Improvements in the Method of Making the Plates or Elements of a Secondary or Storage Battery.
Year: 1891

page_text: Date of Application, 15th Sept., 1891-Accepted, 17th Oct., 1891
COMPLETE SPECIFICATION.
Improvements in the Method of Making the Plates or Elements of
a Secondary or Storage Battery.
I, STANLEY CHARLES CUTHBERT CURRIE, Room 841, Drexel Building,
Fifth and Chestnut Streets, in the City of Philadelphia, in the County of Phila-
delphia and State of Pennsylvania, Electrical Engineer, do hereby declare the
nature of my invention for IMPROVEMENTS IN THE METHOD OF MAKING THE
PLATES OR ELEMENTS OF A SECONDARY OR STORAGE BATTERY, and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statements :—
My invention relates to the method of making the plates or elements of a
so-called secondary or storage battery.
Hitherto the methods generally employed for the manufacture of the plates or
elements of a secondary or storage Lottery have either been the purely electrolytic
or the mechanical of applying under pressure lead oxides to a conducting frame or
support.
My present invention has relation to and is based upon the former method but
involving certain novel and important features in connection with the manufacture
of plates or elements for use as a secondary or storage battery.
My invention consists of an efficient and expeditious method of subjecting cast
or rolled lead enveloped or encased in woven or braided fibrous material, in a
suitable solution, to electrolytic action to cause a partial penetration and conversion
of the same to a salt state and the reduction of the enveloped or encased partially
penetrated and converted lead to a spongy or porous metallic condition without
affecting the internal metallic body thereof which forms the conducting part or
portion of the plate or element, when mounted in battery.
My invention further consists of the certain other features in the method of
producing a battery plate or element hereinafter described and pointed out in the
claims.
Hitherto the principal objections to the method of reducing a plate of lead or
similar material by electrolytic action to a spongy state or condition in a solution
of dilute sulphuric acid has been the extreme length of time required to render
the same spongy or porous and of sufficient thickness or bulk for practical purposes.
This method as is well known, requires a number of reversals of the electric current
so that it is impossible to attain the required result without a constant repetition
of the treatment. The principal reason being that only the surface of the lead
was oxidized at first, but just as soon as this small amount was fully oxidized the
oxygen being unable to be further taken up by the lead escaped in the form of a
gas. This of course is the case when simple lead constitutes the elements and
they are immersed in a bath composed of dilute sulphuric acid. I have discovered
by a series of experiments, that it is possible to penetrate into a plate or block of
ordinary lead by electrolytic action in such a manner as that but one or two
reversals of current are required and that the lead can be quickly and effectually
penetrated to the required depth; and moreover, that the salt of lead into which
such plate or block is converted in the first instance is brought to such a state or
condition as to be readily reducible again to lead in a soft spongy or porous
metallic condition and afterwards formed by the ordinary process or treatment
with but one or two reversals. The principle above defined forms the basis upon
which my present invention is founded and I adopt the line of action hereinafter
prescribed for practically and efficiently carrying the same into effect.
For example, two plates or blocks of lead are immersed in a suitable liquid or
bath and in a solution in which the lead is insoluble. The blocks or plates of

page_text: lead being arranged therein as anodes and cathodes. An electric current is then
passed which causes in a short period of time the anode to be gradually but
uniformly transformed to the required depth forming thereby a layer or thick film
of lead salt as a part thereof and of such general character as experience has
demonstrated may be quickly transformed by a simple reversal of current into
porous metallic lead or to a spongy metallic state or condition for use as an element
of a battery when mounted in a suitable electrolyte, such as dilute sulpuric acid.
The element being formed therein in the ordinary manner. As the plate or element
is thus produced in a porous or spongy condition no constant reversals of current
are required. The solution to mount the plate or block of lead in for its conversion
in the first instance, is preferably composed of dilute chloride of zinc (zn. clę).
It has been ascertained by practical experiment that if a current is passed from
a lead anode to a lead cathode in a solution of zinc chloride, lead chloride is
formed upon the surface and extending into the body thereof (without any
escape of gas) yet if the plate so treated was not otherwise protected, this lead
chloride would fall to the bottom of the tank, thereby rendering the plate or block
practically useless.
To obviate such difficulty presented or disadvantageous feature arising means
have been devised forming a part of the present invention in which the lead
chloride so formed is retained to the internal body of the plate or block without
interfering in any manner with the converting or transforming step of the process
for the production of the battery element. This step being permitted according
to my invention to continue under due regulation until the required depth of lead
chloride is formed. As soon as the required depth of chloride surface has been
obtained, which can be readily ascertained from the quantity of current permitted
to pass, it is transferred and becomes the cathode element of the tank. As the
solution of the tank is dilute chloride of zinc when a current is caused to pass,
there is deposited metallic zinc on the cathode. This metallic zinc it has been
found hastens the reduction of the lead chloride of the cathode to a metallic state
or condition and remains, that is to say, the zinc in the solution and thus it may
be used over and over again. The retaining medium for the plate or block of
lead during its aforesaid treatment as well as during its use as a battery element,
preferably consists of a casing or covering of woven or braided asbestos or
analogous material.
In the practice of the present invention it is preferred that the lead plates or
elements in the first instance should be simply a series of rods or wires. When
the plates are in the form of blocks or plates of lead as in the first instance
mentioned, the asbestos will be cut in lengths and suitably applied thereto and the
lead in molten state poured into suitable molds and the lengths of asbestos sub-
sequently caused to surround or envelop the same; while in the latter case the
asbestos will be braided or otherwise caused to surround the lead wires or rods
and the rods or wires then preferably formed into a series of loops with a single
conductor therefor. Each series of the rods or wires with the woven or braided
asbestos around them constituting a plate. The herein before described method
and manner of constructing the plates applies more particularly to the peroxide
plates. The asbestos covering of the plates is retained and effectually prevents
disintegration of the peroxide plates after continuous action in use as a storage
battery.
Having fully described the nature of the invention and pointed out the particular
features thereof I will now refer to the accompanying drawings illustrating the
mode of treating such materials for the production of a battery plate or element
such as herein before described; and in which
Figure 1, is a perspective view of a tank showing two plates embodying the
features of my invention arranged as anodes and cathodes therein immersed in a
suitable solution, and this view illustrating a preferred mode of carrying my
invention into effect.
Fig. 2, is a vertical section through a tank showing a plate composed of a series

