Improvements in Secondary Batteries and Electrodes therefor.
Year: 1890

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by GEORGE AUGUSTINE JOHNSON, of 18, Mystic Street,
and SIDNEY LATHAM HOLDREGE, of 9, Harwick Street, both in Boston, Massa-
chusetts, United States of America, Electrical Engineer.]
Improvements in Secondary Batteries and Electrodes therefor.
I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 secondary batteries and electrodes therefor.
The main feature of that part of our invention relating to the battery is the arrange-
ment of the active material in a number of masses, each of which is in the form of a
strip substantially rectangular in cross section, and surrounded on all sides with the
enveloping material; each electrode being made up of a number of metallic boxes
filled with the active material and so arranged and secured together as to form a
compound box divided by partitions into a number of compartments, each compartment
containing a mass of the active material in the form of a long strip, with four sides; and
the enveloping material being perforated to allow proper circulation of the electrolyte.
Another feature of our invention relates to the formation of the outer plates or
electrodes when three or more are used in one cell and consists in making the outer
plates considerably thinner than the plate or plates between them.
A third feature of our invention consists in supporting the plates by two or more
rods of non-conducting material from which the plates are suspended.
In the accompanying drawings,
Figure 1 is a sectional elevation on line 1-1 of Figure 2 of one form of battery
embodying our invention.
Figure 2 is a plan view of the same.
Figure 3 is a sectional elevation on line 3-3 of Figure 2.
Figure 4 is a plan of a box divided into compartments and made from a novel
plate of lead,
Figure 5 is a plan and
Figure 6 a section of the same.
Figure 7 is an illustration in section of an envelope composed of two of the plates
illustrated in Figures 4, 5 and 6, and
Figure 8 is a like illustration of an envelope composed of one of the plates illustrated
in Figures 4, 5 and 6, and a flat sheet.
Figure 9 illustrates a modification.
Figure 10 is a sectional view, enlarged for clearness, illustrating one form of
electrode embodying our invention.
Figure 11 is a sectional view, also enlarged, illustrating our mode of manufacture.
In Figures 1 and 2 we have shown a cell containing seven plates; the plates 1 and 7
are about one quarter of an inch thick, while the plates 2, 3, 4, 5 and 6 are about half
an inch thick. The active material in the intermediate plates is in the form of a strip
which, in the cell shown, is about 5 inches long by three quarters of an inch wide and
nearly half an inch thick. The lead envelope of the intermediate plates is about one-
twentieth of an inch thick and is composed of two sheets of lead each in the form of a
shallow box divided into seven compartments by the partitions a as shown in Figure 4.
Two of these shallow boxes A are placed together after being filled with the active
material, and secured together by a strip a of lead, which is soldered or burned to cause
it to firmly connect the two boxes A as shown. In the cell shown in Figure 1 each
intermediate finished electrode is nearly six inches by five and one-half by one-balf ;
and a cell of seven plates of these dimensions will furnish an out-put of about two
hundred ampère hours.

page_text: The great advantage of the invention is that a very thin envelope can be used while
still maintaining practically abundant strength and stiffness, and a much larger mass
of active material can be utilized for a given weight of envelope.
In practice, an output of ten ampère hours per pound of element has been obtained
from a battery constructed as shown, which is more than double the output obtained
in practice in any other form. The reduction of the thickness of the outer plates 1
and 7 does not reduce the output, while it does of course reduce the weight of the elements.
The stiffness and strength obtained by making the enveloping material in the form of
a compound box or a number of boxes secured together to form a plate is one of the
main advantages of the invention, but the partitions therein which divide the active
material into a number of four sided strips serve as conductors by means of which
the area of contact surface between the envelope and active material is largely increased.
Practically it is desirable to form the perforations with burrs projecting into the active
material, for the same reason.
It will be obvious that the enveloping material may be used in the form of a number
of independent boxes, two of which are secured together temporarily after each is
filled and then a number of these pairs thus filled, arranged together and held by a
strip secured to them, thus making a plate in which the requisite stiffness and strength
and the extension of the envelope into the mass of active imaterial, are provided for,
as in that form of the invention shown in Figure 1.
In Figure 9 we have shown a slightly different form of our invention, the boxes A
being formed each of a rectangular perforated strip of lead folded to form a four
sided tube open at the ends, a number of these tubes are closed at their ends and united
by a strip at one end and by a second strip at the other. This form as will be clear,
also embodies the main feature of our invention, namely the subdivision of the active
material by the envelope which is also arranged to give great stiffness and strength to
the plate; which is in effect a compound box formed of a number of boxes held together.
While we have contemplated several other forms of boxes adapted to be arranged to
form an electrode we prefer the forms shown for constructional reasons but it will be
obvious that other forms may be used which will embody our invention, the main
feature of which is arranging the active material in the form of a long flat strip,
with the perforated enveloping material wrapped closely about it, and forming a
compound box so shaped that it contains a number of four sided strips of the active
material to form the plate or electrolyte.
The seven plates shown are suspended from the rods R R which pass through the
eyes or secured to or formed in the upper edges of the plates, these rods rest at their
ends in notches formed in the wall of the cell, thus leaving the plates suspended in the
electrolyte and at such a distance from the bottom of the cell that they are not liable
to be short circuited by the collection of matter deposited from the electrolyte ; this
being a practical objection to batteries in which the plates are supported directly or
indirectly on the bottom of the cell.
The strip d is connected to the odd numbered plates by the arms d' which are
soldered or burned to their plates and the strip d' is in like manner connected by the
arms d³ to the even numbered plates.
The outer surfaces of the outer plates 1 and 7 are electrically of small service, and
hence need not be perforated, but we find it somewhat better to perforate them.
While we have shown them as plates of the same polarity it will be obvious that
when an even number of plates are used the outer plates will be of opposite polarity,
but that part of our invention which consists in making the outer plate considerably
thinner than the intermediate plates is applicable whether the number of plates in
each cell be odd or even. We find that the odd number is somewhat bettor practically.
The plate shown in Figures 5 and 6 is also new with us. It is best formed by the
familiar lead pipe process, that is the lead is forced out through a die of the proper
shape to make a sheet or strip of the desired width and thickness with the desired
number of ribs upon one side, as clearly shown in Figures 5 and 6. The long strip
thus formed is a new article of manufacture, and is used by first removing the ribs, as
shown by dotted lines æ æ in Figure 5, then cutting the long strip into pieces of the proper

