Improvements in the Method of and Apparatus for "Forming" or Charging Plates for Electrical Accumulators.
Year: 1889

page_text: Date of Application, 1st Oct., 1889-Accepted, 2nd Nov., 1889
COMPLETE SPECIFICATION.
Improvements in the Method of and Apparatus for "Forming" or
Charging Plates for Electrical Accumulators.
I, STANLEY CHARLES CUTHBERT CURRIE, a subject of the Queen of Great Britain,
but now residing at the City of Philadelphia, in the County of Philadelphia, and
State of Pennsylvania, Electrical Engineer, 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:-
Heretofore in the construction of plates to form the electrodes or elements of
secondary or storage batteries it has been customary to take the salt of a metal, such
for instance, as the oxide of lead, red-lead, litharge, in a pasty or granular mass and
press it in the form of plates or sheets into perforated or other supports.
to
Still another method that has been practised is that of reducing by electrolysis, a
pasty mass of sulphate of lead to a similar condition or form. Plates thus produced
by either of the above-mentioned methods require no additional treatment to cause
them to arrive at a condition to constitute the positive elements of an accumulator
of electrical energy, but the plates which are to become the negative elements thereof
have to undergo a process of
" formation or conversion of the pure lead of which
they are composed into a peroxide state.
"
As is well understood such metal in taking up its relative chemical equivalent of
oxygen increases sensibly both in bulk and weight and consequently the negative
plates during their "formation "increase in bulk and the general tendency is to
expand in all directions. Of course such expansion depends upon the degree of
porosity and the compactness of the mass, from which the plate is "formed "in the
first instance, and the proportion thereof capable of being converted into the peroxide
state. As is well known the expansion of the lead, the material commonly used for
accumulator plates or elements, is greatest when the mass is most porous.
The principal object of my invention is to produce "formed negative elements
for electrical accumulators having a hard, compact, uniform and homogeneous body.
This end is attained by a novel method of "forming" the plates by which they are
prevented from expanding outward and particularly in the direction of their planes
and in which the expanding force is expended within the plate itself, which expansion
exerts a uniform and even pressure throughout its body, thereby increasing its density
without correspondingly increasing its bulk.
A further object of my invention is to provide a cheap, simple and efficient
apparatus in which the parts thereof can readily be assembled and separated and so
that the plates to be "formed" may be held during the process of "formation "
rigidly and firmly against expansive action, whereby hard and compact plates or
elements of uniform density are produced.
These ends are accomplished by surrounding the active material in the form of a
plate or sheet with a flange, bead or rim adapted to be readily inserted into or
removed from an enclosing frame, in which the same is held during the process of
"formation" and the electrical connections attached to the frame in such manner
that the plates can be readily removed or inserted without necessarily connecting the
same up every time as has heretofore been the case. A tag on the plate is provided
extending beyond and across the same for the usual terminal connection.
The above-mentioned compound plate is arranged in a suitable tank alternately
with the ordinary positive plates of an accumulator separated from the negative plates.
by an insulated sheet, board or plate containing numerous transverse perforations and
also corrugated vertically to permit of the free circulation of the electrolytic fluid
and the escape of gases generated in the process of charging the plates.

page_text: The respective positive and negative plates or elements are mounted in a tank and
securely locked therein by suitable wedges or other equivalent fastening devices.
In the accompanying drawings is illustrated apparatus embodying the essential
features of my invention susceptible of carrying out my method of forming" plates
or elements for an electrical accumulator; and in which,
"
Figure 1, is a vertical longitudinal section of a cell or tank with a plate to be
formed mounted therein.
"
Fig. 2, is a vertical transverse section of the apparatus on the line, a, of fig. 1.
Fig. 3, is a top or plan view in detail of the respective plates mounted in the tank
and showing the mode of connecting up the several plates; and
Fig. 4, is a view in detail of one of the grooved and perforated insulating plates
for separating the positive and negative elements from one another in the process, of
"formation" and in said figure a face view of the plate being shown as well as a
cross-section therethrough.
Referring to the drawings A is a cell or tank of any preferred construction
containing a suitable electrolytic bath in which the plates are immersed, with their
lower edges resting upon insulating rods G. The negative elements or plates (), are
provided with stiff beads, flanges or rims c, of the same metal or material as the
plates themselves, and they are enclosed within rigid frames D, of any suitable
construction and material such as lead, closely surrounding the edge of the plates.
The casings or frames D), constitute contacts or electrodes for the terminals of the
circuit and thus avoid the necessity of constantly connecting them up each time a
plate is changed.
When an ordinary lead lined tank is used, the frames are wedged against the
lining so as to maintain electrical contact. When, however, an insulated lining is
used for the tank, the connections must be made across the same by suitable
conductors. A good way of carrying out such method is illustrated in fig. 3, in
which the wires e, are connected with the frames in horizontal loops, thereby permitting
the plates to be slid in and drawn out of the frames in a vertical direction. The tops
of the frames being constructed so as to be readily removed. The beaded plate and
enclosing frame is termed a 16
compound plate" in contradistinction to the plain or
positive plate or element. The usual tags f, project from the rim c, through slots or
apertures g, in the frame D.
The plates C and frames D, constituting said "compound plates" are then inserted
into the tank alternately arranged between the usual positive plates or elements E,
but separated therefrom by plates or rods G, of suitable insulating material. These
insulating plates or rods G, are by preference perforated hoth horizontally and
transversely and corrugated or grooved in vertical directions as illustrated for instance
in fig. 4, to permit not only of the free circulation of the electrolytic fluid along the
corrugations and through the perforations of the insulating plates, but also to afford
the free escape of all gases.
The two systems of plates mounted in the tank or cell are firmly held to position
therein by means of keys or wedges F, inserted between the sides and ends of the
plate and walls of the tank or cell or they may be held in such position by other
equivalent means or insulated devices.
The negative plates or elements are "formed " or converted into the peroxide state
by the passage of a current of electricity in a well understood manner and as the
respective plates are rigidly held in proper position at ther edges by the frames D,
and wedges F, and to some extent at their sides by the insulating plates G, the
expansion accompanying the "formation" of the plates expends its force within the
body of the plate itself, resulting in the production of strong, compact, unwarped
plates of uniformi consistency.
I am aware that salts of lead in the form both of oxides and sulphates have been
subjected to external pressure with or without the addition of steam, and therefore, I
do not claim broadly subjecting accumulator plates to pressure. My invention is,
however, discriminated from former processes by the fact that lead in its reduced

page_text: spongy condition or form, that is, pure spongy lead, is taken and formed into plates,
which are prevented from expanding outwardly, so that the distinguishing characteristic
feature of my invention over prior methods resorted to, is to cause the expansive
action of the material during the process of "formation" to condense the plate
instead of having to subject it to mechanical pressure from an external source.
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 "forming" elements of electrical accumulators,
which consists in converting the plates into the peroxide state while confined against
expansion, substantially as and for the purposes set forth.
2. The herein described method of "forming" elements of electrical accumulators,
which consists in converting the plates into the peroxide state while confined at their
edges against expansion, substantially as and for the purposes set forth.
3. The herein described method of making plates or elements for electrical
accumulators, which consists in reducing a metal to a soft spongy state and then
forming the same while confined against expansion, substantially as and for the
purposes set forth.
4. The herein described method of making plates or elements for electrical
accumulators, which consists in condensing the mass constituting the body of the
plate by the force exerted in the expansive action of the "forming" process itself, in
contradistinction to external mechanical pressure, substantially as and for the purposes
set forth.
5. The combination of a plate of active matter, its rim and the detachable enclosing
frame, substantially as and for the purposes set forth.
6. The combination of the detachable enciosing frame, the plate of active material,
its rim and tag extending beyond the enclosing frame, substantially as and for the
purposes set forth.
7. The combination of a plate of active material, its enclosing rim, the closely
fitting detachable enclosing frame and the electric circuit connections constituting it
an electrode, whereby the plate may be removed or inserted without affecting the
electrical contacts of the elements, substantially as set forth.
8. The combination of a series of compound negative elements composed of plates
of active material with rims and enclosing frames and interposed plain plates
constituting the positive elements, substantially as and for the purposes set forth.
9. The combination of compound negative plates, the positive plates and the
interposed grooved and perforated insulating plates, substantially as and for the
purposes set forth.
10. The accumulator plate "forming" apparatus, consisting of the cell or tank
containing a fluid, the elements or plates, the insulating plates and the wedges for
locking the removable parts in position, substantially as and for the purposes set
forth.
Dated this 2nd day of May A n 1890
STANLEY CHARLES CUTHBERT CURRIE.