page_text: of depending blocks of lead or analogous material shown partly in elevation and
partly in section to more fully illustrate the manner of penetrating into the body of
each block or rod of the series constituting the plate on each side or around about
the outer surface thereof and showing also the central core or body of ordinary lead
undisturbed by such action to become a part of the conducting means with the
horizontal bar or rod burnt or otherwise applied to the upper parts of the series of
blocks constituting the battery plate; and
Fig. 3, is a modified form of plate embodying the particular features of my
invention.
Referring to the drawings a, is a tank constructed of any suitable material and
of any preferred form. b, is a suitable solution contained in said tank and preferably
composed of dilute chloride of zinc. r, are the series of blocks, rods or wires of
lead or analogous material enveloped or encased in a covering or case d, preferably
composed of woven or braided asbestos or analogous material and e, is a conductor
burnt or otherwise applied to the top of the series of blocks, rods or wires c,
constituting the plate. f, Figs. 2 and 3, represents in section the blocks or rods
eaten into or penetrated by the electrolytic action permitted to take place in the
tank a, and converted by such action into a condition of lead chloride and then by
a simple reversal of current reduced to a soft spongy or porous metallic condition,
and represents the internal body or solid core maintained free from such action
and in its normal state or condition as metallic lead and in such condition becomes
a most excellent conductor in the subsequent use of the plate as an element of a
secondary battery.
g
The method of carrying my invention into effect, is as follows:-
The plate or anode designated in Fig 1 by the letter f¹, mounted in the tank a,
after the passing of a current for a required time, becomes coated on the surface of
the lead beneath the asbestos or analogous outer woven or braided covering or
casing with a layer of chloride of lead (PbCl,) and to the required depth thereof.
It is then removed and replaces the plate or cathode designated by the letter f³, in
the tank a, which by this time has been reduced as far as the internal core or body
thereof to a porous or soft spongy metallic state or condition for use and so on in
regular succession and in a similar manner, plates to be treated are placed in the
tank a, immersed in the solution composed preferably of dilute chloride of zinc for
the aforesaid treatment. The solution being constantly recovered in the manner
herein before fully described. Instead of employing chloride of zinc use may be
made of chloride of iron, but preference is given to the employment of the former
for the purpose.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described method of making a battery plate or element, which
consists in subjecting a suitable solution of a chloride of a metal, lead enveloped or
encased in woven or braided fibrous material to electrolytic action to cause a partial
penetration and conversion of the lead to a state or condition of a salt of lead and
then reducing the same to a soft spongy or porous metallic state or condition, for
the purposes set forth.
2. The herein described method of making battery plates or elements, which
consists in immersing as anodes and cathodes provided with conductors in a solution
of a chloride of a metal, lead plates, blocks, rods or wires containing a surrounding
covering or casing of a fibrous material and then causing an electric current to pass
so as to penetrate a portion thereof and convert the same into the condition of a salt
of the metal and then reversing the current to reduce the same to a spongy state or
condition, for the purposes set forth.
3. The herein described method of making a battery plate or element, which
consists in immersing in a solution of chloride of zinc cast or rolled lead enveloped
or incased in woven or braided asbestos as anodes and cathodes in said solution,

page_text: then passing a current and penetrating the lead to the required depth for converting
the same to a salt state, and then reducing the penetrated and converted lead to a
spongy or porous metallic state or condition, for the purposes set forth.
4. The herein described method of making a battery plate or element which
consists in immersing in a solution of chloride of zinc cast or rolled lead enveloped
or incased in woven or braided asbestos by electrolytic action to cause the
penetration of the lead to a defined depth and its conversion into chloride of lead
while the solid core or internal body is maintained in a metallic state and then
reducing said chloride of lead to a soft spongy or porous metallic state, for the
purposes set forth.
5. The herein described method of making a battery plate or element, which
consists in converting electrolytically cast or rolled lead enveloped or inclosed in
asbestos or analogous material in a solution composed of a chloride of a metal to a
salt state then reducing the same to a spongy or porous metallic condition and then
employing said solution for immersing other plates, bars, rods or blocks enveloped
or incased in asbestos or analogous material therein, substantially in the manner
described and for the purposes set forth.
Dated thin 10th An of A 1201
STANLEY CHARLES CUTHBERT CURRIE.
W. P. Thompson & Boult,
Agents for the Applicant.