IMPROVEMENTS IN SECONDARY BATTERIES
Year: 1882

page_text: "
LETTERS PATENT to Thomas John Handford of 42 Southampton Buildings
in the County of Middlesex Patent Agent for an Invention of "IMPROVEMENTS
IN SECONDARY BATTERIES A communication to him from abroad by Thomas
Alva Edison of Menlo Park in the State of New Jersey, United States of
America.
PROVISIONAL SPECIFICATION left by the said Thomas John Handford at
the Office of the Commissioners of Patents on the 18th August 1882.
THONAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex, Patent Agent, "IMPROVEMENTS IN SECONDARY BATTERIES" a commu-
nication to me from abroad by Thomas Alva Edison, of Menlo Park in the State of
New Jersey, United States of America
Heretofore in secondary batteries the electrodes have been formed of lead plates
or of lead plates having oxide of lead secured thereto, or of lead plates carrying
chemically precipitated metallic lead; but all these constructions have defects which
detract greatly from their efficiency.
The simple lead plates present a very small surface, and hence have a low
efficiency, and in addition, it becomes necessary for that reason to reduce the
surface of the plates to oxide to a considerable depth. This thick coat of oxide
cracks off and separates at points from the plates, producing bad contact, and high
resistance, and making portions of the oxide inert, and reducing greatly the
efficiency of the battery. With the second construction,-that of the oxide secured
to lead plates, the oxide also becomes separated from the lead plates, resulting in
bad contact high resistance, inert portions, and loss of energy. The spongy or
chemically precipitated lead carried by lead plates is also open to the same objection,
the precipitated lead not being integral with the plates which carry it, or the
particles of the lead with one another, and becoming detached from such plates
in use.
The object therefore of this Invention is to produce electrodes of metallic lead
for secondary batteries, without the use of chemically precipitated lead or salts or

page_text: compounds of lead, which electrodes will be integral throughout and will present,
an exceedingly large surface producing a highly efficient battery, by a small
reduction to an oxide of the surface of the lead, and not having the defects before
stated.
According to one mode of carrying out this Invention, the object before
mentioned is accomplished by constructing each electrode or the exposed surfaco
thereof of integral arborescent metallic lead. This form of lead is obtained by
pouring molten lead from a height into water, or into powdered material such as
powdered chalk, or lime, or by blowing air through molten lead. The crystallization
of the lead being disturbed at the moment of setting the lead assumes, an arborescent
form, presenting a large surface, and being integral throughout its mass.
This integral arborescent lead may be fused to lead plates, by fusing the surfaces
of the plates, and pressing the arborescent lead upon them.
The arborescent lead is thus made integral with the plates, which carry it, the
plates forming means for making connection.
Or molten lead may be blown on to lead plates in dropping from a height, and
will be fused with the plates and assume upon them the arborescent form.
The electrodes however, may be made entirely of arborescent metallic lead, and
they may be so constructed by pouring molten lead into suitably shaped troughs or
receptacles containing water. The arborescent lead will take the shape of the
troughs, and lugs for making connections may be formed by pinching or fusing
the arborescent lead together. This form of electrode has openings entirely through
it, and has the advantage in a battery of bringing the back sides of the outer
electrodes into action, increasing the efficiency of the battery.
Or the same object may be accomplished by the use of threads of metallic lead to
which is given the name of filamentary or "stringy" lead.
This filamentary lead is woven braided or otherwise formed into mats, the edges
of which are reduced to a solid condition by pressure or heat or both heat and
pressure, so that the mat will retain its shape, and the mat may further be reduced
to a solid state on lines crossing at the centre of the mat.
The electrode may be a single mat, or a number of mats may be laid one on top
of another, and all secured together, at the edges by pressure, or heat, or both, and,
also if desired on one or more cross lines.
Instead of weaving or braiding the filamentary lead it may be formed into mats
by laying the threads parallel with each other, or massing them together in any
other manner, and making the mat solid at the edges and on one or more cross
lines.
A convenient
The filamentary lead may be obtained in any suitable manner.
method is to mount a block of metallic lead in a lathe, and to turn, a thread spirally
from the face of the same by means of a regularly advancing tool.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas John Handford in the Great Seal Patent Office on the
17th February 1883.
THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex, Patent Agent "IMPROVEMENTS IN SECONDARY BATTERIES" A commu-
nication to me from abroad by Thomas Alva Edison of Menlo Park, in the State of
New Jersey, United States of America
The said Invention relating to improvements in secondary batteries bas for its
object the production of electrodes therefor of metallic lead without the use of
chemically precipitated lead or salts or compounds of lead, which electrodes shall
be integral, throughout, and present an exceedingly large surface, producing a
highly efficient battery by a small reduction to an oxide of the surface of the lead.
This object is accomplished by constructing each electrode or the exposed surface
thereof of integral arborescent metallic lead formed from molten lead.
In carrying out the said invention molten lead is poured from a height, into
water, or into powdered material, such for example as powdered chalk or lime, or
air is blown through molten lead. As the crystallization of the lead is disturbed ut
the moment of settling, the lead assumes an arborescent form presenting a large
surface and being integral throughout its mass.
This integral arborescent lead may be fused to lead plates, by fusing the surfaces
of the plates and pressing the arborescent lead upon them. The arborescent lead is
thus made integral with the plates which carry it the plates forming means for
making connection. Or molten lead may be blown on to lead plates in dropping
from a height and will be fused with the plates and assume upon them the
arborescent form.
Figure 1 of the accompanying drawings represents a vertical section of a secondary
cell having the electrodes made partly of integral arborescent metallic lead formed
from molten lead as hereinbefore described.
The electrodes consist of lead plates A, B, having exposed surfaces C, D, of
integral arborescent metallic lead formed from molten lead and fused to the said
plates. They are immersed in dilute sulphuric acid or other suitable liquid
contained in a vessel E and fitted with connections in the usual manner.
The electrodes however may be made entirely of arborescent metallic lead by
pouring molten lead into suitably shaped troughs or receptacles containing
water. The arborescent lead will take the shape of the troughs and lugs for
making connections may be formed by pinching or fusing the arborescent lead
together.
Figure 2 represents a vertical section of a secondary cell having electrodes C, D,
so formed, a, a, shewing the lugs for making connections.
This form of electrode has openings entirely through it, and has the advantage
in a battery of bringing the back sides of the outer electrodes into action thus
increasing the efficiency of the battery.
Having now described and particularly ascertained the nature of the said
invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the invention secured to me by the hereinbefore in part
recited Letters Patent is :-
In secondary batteries, the employment of electrodes composed partly or

page_text: entirely of arborescent metallic lead formed from molten lead, the said electrodes
hereinbefore
being made integral throughout their mass, substantially as
described.
In witness whereof I the said Thomas John Handford have hereunto set my
hand and seal this seventeenth day of February in the year of Our Lord One
thousand eight hundred and eighty three.
THJ HANDFORD (L.S.)