Improvements in and relating to Electric Accumulators.
Year: 1895

page_text: Date of Application, 24th Jan., 1895
Complete Specification Left, 4th Oct., 1895-Accepted, 9th Nov., 1895
PROVISIONAL SPECIFICATION.
Improvements in and relating to Electric Accumulators.
I, OSCAR PIRSCH, of 97 Rue Saint-Laurent, Liège, in the Kingdom of
Belgium, Electrician, do hereby declare the nature of this invention to be, as
follows:-
:-
My invention relates to electric accumulators.
Up to the present time the theory of the electric accumulator has led electricians
to construct these apparatus entirely with regard to the exterior surface, that is to
say to make the electrodes of comparatively thin plates but offering a large external
surface for a given weight. The proof of this is that the capacity is calculated
per square decimetre or square inch of surface. Hence a cumbersome volume and
a restricted capacity, considering the small quantity of active material which may
be arranged either by electric means or by mechanical means upon the two faces of
the electrodes.
The improved arrangement of accumulator plates hereinafter described has for
its object to obviate this inconvenience of plates with a large surface by reducing
the volume to a great extent. Moreover it enables the quantity of active material
to be increased at will and the dead weight to be reduced to a minimum, while
adding to its own qualities those of the plates presenting a large surface.
According to my said invention the electrodes or plates of accumulators are
constructed as follows: The conducting part of the electrode, that which serves
for collecting and transmitting the electric energy produced by the active material
applied thereto, is composed of a sheet of metal or a metallic alloy which can
scarcely be attacked or cannot, be attacked by the electrolyte. This sheet is
surrounded by a frame made of the same metal and forming one piece with it. The
width of this frame may be varied within wide liquids. It has the effect of giving
rigidity to the electrode, preventing the lateral fall of the active material, and
enabling a greater thickness of the latter to be employed than in any other case.
The metallic sheet constituting the collecting core proper is perforated not by a
punch, but by upsetting the metal with the aid of any suitable instrument or tool so
as to produce protuberances or,projections of metal whose height reaches the same
level as the edges of the frame. To the two faces of the collecting core I apply,
without compressing it, the active material of the electrode in such a manner that
its level reaches that of the edges of the frame and of the extremities of the
protuberances or projections of metal produced by, the perforation.
It will thus be seen that this active material is maintained against the core by
the protuberances of the metal whose enlarged or expanded parts recede from one
another and present the appearance of claws. These protuberances are made as
numerous as possible in order to multiply the points of contact of the core with the
active material throughout its depth.
If necessary the frame of each electrode may be kept exteriorly from direct
contact, of, the liquid by, a coating which the, latter cannot attack.
Such accumulator plates are connected by the customary means.
1
From this it will be seen that I may employ a very considerable thickness of
active material without increasing the dead weight of the plate, and despite this
great thickness may realize the best conditions for a good accumulator, and this.
contrary to the theories generally admitted up the present time:

page_text: In fact for the active material to operate with a very great thickness it is
necessary first that it shall be penetrated largely throughout its mass by the
liquids enclosing the reacting materials, which is obtained by not compressing the
active materials; secondly that the reactions shall be effected at the same time in
the whole mass and that the osmotic exchange shall take place rapidly and without
obstructions; and thirdly that the collecting core shall draw into the entire active
mass the electric energy produced by these reactions, which is rendered possible
by the numerous expanded parts of the metallic core.
Accordingly my improved arrangement of accumulator fulfils the required
conditions.
Other inventors have likewise been able to employ a more or less thick layer
of active material upon their electrodes, but the mode of construction and action
of their accumulators did not permit them to exceed a layer of material of from
2 to 3 millimetres in thickness. In fact the active materials are bad conductors
of electricity and if their thickness on the surfaces of the plates exceeds from
2 to 3 millimetres the parts beyond this limit are inert by reason of their distance
from the conducting core and the resistance which they oppose to the electrolytic
action.
It is therefore necessary, in order to diminish this resistance and utilize all the
active material, for the collecting core to bring the electric energy into the whole
mass and by numerous points of contact. I achieve this by the arrangement of
electrodes herein before described. It will be readily understood that if the thickness
of reacting material is to be augmented it will be sufficient that the protuberances
or projections on the core due to the perforations shall be sufficiently prolonged
until they reach the external surface of this layer of material.
Under these circumstances the dead weight of the electrode, that is to say the
weight of the collecting core which does not participate in the chemical reactions
must be lower than in other systems, and that the relation between this weight
and that of the active material is more advantageous for the latter than in any other
accumulator.
In fact the central part of the said core which serves as a collector for the
current may also be as thin as desired; it does not require to have the rigidity
necessary for the other types of accumulators, for the surrounding frame fixes it
in a rigid and invariable position and maintains laterally the active materials,
enabling the thickness of the latter to be increased and leaving to the core its
original thickness. Moreover the active material completely covering the core
prevents the attack of the latter by the electrolytic liquid which first of all brings
its action to bear upon the reacting material.
I therefore completely obviate the numerous inconveniences inherent in the
electrodes whose active mass is surrounded by a perforated metallic sheet which
serves as a collecting core and retains this material.
Dated this 24th day of January 1805
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in and relating to Electric Accumulators.
I, OSCAR PIRSCH, of 97 Rue Saint-Laurent, Liège, in the Kingdom of
Belgium, Electrician, 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 :-
My invention relates to electric accumulators..
Up to the present time the theory of the electric accumulator has led electricians
1

page_text: to construct these apparatus entirely with regard to the exterior surface, that is-to-
say to make the electrodes of plates, comparatively thin, but offering a large
external surface for a given weight. The proof of this is that the capacity is
calculated per square decimetre or per square inch of surface. Hence a cumber-
some volume and a restricted capacity is obtained considering the relatively small
quantity of active material which may be provided upon the two faces of the battery
plates either by electrical or mechanical 'means.
'
The improved construction of accumulator plates hereinafter described has for
its object to greatly reduce the volume of the plates. Moreover this improved
construction enables the quantity of active material to be increased at will and the
dead weight to be reduced to a minimum, while adding to its own qualities those
of the plates presenting a large surface.
In order that my invention may be clearly understood will now describe the
same with reference to the accompanying drawing in which
Figure 1 is a front elevation of a battery plate constructed according to this
invention and
Figure 2 is a vertical section on the line A B; Figure 1.
According to my said invention the accumulator plates are constructed as
follows:-
The conducting part of the plates, viz. that which serves for collecting and
transmitting the electric energy produced by the active material applied thereto,
is composed of a sheet F of any suitable metal or alloy which is only very slightly,
or not at all, acted on by the acid or other active fluid of the battery. The metal
sheet F is surrounded by a frame E made of similar metal and forming one piece
with it. The frame E, the width of which may be varied within wide limits, gives
rigidity to the plate, prevents the active material from falling from the plate and
enables a greater thickness of active material to be employed than with other
constructions of plates.
The metal sheet F is perforated not by a punch, which removes the metal
punched out but by tearing holes in the metal by means of any suitable instrument
or tool so as to produce protuberances or projections P therein; of such'a size that
the front faces of the protuberances P P are substantially on a level with the edges
of the frame E. The curved outer ends of the said protuberances P P are made
somewhat claw-shaped so as to hold the active material in contact with the metallic
core.
To the two faces of the plate F 1 apply, without compression, the active
material M of the plate in a sufficient quantity to cover the plate to such a
thickness that the surface of the active material is on a level with the edges of the
frame and of the extremities of the protuberances or projections P P produced by
the perforation of the metal.
It will thus be seen that the active material M is maintained in contact against
the plate core F by the protuberances P P the enlarged or expanded parts of
which recede from one another and present the appearance of claws as shown in
the drawing. The protuberances P P are made as numerous as possible in order
to multiply the points of contact of the piate F with the active material throughout
its depth.
If necessary the frame of each plate may be kept exteriorly from direct contact
with the active liquid of the battery by a coating which the latter cannot attack.
Such accumulátor plates are connected in the usual manner.
From the preceding description it will be seen that I may employ a very
considerable thickness of active material without increasing the dead weight of the
plate, and despite this great thickness inay obtain the best conditions for a good
accumulator, and this contrary to the theories generally admitted up to the present
time.
In fact for the active material to operate when of a very great thickness it is
Decessary first that it shall be penetrated largely throughout its mass by the active
liquids of the battery; this effect is obtained in my improved plate by not
compressing the active material; secondly it is necessary that the reactions shall
;
·
1

