Improvements in Secondary Batteries.
Year: 1890

page_text: Date of Application, 18th Oct, 1890-Accepted, 22nd Nov., 1890
Improvements in Secondary Batteries.
We, CHARLES WESLEY KENNEDY and HENRY GROSWITH both of 1430 South
Penn Square Philadelphia in the State of Pennsylvania, United States of America,
Inventors, 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 :-
Figure 1 is a perspective view of our secondary battery.
Figure 2 is a longitudinal sectional view of the same, on a vertical plane.j
Figure 3 is a vertical sectional view on the transverse plane indicated by the broken
line marked x-x in Figure 2.
Figure 4 is a similar view, but taken on the parallel plane indicated by the line
marked y-y.
Figure 5 is a sectional view on the horizontal plane indicated by the line
marked z-z.
Figure 6 is a perspective view of the inner side of one of the plates from which the
electrodes are built up.
"double"
Figure 7 is a sectional view, on a transverse vertical plane, illustrating a modified
construction of the electrodes which we adopt in building what we term a
battery..
Figure 8 is a perspective view of the upper part or portion of one of the electrodes
employed in building our "double" battery, showing the connections on opposite sides
of the electrode..
Figure 9 is a view illustrating the manner of building up the battery from a
number of previously prepared electrode "grids" or plates.
Figure 10 is a perspective view of one of our improved plates, used in building up
our improved grid or electrode; said plate being composed of thin rigid material
coated with metallic lead.
Figure 11 is a sectional view through one of the complete grids or electrodes, at
right angles to the same.
Figure 12 is a sectional detail view of one of the improved plates, two of these
plates being necessary in the construction of each separate grid or electrode ; and
Figure 13 is a similar view, illustrating a slightly modified construction of the
plate.
Our invention relates to electrical secondary or storage batteries of that class or
type on which the so-called "active" material is held in place by and between
perforated plates or "grids" made of lead or other suitable material, two of these
plates, with the active material between them, constituting one element. or
"electrode" in the battery; and our improvements have for their object to improve
such batteries in the following particulars, viz.: to prevent short-circuiting of the
battery by the bending or so-called "buckling" of the plates; to make it optional
whether to use the "active material" in a powdered (dry) or in a plastic form; to
increase the capacity of the electrodes for active material and thereby proportionately
increase the electrical storage capacity of the battery as a whole; to so construct the
electrodes that the inside active material will be retained firmly in its place and
prevented from displacement in any direction; to so construct the electrodes that,
by simply inserting a thin sheet of insulating material between the two plates each
pair of plates will form what we call a "double" electrode; and, finally, to simplify
the construction of the battery as a whole, and build up a secondary battery of great
storage capacity combined with a minimum of weight. With these several objects in
view, our improvements consist, first, in the construction of the elements or electrodes
separately considered, and, secondly, in the construction and combination of parts of

page_text: the complete battery, resulting, as above stated, in the production of a storage battery
wherein the following three important conditions will be found combined in an
imminent degree, viz.: 1st, great electrical storage capacity; 2nd, lightness of weight
in proportion to the size and capacity of the battery; and, 3rd, durability, simplicity
and cheapness of construction.
It is also the purpose of the invention to construct the metallic plates or walls,
between which the so-called "active material" is confined, not wholly of lead, as has
heretofore been the practice, but of some other metal which is stiffer, lighter, and
less expensive than lead, such, for example, as thin iron, steel, or any other metal
which possesses sufficient stiffness and rigidity when rolled or beaten into thin plates,
which plates (themselves neutral or inactive) are then coated with a thin film of pure
metallic lead. In this manner, by forming an interior thin body-plate, or skeleton-
plate, and coating the same with metallic lead, (in other respects constructing the
lead-coated plate in any of the numerous ways in which such plates are made in the
construction of the so-called "grids") I am enabled to make grids or electrodes which
will weigh considerably less than any grids having the same amount of active super-
ficial area, which it will cost less to produce than grids of the same capacity made of
pure lead; while, at the same time, our improved electrodes will be found capable
of "forming" and developing the same amount of energy as electrodes, the grids of
which are made wholly of lead and some active material and which present the same
superficial area to be acted on by the exciting liquid.
