mprovements in Secondary Battery Plates or Elements and in the Process of Preparing same.
Year: 1892

page_text: Date of Application, 14th Dec., 1892-Accepted, 21st Jan., 1893
mprovements in Secondary Battery Plates or Elements and in the
Process of Preparing same.
A communication from abroad by WILLIAM WOODNUT GRISCOM, Electrical
Engineer, residing at Haverford, Montgomery County, Pennsylvania, in the
United States of America.
I, PHILIP MIDDLETON JUSTICE of 55 and 56, Chancery Lane, in the County
of Middlesex, Fellow of the Chartered Institute of Patent Agents, do hereby
declare the nature of this invention 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 manufacture of secondary battery plates or
clements, and it has for its object to produce an improved plate which shall be
cheap of construction and which shall furnish the largest possible amount of active
surface, and which will have the lougest possible life for a given weight. To these
ends the invention consists in the process substantially as hereinafter set forth for
preparing the plates, and in the plate having the features of construction, and
capable of the uses, substantially as are hereinafter more particularly pointed out.
Referring to the accompanying drawings
Figure 1, is a side view of a plate embodying the invention, the plate being
shown with various forms of frames and corresponding strips, sheets or bars; and
Figure 2, is an enlarged vertical section of a portion of the plate.
Heretofore in the manufacture of plates for secondary batteries, two general
methods have been followed. One, which is generally termed the Planté method,
in which sheets of lead, or other similar material, are subjected directly to the
action of an electric current in the process of " forming," the current being reversed
at intervals, until the surface of the lead plate presents a sufficient thickness of
active material in the form of lead sponge or an oxide of lead, while the other
type, generally known as the Faure method, consists in mechanically coating the
lead or other plates with the active material preferably in the form of a paint,
paste, or cement. This latter type is the one which has been the more extensively
used, and many and various attempts have been made to provide means whereby
the active material may be securely held on the plate, and at the same time be
properly exposed to the action of the electrolyte, the plate as a rule being formed
with perforations, openings, recesses, or depressions into which the active material
is forced, or otherwise mechanically applied.
The objections to both these types of plates, as well as the advantages, are well
known to those skilled in the art, and need not be recited, and it is one of the main
objects of the present invention to provide a plate which shall possess the
advantages of both systems, and which shall be cheap of production and furnish a
large surface of active material, and at the same time have a life practically equal
to the sum of the lives of both these types of plates.
It will be understood by those skilled in the art that the invention may be
carried out and embodied in various forms and materials, and while my correspondent
does not wish to limit himself to any particular form or material, 1 will now proceed
to describe what he has found to be a practical and effective embodiment of the
invention.
Referring to the drawings A, represents a plate in the form of a grid forming a
group of frames of comparatively thick material, and the plate may be provided

page_text: 1
with the lugs or supports a; and the projections a², serving as a lug for connecting
the plate to the electric circuit.
The frames of the group are each provided with a series of thin sheets, strips or
bars C, of metal enclosed within the frame-work, and forming an integral part of
the walls of the frame, and these sheets are shown as being parallel to each other
in various ways, and as being relatively thin, leaving spaces between the sheets,
strips or bars of say one or two hundredths of an inch, more or less.
These plates may be made of different materials, but it is preferred to make them
of lead, and preferably of what is known in the art as forced lead, rather than cast
or rolled lead, inasmuch as the rolled lead has the disadvantage of possessing a
hard and skinlike surface, and the cast lead has a more or less crystalline structure,
while the forced lead presents a compact, homogeneous and solid body, rendering
it not only more durable, but capable of being treated and formed into a perfect
and satisfactory electrode. Forced lead is usually made by forcing lead in a semi-
fluid condition, into or through dies or moulds. It can also be made from lead in a
molten.condition moulded under pressure.
The plate as thus constructed is subjected to the action of some proper solution
,which produces a honey-combing or pitting of the surface, not only of the frame-
work, but of the sheets, strips or bars contained within the frame-work, and this
honey-combed surface receives a deposit of finely divided lead, or equivalent, either
from the liquid in which it is treated, or otherwise. The plate is then in condition
to be "formed" for use in a battery, becoming practically a Planté plate, until
finally, through use, the sheets, strips, or bars become practically converted into
active material, and swelling under this treatment, fill the spaces or openings, and
then the plate becomes similar to a Faure plate, except that the active material has
not been mechanically applied. In this way the plate practically combines the life
of a Planté and of a Faure type of plate.
While various solutions may be used in carrying out the invention, it is preferred
to submit the plate to the action of an alkaline solution in which it is boiled until
the surface of the plate becomes honey-combed to a depth, say of one two-
hundredths of an inch, more or less, and within these honey-combings, and on the
surface, the active material, or material to become active, is deposited, either from
the solution itself, or otherwise. The active material is preferably in the form of
finely divided lead, and by this is meant metallic lead or any of its oxides or salts
in a state of fine sub-division, forming a coherent mass, the particles of finely
divided lead cohering together as well as adhering to the plate.
For example, an alkaline solution containing about two per cent. ammonium
nitrate, aqueous solution, is taken, and the plate is immersed therein, the solution
is then boiled for a greater or less time, depending upon many conditions, as the
size and character of the plate and the strength and materials of the solution, and
when thus treated the surface of the plate becomes thoroughly honey-combed or
pitted to a greater or less depth and within these honey-combs is deposited the
finely divided lead.
The plate thus treated may be then removed from the solution and dried and
subjected to the "forming" process, by being immersed in an electrolyte solution
preferably consisting of dilute sulphuric acid, and connected to the positive pole of
an electric circuit and the finely divided lead is converted into a peroxide by the
action of the electric current, when the plate is ready to be used as a positive plate
of a secondary battery. This positive plate can be converted into a negative plate
in the well known way.
These plates thus treated may constitute the positive and negative plates of a
storage battery analogous to the Planté type and the battery can be used for
useful purposes. In the course of such use the thin sheets, strips or bars of lead
are practically converted into active material, and these sheets, strips or bars
become, a substantially compact mass, swelling under the treatment, filling the
spaces and causing the plate to be in a condition analogous to the well-known
Faure-Swan type of plate.

