Improvements in Secondary Batteries.
Year: 1892

page_text: Date of Application, 8th June, 1892
Complete Specification Left, 8th Mar., 1893-Accepted, 20th May. 1893
PROVISIONAL SPECIFICATION.
Improvements in Secondary Batteries.
HUGH FITZALIS KIRKPATRICK-PICARD 59 Abbey Road London N.W. in the
County of Middlesex, Metallurgical Engineer, and HENRY TILAME 112 St. Stephens
Avenue Shepherds Bush in the County of Middlesex Electrical Engineer do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in secondary batteries and has for its
object the obtaining of a plate or element which shall be as near as possible in the
form of spongey lead before the application of any electric current to the said plate
or element.
The manufacture is based upon the fact that red lead Pb,O, can be reduced to
metallic lead by an admixture of a due proportion of sulphide of lead PbS with
the simultaneous formation of sulphur dioxide.
Let it be understood that we do not confine ourselves to any definate quantity
or proportion of either constituent nor do we necessarily confine ourselves to
sulphide of lead as the only available reducing agent nor to red lead as the only
available oxide of lead. Any other suitable material may do.
The method of manufacture may be as follows :-
Red lead is mixed mechanically or otherwise with sulphide of lead either
artificially fused pulverized, or precipitated or the natural mineral galena may be
employed.
The mixture may also contain a suitable amount of bone ash or other binding
material as may be thought desirable, or asbestos or other fibre may be incorporated
and sprinkled with the mixture.
An amount of the said mixture sufficient to make one plate or element, damped
with water, stale beer or any suitable damping agent, is then moulded by pressure
in a mould or suitable contrivance, which may be rectangular, bevelled dovetailed,
slotted or any other shape as may be required, and any suitable means of obtaining
pressure may be employed.
The moulded plate or element is then transferred to a suitable fireproof bed as
brick, cast iron, or other convenient material.
The bed may or may not be previously sprinkled with charcoal, or other reducing
material to prevent atmospheric oxidation from travelling too deep into the element
during the subsequent firing.
Having transferred the element a further sprinkling of charcoal or other reducing
material, may cover the element for the same reason as stated when placing charcoal
under the said element.
The elements are then allowed to dry for a convenient time, when dry they are
fired in a suitable furnace which may be a muffle, a wind furnace, or any convenient
apparatus for applying heat to the said elements.
The heat to be applied is to be such that the chemical re-action between the
sulphide of lead or other reducing material with the oxide of lead shall take place,
but the heat must not be sufficient to cause the complete fusion of the subsequent
element.
The element may be annealed both during the putting in and the removal from
the furnace if thought desirable.
After a convenient time according to the heat of the furnace, which time may
vary from five minutes to half an hour, or beyond these limits, if necessary, the
plates may be withdrawn from the furnace. The time must not be so long as to
allow atmospheric oxidation to penetrate throughout the plate and cause the spongy
plate produced to re-oxidize to litharge.

page_text: The resultant element consists of a central layer of spongy lead, with the edges,.
top and bottom, somewhat oxidized to litharge.
The element is porous to a high degree owing to the evolution of sulphur
dioxide, during the re-action, should any fractures occur in the element at any time
they may be repaired by fusing in oxide of lead or lead under a suitable source
of heat.
The element or plate so prepared is now ready to receive a lead frame or suitable
conducting pieces for connecting on to other similarly prepared elements. This
may be done by placing the plate or element in a frame and pouring molten lead
round the edges in a suitable mould or by dipping or allowing the edges of the
element or plate to rest in molten lead, or other suitable metallic mixture which
at a certain temperature rigidly and firmly adheres to the edges of the plate or
element on solidification. The element or plate thus produced with its metallic
frame can then have its frame, edges and connecting piece or pieces covered with
semi vulcanized india rubber and vulcanized in any of the known ways. Seperators,
feet, and projections, for keeping the plates apart at any suitable distances can also
be vulcanized on to suit any requirements. They are then ready to be placed into
cells or the usual receptacles with acid and water, sulphate of soda or any of the
commonly employed media and be charged electrically by any of the usual
methods.
Dated this Eighth day of June 1892.
HUGH FITZALIS KIRKPATRICK-PICARD,
59, Abbey Road, London, N.W., Middlesex.
HENRY
THAME,
112, St. Stephen's Avenue, Shepherd's Bush, London, W.
เ
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COMPLETE SPECIFICATION.
Improvements in Secondary Batteries.
We, HUGH FITZALIS KIRKPATRICK-PICARD, of 59 Abbey Road, London,
N.W. in the County of Middlesex, Metallurgical Engineer, and HENRY THAME
of 112 St. Stephens Avenue, Shepherds Bush, in the County of Middlesex,
Electrical Engineer, do hereby declare the nature of our 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 the manufacture of porous metallic lead plates for
secondary electrical batteries and to supports for the same.
The object of this invention is to get a plate or element which shall as near as
possible be in the form of true spongy lead before the application of any electric
current to the said plate or elements.
Our invention consists in the specific process of manufacure of the said plates
hereinafter described, and in the plate produced therefrom, also in the frames and
supports for same.
The process of manufacture is based upon the fact that an oxide of lead, such as
red lead (Pb,O) can be reduced to metallic lead by an admixture of a reducing
agent therewith, such as sulphide of lead (PbS), with the simultaneous formation
of a gas, which in the above example would be sulphur dioxide. Let it here be
understood that we do not confine ourselves to any definite quantity or proportion
of either constituent, nor do we necessarily confine ourselves to sulphide of lead as
the only available reducing agent, nor to red lead as the only available oxide of
lead. Any other suitable material which will act equivalently may be employed.
The method of manufacture may be as follows:
Red lead is mixed mechanically with sulphide of lead, either artificially fused and
pulverized or precipitated or the natural mineral, "galena," may be employed.
We find that about three parts of PbS, to one part of said oxide, are about the