of
Referring to Figures 1 to 9 inclusive of the drawings we have illustrated a battery
consisting of seven electrodes, each electrode being composed of two plates or "grids
with active material between them; but it is obvious that the number of electrodes
may be varied at will, and their number either increased or decreased, according to
the capacity desired for the battery in any given case. Each electrode is built up
two plates, A and B, of lead, or other suitable material (preferably made by casting
in a suitable mould), and an intermediate layer of "active material," C, which may
be litharge, red lead or minium or any other material adapted for the purpose, either
in a dry or plastic state.
The plates or "grids" A and B being alike, they may be cast in the same mould,
each plate being cast on its face or outside with knobs or protuberances D, arranged
in parallel rows, and on its inner side, facing the layer of active material, with a
raised flange or edge, E, so that when the two plates and B are placed upon each
other in building up the electrode, a hollow space or chamber, F, will be formed
between them, which is closed on all sides by the inwardly projecting flanges E and
forms a receptacle for the active material C.
The edges of the electrode plates A and B are cast with registering bolt-holes, G,
said bolt-holes being reinforced by a web, H, formed by extending the thickened
edge or flange E inwardly around them (see Figure 6). Each plate is further
provided with rows of apertures, I, arranged alternately between the knobs or
protuberances D; a portion of the metal which is displaced in drilling these apertures
being upset on the inner face of the plate so as to form a burr or roughened edge
encircling each aperture I, as illustrated more clearly at J, in Figure 6. In order
to form this boss or burr on the inside of the plate around the apertures I, we prefer
to drill said apertures through the plates in pairs, by placing two plates A and B,
upon each other in the same relative position in which they are in the finished
electrode, i.e. with their inner flanges E H resting upon or bearing against each
other, so as to form a hollow space between the body of the plates; and by now
drilling the holes I while the plates are in this position, room is left on their inner
sides facing each other, for the burrs J to be formed around each aperture by the
metal which is displaced from the plate in drilling the hole. As these burrs or bosses
have an important function, we have been thus particular in describing one way in
which they may be formed, although we do not limit ourselves to this or any other
particular means or method of forming the apertures or the circumferential burrs on
their inner sides.
grids" A B have been cast, drilled and finished, they are
After the plates or "

page_text: placed in a flat position upon a bench or table with the flanged sides upwards, and
the shallow chamber or compartment F is packed with the active material (e.g.
litharge) either in the form of a dry powder, or it may first be made into a paste, if
desired. We have found by actual experience that there is no need whatever to pack
the plates with the active material (whatever this may be) in a plastic state, and we
prefer to use the litharge or minium (or any other suitable material selected for the
purpose) in the form of a coarse dry powder; and it is here where the inside burrs or
protuberances J come into play, because they serve to retain the powder so that it
will not easily sift out through the apertures in the plates, neither will it (if properly
spread and packed in the first instance) become dislodged so as to drop to the bottom
of the plates; but it (the active material) will be found to maintain its proper
position between the plates even though the battery is subjected to much jolting and
other rough usage, as, for example, when the battery is used as a motor for street
cars over rough and uneven tracks.
After the plates have been filled with the tightly packed and compressed active
material C, the battery is built up as illustrated in the sectional view Figure 9, that is
to say, we commence by placing the filled bottom plate A, flat on the table, inserting
a bolt, K, vertically through each of its reinforced bolt-holes G, each bolt K having a
nut L, of hard rubber or other suitable insulating material. Next, the mate B of
plate A is placed upon the latter (all the plates having been first filled with the active
material) but in an inverted position, so that the filling C, of the two plates will merge
together and form one homogeneous and compact flat body of active material, con-
fined in the compartment F between the two flanged and perforated plates A and B ;
said two plates A and B constructed as described, with their intermediate filling C,
constituting one of our improved electrodes.
