IMPROVEMENTS IN SECONDARY BATTERIES
Year: 1882

page_text: LETTERS PATENT to Desmond Gerald FitzGerald of Brixton in the County of
Surrey and Charles Henry Walker Biggs and William Worby Beaumont both
of the Strand in the County of Middlesex for an invention of "IMPROVEMENTS
IN SECONDARY BATTERIES
"
PROVISIONAL SPECIFICATION left by the said Desmond Gerald FitzGerald,
Charles Henry Walker Biggs & William Worby Beaumont at the Office of
the Commissioners of Patents on the 19th April 1882.
DESMOND GERALD FITZGERALD of Brixton in the County of Surrey; and
CHARLES HENRY WALKER BIGGS and WILLIAM WORBY BEAUMONT both of the
Strand in the County of Middlesex "IMPROVEMENTS IN SECONDARY BATTERIES.'
"
In the Provisional Specification of the patent granted to us dated 6th December
1881 No 5338 we refer to the obtaining by chemical precipitation the lead of
which by pressure we construct the electrodes or elements of our secondary
batteries, as for example the action of zinc on acetate of lead.
According to our present invention we deposit lead electrolytically either within
moulds or dies in which the material is to be compressed, or in other moulds of
similar form, or we deposit in bulk so as to obtain a mass of finely divided
crystalline lead such mass constituting the material from which porous plates or
cakes flat or otherwise may be obtained by compression. For example we place
borizontally within a suitable mould a plate of metal or other conductor disposed
horizontally and constituting the cathode or negative electrode in a solution of
acetate or other suitable salt of lead and support the anode which is a plate of
lead preferably above the mould and the negative electrode. The mould and the
anode and cathode may be all placed in a bath of the solution or the solution or
the materials for it may be placed in each mould separately.
When a current from a dynamo machine or other generator is passed through
the solution by means of the above mentioned electrodes lead is dissolved at the
anode and thrown down at the cathode, and if the current be of sufficient strength
the lead is deposited as a finely divided crystalline mass not adherent to the
[Price 6d1

page_text: cathode. The cathode plate is then preferably with as little disturbance of the
mass as possible removed from the bottom of the mould, which is taken out of the
. electrolytic bath and the crystalline mass is subjected to a sufficient pressure to
constitute it a firmly coherent but porous cake or plate either immediately on
being taken from the electrolytic bath or after a process of partial oxydation by
air or otherwise.
Or we deposit the crystalline mass of lead in bulk upon a large cathode in the
bottom of an electrolytic bath or by action of zinc on a solution of acetate of lead,
the deposited material being afterwards washed and divided into weighed masses
from which the porous plates are made by compression as before.
In order to obviate the possibility of accidental metallic connection or contact
between the plates constituting the elements of secondary batteries when placed
together in cells or troughs and in order to obviate the effect of any partial
disintegration or fracture of the plates we may fill up the cells containing the
plates with plaster of Paris. This material is mixed with water in the usual
nanner and when set is in this case moistened with dilute sulphuric acid, or the
plaster may be mixed with dilute sulphuric acid in the first place. The plaster of
Paris filling is to be maintained in a moist condition by the addition of water from
time to time as evaporation takes place.
When pouring in the plaster of Paris filling we sometimes place a number of
wires against the surface of the plates forming the cathode surfaces and afterwards
withdraw them leaving a number of vent holes from which hydrogen gas may
escape. We sometimes adopt a similar precaution in the case of the anode
surfaces.
We do not confine ourselves to acetate of lead for the production of our
compressed porous lead plates but may employ any known suitable salt of lead for
obtaining spongy metallic lead by electrolysis; neither do we confine ourselves to
pure plaster of Paris but may use other suitable porous cements either alone or in
admixture with Plaster of Paris.
In some cases we compress a tang with fangs made of suitable metal as lead into
the thickness and at one of the edges or corners as the compressed cake or plate of
porous lead leaving a part projecting therefrom to act as a contact piece and we
may compress into the body of the cake or plate a sheet of suitable metal as lead
the sheet having a number of large holes made in it and a small piece projecting
from the porous plate or cake to act as a contact piece. The insertion of either
the tang or sheet of metal we effect by placing them with the mould in which the
material of the plate is deposited when the process of deposition is about half
completed, and a suitable aperture or space is inade in the mould to allow of its
projection from the general contour of the cake or plate.
We may also make our elements or electrodes of very finely granulated or
pulverized lead obtained by means which for distinction from the chemical and
electro chemical methods, we will call mechanical means, and this finely granulated
or pulverized lead after partial oxydation in air or otherwise we compress into
cakes or plates with the necessary pressure say in a mould or die in the manner
before described or just as ornamental tiles are compressed into hard cakes from
powdery clay. One way of obtaining the finely granulated or powdered or
pulverized lead is by revolving rasps with suitably formed teeth or by pouring
molten lead into powdered material such as carbonate of lime or plaster of Paris
and agitating it until it is disintegrated and has solidified in the same way as
powdered tin is obtained for the purpose of making amalgam.
We may in some cases use powdered, granulated or pulverized lead, mixed with
pulverized zinc and some sulphate of lead and other suitable materials mixed with
the mass for compression into cakes, in which case the zinc would be dissolved out

