Improvements in Electrical Accumulators or Secondary Batteries.
Year: 1893

page_text: Date of Application, 15th Apr., 1893
Complete Specification Left, 15th Jan., 1894-Accepted, 14th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in Electrical Accumulators or Secondary Batteries.
I, PAUL SCHOOP of 90 Seestrasse Zürich, Switzerland, Electro Chemist, do
hereby declare the nature of this invention to be as follows:-
My invention relates to an improved construction of electrical accumulators or
secondary batteries wherein a circulation of the electrolyte is effected.
It is well known that with primary batteries various arrangements have been
adopted for renewing the liquid electrolyte from time to time, mainly during the
working of the battery.
The electrical energy which is developed by primary batteries in all cases
produces a consumption and neutralization of the liquid electrolyte, so that when
this is exhausted or neutralised; no further production of energy is possible. When
however the exhausted liquid is removed from the primary cells and is replaced
by fresh electrolyte, the primary battery is again ready for producing electrical
energy. A great variety of nodes have been proposed for automatically renewing
electrolytes whenever they become more or less exhausted. The renewal in such
cases has to take place intermittently.
In my invention, which relates to secondary batteries, accumulators or polarisation
batteries, and not to primary batteries, it is not a question of replacing exhausted
electrolytes by fresh liquid but of producing in the accumulator a continual
circulation of one and the same body of liquid.
The object and practical advantage of this invention consists in that the
electrodes of the secondary battery are continuously brought into renewed contact
with a liquid which has a perfectly uniform composition throughout all parts of the
cell or battery. By this incans the working capacity of the secondary battery is
made to rise considerably above that which it would possess without any circulation
of the electrolyte.
In addition to this, a very uniform working of the electrodes is attained, resulting
in the development of a greater useful effect and an increased durability thereof.
My invention relates not only to ordinary secondary batteries or accumulators
of known construction but also generally to all electro chemical combinations by
means of which electrical energy can be stored up and given off again.
While on the one hand with the known lead accumulators having dilute sulphuric
acid as electrolyte both the clectrodes are insoluble in the electrolyte, there are
on the other hand other secondary batteries in which the one or the other or both
ions are present in the electrolyte and are dissolved or precipitated during the
charging or discharging.
My invention is more particularly of great importance when applied to lead
accumulators, for the reasons above stated..
According to one arrangement of secondary battery with insoluble electrodes
according to my invention, each separate secondary element consists of a vessel of
glass, ebonite or other similar insulating material with vertical positive and negative
electrode plates placed at equal distances apart, the negative plates being made to
fit tightly against the sides of the vessel but not to touch the bottom, while the
positive plates fit tight both against the sides and the bottom.
By this means the liquid electrolyte entering the cell at the one end is obliged
to flow in a vertical serpentine direction, successively over the surfaces of all the
plates from the one end to the other.

