lip on the inside walls of the tube around each
perforation, which burr acts to retain the powder in position and prevent its escape
through the perforations.
One end, C, of the tube projects above the folds and to this projecting end is
secured a bar of metal, D, which connects alternate electrodes. To this bar the
conducting wire is attached or by means of the bar the several cells are connected
together. The electrodes are arranged so that there is a bar D on each side of the
cell. The projecting end C of the tube is closed, and a preferable method of closing
this end is by pouring molten lead into the tube by which means the bar D, is soldered
to the tube. It is preferable to make this bar of lead.
It is obvious that this method of attaching the electrode to the connecting bar D,
insures a perfect and solid connection and is easily and cheaply performed.
I do not however limit myself to this manner of attaching the electrode to the
connecting bar and any other suitable method may be adopted.
By reason of the compression to which the tubes are subjected, they have a
rectangular section.
For various reasons tubes having this section may be found preferable to
cylindrical tubes. I can give the tubes this form in any suitable manner and I do
not limit myself to forming cylindrical tubes by compression into tubes having a
rectangular section.
E, is the cell which is made of earthenware, porcelain, glass, hard rubber, or any
other suitable material for the cells of storage batteries.
The electrodes are arranged side by side in the cell alternate electrodes being
connected to a bar, D, on each side of the cell, and the electrodes are separated from
one another by transverse bars, F, of hard rubber, or by any other suitable device.
The electrodes are held together by encircling bands of rubber G, or in any other
suitable manner.
Non-conducting supports, as for example, glass rods or tubes, H, may be used for
supporting the electrodes on the cells and they may also be suspended in the cell by
bars I, of suitable non-conducting material, which pass through openings formed
between the adjacent cells in the upper part of each electrode and rest upon ledges, K,
formed on the inside of the cells.
The electrolytic solution comes in contact by means of the perforations a with
the powder contained in the tube so that when the cell is charged the oxide contained

page_text: in the positive electrode is converted into a peroxide and the oxide contained in the
negative electrode is reduced.
The number of perforations in the tube will be determined by the rate of
discharge which is desired for the battery. The fewer the perforations the slower the
discharge.
It will be seen that this construction avoids the possibility of any short circuiting
of the cell by the detachment of fragments of the coating from the plate and also
as before explained contact of adjacent plates due to "buckling" will not take place.
In efficiency and capacity this battery has been found to be equal, if not to surpass,
any other form of storage battery in which lead is used.
I do not limit myself to the use of lead tubes as the electrodes may be formed of
any other metal and the tubes may be filled with any substance suitable for use in the
construction of a storage battery.
I am aware that an electrode for a storage battery has been made which consists of
two plates of metal united together at top and bottom and enclosing a metallic oxide
in the form of a powder and having perforations on the plate, but this electrode is
liable to the objection of "buckling" and moreover does not afford the amount of
surface which is afforded by an electrode constructed according to the principles of my
invention.
In Fig. 5 an electrode is shown consisting of a tube bent into the form of a flat
helix or scroll. Fig. 6 shows an electrode composed of vertical tubes connected
together at the top and bottom by a horizontal tube, and Fig. 7 shows an electrode
formed from a folded tube on which the sections are horizontal instead of vertical.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
First: In a storage battery, an electrode, substantially as described, consisting of a
tube of lead, or other suitable metal, filled with a powder composed of the material
which is acted upon by the charging current, provided with perforations upon its sides,
folded vertically upon itself and having adjacent folds united by "burning" at points
near the top and bottom of each fold.
Second: In a storage battery an electrode substantially as described consisting of
a tube of lead or other suitable metal filled with a powder composed of the material
which is acted upon by the charging current, provided with perforations upon its
sides, folded vertically upon itself, flattened by compression, and having adjacent folds
united by "burning" at points near the top and bottom of each fold.
Third: In a storage battery, the combination substantially as and for the purpose
set forth, with a series of tubular electrodes of two or more non-conducting bars passing
between the tubular electrodes and used for sustaining a position of the weight of the
same and openings made between the tubes, forming the plates, through which
openings the bars pass.
Fourth In a storage battery, the combination substantially as and for the purpose
set forth, of a series of tubular electrodes as described, non-conducting supports
under the tubular electrodes and non-conducting suspending bars passing through
openings made between the tubes constituting the electrodes.
Fifth In a storage battery electrodes substantially as described, having a tubular
terminal which is united by filling with molten lead to a bar connecting the several
terminals of the electrodes.
1004
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.