IMPROVEMENTS IN THE PRODUCTION OF PLATES OR ELECTRODES FOR SECONDARY BATTERIES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, HERBERT JOHN HADDAN, of the firm of Herbert and Company, Patent
Agents, of 67, Strand, in the City of Westminster, Civil Engineer, do hereby
declare the nature of said Invention for "IMPROVEMENTS IN THE PRODUCTION OF
PLATES OR ELECTRODES FOR SECONDARY BATTERIES, a communication to me froin
abroad by Ludwig Epstein, (care of Otto Sack, 18, Katharinenstrasse, Leipzig,
Saxony) to be as follows:-
This invention relates to the production of a finely divided lead compound and
to its application for forming electrodes or plates of secondary batteries.
In order to obtain a finely divided lead compound suitable for secondary
batteries, a lead oxide or a lead salt is added to molten metallic lead, and the mass
constantly stirred until it has been transformed from the liquid state into finely
divided solid particles.
The process. may be carried out by melting lead in a suitable vessel or ingot,
removing the latter from the fire, and adding an oxide or salt of lead in the shape
of powder, preferably in the proportion of 5 parts (in weight) of lead oxide or
7 parts of lead salt to 100.parts of lead, and stirring the mixture, while it is
cooling, with an iron rod or other suitable instrument.
Various methods may be employed for forming electrodes from the lead compound.
For instance lead plates which are perforated, recessed or otherwise adapted for
the reception of the material are used as a base or skeleton to which the mass is
applied after having been transformed into a thick paste by the addition of water,
and stirring. By drying the plate in the open air or with the application of
moderate heat, the pasty mass is converted into a hard cement which strongly
adheres to the lead plate.
Another method consists in converting the finely divided lead into a paste and
forming the same into blocks or plates by means of suitable moulds and pressure,
the said plates being either solid or grooved or recessed for the reception of molten
lead, or for facilitating the circulation of the electrolyte, or for increasing the active
surface. The molten lead may then serve to unite several plates or blocks of finely
divided lead, so as to form a complete frame or net-work.

page_text: COMPLETE SPECIFICATION.
I, HERBERT JOHN HADDAN, of the firm of Herbert and Company, of 67 Strand,
in the City of Westminster, Civil Engineer, do hereby declare the nature of my
invention for LMPROVEMENTS IN THE PRODUCTION OF PLATES OR ELECTRODES FOR
SECONDARY BATTERIES, a communication to me from abroad by Ludwig Epstein
(care of Otto Sack, 18, Katharinenstrasse, Leipsig, Saxony), and in what manner
the same is to be performed, to be particularly described and ascertained, in and by
the following statement :-
This invention relates to the production of a finely divided lead compound and
to its application for forming electrodes or plates of secondary batteries.
Such a compound or preparation of lead is obtained by adding an oxide or salt
of lead to molten metallic lead, and stirring the mixture continually and thoroughly,
until the liquid mass has been transformed into a finely divided solid body. It is
advisable to perform this operation in a vessel containing a mechanical agitating
apparatus.
On a small scale, the material can be produced by melting lead in a suitable
vessel or crucible, then removing it from the fire and adding to it an oxide or
a salt of lead in the form of powder.
The proportion preferred by the inventor is from 50 to 70 grammes of some oxide
of lead or salt of lead to one kilo of lead. The mixture is well stirred with an iron
rod or a small shovel, while. it is cooling, and the preparation in question is
obtained.
On a large scale, the metal is melted in a special vessel, and then poured or
conducted into another vessel, containing an agitator reaching almost to the bottom
and provided with numerous scoops or teeth, the said agitator being set in motion
by steam power or some other suitable means.
The product obtained is a fine powder.
To produce an electrode with this material, the inventor has recourse to several
methods, the two most important being the following-
In the first case, the inventor uses lead-plates, perforated, branched, or, in some
other way rendered suitable for receiving the material, and places the mass upon
them after it has been converted into a thick paste by the addition of water and
being stirred.
Dried by the air or moderate heat, the mass hardens and combines mechanically
and intimately with the supporting plates, on which it is laid.
According to a second method, the material for the plates of a secondary electric
battery is worked up as follows:
The porous or finely divided lead is reduced to a semi-fluid or pasty state, and
then made into any shape by means of a lever-screw-or hydraulic press, or by
an apparatus resembling a tile-making machine, or by any other suitable appliance.
These masses, so-formed, may be quite solid or notched or grooved, the said
notches or grooves serving, partly to receive the molten lead mentioned further on,
and partly to permit the free circulation of the electrolyte, and to obtain a greater
surface.

page_text: Referring to the accompanying drawings-Figs 8 to 17 give a general idea of
some of these bodies or blocks.. Figs 18 and 19 represent a mould for forming
square blocks.
These bodies are grouped, in a suitable mould, side by side, or one over the other,
or both kinds of grouping are combined, and by running lead into the apertures oo
or into the notches 66 provided in the contact surfaces they are connected together,
Figs 1 to 7.
By the flow of lead into the channels or openings, thus formed or left, and owing
to the contraction which naturally takes place when the lead is cooling, a cohesive
frame or network is formed round or through these bodies adapted to give the
plates or blocks a great degree of stability.
Any number of electrodes, thus formed, can then be arranged in a vessel in the
usual way as secondary cells, and any number of these cells as secondary batteries.
The material can also be employed in a battery-cell in such a manner, that it is
packed round a metallic band or rod in a porous vessel of earthenware or other.
material.
In smaller batteries, these bodies can be used singly, by pouring in lead to form
end-electrodes d, d¹ Fig 14-17.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed; I declare that what
I claim is
1. The preparation of a finely reduced lead compound, suitable for the electrodes
of secondary batteries, and made in the manner described, by the addition of some
oxide or salt of lead.
2. The fixing of such masses on perforated, branched, or otherwise suitable, lead
plates.
3. The production of single bodies made of porous or finely reduced lead, and
the connection of the same with each other by running lead into the openings o or
the notches b.