An Improved Method of Manufacture of Elements or Plates for Secondary Batteries.
Year: 1893

page_text: Date of Application, 11th, Jan., 1893
Complete Specification Left, 10th- Oct., 1893-Accepted, 6th Jan., 1894
PROVISIONAL SPECIFICATION.
An Improved Method of Manufacture of Elements or Plates for
Secondary Batteries.
We, HUGH FITZALIS KIRKPATRICK PICARD of 59 Abbey Road in the
County of Middlesex, Metallurgical Engineer, and HENRY THAME of.
67 Macfarlane Road, Shepherds Bush, in the County of Middlesex, Engineer, do
hereby declare the nature of this invention to be as follows:-
Our invention relates to an improved method of manufacture of elements or
plates for secondary batteries, and has for its object the production of an element
or plate of which the body is of finely crystalline salts of lead, or salts of lead and
metallic lead intimately commingled, and is homogeneously and metallically con-
nected to an upper rim of lead, by which, or on which, a pole piece may be formed
with perfect metallic continuity from the body of the plate or element.
We are aware that many attempts have been made to produce a compound
plate or battery element of lead and salts of lead, but without the perfect
attainment of the above objects for which our improved manufacture has been
devised.
To obtain absolute metallic continuity between a pole piece of lead, and a body
of salts of lead, or mixed salts and metallic lead, we find it necessary to use a
metallic mould of which the internal walls are first lubricated by some suitable
material, such as talc, chalk, or graphite (which last material is that we most
prefer). The mould is then heated to a dull red, and allowed to cool until the red
colour just disappears. We attach importance to the above described temperature
of the mould, as the fine crystalline character of the element when cooled is greatly
dependent upon the high temperature of the mould when the molten salt is poured,
and the consequent gradual cooling.
+
The mould is preferably placed in a vertical position, and a suitable amount of
metallic lead is poured into the bottom of the mould to form a pole-rim, on which
a pole piece can be cast or afterwards easily attached.
Whilst the said lead pole-rim is still molten, the body of the element or plate is
poured in, supplied from any suitable fused salt of lead, and, on cooling, the salt is
found to be finely crystalline in structure, and homogeneously and metallically
connected to the lead pole-rim.
.
The body of the plate or element may be prepared and cast as an intimate
mixture of a salt of lead (such as galena) and minute particles of metallic lead, in
the following manner.
We melt the salt of lead such as the galena, in one crucible and metallic lead
in. another crucible which should be raised at least to the same temperature as that
of the molten galena, so that there may be no premature cooling and solidification
of the galena upon mixture. We then mix the molten lead with the fused salt or
galena by pouring the contents of one crucible into the other, preferably the lead
on to the fused salt. The admixture of the lead with the salt, is facilitated by
pouring the lead slowly and from a considerable height into the other crucible.
We further rely upon the material mixing during the pouring of the salt and lead
into the body of the mould, which is now done, and the complete element or plate
formed with pole rim.
If it is thought desirable the plate may be submitted to a roasting process to
oxidize the lead salt, means being taken to protect the lead pole-rim from excessive
or oxidizing heat.

page_text: These plates or elements may, after having been prepared by our improved
method of manufacture as hereinabove described, be submitted to any suitable
vulcanizing process.
Dated this 11th day of January 1892.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.
An Improved Method of Manufacture of Elements or Plates for
Secondary Batteries..
We HUGH FITZALIS KIRKPATRICK PICARD of 59 Abbey Road in the County
of Middlesex, Metallurgical Engineer, and HENRY THAME late of 67 Macfarlane
Road Shepherds Bush in the County of Middlesex, but now of 3 Lawn Terrace,
East Hill, Wandsworth, in the County of Surrey, 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:—
Our invention relates to an improved method of manufacture of elements or
plates for secondary batteries, and has for its object the production of an element
or plate of which the body is of a finely crystalline and strong salt of lead, namely
a sub-sulphide of lead, artificially prepared as hereinafter described, and though
eventually becoming more porous by elimination of sulphur is durable and where
desired is homogeneously and metallically connected to an upper rim or portion of
a rim of lead, on which a pole piece may be formed with perfect metallic continuity
from the body of the plate or element.
We are aware that many attempts have been made to produce a compound plate
or battery element of lead and salts of lead, in which the salts such as lead sulphide
have been packed within a supporting frame of lead, but such crushed, packed lead
sulphide has proved too rotten under subsequent electrical action to stand alone,
and such plates have not attained the above objects for which our improved
manufacture has been devised.
.
To carry our invention into effect we use a metallic mould of which the internal
walls are first lubricated by some suitable material, such as talc, chalk, or graphite
(which last material is that we most prefer).
We heat the mould and gates of the mould to prevent the chilling of the molten
material when poured into the mould and to maintain the molten condition of a
first charge of lead to form a pole rim until the body of the plate has formed a
homogeneous and metallic attachment thereto.
The mould is preferably placed in a vertical position, and a suitable amount of
metallic lead is poured into the bottom of the mould to form a pole rim on which a
pole piece can be afterwards burnt.
Where a. complete lead pole rim is not needed we have found that our plate,
made as described above, is so strong and durable that a part rim or a piece
restricted to a corner is sufficient for the attachment of the pole piece, and the
plate is sufficiently durable and homogeneous to enable us to cut out a piece of the
plate cast without a lead pole rim and to burn in a pole piece.
Whilst the said lead pole-rim where used is still molten, the body of the element
or plate prepared as hereinafter described is poured into the mould, and on cooling
the salt of the body of the plate is found to be finely crystalline in structure, and
though even somewhat porous, now by crystallisation and afterwards still more
porous by elimination of the sulphur, to be strong, durable and self supporting
without a frame, and also to be homogeneously and metallically connected to the
lead pole rim.

page_text: The body of the plate or element is prepared as follows:-
We melt galena in one crucible and metallic lead in another crucible, raising
them to about the same temperature.
We then mix the molten lead and galena together preferably in about equal
weight. This is most conveniently done by pouring the lead slowly and from a
considerable height into the crucible containing the molten galena, and the mixture
which thus becomes an artificial sub-sulphide of lead and is finely crystalline on
cooling, and homogeneous, is poured into the heated metallic mould to form the
plate or element. The plate may be cast in any desired form, either flat,
corrugated, cylindrical, or in any convenient shape.
If it is thought desirable the plate may be submitted to a roasting process to
oxidize the lead salt forming the body of the plate, means being taken to protect
the lead pole rim from excessive or oxidizing heat.
These plates may after having been prepared by our above described method of
manufacture be submitted to any suitable vulcanizing process to insulate them
from one another and the cell; or feet of vulcanite or other insulating material
may be fitted into the under side of the plate. The plates are now ready to be
put into cells and formed by any suitable method.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1st. A method of manufacture of elements or plates for secondary batteries,
consisting of melting separately galena and metallic lead, mixing the same, and
pouring the mixture in a molten condition into a heated metallic mould substan-
tially as described,
2nd. An element or plate for secondary batteries, consisting of a mixture of
molten lead and molten galena, and manufactured substantially as described.
3rd. In the manufacture of elements or plates for secondary batteries, the
placing of a molten lead pole rim or portion of a rim at the bottom of a heated
mould, and the pouring thereon a molten mixture of metallic lead and galena to
form a homogeneous plate substantially as described.
4th. An element of plate for secondary batteries, consisting, as to its body, of a
mixture of molten lead and molten galena, and, as to one end or portion of one end
of a pole rim of metallic lead, homogeneously and metallically connected to the
said body by the method of manufacture substantially as described.
Dated this 11th day of January 1893.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.