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Desmond Gerald FitzGerald, Charles Henry Walker Biggs,
& William Worby Beaumout in the Great Seal Patent Office on the
19th October 1882.
DESMOND GERALD FITZGERALD of Brixton in the County of Surrey and
CHARLES HENRY WALKER BIGGS and WILLIAM WORBY BEAUMONT (both of the
Strand in the County of Middlesex "IMPROVEMENTS IN SECONDARY BATTERIES
"
In the Specification of the Patent granted to C. H. W. Biggs and W. W. Beaumont
dated 28th November 1881 No. 5198 and in the Specification of the Patent granted
to us dated 6th December 1881 No. 5338 we refer to the obtaining by chemical
precipitation the lead crystals of which by pressure or compression we construct
the electrodes or elements of our secondary batteries as for example the action of
zinc on acetate of lead.
According to our present invention we deposit lead electrolytically, either within
moulds or dies in which the material is to be compressed or in other moulds of
similar form or we deposit in bulk so as to obtain a mass of finely divided
crystalline lead such mass constituting the material from which porous plates or
cakes flat or otherwise may be obtained by compression. For example we place
horizontally within a suitable mould a plate of lead or other conductor disposed
horizontally and constituting the cathode or negative electrode in a solution of
acetate or other suitable salt of lead and support the anode which is a plate of lead
in any convenient position in the same bath; it may be of any convenient form;
it may thus for instance form an inner lining to the vertical side of the bath,
containing the electrolytic solution. The mould and the anode and cathode may
be all placed in a bath of the solution, or the solution or the materials for it may
be placed in each mould separately.
Preferably we employ a battery consisting of such a number of these baths in
series so that the resistance of the battery is equal to the internal resistance of the
machine which supplies the current.
Figure 1 is a perspective view of three baths B in each of which is placed a
plate cathode C forming the bottom of two moulds M and covered with non-
conducting varnish or other coating except in the interior of the mould. A is the
anode. Figure 2 is a vertical section through a series of three baths B in each of
which are provided three cathode plates C for mould M to rest on.
When a current from a dynamo machine or other generator is passed through
the solution by means of the above mentioned electrodes lead is dissolved at the
anode A and thrown down at the cathode C that is within the moulds M and if
the current be of sufficient strength the lead is deposited as a finely divided
crystalline mass not adherent to the cathode or interior of the mould M.
The cathode plate with mould or moulds is then with as little disturbance of the
mass as possible removed from the electrolytic bath B and the crystalline mass in
its mould having been removed from the cathode plate C and placed on a strong
metallic plate such as P Figure 2A is put in a press and subjected to a sufficient
pressure to constitute it a firmly coherent but porous cake or plate either
immediately on being taken from the electrolytic bath or by preference after a
process of partial oxidation by air or otherwise but if the electrolytic bath contains
free acid the aforesaid special partial oxidation before the compression is not
indispensable as the said free acid adhering to the lead particles in the mould
will sufficiently prevent complete metallic union of the particles. The pressure
employed should be about from 400 to 1000 pounds per square inch, or more according

