Improvements in Secondary Batteries, and Process of Forming same.
Year: 1897

page_text: Date of Application, 5th Jan., 1897-Accepted, 6th Mar., 1897
Improvements in Secondary Batteries, and Process of Forming same.
We, GEORGE WASHINGTON HARRIS, Broker, and RICHARD JOSIAH HOLLAND,
Electrical Engineer and Chemist, both of 150 Nassau Street, in the City, County and
State of New York, one of the United States of America, 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 :-
Our invention has for its object to provide improved electrode-plates, for use in
storage or secondary batteries, of such construction as to have the greatest possible
capacity, consistent with proper strength and durability, so that the peroxide of lead,
or active material, will be so distributed as to present the greatest possible amount of
surface to the action of the electrolyte. Our invention also comprises an improved
Plante "formation process, whereby the greatest possible durability, consistent with
the greatest possible expedition in " forming," is given to the formed plates..
In the accompanying drawings, Fig. I is a side view representing two of our
improved electrode-plates, one being behind, and of opposite polarity, to the other.
Fig. 2 represents a battery of these plates, the latter being shown in end view.
Fig. 3 is a top view of the battery represented in Fig. 2, and Fig. 4 is a cross-
section, on line 4-4 of Fig. 1, of one of our improved electrodes.
A denotes an electrode-plate, consisting of a single integral piece of lead, each of
these plates being provided at its top with a lug B, having a notch C, for the
reception of a connecting bar D or E; the last-named bar, as shown in Figs. 2 and 3,
being the positive connecting bar, while D is the negative connecting bar. These
connecting bars are burned into the lugs B, in the usual manner. In the battery.
represented by Figs. 2 and 3, we have shown five electrode plates, two positives and
three negatives; the outer negative plates being of about one-half the capacity of the
inner ones, so as to equally balance the battery. Each of the plates A is composed of
oppositely-inclined ribs, (one series on either side of the electrode or plate) alternating
with grooves; the ribs a, on one side of the plate, being inclined oppositely to the
ribs b, on the other side thereof, so that these two series of ribs intersect each other
at short intervals, and are bodily joined to each other only at their points of inter-
section, thereby forming a skeleton-like structure with openings c, between their
points of intersection. The ribs a and b are of rectangular or quadrilateral form in
cross-section, as this is deemed to be the best embodiment of our invention. The
grooves alternating with the ribs on one side of the plate, extend to the grooves on
the opposite side of the plate, thereby forming an open-work or skeleton structure,
with openings, c, through the plate, between the points of intersection of the ribs a
and b. The grooves, which alternate with the ribs a and b on both sides of the plate,
are open to the edges of the plate, at the sides and bottom, thereby producing what
may be termed a practically borderless plate, as the grooves are only closed, or partly
closed, only at the top edges of the plates, by the lugs B.
The plates are preferably made in such a way that the ribs, terminating at the
edges thereof, alternate with each other, as shown more clearly in Fig. 2. The
grooves are extended out, so as to be open at the side and bottom edges of the plate,
in order to overcome the tendency of the latter to buckle during "forming," as also
during excessive charging and discharging. The object in constructing the plates
with oppositely inclined ribs and grooves, on their opposite sides, and with the
grooves on one side extending to the grooves on the other, to form an open work or

page_text: skeleton plate, is, first, to secure the greatest possible strength in proportion to weight;
second, the greatest possible surface and capacity, in proportion to the amount of
material required in their construction. Furthermore the open-work structure of our
plates affords free circulation of the electrolyte, during the process of forming, as
well as in the operation of charging and discharging. Our improved plates may be
made either by casting, rolling or sawing out, to form the grooves between
the ribs.
a thin
Our process of formation is as follows:-In the case of cast plates, it is advisable,
first to immerse them for a short time in a bath that produces on said plates
coating of lead sulphate. This bath is composed of dilute sulphuric acid (which is
practically a non-solvent of lead) and an acid (preferably acetic or nitric) which is a
solvent of lead. This step, however, is not positively essential, and may be dispensed
with, its object being merely to secure greater uniformity of electro-chemical action
in the "formation" of cast plates, in which there is a lack of uniformity of molecular
structure. The plates either with or without the treatment just referred to, are then
"formed" by being subjected to the action of an electric current in an electrolyte or
bath consisting preferably of a moderately strong solution of magnesium sulphate,
or its equivalent, as aluminium sulphate, and proportionately small quantities of
sulphuric and acetic acids and magnesium acetate, or equivalents therefor; but the
substances mentioned are preferred, as they give the best results, so far as is
known to us.
The essentially new result of this process of "formation," with the combination of
substances above stated constituting the electrolyte, is the production on the surfaces
of the electrode, during " forming," of a salt of lead, (lead sulphate) which is insoluble
or difficultly soluble in the electrolyte, but which salt of lead, by virtue of the
substances composing the electrolyte, is capable of being convertible into peroxide.of
lead thus the use of magnesium sulphate and magnesium acetate, or their equivalents,
is to facilitate the peroxidation of the otherwise difficultly peroxidizable sulphate.
Thus the two main actions proceed simultaneously during "formation," to wit: the
constant production of sulphate of lead over the surface of the electrodes, and a
constant, though somewhat slower peroxidation of the lead sulphate coating at its
outer surface.
6:
In order to make clear the sense in which we use the term equivalent" or
equivalents" in the preceding and to show the scope of our process of "formation,"
as to the various combinations of substances that may be used to constitute compound
electrolytes that are strictly similar or analogous in composition to the one we give
above as the preferable, we add the following by way of explanation.
11.
Thus, starting out with any particular acid that is non-solvent, or a poor solvent
of lead, for example, sulphuric acid; with this particular acid we may use any one of a
series of suitable metallic sulphates; for example, magnesium sulphate, with, any one
of a series of suitable acids that are ready solvents of lead, for example, acetic acid,
with, lastly, a corresponding salt for the lead solvent, viz.: magnesium acetate.
If we
use in place of magnesium sulphate, aluminium sulphate, then, the corresponding salt for
the acid solvent of lead, becomes aluminium acetate. If we vary the acid solvent of
lead, say, to nitric, in place of acetic, then the corresponding salt used will be
magnesium or aluminium nitrate, and so on. It is thus seen that many suitable
compound electrolytes are available, by the use of one particular acid, that is a non-
solvent, or a poor solvent, of lead. We do not limit ourselves, however, to the use of
sulphuric acid as the only non-solvent acid that we can use in our chemical and
electro-chemical process of "formation." Any other suitable acid that is a non-solvent,
or a poor solvent, of lead may be used, just in the same way as sulphuric. Thus, selenic
acid might be used in place of sulphuric; the selenates would then be used, instead of
the sulphates, and lead selenate would be the insoluble or difficultly soluble salt of
lead, produced during "forming," on the surface of the electrodes." In some cases
we may use two or more equivalent substances in the same compound electrolyte, or,
even compound two compound electrolytes, prepared as above, without in any way
altering the fundamental and essential feature of our process.
U

