Improvements in the Construction of Accumulators or Secondary Batteries.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Construction of Accumulators or Secondary
Batteries.
I, HENRY LEITNER, of 207, Piccadilly, London, W., Electrical Engineer, do
hereby declare the nature of this invention to be as follows;-
This invention relates to improvements in connection with the construction of
accumulators or secondary batteries, and has for its object to provide an accumu-
lator which will be more durable and less likely to get out of order than those
hitherto employed, with also the special advantage of ensuring perfect contact
between the active material of the plates and the carriers under all conditions of
charge and discharge and expansion and contraction.
The main feature of my invention consists in the utilisation in a peculiar manner
of the pressure produced by the expansion of the peroxide plate so as to ensure
that the parts be kept in proper position, and to prevent the lead peroxide from
dropping out of the plates, the arrangement also ensuring a larger contact surface.
The peroxide plate I propose to employ is formed as follows;-A double grid or
frame is employed consisting of two lead sheets of suitable proportions provided
with contact bars or extensions at one side. Each of these plates is formed with
a series of holes which may be hexagonal in shape. These are stamped from the
plate by cenical dies so that the sides of each hole are bevelled. The hole is thus
slightly larger at one side than at the other.
Two of these plates are taken and after they have been filled with the paste or
material from which the peroxide is to be forined, they are placed face to face so
that the larger sides of the holes are at the inside. The plates are also arranged
so that the holes do not register with each other, the bars of one plate crossing
the holes of the other. Owing to the bevelled form of the holes, the plugs of paste
will not be liable to fall out even without the pressure produced in the manner
hereinafter described.
The peroxide I propose to employ is made from porous lead as described in my
Specification No. 780 January 11th. 1896 for "a new or improved method of
manufacturing electrodes for secondary electric batteries."
On one side of each plate separating pieces of elastic material such as celluloid
are fixed arranged parallel, three being preferably employed in plates of ordinary
size but a larger number may be used. These separating pieces which are used to
transmit the pressure as hereinafter described and not merely as distance pieces,
I prefer to make of triangular shape in cross section and generally hollow. This
form allows the sides of the pieces to bulge out on transverse pressure being
applied tending to press the plates together. As the material is elastic any com-
pression which may occur will not permanently change the shape of the bars,
but these will spring back again into their normal shape on the pressure being
relieved. A series of plates so constructed are placed together, the surface of one
plate resting against the separating rods or tubes of the other.

page_text: On both sides of the series or block of plates so formed, a plate of impregnated
wood or other suitable material is placed. This is preferably grooved at two or
more parts and in the grooves bands of the elastic material above described are
Etted. The bands are continuous and of considerable width to give the required
strength. When the arrangement is complete a solid mass is formed, the plates
being pressed closely together, separated only by the elastic tubes or bars.
Instead of the bands above described, bolts and nuts may be used, the bolts
passing through the plates and the nuts bearing upon the outside supporting
plates. These bolts and nuts are made of any suitable material which possesses
the required strength and resiliency, celluloid, vulcanite, wood fibre, or other
similar material being used.
The material requires to possess considerable strength and to stretch very little
for a large pull so that the amount of expansion which occurs in the accumulator
will cause a very powerful reaction which presses the balves of the plates tightly
together. When the peroxide in the plates expands, its tendency will be to cause
the two sheets or perforated plates of lead of which each plate is built up to
separate, this action taking place owing to the bevelled forin of the holes, and
the fact that the plates are placed back to back and are fixed together at the
edges only. Each plate will thus bulge slightly out on both sides so as to become
thicker and increase the length of the block of plates formed as above described.
This expansion is resisted by the outer bands or bolts and the separating pieces
and as these are all resilient they will give slightly to the great pressure produced
by the expansion. The expansion owing to this back pressure will thus cause the
peroxide plugs to be pressed firmly against the lead grids giving the largest
possible conducting surfaces.
Any slight side expansion of the grid which may occur is taken up by a frame
around the plate which may be of celluloid connected by resilient material.
The frame consists of a rim of resilient material extending around the frame
and protecting the lug. To this rim is fixed side strips on both sides of the plate
encircling the edges of the latter. Below these strips perforated sheets may be
fitted so that the plate is completely enclosed, but these may be dispensed with.
The bars are fixed to the strips at their ends and a cross piece is also fixed at the
centre extending transversely. The bars and transverse strip thus take up the
side expansion of the plate. At the same time the conducting lug is protected
from the solution as it is completely enclosed.
As the peroxide contracts instead of the pressure being at once taken off as
would be the case if the parts were not resilient, the extension or compression of
these resilient parts is utilised to recompress the plates until they return to their
former size. The plates are thus again pressed quite flat and the active material
in both plates is still kept tightly against the grid. The peculiar formation of
the grids enables this action to take place as the expansion does not tend so much
to open the holes and thus to be transmitted sideways, but only slightly separates
the two plates against the force of the binding material of the whole block.
The peroxide I employ expands to a far greater extent than the peroxide com-
monly used and this increased expansion is utilised by the arrangement above
described to render the whole accumulator more efficient as the peroxide is thereby
compressed with greater force against the grid.
This arrangement also allows a large number of thin plates to be employed
instead of a smaller number of thick ones, as in the present construction of
accumulators. A greater surface is thus provided which substantially increases
the efficiency of the accumulator. At the same time the block of plates formed
in the manner described is quite solid and will not be injured by rough usage,
whether mechanical or electrical,
As applied to zinc accumulators sufficient space is left between the separating
pieces to allow of the zine plates being inserted. These zinc plates are constructed
so that they are quite free from pressure being held in parts by means of insulat-
ing pieces which do not however bear upon the zinc. These plates are formed