page_text: take place simultaneously throughout the whole mass and that the osmotic exchange*
shall take place rapidly and without obstructions; and thirdly that the collecting
plate shall draw into the entire.activé mass the electric energy produced by these
reactions: These effects arc, rendered possible, by means of expanded parts or
protuberances P P of the metallic core F.
Accordingly in my improved construction of accumulator plates all the required*
conditions are fulfilled.
Other inventors have likewise been able to employ a more or less thick layer of.
active material upon their plates, but the mode of construction and action of their
accumulators did not permit them to exceed the use of a layer of material of
from 2 to 3 millimetres in thickness. In fact the active materials are bad conductors
of electricity and if their. thickness on the surfaces of the plates exceeds from
2 to 3 millimetres the parts beyond this limit are inert by reason of their distance
from the conducting core and the resistance which they oppose to the electrolytic
action.
It is therefore necessary, in order to diminish this resistance and utilize all the
active material, for the collecting core to bring the electric energy into the whole
mass and by numerous points of contact. I achieve this by the herein before.
described construction of the plates. It. will be readily understood that if the
thickness of reacting material is to be augmented it will be sufficient that the
protuberances or projections P P on the core or plate F shall be sufficiently.
prolonged so as to reach to the level of the external surface of this layer of active
material.
Under these circumstances the dead weight of the electrode, that is to say the
weight of the collecting core F which does not participate in the chemical reactions
must be lower than in other systems, and that the relation between this dead weight
and that of the active material is more advantageous for the latter than in any
other accumulator.
i.
The central part of the core F which serves as a collector for the current may be
as thin as desired; it does not require to have much rigidity, for the frame E which
surrounds it holds it firmly and rigidly and also holds the active materials from
lateral displacement, enabling the thickness of the latter to be increased while
leaving to the core F its original thickness. Moreover the active material
completely covering the core prevents the latter being attacked by the active fluid
or liquid which first of all brings its action to bear upon the active material.
I therefore completely obviate the numerous inconveniences inherent in those
accumulator plates in which the active material is surrounded and retained by a
perforated metallic sheet which serves as a collecting core.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, declare that what I
claim is :-
:
1. A construction of electric accumulator plates allowing of the utilization of a
considerable thickness of reactive material by employing, as the collecting core for
the current, a thin metal plate surrounded by a frame of similar metal, and of any
convenient width the said core being provided with protuberances or projections or
rents in the metal which are so arranged that their curved outer extremities
are somewhat claw-shaped and which hold the active material in contact with the
metallic core.
2. An accumulator plate as described in Claim 1, the collective core of which is
constructed as herein before described and as shown in the accompanying drawing,
and the variable width of the frame of which serves to permit of the employment
of a more or less large thickness of active material and also to prevent the lateral
displacement of the same.
3. An accumulator plate, such as described in Claim 1 the core of which is
provided with protuberances or projections the extremities of which extend to the
level of the edges of the frame, the object of which protuberances is not only to

page_text: maintain the active material in contact with the collective core but also to enable
the whole of the active material to be utilized while permitting, by its numerous
ramifications, the electric energy to be conveyed into a large number of approached
points, of this mass, this method of construction diminishing moreover the interior
resistance of the accumulators in general, in which the collective core is guarded
against direct contact with the liquid of the element by an uninterrupted layer of
active material.
4. An accumulator plate, such as described in Claim 1, the metal frame of which
serves to maintain the plate in rigid position and to permit of employing a thin
sheet metal plate as a collective core, which metal plate cannot augment in
thickness even on increasing the thickness of the active material, the effect of which
is to reduce the dead weight of the core to a minimum.
Dated this 4th day of October 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.