The next step is to properly space and insulate, this first electrode from the one
which is to be built adjacent to it, and this we accomplish by placing insulating
washers, M, upon the knobbed surface of plate B at suitable distances apart from one
another. These washers (preferably of hard rubber or vulcanite) are disposed upon
the plate around the knobs or protuberances D, so that said knobs will form a central
hub or bearing for the washers placed around them. When the third plate A, (which
is the first plate of the second electrode) is placed in position by slipping it, by means
of its bolt-holes G, over and upon the upright bolts K, it will be found that its
knobs D, registering with the corresponding knobs of plate B below, will enter the
washers M from the other side; said washers being of sufficient depth to prevent the
contiguous or opposite points of the knobs, which project into them from opposite
sides, from touching each other. Thus it will be seen that in addition to the other
functions hereinafter ascribed to them, the knobs or protuberances D (which are
integral with the plates) operate to hold the insulating and spacing washers M firmly
in position between the pairs of plates, preventing them from displacement both in a
longitudinal and lateral direction.
This process of building up the plates A and B in pairs, and separating each pair
by the interposed insulating washers M, is repeated until a sufficient number of
electrodes have been placed in position to form a battery of the desired capacity; the
bolts K serving, during this process of building up the battery, as guides for the
plates A and B as these are successively placed in position in the battery, so that
the outwardly projecting knobs D on adjacent electrodes will be immediately opposite
to each other. After the last plate has been placed in position, the series of electrodes
are bound firmly together, and, at the same time, the two plates of each electrode are
bound firmly together, by nuts L, of insulating material, being screwed up upon the
projecting threaded ends of the bolts, so as to bind the whole firmly and compactly
together, when the battery (after first making the proper connections) is ready for
"forming" or charging in the usual well-known manner.
It should have been stated that, in building up the battery in the manner described
and illustrated on Figure 9, insulating washers M, are also placed around the bolt K
between the electrodes, for the purpose of, in conjunction with the washers M around
the knobs, properly spacing the electrodes and prevent contact between them.

page_text: The connections between the elements of the complete battery are formed in the
usual manner, by connecting the oxygen elements to one another by means of their
tongues and a connecting strip P, and similarly connecting the hydrogen elements
to one another by means of their tongues or extensions Q and a connecting strip R;
the terminal of the strip P forming the anode and that of the connecting strip Ŕ the
cathode of the battery.
If it is desired to build what we term a "double" battery, then, during the process
of building up the battery, a thin sheet of hard rubber or other suitable material S,
is placed between each pair of electrode plates A and B (see Figures 7 and 8), the
insulating sheet S being clamped firmly between the flanges E of the plates and
provided with holes around the edges for the insertion of the binding-bolts K. In
that case, each plate, instead of each pair of plates, is provided, on opposite sides or
in opposite corners, with its appropriate connecting tongue T, as, in that case, one
side forms the oxygen and the other the hydrogen element in the electrode, separated
from each other by the intermediate insulating plate or diaphragm S. In building
this form of battery, a different filling of active material is used for each plate of a
pair, a filling of red lead being used for the oxygen (anode) side of the electrode, and
of litharge for the hydrogen (cathode) side. While this construction of a "double
battery increases the electrical resistance, yet it will be found to increase the storage
capacity and energy of the battery in a still greater ratio, showing a clear gain in
energy and storage capacity over a "single" battery containing the same number of
electrodes and of the same weight.
6.