page_text: •
The fitting of the plates in a liquid-tight manner against the bottom and sides of
the vessel may be effected in any suitable manner, the vessel being advantageously
made with grooves for the reception of the plates.
The negative plates may be secured in these grooves by means of caoutchouc
packing, while the positive plates are fitted tight to the bottom of the vessel by
means of a suitable cement, such as Chattertons compound caoutchouc solution,
lead oxide paste, water glass &c. The positive electrode plates may be fitted tight
to the sides by means of caoutchouc tubing, so as to leave a certain amount of play
for expansion; or a packing of a gelatinous material may be used, such as silicic
acid in gelatinous form. When the liquid has arrived at the end of the battery in
the above described manner it is withdrawn through a pipe and conveyed by a
pump or other propelling device back to the charging end, the speed of the
circulation being regulated by varying the speed of the pump.
With this arrangement of battery a partition is advantageously fixed on top of
each of the negative electrodes of such a height as to produce a sufficient head of
liquid above the tops of the positive electrodes to produce the serpentine flow of
the liquid through the battery as described.
Instead of effecting the circulation in the above described manner throughout
the entire battery a circulation can be effected through each separate secondary
element, these elements being then arranged in stepped form so that the liquid can
flow from the first element into the second and so on to the last.
In describing the application of my invention to secondary batteries in which
the one or the other of the active bodies or both of them are soluble in the
electrolyte, and to which my invention is applicable with particular advantage, I
will describe by way of example the application to a battery with zine for the one
active body, and mercury for the other, the electrolyte being a solution of zine
oxide in a hydrate of potash solution. In charging such a secondary element,
there is separated on the cathode metallic zinc in combination with mercury,
while on the anode mercury of a low stage of oxidation is converted into mercury
of a higher stage of oxidation. On discharging the battery, the zine on the
cathode is oxidized and taken up by the hydrate of potash solution, while the
higher oxidized mercury compound is transformed into one of lower oxidation.
With such a battery according to one arrangement both electrodes are placed
vertically the one being in the form of rods surrounded by a tubular porous
partition of parchment paper, or preferably magnesia, while the other electrode is
in the form of tubes surrounding the rods outside the partition. Or both the
electrodes may be in the form of cylinders placed concentrically one within the
other; or the one electrode may be of a rod or tubular form and the other in
the form of superposed flat horizontal plates; or both electrodes may be in the
form of flat or coned horizontal or inclined plates, the cathode plates being
arranged to alternate with the anode plates. In all these cases there is provided
a ceutral tube open at top and bottom in which is a revolving screw or worm by
the rotation of which the electrolyte is raised from the bottom to the top of the
cell, so as to flow down again in contact with the electrodes in the space
surrounding the tube. When the electrode plates are arranged horizontally or
inclined as last above described, the one electrode, as for instance the cathode
plates, may be made as discs fitting with their outer periphery against the sides of
the cell and having a central opening of such a size as to leave an annular opening
between them and the central tube with screw, while the anode plates are made as
dises, fitting with a central hole tight against the central tube, and leaving an
annular space between their outer periphery and the sides of the cell. Thus on
the liquid being raised to the top of the cell by the screw, it is made to flow down
in a serpentine direction through the zig zig passage formed between the cathode
and anode plates.
The above described constructions are also applicable for other kinds of
secondary batteries, such as those in which the cathodes are of steel and the anodes
of copper.

page_text: The rotation of the screw may be effected by a small electromotor worked by a
current derived either from the secondary battery itself, in shunt or otherwise or it
may be worked by an extraneous current, or again, the rotation of the screw may
be effected by any other motor.
For secondary batteries that require the electrolyte to be heated, this may be
effected by means of a resistance coil placed in the lower part of the cell, through
which an electric current is passed that may be derived from the secondary battery
itself or from an independent generator.
Dated this 15th day of Annil 1902
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electrical Accumulators or Secondary Batteries.
I, PAUL SCHOOr, of 90" Seestrasse, Zurich, Switzerland, Electro Chemist, 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 an improved construction of electrical accumulators or
secondary batteries whereby a circulation or flow in a definite direction of the
electrolyte through the vessel is effected.
It is well known that with primary batteries various arrangements have
been adopted for renewing the liquid electrolyte from time to time, mainly during
the working of the battery.
The electrical energy which is developed by primary batteries in all cases
produces a consumption and neutralization of the liquid electrolyte, so that when
this is exhausted or neutralized, no further production of energy is possible. When
however the exhausted liquid is removed from the primary cells and is replaced by
fresh electrolyte, the primary battery is again ready for producing electrical
energy. A great variety of modes have been proposed for automatically renewing
electrolytes whenever they become more or less exhausted. The renewal in such
cases has to take place intermittently.
In my invention which relates to secondary batteries, accumulators or
polarisation batteries, and not to primary batteries, it is not a question of replacing
exhausted electrolytes by fresh liquid but of producing in the accumulator a
continual circulation of one and the same body of liquid.
The object and practical advantage of this invention consists in that the
electrodes of the secondary battery are continuously brought into renewed contact
with a liquid which has a perfectly uniform composition throughout all parts of the
cell or battery. By this means the working capacity of the secondary battery is
made to rise considerably above that which it would possess without any circulation
of the electrolyte.
In addition to this, a very uniform working of the electrodes is attained,
resulting in the development of a greater useful effect and an increased durability
thereof.
My invention relates not only to ordinary secondary batteries or accumulators
of known construction but also generally to all electro chemical combinations by
means of which electrical energy can be stored up and given off again.
While on the one hand with the known lead accumulators having dilute
sulphuric acid as electrolyte both the electrodes are insoluble in the electrolyte,
there are on the other hand other secondary batteries in which the one or the
other or both ions are present in the electrolyte and are dissolved or precipitated
during the charging or discharging.
According to one application of my invention, I construct a secondary battery

