Improvements in Electrodes Applicable for Use in Primary or Secondary Batteries.
Year: 1887

page_text: Date of Application, 26th Mar., 1887.
Specification Accepted, 13th May, 1887.
COBIT LEIE DIECIFICATION.
Improvements in Electrodes Applicable for Use in Primary or
Secondary Batteries.
I, LUDWIG EPSTEIN of Martinikenfelde, near Berlin in the Kingdom of Prussia and
Empire of Germany, Inventor, 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:-
In order to obtain a large active surface, allowing strong currents for charge or
discharge, it was up to the present, necessary to have in a battery-cell a large number
of electrodes. As a rule these clectrodes were placed in short distances from each
other, to keep the internal resistance of the cell as low as possible generally, or from
want of space in particular.
The danger consequent upon this arrangement is that such cells get rather frequently
short circuited, partly by the dropping out of active material, partly by the buckling
and warping of the plates, whereby the efficacy and practicability of such cells is
materially impaired, and frequent testing and examining rendered necessary.
My invention has for its object to overcome these difficulties and produce electrodes
for primary or secondary batteries which require in this respect only very little
attention, if any at all.
To attain the object in view I construct the electrodes in such a manner, that
adjacent parts of electrodes of different polarity do not contain the active material
which is liable to disintegration or change of shape, but those parts consist of a frame
or border made of some suitable conducting or non-conducting material, which is little
or not at all acted upon by the electrolyte or the action, in the cell.
To produce electrodes answering the above purpose I employ several methods, of
which the most important are the following viz.
According to one method, I first produce strips, consisting of the active material and
a frame or network of lead or other suitable conducting material (Figure 1 a, b, c, d.).
Or strips may be used which are either solid or perforated, flat or corrugated or serrated

page_text: or otherwise prepared, to receive or retain the active material, and they may contain the
active material in the holes, perforations etcetera, or the same may be applied to the
surface of the support mechanically, or chemically produced, or electrically deposited,
or directly formed by the Planté or any other similar process.
I then arrange a number of such strips in rows in a suitable mould, leaving an
adequate space between each row, and run them together by casting, soldering or any
other suitable means.
The electrodes thus formed present the appearance of a grid, railing or venetian
blind, they allow a free circulation of the electrolyte, afford a large active surface and
give the electrodes great mechanical strength, Figure 2.
I generally keep the spaces a between the strips, smaller than these latter parc, in
order to retain in its own electrode any material, that may have become detached,
thereby preventing such material from overbridging the space between opposite
electrodes, and thus short circuiting the cell.
To maintain the interstices between the strips these latier may be provided with
teeth or other protrusions or instead thereof strips made of some suitable material
may be inserted between them.
To obviate any inconveniences, which may arise from the growing of the positive
electrode I sometimes arrange then in such a manner, that only one end of them is
fastened to the frame, any growing therefore taking place in the direction of that
end which remains free to move. (Figures 3 to 5).
Another method to produce such electrodes is the following, namely:-
I first produce a plate or cake of finely divided lead compound. This plate or cake
is placed in a mould and a frame or cover of lead or some other suitable conducting
material is cast round it, preferably completely enveloping it Figure 6. The plate or
cake may be perforated before putting it into the mould, in order that the metal on
running it in may enter and fill the perforations, thus strengthening the metallic
envelope, rendering it more adhesive and increasing its conductivity (Figure 7).
This new plate consisting of the cake of active material inside and the metallic frame or
envelope outside, is now placed under a circular saw, a shaping or boring or perforating
machine and by this or any other suitable appliance slits or holes are cut or bored
right through. Figure 8.
According to another method I take the cake made of the finely divided lead compound
and provide it with slits, holes or perforations. These slits, holes or perforations are
now filled up with molten metallic lead or some suitable conducting material.
The outsides of the plate are now covered with same material which adheres firmly to
the plate and which may be non-conducting, for instance, I place the plate or cake in
a bath of Chatterton compound or any glue or varnish not easily attacked by the acid
in the cell, or I prepare a compound of paraffin and bec's-wax or any other suitable
material, or I put the materials on the plate by means of a painter's brush or any other
suitable means.
This new plate consisting of active matertal and metallic lead or other suitable
conducting material inside, and the adhesive covering outside is now treated in a
circular saw or a boring or perforating machine in the manner as before described.
Any desired number of electrodes produced by any of these methods may now be
united to groups and formed in the usual way.
Figure 9 shows such a cell in plane and section.
It is evident that such a cell possesses notwithstanding its limited number of
electrodes a comparatively large capacity, that strong charging or discharging currents
may be employed, that the more robust character guarantees a longer life time as
compared with the ordinary thin plates, that they stand the wear and tear of moving
about much better and, that a dropping out of active material cannot take place in the
space between electrodes of opposite sign.
In primary batteries the electrodes whose construction is described may be used
either as anodes or as cathodes in conjunction with electrodes, which will set up an
electrical current with the former. For instance such a cell may be constructed
consisting of electrodes of the described construction and containing reduced

page_text: (hydrogenised) lead as positives, and copper, platinum or carbon as negatives, or
consisting of electrodes of the described construction and containing lead peroxide as
negatives, and zinc as positives.
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, I declare that what I claim is :-
1. Electrodes presenting the appearance of a grid railing or venetian blind, or of a
sieve consisting of the active material, and a frame or support of lead or some other
suitable conducting material, substantially as described.
2. Electrodes presenting the appearance of a grid, railing, or venetian blind, or of a
sieve consisting of the active material and conducting support or frame, and of a frame
of some non-conducting material, substantially as described.
3. The manufacture of primary or secondary batteries with electrodes produced in
the manner hereinbefore described, the manufacture of secondary batteries produced in
the manner hereinbefore described.
WM. P. THOMPSON & Co.,
6, Lord Street, Liverpool,
Agents for the Applicant.