IMPROVEMENTS IN THE PREPARATION OF LEAD FOR USE IN THE CELLS OF SECONDARY BATTERIES.
Year: 1882

page_text: LETTERS PATENT to Ludwig Epstein of 144 High Holborn, in the County
[f
of Middlesex, for an Invention of IMPROVEMENTS IN THE PREPARATION OF
LEAD FOR USE IN THE CELLS OF SECONDARY BATTERIES.'
PROVISIONAL SPECIFICATION left by the said Ludwig Epstein at the
Office of the Commissioners of Patents on the 8th August 1882.
LUDWIG EPSTEIN of 144 High Holborn, in the County of Middlesex
MENTS IN THE PREPARATION OF LEAD
BATTERIES
"
"
IMPROVE-
FOR USE IN THE CELLS OF SECONDARY
This Invention has for its object improvements in the preparation of lead for
use in the cells of secondary batteries.
I obtain a spongy preparation of lead, suitable for use in the cells of secondary
batteries by adding permanganate of potash to molten lead.
The permanganate should be added little by little to the molten lead and the
mass constantly and energetically, stirred, until the whole has solidified in a crumb
like state.
The operation is by preference conducted in a pot or vessel containing a
mechanical agitator.
The spongy or crumb like lead is employed to form the elements or secondary
battery cells.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Ludwig Epstein in the Great Seal Patent Office on the 8th
February 1883.
LUDWIG EPSTEIN of 144 High Holborn in the County of Middlesex
MENTS IN THE PREPARATION OF LEAD FOR USE IN THE CELLS OF
BATTERIES
"
"
IMPROVE
SECONDARY
This Invention has for its object improvements in the preparation of lead for
use in the cells of secondary batteries.
I obtain a spongy preparation of lead, suitable for use in the cells of secondary
batteries, by adding permanganate of potash to molten lead.
The permanganate should be added to the molten lead and the mass constantly
and energetically stirred, until the whole has solidified in a crumb like state.
The operation is by preference conducted in a pot or vessel containing a
mechanical agitator.
The spongy or crumb like lead is employed to form the elements of secondary
battery cells.
The operation may be conducted on a small scale by melting lead in a pot or
crucible, then removing it from the fire and adding permanganate of potash in
powder or crystals. The proportion which I prefer is one ounce of permanganate
or thereabout to each pound of lead. Then with an iron blade or rod the mixture
should be vigorously stirred as it cools and so the metal is obtained in the desired
spongy state.
The
On a large scale the metal may be melted in one vessel and then poured into
another in which is an agitator having numerous blades or teeth dipping down
into the metal and by steam power or otherwise put into rapid movement.
vessel should be a shallow one and the temperature at which the metal is poured
in should be such that solidification does not coinmence until there has been time
for the addition of the permanganate in the proportion above stated and the
admixture thereof with the metal.
The permanganate is decomposed in the operation, oxygen is given off and solid
products are left behind in a finely divided condition.
The lead is broken up partly by the action of the agitator and partly by the
Jiberation in the midst of it of gas from the permanganate; and when so broken
up the particles of lead are prevented from reuniting by the pulverulent material
which forms a permanent parting between them.
Permanganate of potash is the material which I prefer to employ, and that
which in my experience gives the best result, still a like although inferior product
may be obtained by the mechanical agitation under suitable conditions of melted
lead with other matters in a finely divided state or which becomes so in the course
of the operation. I take the spongy lead prepared in the way which I have
described and if the presence of the potash salt be deemed objectionable I dissolve
it by washing with water.
To produce electrodes from the spongy lead I prepare a mould of suitable
dimensions and of the form desired (the rectangular form is usually the most
convenient) and I place in this mould in the first place one half of the weight of
spongy lead which I intend to employ and moistened with water or dilute
sulphuric acid. I then lay into the mould a piece of lead cut to the form of a fork
with three or more prongs or any other suitable shape leaving the part corre-
sponding to the stem of the fork projecting out of the mould, this is to form the
connection by which the electrode is to be coupled in circuit. I then complete the

page_text: charge in the mould by spreading in it the remainder of the spongy lead moistened
as above; the spreading should be performed evenly but allowing rather a greater
thickness of the lead sponge around the edges than elsewhere. The mould is then
closed and hydraulic pressure is applied, about a ton and a half to the square inch
of surface is a suitable pressure. By this pressure the metallic sponge is so far
consolidated as to hold firmly together or even to admit of connections being
soldered to it if desired.-But nevertheless it remains porous and when these
electrodes are arranged in the usual way in the cells of a secondary battery they
are freely permeated by the liquid in the cells. Hence the operations of forming
and charging the battery can be rapidly performed.
Sometimes to strengthen the electrodes at the edges I introduce into the mould
in the first place strips of sheet lead or it may be a frame of lead produced by
casting or otherwise.-I then put in the porous lead and by the pressure the whole
is consolidated.
The spongy lead prepared in this way may also be employed in a battery cell
by packing it into a cylinder of porous earthenware around an electrode of lead
or other material.
What I claim is:-
First. The preparation of spongy lead suitable for use in the cells of secondary
batteries by the treatinent of lead with permanganate of potash substantially as
described.
Second. The preparation of lead by the agitation of the melted metal with
permanganate of potash or other material in such manner as to produce a spongy
metal suitable to be employed in the cells of secondary batteries.
In witness whereof I the said Ludwig Epstein have hereunto set my hand
and seal this sixth day of February in the year of our Lord One thousand
eight hundred and eighty three.
DAN
L. EPSTEIN.
(..)