"
We have already seen that one function of the knobs D which are cast upon the
plates is to serve as means for retaining the intermediate washers M in place between
the electrodes; but, in addition to this, they have other important functions. Thus,
they increase the superficial area (and consequently the storage capacity) of the plates
and they also effectually prevent contact of the active material in adjacent electrodes,
even if the plates should bulge or
" buckle "at any point between the intermediate
spacing-washers M. If such buckling" should take place, it will simply result in the
points of the knobs on one plate striking the points of the registering knobs on the
plate opposite, so that the flat bodies of the plates cannot touch under any
circumstances, nor can the active material of one plate touch that of the adjacent
plate, so that short-circuiting between the plates by reason of contact between the
active material with which they are respectively charged is impossible. Again, should
any of the active material between a pair of electrode plates escape through the
apertures in the plates and run down the outside of the plates, it will be intercepted,
arrested and accumulate upon and around these knobs and thus serve a useful purpose,
instead of scaling off and falling to the bottom of the vessel in which the electrodes
are immersed.
By making the flanges E thin or narrow around the inner edges of the plates,
except where the bolt-holes G pierce the plates, we increase the capacity of the
chamber F for active material, the whole inner area being covered with this material
with the exception of the space occupied by the narrow flange E and reinforcing
webs H surrounding the bolt-holes. This construction also materially reduces the
weight of the plates by doing away with all superfluous or non-active metal.
In order to prepare my improved plates coated with metallic lead and illustrated on
Figures 10 to 13, we first take a thin sheet or plate of steel, iron, aluminium or any
other suitable metal, or other material. This plate is represented by the black part
marked with the letter A in the figures, and is what forms the inner body, skeleton, or
stiffening of the complete plate. This skeleton-plate A, is punctured or perforated
(preferably by punching or drilling) so as to present rows of apertures 1; and the
boit-boles, shown at G, are also formed at this stage, and before the plate receives its
coating of lead. After the plate A has been prepared in this manner, to give it the
outward resemblance or appearance of an ordinary grid-plate, we cover it with a thin
film or coating of pure metallic lead, shown at X, in such a manner that the film of
lead wil not only completely and absolutely cover the flat sides or surfaces of the plate
on both sides, but also the edges of the plates. and the edges of the bolt-holes and

page_text: apertures I, so that no part of the body of the skeleton-plate A, itself, however minute,
is devoid of covering. It is of the utmost importance that the lead covering. or
coating be absolutely integral and perfect; hence, the necessity of making all
apertures and bolt-holes in the skeleton-plate before it is coated with lead, as, if the
plate received its lead coating before being punctured, the drilling or punching of
the holes would rupture the film of lead and expose the material of which plate A,
itself is made; the object of the apertures I, being to afford access of the acid solution,
into which the electrodes are immersed, to the "active material," C, which is confined
between the plates. But by perforating the plates before they are covered with the film
or lead, then this film (assuming that proper care is taken in the process of manufacturing
the plates) will cover and protect even the most minute part of the inside skeleton-
plate A.
It is also of the utmost importance that the lead film X, should adhere tenaciously
to the plate A, so that it will not peel or scale off, but will at all times adhere firmly
to plate A. I have found by experiment that we can coat a plate of iron or steel with
absolutely pure metallic lead in such a manner that this thin lead coating cannot scale off
or peel off, no matter how rough the usage to which the plate may be subjected; and
we have also found that the capacity (ie., development of electrical energy) of the
electrode does not depend upon the thickness or depth of the lead coating, as, in a
properly constructed secondary battery, no action takes place in the body of the plate
itself, but only on the external surface of the lead, and in the peroxide C, which is
confined between the plates, and which is what constitutes the so-called active
material," in contradistinction of the plates themselves, which are, by comparison,
"inactive," and the object of which, in this class of electrodes, is merely to confine, or
form a foraminated casing for, the active material.
+
In Figure 13 of the drawing, we have shown the skeleton-plate, A, provided with
an intermediate casing Y, of tin, which in its turn, is coated with the lead film X.