page_text: "
When the electrodes are sufficiently formed they are preferably removed from the
forming" electrolyte or bath, and washed, to remove any retained portion of the
bath just referred to, and are then subjected to the action of an electric current, in
an electrolyte or bath composed of dilute sulphuric acid and a proportionately small
quantity of an acid sulphate, as that of sodium or potassium. The treatment in this
last named bath completes the "formation" of the electrodes, as positives, by
converting any remaining portions of the lead sulphate into peroxide. This treat-
ment, however, does not increase the depth of "formation." When thus fully
formed, such of the positives as are intended to become negatives are "reduced
in this same electrolyte.or bath, by being connected with the negative terminal of
the charging current. The electrodes are then ready to be assembled to form cells
and are then charged in the usual way.
By the above-described process well-formed, highly effective battery plates can be
"formed," from raw material, in from thirty to fifty hours, the time depending
chiefly on the strength of the forming current. It is advisable, however, not to
use too strong a current in." forming."
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. An electrode formed of a single integral piece of lead, for use in secondary
or storage batteries, and consisting of an open-work or skeleton plate composed
of oppositely inclined intersecting or crossing ribs and grooves on its opposite sides,
said ribs being of rectangular or quadrilateral form in cross-section and the said
grooves on one side of the plate extending to the grooves on the opposite side
thereof and all of said grooves being open at the side and bottom edges of the plate
to make the latter borderless except at its top where it is provided with a lug, as B,
substantially as set forth.
2. The herein described process of "forming" electrodes for secondary or storage
batteries, consisting in subjecting lead plates to the action of an electric current in
an electrolyte or bath composed of two acids, one of which acids is a solvent and
the other of which is a non-solvent, or a poor solvent, of lead, together with one
or more salts of each of said acids, and afterwards subjecting the partly-formed
electrodes to the action of an electric current in another electrolyte or bath composed
of dilute sulphuric acid and an acid sulphate, substantially as described.
3. The herein described process of "forming" electrodes for use in secondary or
storage batteries consisting in subjecting lead plates to the action of an electric
current in an electrolyte or bath composed of magnesium sulphate, sulphuric acid,
acetic acid and magnesium acetate, and afterwards subjecting the thus partly-formed
electrode to the action of an electric current in another electrolyte composed of
dilute sulphuric acid and an acid sulphate, substantially as described.
4. The herein described process of "forming" electrodes for secondary or storage
batteries, consisting in subjecting lead plates to the action of an electric current in
an electrolyte or bath composed of a solution of magnesium sulphate and two acids
one of which acids is a solvent and the other of which is a non-solvent, or a poor
solvent, of lead, together with a suitable metallic salt of the solvent acid, and after-
wards subjecting the partly-formed electrode to the action of an electric current in
another electrolyte or bath composed of dilute sulphuric acid and an acid sulphate,
substantially as described.
5. The herein described process of forming" electrodes for secondary or storage
batteries, consisting in first subjecting the lead plates to an acid bath which will
react thereon, to form a thin coating of lead sulphate, next subjecting the lead plates
to the action of an electric current, in an electrolyte or bath composed of a solution
of magnesium sulphate and two acids, one of which is a solvent and the other of
which acids is a non-solvent, or a poor solvent, of lead, together with a suitable
metallic salt of the solvent acid, and afterwards subjecting the partly-formed electrode

page_text: to the action of an electric current in another electrolyte or bath composed of dilute
sulphuric acid and an acid sulphate, substantially as described.
6. The herein described process of "forming" electrodes for secondary of storage
batteries, consisting in subjecting the lead plates to the action of an electric current,
in an electrolyte or bath composed of a solution of magnesium sulphate and two
acids, one of which acids is a solvent, and the other of which acids is a non-solvent,
or a poor solvent, of lead, together with a suitable metallic salt of the solvent acid,
and afterwards subjecting the partly-formed electrode to the action of an electric
current in another electrolyte or bath composed of dilute sulphuric acid and an acid
sulphate and finally reducing positive electrodes, to form negatives, by subjecting
said positives to the action of an electric current, from a negative terminal, in the
last-mentioned electrolyte or bath, substantially as described.
Dated this 4th day of January 1807
CRUIKSHANK & FAIRWEATHER,
Chartered Patent Agents,
62 St. Vincent Street, Glasgow, Agents for the Applicants.