Improvements in Secondary Batteries.
Year: 1890

page_text: Date of Application (in United Kingdom), 28th Aug., 1890
Complete Specification Left, 28th Aug., 1890-Accepted, 17th Jan., 1891
COMPLETE SPECIFICATION.
Improvements in Secondary Batteries.
I, THERON SOLYMON EUGENE DIXON, Lawyer, residing at No. 53, Dearborn Street,
Chicago, in the County of Cook and State of Illinois, one of the United States of
America, do hereby declare the nature of my invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by the following
statement:-
The storage-battery cell as at present constructed contains in the dilute sulphuric-
acid fluid two electrodes, usually in the form of grids, holding the active material
which when the cell is charged, becomes, for example, peroxide-of-lead upon the
so-called "positive" electrode and spongy-lead upon the negative electrode. The
usual electro-motive force of such a cell when charged and put into use is about two
volts. The whole of the charge cannot be practically utilized, for when in the
discharge of the cell the electro-motive force falls below one and nine-tenths volts
the effect upon the plates is injurious, ultimately causing their destruction.
I have discovered that if a third electrode-for example, a plate of zinc-is inserted
in the cell in the relative order of, first, the peroxide-of-lead plate; second, the spongy-
lead plate, and third, the zinc plate, detached from conducting metallic connection
with each other, and with the circuit connected, respectively, to the peroxide-of-lead
plate and the zinc plate, the electro-motive force of the cell becomes about two and
one-half volts, affording an increase in the electro-motive force of the cell of about
twenty-five per cent. So far as this increase of electro-motive force is concerned, the
presence of the smallest piece of zinc on the end of the conducting-wire when it touches
into the electrolyte produces the same increase; and if in place of zinc a piece of
aluminium be employed the increase of electro-motive force is about one-half of that
given by a third electrode of zinc, or about two and one-half tenths of a volt.
"
In general any third electrode may be employed which has a so-called "negative
differential of potential from that of the spongy-lead plate, and this difference of
potential will be added to the electro-motive force of the cell. In like manner the
addition of an electrode at the opposite side of the peroxide-of-lead plate, which has a
so-called "positive" differential of potential from the peroxide-of-lead plate, will add
the amount of this differential to the electro-motive force of the cell. Moreover,
electrodes of the proper potential may be inserted between the outer electrodes in a
cell. For example, a perforated plate or bar of copper or silver may be inserted
between the peroxide and the spongy-lead plates, and likewise four or more electrodes
may be employed, as plates of peroxide-of-lead, copper, spongy-lead, and zinc in the
order mentioned. The addition of such intermediate electrodes, however, while they
take a part in the operation of the battery, does not add to the original electro-motive
force of the cell. The law, so far as I have discovered it, is that when the several
electrodes are arranged in the order of their respective electro-motive potentials to
each other the total electro-motive force of the cell is always equal to the sum of the
potential differentials of the respective plates in the order of their arrangement. The
difference of electro-motive potential between any two electrodes is readily ascertained