page_text: to the porosity desired. The moulds M Figures 1 and 2 may be of wood or of
metal coated with a nonconducting material or varnish. When made of metal the
moulds may be used as the pressing die D in Figure 2A which also shows the
upper die D' and the tang T which latter will be referred to later on.
Or we deposit the crystalline mass of lead in bulk upon a large cathode in the
bottom of an electrolytic bath, the deposited material being afterwards washed
and divided into weighed masses from which the porous plates are made by
compression as before
In order to obviate the possibility of accidental metallic connection or contact
between the plates constituting the elements of secondary batteries-when placed
together in cells or troughs and in order to obviate the effect of any partial
disintegration or fracture of the plates we may fill up the cells containing the
plates with plaster of Paris. This material is mixed with water in the usual
manner and when set, is in this case moistened with dilute sulphuric acid, or the
plaster may be mixed with dilute sulphuric acid in the first place. The plaster of
Paris filling is to be maintained in a moist condition by the addition of water from
time to time as evaporation takes place. When pouring in the plaster of Paris
filling we sometimes place a number of wires or other pieces such as straw or wood
slips against the surface of the plates forming the cathode surfaces and afterwards
when required as when wire is used withdraw them leaving a number of vent
holes from which hydrogen gas may escape. We sometimes adopt a similar
precaution in the case of the anode surfaces.
We do not confine ourselves to acetate of lead for the production of our
compressed porous lead plates but may employ any known suitable salt of lead
for obtaining spongy metallic lead by electrolysis; neither do we confine ourselves
to pure plaster of Paris but may use other suitable porous substances such as
sulphate of baryta either alone or in admixture with plaster of Paris.
We may also make our elements or electrodes of very finely granulated or
pulverized lead obtained by means which for distinction from the chemical and
electro-chemical methods we will call mechanical means, and this finely granulated
or pulverized lead after partial oxidation in air or otherwise we compress into
cakes or plates with the necessary pressure say in a mould or die in the manner
before described or just as ornamental tiles are compressed into hard cakes from
powdery clay. One way of obtaining the lead fragments is by cutting up lead foil
for instance by a machine similar to a chaff cutter or tobacco cutting machine.
In some cases we compress a tang with fangs made of suitable metal as lead
into the thickness and entering at one of the edges or corners of the compressed
porous lead cake or plate the part projecting therefrom acting as a contact piece.
Or we may compress into the body of the cake or plate a thin sheet or skeleton
frame of suitable metal such as lead the said sheet having a number of large holes
made in it, a small piece of this skeleton frame projects from the porous plate or
cake to act as a contact piece. The insertion of either the fanged tang or the
skeleton sheet of metal we effect by placing them into the mould in which the
material of the plate is deposited when the process of deposition is about half
completed and a suitable aperture or space is made in the mould to allow of its
projection from the general contour of the cake or plate as shown in Figure 2ª
already referred to. By the ramification of the tang throughout the interior of
the porous electrode we diminish the internal resistance and form a firm connection
thereto
Figure 3 shows a form of tang T embedded edgeways in a porous electrode and
made of flat wire or ribbon lead; Figure 4 is a side view of the electrode ;
Figure 5 shows an electrode in which the flat wire tang is placed flat in the
electrode.
Figures 6 to 104 show various forms of tangs made of round, flat, or other wire
and embedded in electrodes.
Figure 11 shows a thin skeleton frame tang made by forming large holes in thin

page_text: sheet lead. Figure 12 shows a flat tang cut from a thin sheet of lead and having
fangs or branches embedded in the electrode.
We claim:
First: The construction of porous lead electrodes for secondary batteries by the
combined process of electro depositing lead in a loosely coherent or crystalline form
partially oxidizing the same or chemically acting thereon with an acid such as
sulphuric acid and then compressing the mass into cakes, plates or any other
suitable form substantially as and for the purpose set forth.
Second: The mode herein described of obtaining lead in a loosely coherent or
crystalline form by electro deposition in the interior of a mould the bottom of
which constitutes the cathode in an aqueous solution of a salt of lead containing
also a lead anode substantially as and for the purpose set forth.
Third: The construction of porous lead electrodes with ramifying or otherwise
distributed tangs embedded in their mass and fixed therein by the pressure under
which the mass is compressed into a firmly coherent form substantially as and for
the-purpose set forth.
In witness whereof I the said Desmond Gerald Fitz-Gerald for myself and
on behalf of the said Charles Henry Walker Biggs and William Worby
Beaumont have hereunto set my hand and seal this Nineteenth day of
October in the year of our Lord One thousand eight hundred' and
eightytwn.
DESMOND GERALD FITZ-GERALD. (L.S.)