Improvements in or connected with the Manufacture of Electrodes for Electric Accumulators.
Year: 1893

page_text: Date of Application. 13th Jan., 1893
Complete Specification Left. 12th Oct., 1893-Accepted, 18th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in or connected with the Manufacture of Electrodes
for Electric Accumulators.
I, CHARLES POLLAK, of 147 Hanauer Landstrasse, Frankfort on the Main,
in the Empire of Germany, Electrical Engineer, do hereby declare the nature of
this invention to be as follows:-
In order to effect the rapid formation of electrodes after the so-called "Plant's "
method, and to obtain greater receptive power with small weight, I use porous
compressed lead which I obtain by wet process or by electrolysis in the following
manner. Pulverized carbonate of lead is mixed with caustic soda or with caustic
potash into a hard paste, and this is worked into the form of the electrodes to be
produced. To manufacture electrodes in the form of plates, sheets or discs of
corresponding thickness are cut, which (when plates without cores are to be formed)
are laid upon metal sheets or boards; for plates with cores, the sheets or discs
are laid on one or both sides of the plates serving as cores (with smooth or
roughened top surfaces, stamped or woven with or without projections) and pressed
together, after which they are dried. After drying, the plates are set in an alkali
solution of caustic soda, caustic potash, carbonate of soda or the like. Discs that
are-without-metallic-core-are-fastened to good conducting plates and are then set
in the alkaline solution; the plates provided with metallic cores need not be
fastened to other metallic plates. The reduction takes place, either by zinc plates
being placed between the plates to be reduced and electrically connected with the
same; or other separate suitable metallic plates are placed between and connected
with the positive pole, the plates to be reduced with the negative pole, of an electric
generator. After some time the carbonate of lead is reduced to metallic lead.
In this condition it is, however, too porous for practical purposes; it is therefore
compressed wet, whereupon a solid metallic lead is produced, which is rollable and
workable under the hammer and shews a perfectly metallic brilliant fracture. To
the plates which are made without conducting core or with non-conducting core,
other conducting strips are either soldered or otherwise brought into good contact,
or smooth metallic plates are covered on both sides with plates of the porous lead.
Pieces of this porous lead can also be provided with frames, or several can be laid
near to each other in a mould, and metal poured round them."
Such plates are then placed in diluted sulphuric acid and supplied with the
current, and indeed in both directions in cases where the maximum capacity is to
be quickly reached. The super-oxide of lead formed from this lead by the current
does not crumble, it is therefore not necessary to mechanically hold fast the same
by specially constructed crossbars. The colour of such positive plates in a charged
condition is black.
Dated this 13th day of Januar 1803
CHARLES POLLAK.
Brewer & Son,
Agents.
COMPLETE SPECIFICATION.
Improvements in or connected with the Manufacture of Electrodes
for Electric Accumulators,
I, CHARLES POLLAK, of 147 Hanauer Landstrasse, Frankfort on the Main,
5 in the Empire of Germany, Electrical Engineer, do hereby declare the nature of
[Price 8d.]

page_text: 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 effect the more rapid formation of electrodes of the so-called
"Plantè " kind, and to obtain greater receptive power with small weight, I use
porous compressed lead, which I obtain by wet process through electrolysis in the
following manner. Pulverized carbonate of lead is mixed or stirred with caustic'
soda or with caustic potash into a stiff paste, and this is worked into the form of
the electrodes to be produced. To manufacture electrodes in the form of plates,.
sheets or discs of suitable thickness are cut, which (when plates without cores, are:
to be formed), are laid upon metal sheets or boards; for plates with cores, the
sheets or discs are laid on one or both sides of the plates that serve, as cores (said
plates having smooth or roughened surfaces, with or without projections, perforated,
plaited, or interwoven) and are compressed, and then they are dried. After drying,,
the plates are set in an alkaline solution of caustic soda, caustic alkali, sodium:
carbonate or the like. Discs that are without metallic core are fastened to good:
conducting plates and are then set in the alkaline solution; plates provided with,
good conducting cores need not be fastened to other metallic plates. The reducing
process is effected either by zinc plates being placed between the plates to be:
reduced and electrically connected with the same; or other separate suitable.
metallic plates are placed between the plates and connected with the positive pole,:
whilst the plates to be reduced are connected with the negative pole, of an electric
generator. After some time the carbonate of lead is reduced to metallic lead. .In.
this condition, it is, however, too porous for practical purposes; it is therefore
compressed in a wet state, whereby a firm metallic lead is obtained, which is.
capable of being rolled and worked under the hammer, and shews a perfectly bright
metallic appearance when cut. To the plates which are made without conducting
core or with non-conducting core, conducting strips are either soldered or otherwise.
brought into good contact; or smooth metallic plates are covered on both sides
with plates of the porous lead. Pieces of this porous lead can also be provided.
with frames, or several pieces can be laid near to each other in a mould, and metal
poured round them.
Such plates are then placed in diluted sulphuric acid and supplied with the
current, and indeed in both directions in cases where the maximum capacity is to
be quickly reached. The peroxide formed from this lead by the current does not
crumble; it is therefore not necessary to mechanically hold fast the same by
specially constructed grating or lattice work. The colour of such positive plates
in a charged condition is black.
Having now particularly described and
invention, and in what manner the same is
I claim is:
ascertained the nature of my said
to be performed, I declare that what
The method or process of making electrodes for electric accumulators, by stirring
carbonate of lead into a paste with caustic alkali, then reducing this paste (after
imparting the desired shape to it, by means of suitable supports if necessary, and
it has become dry) in an alkaline solution by electrolysis, and finally compressing
the porous lead thus formed, to a greater or less degree, immediately after the
reducing process, and whilst it is still wet, all substantially as aud for the purposes
herein set forth.
Dated this 19th daw of October 1802
BREWER & SON,
Agents.