page_text: Thus an additional life is given to the plate after the active material, formed
from the sheets, strips or bars would have become too much disintegrated to be
effective in a Planté battery.
It is further observed that additional life may be given to the plate by supplying
it initially with active material mechanically applied, and it can be thus used until
the mechanically applied material has fallen out, at which time the plate will
begin to operate as a Planté plate, and so continue until, through disintegration,
the sheets, strips or bars fill the frame-work with active material held in place as
described, and then it begins a new life as a modified form resembling the Faure-
Swan plate.
It may be remarked that the masses of active material formed out of the
disintegrated sheets, strips or bars are held in place not only by being confined by
the heavier frame work, but there will remain for a long time small conducting
filaments of lead, remnants of the disintegrated sheets, strips or bars, extending from
the frame-work into the mass, which tend to retain the active material in place
and also to maintain a large contact surface between the frame of the plate and the
active material.
Another advantage is that the plate thus formed is less liable to buckle owing
to the fact that the sheets, strips or bars have an opportunity to bend or buckle
independently without producing any material strain on the framework of the plate
as a body, and in some instances this result may be still further provided for by
corrugating the sheets, strips or bars as indicated in the drawings.
It will thus be seen that an exceedingly effective plate is produced with a great
economy of production, and one which is capable of an exceedingly long life. It
may commence its life as a Faure-Swan plate pure and simple, and after the
active material falls out, as is usual with Faurc-Swan plates, it will begin a new
life as a Planté element, and after disintegration has proceeded so far as to make
it useless as an ordinary Planté plate, it will have still another lease of life as a
species of Faure-Swan plate, except that the active material in this last phase of
its existence will not have been applied mechanically.
If it be preferred to omit the first phase of existence as above described, to
wit, the Faure-Swan type, which has the disadvantage of shedding its active
material, causing short circuits and filling the bottom of the jar with a conducting
mud which renders the battery impracticable for certain purposes, the improved
plate may commence its life as one of a Planté type, and after disintegration has
proceeded as above described it becomes converted into a modified form of Faure-
Swan plate from which it differs mainly in that its active material is not
mechanically applied, aud in that the mass of active material is permeated by con-
ducting filaments.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. The process substantially as hereinbefore set forth of preparing secondary
plates or elements, which consists in subjecting a plate to the action of an alkaline
solution thereby first producing honey-combs in the surface of the plate, and
subsequently chemically depositing thereon active material or material to become
active and then " forming" the plate electrolytically in the usual way.
2. The process substantially as hereinbefore set forth of preparing secondary
battery plates or elements, which consists in subjecting a lead plate to the action
of a hot alkaline solution thereby first producing honey-combs therein and subse-
quently chemically depositing active material, or material to become active in the
honey-combs, and then "forming" the plate electrolytically in the usual way.
3. The process substantially as hereinbefore set forth of preparing secondary
battery plates or elements which consists in subjecting a lead plate having spaces
filled with thin sheets, strips or bars, to the action of a hot solution of nitrate of
ammonia, thereby first producing honey-combs in the surface of the plate, and

page_text: subsequently chemically depositing in said honey-combs finely divided lead, and
then forming" the plate electrolytically in the usual way.
4. A lead plate or grid consisting of a group of conducting and supporting walls
or frames filled with thin integral sheets, strips or bars with their broad faces
opposed to each other, and which are separated from one another by narrow inter-
stices, said group being in turn surrounded by a frame forming the boundary of
the plate, substantially as described.
5. A lead plate or grid consisting of a group of conducting and supporting
frames filled with thin integral sheets, strips or bars which are separated
from one another by narrow interstices of such a width as to be filled when the
sheets, strips or bars are sufficiently converted into active material, substantially as
described.
6. A lead plate or grid consisting of a group of conducting and supporting frames
filled with thin integral sheets, strips or bars which are separated from one another
by narrow interstices of such a width as to be filled when the sheets, strips or bars
are sufficiently converted into active material the whole being composed of forced
lead, substantially as described.
Dated the 14th day of December 1809
PHILIP M. JUSTICE.