page_text: The
with cores of celluloid or like material which extend a little beyond the ends of
the lead on which the zinc is deposited. This lead base surrounds these plates
of celluloid so as to form a sheath, slightly shorter however than the core.
contact bars are formed from extensions of this lead projecting above the top of
the core, a central strip of lead being inserted between the two sides of the exten-
sions to form a proper bar.
The projecting parts of the core are provided with small blocks of celluloid or
other insulating material, which serve as distance pieces. When these plates are
dropped in between the peroxide plates, these distance pieces bear against the
plates and keep the zinc entirely clear of any contact. There is thus no danger of
zinc being deposited from the solution on any part, such deposit generally taking
place when the zinc plates are in contact with any external part.
As an accumulator of this kind is adapted to discharge very rapidly if desired,
without danger of injury, the contact hars require to possess a very low resistance.
In order to obtain bars of this kind without great weight, I propose to form each
bar with a core of copper. This core is entirely concealed so that there is no
danger of its being attacked, the lead being placeil or cast around it and a proper
joint made. The bar will thus possess a high conductivity and will not be liable
to get heated by large currents, but at the same time will not be heavier than the
ordinary bars.
Hotel this 5th
S
1005
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.
Improvements in the Construction of Accumulators or Secondary
Batteries.
I, HENRY LEITNER, of 207, Piccadilly, London, W., 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 follow-
ing statement:-
This invention relates to improvements in connection with the construction of
accumulators or secondary batteries, and has for its object to provide an accumu-
lator which will be more durable and less likely to get out of order than those
hitherto employed, with also the special advantage of ensuring perfect contact
between the active material of the plates and the carriers under all conditions of
charge and discharge and expansion and contraction.
The essential feature of my invention consists in the utilisation in a peculiar
manner of the pressure produced by the expansion of the peroxide plates reacting
against highly resilient material so that the peroxide itself is formed under great
pressure and is kept under pressure depending upon the amount of expansion.
The result of this pressure is that the peroxide is rendered very dense and of great
strength and is also kept tightly against the conducting parts under all conditions.
In order that the invention may be more clearly understood, reference is had
to the accompanying drawings, which show two forms of accumulator to which
my invention is applied, and in which Fig. 1 is a plan of an accumulator, Fig. 2
is a vertical section of the same taken between two of the plates, Fig. 3 is a cross
section of part of the peroxide plate shown to a larger scale. and Figs. 4 and 5
are respectively a plan and a vertical section of a zinc accumulator.
The peroxide I propose to employ is preferably formed in the manner described
in my Specification No. 780, January 11th, 1890 for a new or improved method