page_text: by observing the direction and extent of the movement of the needle of a voltometer
in the circuit when the terminals are attached to such electrodes. The intermediate
electrodes, moreover, coact with the exterior electrodes in other respects. Take, for
example, the simple case first mentioned of the three electrodes, plates of peroxide-of-
lead, spongy-lead, and zine in a cell containing an electrolyte the ordinary aqueous
solution of sulphuric acid. For this purpose I have employed the storage-plates of
the Anglo-American Storage Battery Company, which are each six by six inches in
dimension. I have taken the peroxide-of-lead plate as one electrode and placed in
the cell with it a small strip of zinc as the other electrode, and "short circuited" the
cell. The current of electricity flows through the circuit without any immediately
visible change in the elements, though of course chemical action is taking place. I
have then inserted the spongy-lead plate as an intermediate electrode between the
peroxide plate and the strip of zinc, when immediately the action upon the small strip
of zinc is so intensified that it becomes both audible and visible in the sizzling and
rise of bubbles which occur. By substituting for the strip of zinc an amalgamated
zinc plate of the same or a larger size than the other plates and putting the cell at
work the increased surface of the zinc is enabled to perform its function without the
production of ebullition. I have found, moreover, that the presence of an intermediate
or third electrode performs the very important function of increasing what may be
termed the "staying power of the cell. With a cell containing the three electrodes
mentioned peroxide-of-lead, spongy-lead, and zinc plates, respectively-several times
the electrical energy is evolved and flows through the circuit before the fall in the
electro-motive force of the cell occurs to the danger-point of one and nine-tenths volts.
before mentioned, that there is evolved in the cell containing only the two electrodes,
peroxide-of-lead and spongy-lead plates. Moreover, when the three electrodes are
employed, the period during which the fall of the electro-motive force of the cell
occurs to the point mentioned is prolonged to beyond that which occurs when only
two electrodes are employed, whether they be the peroxide-of-lead and the spongy-
lead or the peroxide-of-lead and the zinc, respectively.
"
I am unable as yet to fully explain the philosophy of this somewhat remarkable
staying" power exhibited in a cell containing multiple electrodes. Some light may
be thrown upon the phenomenon, however, by certain observations I have made.
When the three electrodes last mentioned are employed and the cell is gradually
exhausted, I have observed, by inaking tests from time to time, that with the fall of
electro-motive force of the cell, while the difference of electro-motive potential
between the peroxide plate and the other plates gradually falls, the difference of
potential between the second and the third plates-to-wit, between the spongy-lead and
the zinc plates remains substantially constant throughout the period of discharge of
the cell, such difference of potential remaining constantly at about one-half a volt.
1 believe that the introduction of this constant into what was before a " variable"
battery contributes powerfully to the staying electro-motive power of the battery,
obviously since a portion of the total current then flowing from the cell is not subject
to variation in its electro-motive force. Taken in connection with the law already
mentioned, that in any cell with multiple electrodes properly arranged the total
electro-motive force of the cell is at all times equal to the sum of the potential
differentials of the respective electrodes in the order of their arrangement, these
observations appear to make evident the general law for guidance that in any battery,
whether "reversible" or not, in which the cell contains two electrodes, and whose
normal electro-motive force diminishes during continued action, the staying electro-
motive power of the cell is, in general, increased by the addition of another electrode
or electrodes, whose difference of electro-motive potential from either or all of the
other electrodes is more constant, or rather less variable than is such difference of
potential between the original two electrodes. This arrangement of multiple
electrodes in the cell of any battery secures a material advantage over the two
electrode cells for many purposes, especially when a constant continued electro-motive
force is desirable. The details of arrangement may be varied in the great variety of
batteries and in many ways without departing from the principle of my
invention.

page_text: Thus in the cell containing the three electrodes already repeatedly mentioned the
peroxide-of-lead plate may be produced chemically or by the action of a current of
electricity upon red-lead paste, or some other positive electrode may be substituted for
it in the combination, or some other negative electrode may be substituted for the zinc
plate, or a plate of metallic lead may be substituted for the intermediate electrode of
spongy-lead, or a piece of other metal of the proper electro-motive potential may be
substituted, or other electrodes may be added in the order of their relative potential.
In the special case of a storage-battery where the cell is charged by the passage
through it of a current of electricity the power of the cell is greatly re-enforced by
the addition of a third electrode. Thus in the cell before mentioned, with the two lead
grids holding the active material, the addition of a third electrode of zinę both adds
to the electro-motive force of the cell and increases its amperage, thus largely
increasing the total available electrical energy of the battery. This affords a material
re-enforcement to its power over that which is available in its usual form, with only
the peroxide-of-lead and spongy-lead electrodes.
For convenience of designation I term a battery in which the cell contains three
electrodes a "triple-electrode battery." Where four electrodes are combined in the
cell, I term the battery a "quadruple-electrode battery," and, in general, where more
than two electrodes are combined in the cell I term the battery a multiple-electrode
battery."
66
In the drawing the figure is a cross-section of a battery-cell, illustrating a convenient
arrangement where multiple electrodes are employed.
In the figure, H represents a cell, which may be of any appropriate form, and which
contains a suitable electrolyte I. The three electrodes A, B, and are placed in the
cell, preferably upon hard rubber bars, K, resting upon the bottom of the cell and are
separated by hard rubber bars or studs J. The three electrodes are arranged in the
order of their electro-motive potential, the more positive one A upon one side and the
other negative one C upon the other side, with the one of intermediate potentials B
preferably between them. The circuit-wires q are attached to the electrodes A and C,
respectively, and the circuit is completed at W in the usual manner for the per-
formance of any work. Another electrode is shown in dotted lines at D in case four
electrodes are employed, the circuit-wire q in such case being connected with D
instead of C, care being taken to connect the circuit-wires respectively to the two
electrodes at the extremes of the electro-motive potential.
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. As an improvement in electric batteries, a secondary-battery-cell provided with
two or more charged plates and one or more supplementary plates differing in their
respective electro-motive potentials, substantially as described.
2. As an improvement in the art of the production of electricity, the method of
re-enforcing secondary batteries, which consists in adding to the usual electrodes one
or more electrodes of different electro-motive potential, whereby an increase of the
available electrical energy of the cell is afforded, substantially as described.
3. In a battery-cell, the combination of two electrodes provided respectively, with
peroxide-of-lead and spongy-lead, with a third electrode of zinc, substantially as
described.
ليفة
1900
ABEL & IMRAY,
Agents for the Applicant.