Improvements in and relating to Secondary Batteries or Accumulators, and the Manufacture thereof.
Year: 1897

page_text: Date of Application, 17th Mar., 1897
Complete Specification Left, 17th Dec., 1897-Accepted, 5th Mar., 1898
Improvements in and relating to Secondary Batteries or Accumulators,
and the Manufacture thereof.
I, AUGUSTUS JOHN MARQUAND, of Dock Chambers, Cardiff, Consulting Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention relates to improved secondary or storage batteries, and has for
its object the production of plates for such batteries by a process giving great
mechanical strength, large storage capacity, and low cost with small wear and
tear in use.
My invention consists of improvements in the method of producing lead plates,
converted partially by the aid of heat into lead sulphide; the sulphide being then
reduced by electrolytic means to the metallic state; which plates are suitable for
negative plates; and the said reduced plates, being peroxidised by electrolytic
means, are suitable as positive plates.
-
In order to prepare plates according to my improved process, so that whilst
having a large amount of porous or active material there should be a continuous
backing or net work of metallic lead, together with sufficiently strong metallic
lead connections for conducting the current from the plates, I proceed as follows:-
I prepare a plate of lead or lead alloyed with antimony, which may be in the
form of a grid in which holes pass right through, or only part way through from.
either side, and which may be produced by casting or stamping. This plate having
solid bars or ribs at the top and in some cases down the side or centre for the
purpose of strengthening the plate, and assisting the distribution of current.
These bars or ribs which are intended in subsequent processes now to be
described to be unacted on, that is, left in the solid metallic state, are covered with
a protecting layer of material which will be unacted on either by heat or by
sulphur melted or in vapour. There are many methods of effecting this, such as
by covering these parts of the plates with strips of iron or other metal, but the
method which I prefer is to coat them with a coating of a fusible enamel, and in
order that this may be done with an enamel infusible at the melting point of
lead I coat the parts to be protected with the said enamel in a state of powder
mixed with a suitable medium, and then rapidly heat the same in a flame of high
temperature such as a blow pipe or an oxyhydrogen flame with a result that the
enamel is fused before sufficient heat has penetrated to the metallic lead underneath
to melt it.
The plate so protected is now placed in a box which may be of cast or wrought
iron having a lid which may be secured, air-tight or nearly so; the plate is placed
in this in this box being covered with sulphur; the amount depending on the
required electrical capacity of the plate.
The box containing the plate is placed in a furnace as nearly level as possible
preferably slightly inclined towards the solid bar at the top of the plate, and
heated to the melting point of lead. By this means portions of the lead of the

page_text: plate to a degree depending on the amount of sulphur placed on the plate, are
converted into sulphide of lead there being however throughout the plate a con-
tinuous net work or conducting backing of metallic lead unacted on by the sulphur
whilst the protected parts of the plate are also unacted on by the sulphur. The
plate so prepared after being allowed to cool is removed from the box, and forms
the cathode of an electrolytic cell containing dilute sulphuric acid, by this means
the suphide of lead is reduced to the state of metallic lead, and in a highly porous
form offering a very large surface but at the same time mechanically and electric-
ally continuous with the lead backing and conducting bars. A plate so prepared
is ready for use as a negative plate of a secondary battery. By reversing the
direction of the current through the electrolytic cell, the plate may be peroxidised
and form the positive plate of a battery.
In certain cases the following modified method of preparing the plate may be
adopted, lead sulphide or a mixture of fine metallic lead and sulphur may be made
into a paste, and pasted or packed into the openings or interstices of a plate as
previously described, and the plate thus pasted being submitted to the action of heat,
the lead sulphide being partially reduced to a sub-sulphide at the surface of
connection between the paste and the plate, becomes mechanically and electrically
continuous with it and may be reduced in manner already described.
Plates so prepared may be used in the ordinary manner in an electrolyte com-
posed of dilute sulphuric acid. But a further part of my invention consists in
the use as an electrolyte of dilute sulphuric acid containing other sulphur compounds
produced by the electrolytic action in reducing the sulphide of lead plates already
described, or other metallic sulphide. By the use of such compound electrolyte
the sulphating of the positive plates due to local action between it and the peroxide
of lead is entirely prevented.
The plates produced according to my invention may be used flat or after they
have been sulphided and reduced to the metallic state may be folded or bent to any
required form, circular or otherwise, before being peroxidised and the plates may
be used enclosed in envelopes, or supporting frames in manner well understood by
those versed in the art.
Dated this 17th
1
1007
FELL & JAMES,
Agents for the Applicant.
Improvements in and relating to Secondary Batteries or Accumulators,
and the Manufacture thereof.
I, AUGUSTUS JOHn Marquand, of Dock Chambers, Cardiff, Consulting 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 following
statement:-
This invention relates to improved secondary or storage batteries, and has for
its object the production of plates for such batteries by a process giving great
mechanical strength, large storage capacity, and low cost with small wear and
tear in use and the employment of a special electrolyte in secondary batteries.
To carry out my invention I prepare lead plates for use in secondary batteries
by their partial conversion by the aid of heat into lead sulphide, the sulphide being
then reduced by electrolytic means to the metalle state which plates are suitable
for negative plates, and the said reduced plates being peroxidised by electrolytic
means are suitable as positive plates.