page_text: This
of manufacturing electrodes for secondary electric batteries." Lead oxide is finely
powdered or mixed with a very small percentage, not exceeding five per cent., 01
pure retort carbon. This mixture is treated with glycerine or any other similar
substance capable of forming a chemical combination with the lead oxide.
compound sets like concrete into a hard ass which expands slightly in the
setting, When set it is reduced electrochemically to porous lead in which state
it is strongly compressed by mechanical or other means, and subsequently con-
verted into peroxide the carbon being oxidised out in the process. The resulting
mass is a pure, porous and very highly conductive peroxide of lead of considerable
rigidity. In its formation very great expansion takes place which is utilised in
the manner described later.
I find that this material, especially when subjected according to this invention
to great pressure during its formation into peroxide forms itself a very strong
plate. There is thus no necessity for supporting grids, and the lead sheet carry-
ing the peroxide serves almost entirely for conducting purposes. The plate A
is provided with the perforated lead sheet B of just sufficient thickness to form a
good conductor.
Between the plates parallel pieces or bars of resilient material such as celluloid
or rubber are placed. These bars do not bear directly on the plates but against
the covering hereinafter described, and are used to transmit and take up the pres-
sure produced by the expansion, and not merely as distance pieces. As the
material is elastic any compression which may occur will not permanently change
the shape of the bars, but these will spring back again into their normal shape on
the pressure being relieved or lessened. A number of plates are taken, separated
in the manner described, and inserted in the case I resting on the supporting bars c
which may be of the same material as the separating bars.
The case D serves to hold the plates firmly in place, and I may make this case
of resilient material so that it can take up some of the expansion of the plates and
serve to compress them. Instead of the case serving this purpose separate bands may
be employed. This arrangement is however practically the same but where separate
bands are used impregnated wooden or other acid proof and insulating plates
should be placed at each end of the block. The encircling part, whether case or
band, must be of great strength and stretch very slightly under great pressure.
When the arrangement is complete a solid mass is formed the plates being pressed
closely together, separated only by the elastic bars.
The peroxide plates are placed between the perforated sheets E of celluloid or
other non-conducting material. The celluloid is not fixed to the plate at any
point but merely encloses it. The resilient separating pieces bear against the
enclosing sheets which help to distribute the pressure evenly over the whole plate.
The material of the encircling part and bars requires to possess considerable
strength and to stretch very little that the amount of expansion which occurs
in the accumulator will cause a very powerful reaction, which presses the peroxide
hard against the conducting surfaces. When the peroxide in the plates expands
each plate will become thicker and tend to increase the width of the block of
plates formed as above described. This expansion is resisted by the encircling
part and the separating pieces and as these are resilient they will give slightly to
the great pressure produced by the expansion.
As the peroxide contracts instead of the pressure being at once taken off as
would be the case if the parts were not resilient, the extension or compression of
these resilient parts is utilised to recompress the plates until they return to their
former size.
The peroxide I employ expands to a far greater extent than the peroxide com-
monly used and this increased expansion is utilised by the arrangement above
described to render the whole accumulator more efficient as the peroxide is thereby
compressed with greater force against the conducting sheet or grid.
After the peroxide has once been formed the material of the plate never returns
during the working of the accumulator to the condition of porous lead, but is only

page_text: partially reduced. Thus the original expansion is much greater than any
later contraction and the plate is kept constantly under pressure, which varies,
of course, during the charging and discharging of the accumulator as described.
The formation of the peroxide under great pressure is most important to the effi-
ciency of the plate, the material being rendered very dense and of great strength.
This arrangement also allows a large number of thin plates to be employed
instead of a sinaller number of thick ones as in the present construction of accumu-
lators. A greater surface is thus provided which substantially increases the effi-
ciency of the accumulator. At the same time the block of plates formed in the
manner described is quite solid and will not be injured by rough usage whether
mechanical or electrical.
As applied to zinc accumulators (Figs. 4 and 5) the zinc plates Fare con-
structed so that they are quite free from pressure, being held in parts by means of
insulating pieces which do not, however, bear upon the zinc. These plates are
formed with cores f of celluloid or like material which extend a little beyond the
end of the lead on which the zinc deposited. The lead base partly surrounds
these plates of celluloid so as to form a sheath leaving however projecting portions.
The contact bars are formed from extensions of this lead projecting above the
top of the core a central strip of lead being inserted between the two sides of the
extensions to form a proper bar.
The corners of the core which are outside the sheath, are provided with small
blocks of celluloid or other insulating materials which serve as distance pieces.
When these plates are dropped in between the peroxide plates, the distance
pieces hear against the plates and keep the zinc entirely clear of any contact
There is thus no danger of zinc being deposited from the solution on any part,
such deposit generally taking place when the zine plates are in contact with any
external part. In the special arrangement shown the lead base of the zinc plate
does not extend completely across the celluloid leaving a central exposed part.
The central separating pieces Care fitted at this part at each side and assist in
holding the zinc plate.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
(1) In accumulators or secondary batteries of the kind described forming the
peroxide plates under great pressure produced by the expansion of the plates dur-
ing the conversion into peroxide reacting against highly resilient material, the
whole process taking place in the cell itself.
(2) In accumulators or secondary batteries formed from a series of flat plates
the utilisation of the pressure produced by the expansion of the plates by means
of separating pieces of strong and highly resilient material placed between the
said plates and hands or encircling parts of great strength to return the plates to
their normal position and shape on contraction and to ensure a thorough contact
between the active material and the conducting parts, substantially as described.
(3) In accumulators or secondary batteries the combination with a series of flat
plates, of separating bars fitted to the plates in a parallel manner and separating
each pair of plates and binding or encircling parts. both binding and separating
parts being of highly resilient material adapted to take up the expansion of the
plates and to utilise the expansion in compressing the plates, substantially as
described.
(4) In accumulators of the kind described the combination of a series of flat
plates and perforated covering sheets of non-conducting material enclosing the
plates, with separating bars between the said plates and binding or encircling
parts, both binding and separating parts being of highly resilient material,
adapted to take up the expansion of the plates and to utilise the expansion in com-
pressing the plates.

page_text: (5) In accumulators, the combination with peroxide plates, separating pieces of
highly elastic material placed between the said plates, and encircling parts binding
the plates firmly together, of zinc plates having a core of celluloid or like material
and distance pieces or blocks carried by the said core and clear of the zinc, the zinc
plates being placed between the resilient separating pieces, substantially as
described and for the purposes specified.
Dated this 25th day of August 1898.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.