page_text: length, on the line y in Figure 5 then folding up the ends to form a shallow box
divided into compartments as shown in Figure 4 then filling these compartments with
the active material, and uniting two of these boxes as shown in Figure 7 to form
intermediate plates or covering one of them by a sheet of lead as shown in Figure 8
to form an end plate. The sheet or strip is of course properly perforated to allow
the proper action of the electrolyte.
A part of our invention relates to plates or electrodes in which the active material
is contained in an envelope perforated to allow access of the electrolyte to the active
material. Heretofore, in electrodes of this class, the active material has been simply
packed between the sheets of lead forming the envelope, and no provision has been
made for the circulation of the electrolyte through the active material itself; the
electrode being, in fact, a body of active material covered by the lead sheets. We
have discovered that in electrodes of this class; that is, with the active material
between two perforated sheets, a far better result can be obtained by carrying the
perforations through or nearly through the active material.
In the drawings we show a cross sectional view (much enlarged for clearness) of
one form of electrode, embodying our invention in which the lead sheets are marked a',
and the active material; the perforations in the lead sheets are made with prickers,
rather than punchers, because the burrs thus formed are desirable, serving to hold the
active material better, and to increase the surface contact between the envelope and
active material. In applying the active material to the sheets thus perforated, we use
a set of prickers c, which fill the perforations in the sheets and about which the active
material is connected; these prickers caro then withdrawn leaving the active material
with perforations, or deep pits, which are continuations of the perforations in the
envelope a. Obviously the active material may be applied to the sheets before
they are perforated, so that when the perforations are formed they will extend
through the sheets and either wholly or partially through the active material.
In the electrode shown, we use two sheets of lead, each of which is perforated and
has the active material applied to one side, as first above described; but the points
of the prickers for convenience need not extend fully through the active material. The
two plates thus formed are united together as in Figure 10.
The perforations or deep pits in the active matorial & coinciding with the perforations
in the sheets a allow a better access of the electrolyte ; somewhat decrease the amount
of active material; greatly increase the surface contact between the active material
and the electrolyte, and diminish the resistance; the result being that a stronger
current can be used in charging and obtained in discharging.
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 correspondents, I declare that what I claim is:-
First. An electrode for secondary batteries in the form of a compound box, perforated,
in which the active material is in the form of a number of long flat strips, each strip
being in a box of enveloping material, all substantially as described.
Second. In a secondary battery of more than two plates or electrodes, the inter-
mediate plates 2, 3, 4, 5 and 6, of much greater thickness of active material than the
outer plates 1 and 7, substantially as described.
Third. In a secondary battery the plates or electrodes suspended from cross rods of
insulating material substantially as described.
Fourth. A sheet of lead with parallel ribs projecting from one of its sides, as aud
for the purposes specified.
Fifth. In an electrode for secondary batteries the sheets a' with the active material b
between them, the sheets being perforated and the perforations in the sheets being
continued into the active material, all substantially as set forth.
Dated this 15th day of August 1800.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.