This construction of the plate may be employed advantageously where the skeleton-
plate, A, is made of some metal which cannot easily be coated or plated with pure
metallic lead without the use of a flux. As is well known, it is important that the
lead covering, which is exposed to the action of the acid solution, should be made of
an absolutely pure metallic lead, in order to enable the electrode to "form" readily,
and we have found that it affects the plates injuriously if the lead, which is to form
the exterior coating, contains any flux or other foreign substance. For this reason, in
all cases where the inside skeleton or frame-plate A, is of some material which cannot
be plated with lead, it will be found that the lead plating or coating may readily be
applied by first" tinning" the plate, or electroplating the same, and afterwards coating
the tinned or electroplated plate A, with pure metallic lead.
In this manner it will be seen that we greatly reduce the weight of the side plates
between which the "active material" is confined, without in the least detracting from
the storage capacity, energy, or efficiency of the electrode, as it is a well-known fact
that only the actually exposed surfaces of these plates enter into play, whereas the
inner body of the side-plate itself is absolutely inert. Yet, owing to the softness and
ductility of pure metallic lead, it has been found impracticable to make these side
plates of the compound electrode very thin, as such thin plates, if made wholly of
lead, would bend or break; but by our invention, that is to say, by constructing a
compound or lead-plated side-plate in the manner herein before described, these plates
may be made very thin indeed (almost as thin as ordinary writing paper), thereby
very greatly reducing the weight of the complete electrode, and yet make it susceptible
of receiving the same charge, and of developing the same electrical energy, as if the
compound side-plate were made wholly of lead.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:-
1. A plate or "grid" for use in and as a component of the electrodes of a secondary
or storage battery, consisting of a plate of lead or analogous material having outwardly

page_text: projecting knobs or projections integral with the plate and arranged in rows or series
alternately with apertures having raised burrs or bosses surrounding them on the
inner or smooth side of the plate, substantially as shown and set forth.
2. A plate or "grid" for use in and as a component of the electrodes of a
secondary or storage battery, consisting of a plate of lead or analogous material having
outwardly projecting knobs or projections integral with the plate; apertures disposed
between and alternating with said knobs and having raised burrs or bosses encircling
them on the inner side of the plate; and provided on its inner side with a raised
flange around the edge, said flange being enlarged laterally, or into the body of the
plate, at the points where the holes for the connecting bolts pass through the plate ;
substantially as and for the purpose set forth.
3. An electrode for use in a secondary or storage battery, composed of two perforated
plates of lead or analogous material having outwardly projecting knobs or studs
integral with the plate and inwardly projecting annular raised burrs or bosses on their
inner sides encircling the perforations, and filled with active material confined between
the perforated faces of the plates and raised flanges along the inner edges of the
plates substantially as shown and set forth.
4. An electrode for use in a secondary or storage battery, composed of two
perforated plates of lead or analogous material having raised flanges along their inner
edges; a partition or diaphragm of insulating material clamped between said flanges
and separating the plates, a layer of active "oxygen" material between said insulating
partition and one of the plates; and another layer of active "hydrogen material
between the other side of said insulating partition and the other perforated plate ;
substantially as and for the purpose shown and set forth.
"
5. The combination, in a secondary or storage battery, of the electrodes having integral
knobs projecting from their outer surfaces; non-insulating washers disposed between
pairs of electrodes around registering knobs; and the bolts and nuts for binding the
electrodes together to form the complete battery; substantially as shown and set
forth.
6. The herein described means for supporting non-insulating washers between the
electrodes of a secondary or storage battery, which consists in providing said electrodes
with projecting integral knobs, adapted to project into the intermediate tubular
washers from opposite sides and thereby support the same upon and between pairs of
electrodes; substantially as shown and set forth.
7. An electrode for electric batteries, consisting of two or more plates of rigid
metal coated on both sides with metallic lead, said plates being connected together with
an intervening space filled with "active material," and provided with apertures for
the passage of the exciting liquid, substantially as shown and described.
Dated this 17th day of October 1890.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.