page_text: proper proportions in practice, as the atmospheric oxidation produced must be
allowed for; which would not be the case, if the quantities demanded by theory
were employed.
An amount of the said mixture sufficient to make one plate or element is damped
with water, stale beer, or any suitable damping agent, but preferably treacle, to
form a plastic mass, and moulded by pressure in a mould or suitable contrivance.
which may be rectangular, bevelled, dovetailed, slotted or any other shape as may
be required.
Any suitable means of obtaining pressure may be employed.
The moulded plate or element is then transferred to a suitable fire-proof bed, as.
brick, cast-iron, or other convenient material.
The elements are then allowed to dry for a convenient time; when dry, they are
fired in a suitable furnace which may be a muffle, a wind furnace, or any convenient
apparatus for applying heat to the said elements. We prefer to fire on thin strips
of carbon so disposed as to allow circulation of air over and under the plate. The
plates may be fired in stacks, each being separated from the other by strips of
carbon rod, disposed according to size of plate etc.
The heat to be applied is to be such that the chemical reaction between the
sulphide of lead or other reducing material with the oxide of lead shall take place,.
but the heat should not be sufficient to cause the complete fusion of the subsequent
element, otherwise a litbarge plate would be produced by reason of the ready
oxidation of the metallic lead by the atmosphere at a high temperature.
We find
a temperature of from 500° to 600° centigrade gives good results.
The element may be annealed both during the putting in and the removal from
the furnace if thought desirable.
After a convenient time according to the heat of the furnace, which time may
vary from five minutes to half-an-hour, or beyond these limits if necessary, the
plates or elements are withdrawn from the furnace, however the time must not be
so long as to allow atmospheric oxidation to penetrate throughout the plate and
cause the spongy plate produced to re-oxidize to litharge.
The resultant element consists of a central layer of spongy lead with the edges,
top and bottom somewhat oxidized to litharge. The element is porous to a high
degree owing to the evolution of sulphur dioxide during the reaction.
Should any fractures occur in the element at any time they may be repaired by
fusing in oxide of lead or lead under a suitable source of heat.
The clement or plate so prepared is now ready to receive a lead frame or suitable
conducting pieces for connecting on to other similarly prepared elements. This
may be done by placing the plates or elements in a frame and pouring molten lead
round the edges in a suitable mould or by dipping or allowing the edges of the
element or plate to rest in molten lead or other suitable metallic mixture, which, at
a certain temperature, rigidly and firmly adheres to the edges of the plate or
element on solidification, but we prefer to cut out a rectangular piece of the plate
about one inch from the edge and having inserted the end of a pole piece, which
should fit the space left by the cutting away, we burn the pole piece to the body of
the plate. We do not put any metal frame round, but a vulcanite one direct on to
the plate.
The edges of the metallic plates or elements thus produced can afterwards be
covered with semi or partially vulcanized rubber and vulcanized in any of the well
known ways. Separators, feet and projections, can now be vulcanized onto the
plates or elements to suit any particular requirements; and the plates are then ready
to be placed into cells or the usual receptacles, containing acid and water, with
sulphate of soda or any of the commonly employed media, and are then ready to be
charged electrically by any of the well known methods.
Having now particularly described and ascertained the nature of our invention
and in what manner the same is to be performed, we declare that what we claim is :-
1st. A process for the manufacture of plates for secondary electrical batteries

page_text: t
consisting of the intimate mechanical mixture of certain proportions of oxide of lead
and a reducing agent such as PbS or carbon, the moulding of the said mixture in a
plastic condition into any shape, treatment of the moulded plate in a furnace at
such a temperature as to produce the mutual reaction of the oxide and reducing
agent to form a porous plate of metallic lead.
2nd. A plate for secondary electrical batteries, consisting of a centre of spongy
metallic lead surrounded by a frame of india rubber, vulcanised thereon, produced
substantially as described.
3rd. The application of india rubber to the sides and edges of a secondary battery
plate, and vulcanising of the said rubber in position to form a frame and separators
upon the said plate, substantially as and for the purposes described.
Dated this 7th day of March 1893.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.