page_text: with vertical electrodes, the positive and negative electrodes being placed
alternately at equal distances apart, the one set of plates being made to fit tight
against the sides of a rectangular vessel of glass, ebonite, or other insulating material,
but not to touch the bottom thereof while the other set of plates are made to fit
tight both against the sides and the bottom.
The one set of plates, either the positive or the negative electrodes are by
preference each surrounded by an envelope of parchment paper, in order to prevent
short circuiting of the cell.
By this means the liquid electrolyte entering the cell at the one end is obliged
to flow in a vertical serpentine direction, successively over the surfaces of all the
plates from the one end to the other.
The fitting of the plates in a liquid-tight manner against the bottom and sides
of the vessel inay be effected in any suitable manner, the vessel being advan-
tageously made with grooves for the reception of the plates.
The one set of these plates may be secured in these grooves by means of a
packing, while the other set of plates are fitted tight to the bottom of the vessel
by means of a suitable cement, such as Chatterton's compound caoutchouc solution
lead oxide paste, water glass, magnesia or a mixture of magnesia and waterglass,
&c. The one set of the electrode plates may be fitted tight to the sides with
caoutchouc tubing, so as to leave a certain amount of play for expansion; or a
packing of a gelatinous material may be used, such as silicic acid in gelatinous
form, or waterglass with magnesia. When the liquid bas arrived at the end of the
battery in the above described manner it is withdrawn through a pipe and conveyed
by a pump or other mechanical propelling device back to the charging end, the
speed of the circulation being regulated by varying the speed of the pump.
With this arrangement of battery a partition is advantageously fixed on top
of each of the one set of the electrodes of such a height as to produce a sufficient
head of liquid above the tops of the positive electrodes to produce the serpentine
flow of the liquid through the battery as described.
In describing the application of my invention to secondary batteries in which
the one or the other of the active bodies or both of them are soluble in the
electrolyte, and to which my invention is applicable with particular advantage, I
will describe by way of example the application to a battery with zinc for the one
active body, and mercury for the other, the electrolyte being a solution of zinc oxide
in hydrate of potash solution. In charging such a secondary element, there is
separated on the cathode metallic zinc in combination with mercury, while on the
anode mercury of a low stage of oxidation is converted into mercury of a higher
stage of oxidation. On discharging the battery, the zinc on the cathode is
oxidized and taken up by the hydrate of potash solution, while the higher oxidized
mercury compound is transformed into one of lower oxidation.
With such a battery-according to my arrangement-both electrodes are placed
vertically the one being in the form of rods or plates surrounded by a porous
partition of parchment paper while the other electrode is in the form of tubes or
plates without or with an envelope of parchment paper surrounding the rods
outside the partition. Or both the electrodes may be in the form of cylinders
placed concentrically one within the other; or the one electrode may be of a rod
or tubular form and the other in the form of superposed flat horizontal plates. In
all these cases there is provided a central channel open at top and bottom and in
communication with the electrolyte surrounding such channel is a revolving screw
or worm by the rotation of which the electrolyte is withdrawn from the top of the
cell, and is discharged thereby into the central channel, from the bottom of which
it again enters the surrounding space.
The above described constructions are also applicable for other kinds of secondary
batteries, such as those in which the cathodes are of steel, and the anodes of copper
as will be presently fully described.
The rotation of the screw may be effected by a small electro motor worked by a
current derived either from the secondary battery itself, in shunt or otherwise or it

page_text: may be worked by an extraneous current or again, the rotation of the screw may, be
effected by any other motor.
For secondary batteries that require the electrolyte to be heated, this may be
effected by means of a resistance coil placed in the lower part of the cell through
which an electric current is passed that may be derived from the secondary battery
itself or from an independent generator.
1 will proceed to describe the said method of circulating the electrolyte in
combination with the form of secondary battery which I prefer to employ for which
purpose I will refer to the accompanying drawings in which Figs. 1 and 2 shew
respectively a vertical section and sectional plan of the battery.
Figs. 3 and 4 shew a vertical section and sectional plan of the form of secondary
battery first above described.
In the secondary battery cell shewn at Figs. 1 and 2, the vessel A, which is
preferably made of sheet steel has a central steel tube B, suitably fixed to the
bottom and upper end of the vessel such tube being open at the upper end and having
also openings at the lower end. The space surrounding this tube communicates
near the top with one end of a casing containing a screw propeller or worm,
rotated by suitable means such as before described, and the other end of the casing
has a tube e passing through the vessel A and having its opening immediately over
the tube B, so that the vessel A being filled with the liquid electrolyte to the level
indicated, this is withdrawn from the top by the propeller at C and is discharged
through e into the tube B, down which it flows in order to issue at the bottom
into the surrounding space again. By this means a complete circulation of the
electrolyte is obtained.
The cathode of this cell consists of the horizontal superposed discs D of thin sheet
steel, of the flanged sectional form shewn, so as to rest upon the bottom and upon
each other, leaving a distance of from to inch between them.
These discs have circular holes D as shewn at Fig. 2, and they are so placed
upon each other that the holes correspond in position so as to form a corresponding
number of vertical passages through all the discs. Through these passages are
passed the rod shaped anodes E which are either of copper or of amalgam of copper
and mercury these being surrounded by tubes F of parchment-paper, so as to keep
the anodes out of contact with the cathode plates D.
The spaces between the rods E, tubes F and cathode plates D are filled with the
liquid electrolyte, which also finds its way through the lower open end of the tube B
into the interior of the latter, so that by the rotation of the screw C the liquid is
continuously circulated through the cell in contact with the cathode and anode as
shown by the arrows.
The upper ends of the anode rods E are connected by a conductor G with the one
terminal of the circuit and the casing A, which is in conducting contact with the
cathode plates D, is connected by a conductor H with the other terminal of the
circuit.
The electrolyte employed with this battery cell consists of a solution of zinc in
caustic potash.
It is also preferred to heat the battery cell Figs. 1 and 2 by providing the same
with a wire coil Q, of high resistance, wound round the casing A, with the inter-
position of insulating material X, the coil being supplied with current from any
convenient source or from the battery cell itself.
Fig. 3 shews a vertical section and Fig. 4 a sectional plan of the first above
described arrangement of secondary battery with vertical insoluble electrodes with
circulation of the electrolyte. R is a rectangular vessel of glass or other suitable
material, formed with internal grooves R' at the sides and bottom into which are
fitted alternate positive and negative electrode plates S T, of which say for instance
the positive plates S are made to fit tight in the grooves both at the sides and the
bottom as before described while the negative plates T only tit tight at the sides,
and terminate at a short distance from the bottom so that the electrolyte which is
supplied through a pipe U is caused to flow vertically up and down through the

page_text: zigzag passages thus formed, being brought Sucessively in contact with the surfaces.
of all the electrodes plates, and finally flowing off through a pipe U₁ to a cylinder
containing a rotating screw C which propels the electrolyte through the pipe U back
to the other end of the battery. The screw is rotated by a motor which may be
worked by a portion of the current of the battery itself, or by any other suitable
source of power. Partitions W are carried up beyond the tops of the electrode
plates to sufficient heights to afford the necessary flow of liquid through the several
passages of the battery.
The one set of electrodes such as T, are by preference enclosed in parchment
paper cases F as previously described with reference to Fig. 1.
The electrode plates are connected in any suitable known manner to the circuit
conductors.
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. In a secondary battery or accumulator, the employment of means whereby a
flow or circulation in a definite direction of the liquid electrolyte through the battery
cell is effected, substantially as described.
2. In a secondary battery or accumulator, the combination of horizontally placed
steel discs having a series of holes and acting as a cathode, vertical rods of copper
or copper amalgam acting as anode passing through holes in the cathode plates, tubes
of parchment paper surrounding the said anode rods, and means for effecting the
circulation of the electrolyte substantially as described.
3. A secondary battery cell having vertically arranged electrode plates, one set
of which fit tight against the sides of the vessel but have a space between their
lower edge and the bottom of the vessel, while the other set, alternating with the
first set fit tight both against the sides and the bottom of the vessel so that the
liquid electrolyte entering at the one end of the vessel, is made to pass in a vertical
serpentine direction in contact with all the plates to the other end, where it is with-
drawn by a revolving screw or worm or equivalent meaus, which conveys it back to
the first named end substantially as described.
Dated this 15th day of January 1894.
ABEL & IMRAI,
Agents for the Applicant.

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