page_text: In order to prepare the foundation plates according to my invention so that
whilst having a large amount of porous or active material there should be a con-
tinuous backing or net work of metallic lead, together with sufficiently strong
metallic lead connections for conducting the current from the plates I proceed as
follows:-
I prepare a plate of lead or lead alloyed with antimony which may be in the
form of a grid in which holes pass right through, or only part way through from
either side, and which may be produced by casting or stamping, this plate having
solid bars or ribs at the top, and in certain cases down the side or centre for the
purpose of strengthening the plate, and assisting the distribution of current.
These bars or ribs which are intended in subsequent processes (now to be
described) to be unarted on, that is, left in the solid metall'e state, are covered with
a protecting layer of material which will be unacted on either by heat or by
sulphur melted or in vapour. There are many methods of effecting this, such as
by covering these parts of the plates with strips of iron or other metal not acted
on by sulphur at the temperature of melting lead or asbestos strips or certain heat
resisting varnishes or japan may be used, but the method which I prefer is to coat
them with a coating of a fusible enamel, and in order that this may be done with
an enamel infusible at the melting point of lead I coat the parts to be protected
with the said enamel in a state of powder mixed with a suitable medium, and then
heat the same in a flame of high temperature such as a blow pipe or oxyhydrogen
flame with a result that the enamel is fused without melting the metallic lead
underneath. Various enamels may be used, but I find the following composition
to be a suitable enamel for the purpose. Calcium fluride 49 per cent,
telspar 45-6%, sodium silicate 25-3%, silicon dioxide 4·9% barium
sulphate 19.3%.
The plate so protected is now placed in a box which may be of cast or wrought
iron having a lid which may be secured, air tight or nearly so. The plate is
placed in this box and is covered with sulphur the amount depending on the
required electrical capacity of the plate. I find the following proportions to hold
good.
For each ampere hour of required capacity I place about two grammes of sulphur
on the plate.
The box containing the plate is placed in a furnace as nearly level as possible,
preferably slightly inclined towards the solid bar at the top of the plate, and
heated to the melting point of lead. By this means portions of the lead of the
plate to a degree depending on the amount of sulphur placed on the plate, are
converted into sulphide of lead there being however throughout the plate a con-
tinuous net work or conducting backing of metallic lead unacted on by the sulphur,
whilst the protected parts of the plate are also unacted on by the sulphur. The
plate so prepared after being allowed to cool is removed from the box, and forms
the cathode of an electrolytic cell containing dilute sulphuric acid, by this means
the suphide of lead is reduced to the state of metallic lead, and in a highly porous
form offering a very large surface, but at the same time mechanically and electric-
ally continuous with the lead backing and conducting bars. This plate whilst
in the soft or spongy state may be compressed in a mould. A plate so prepared is
ready for use as a negative plate of a secondary battery. By reversing the direction
of the current through the electrolytic cell, the plate may be peroxidised and form
the positive plate of a battery.
In certain cases the following modified method of preparing the plate may be
adopted, lead sulphide or a mixture of fine metallic lead and sulphur or lead
oxides and sulphur may be made into a paste, and pasted or packed into the openings
or interstices of a plate as previously described, and the plate thus pasted being
submitted to the action of heat the lead sulphide being partially reduced to a
sub-sulphide at the surface of connection between the paste and the plate,
becomes mechanically and electrically continuous with it, and may be reduced in
manner already described.

page_text: Plates so prepared may be used in the ordinary manner in an electrolyte com-
posed of dilute sulphuric acid, but a further part of my invention consists in
the use as an electrolyte of dilute sulphuric acid containing other sulphur compounds
such as the thionic acids or salts of the same produced by the electrolytic action
in reducing the sulphide of lead plates already described or by equivalent means.
By the use of such compound electrolyte injurious sulphating of the plates is
minimized.
In order that my invention may be the better understood Figures 1 to 4 are
given shewing the construction of the plates according to my invention.
Figure 1 shews a plate composed of parallel bars united at the two ends into
solid conducting bars.
Figure 2 shews a plate composed of a woven net-work or mat of lead wires,
cast or burnt on to solid conducting bars.
Figure 3 shews a grid perforated part way through on each side with a solid
web of metallic lead, and with conducting bars on the top and across the centre
Figure 4 shews a perforated plate or grid with a solid top and centre rib.
The bars a a a are protected as before described against the action of the sulphur
at the heat of melting lead.
The plates produced according to my invention may be used flat or after they
have been sulphided and reduced to the metallic state may he folded or bent to any
required form, circular or otherwise, before being peroxidised, and the plates may
be used enclosed in envelopes, or supporting frames in manner well understood
by those versed in the art.
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. The improved method of producing plates for secondary or storage batteries
consisting of the protection of certain parts of lead plates or foundations against
the action of sulphur, the treatment of such partly protected lead plates or founda-
tion, in a closed box, with sulphur at or near the melting point of lead, and the
subsequent reduction or peroxidation by electrolytic means, of the prepared surfaces,
substantially as described.
2. The improved method of producing plates for secondary or storage batteries
by treating lead plates or foundations protected as to such parts of their surface as
are not intended to be acted upon, in a closed box with lead sulphide or lead oxide
with sulphur at or near the melting point of lead, and the subsequent reduction
or peroxidation by electrolytic means, substantially as described.
3. The arrangement and construction of parts of the improved plates shewn
and illustrated by Figures 1 to 4 in combination with porous or spongy surfaces
or fillings produced by the sulphiding process, claimed in Claims 1 and 2.
4. An improved electrolyte for use with lead plates in secondary or storage
batteries composed of dilute sulphuric acid containing other sulphur compounds.
such as the thionic acids or salts of the same produced by electrolytically reducing
sulphide of lead or equivalent means in dilute sulphuric acid substantially as and
for the purpose described.
5. In the preparation of plates for secondary or storage batteries, the means
for protecting parts of lead plates or foundations from being acted on by sulphur
in a closed vessel at or near the melting point of lead, substantially as described.
DJ L
1511
1
2
1007
FELL & JAMES,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicant.