IMPROVEMENTS IN GALVANIC BATTERIES AND ELECTRO-CHEMICAL ACCUMU- LATORS
Year: 1881

page_text: LETTERS PATENT to Rookes Evelyn Bell Crompton, of Mansion House
Buildings, Queen Victoria Street, in the City of London, Engineer, and
Desmond Gerald Fitz-Gerald, of No. 6, Ackerman Road, Brixton, in the
County of Surrey. Electrician, for an Invention of IMPROVEMENTS IN
PROVISIONAL SPECIFICATION left by the said Rookes Evelyn Bell
Crompton and Desmond Gerald FitzGerald at the Office of the
Cominissioners of Patents on the 25th November 1881.
ROOKES EVELYN BELL CROMPTON, of Mansion House Buildings, Queen Victoria
Street, in the City of London, Engineer, and DESMOND GERALD FITZ-GERALD, of
No. 6, Ackerman Road, Brixton, in the County of Surrey, Electrician.
"IMPROVEMENTS IN GALVANIC BATTERIES AND ELECTRO-CHEMICAL ACCUMU-
LATORS."
This Invention relates to the construction of the electrodes of galvanic batteries,
especially of the type known as secondary batteries or electro chemical accumu-
lators. In these batteries it is desirable to increase as much as possible the surface
of the electrodes, and sometimes to give to them a structure which permits of large
quantities of gas being occluded or retained at or near the surfaces.
We accomplish this by giving to the electrodes a highly porous structure, and
otherwise extending their surface in the following manner :-The electrode is made
of a mixture of lead and some other substance capable of being extracted aud
removed therefrom by the action of water, acids, or other chemical re-agents, or by
heat, or by electrolysis.
When the mixture has been made into a shape suitable for the electrode the
foreign substance is removed, wholly or partially, by some of the means herein
before referred to, and the lead of the electrode is left with a porous structure,
which greatly increases the surface exposed to the electrolyte, when it is made to
form part of a secondary battery.
-

page_text: The method which we prefer to use is to take an alloy of lead and some suitable
metal, such as sodium, potassium, zinc, or tin. The alloys of lead and sodium may
be cheaply made by exposing a mixture of litharge and carbonato of soda to a
strong heat in a covered crucible, and a similar plan may be adopted to procure
the alloy of lead and potassium, but in general the alloys are most conveniently
made by fusing together lead and the other component metal.
These alloys may be cast into the desired shape, but if they are malleable or
ductile they may be rolled out or pressed into plates of the form required, or
drawn out into wires, which may be coiled in any convenient shape to form
electrodes.
These plates or wires may be used either naked or covered with silk, cotton, or
other suitable substance to prevent contact.
We also form compound electrodes by covering a plate of some suitable metal
with plates of some of the alloys above spoken of; the metal to be used for the
former plates should be one not easily acted on by the electrolyte, and capable of
imparting to the electrode the proper degree of strength and stiffness, and is
preferably an alloy of lead with antimony or some other suitable metal. Such
compound electrodes may also be made by immersing a plate of such a metal into
the alloy while in a state of fusion, or into an amalgam of such an alloy similarly,
by covering a cylinder of some suitable metal with one of the above mentioned
alloys, which is ductile, and drawing out the bar so formed, a compound wire may
be made with an outer covering of the alloy.
In all cases, after the electrode is formed or has been made into a shape
sufficiently near to the form it will have in the battery, the component or com-
ponents of the alloy, other than lead, is wholly or partially removed by one of
the methods herein before referred to, preferably by electrolysis, that is to say, by
being made the anode of a depositing cell.
We also in some cases perforate the electrodes so as to give still greater surface
and to reduce the weight, even to the extent of making the electrode take the
form of a grating or strainer. It is not necessary that the two electrodes of the
battery should be alike in size or perforations, but these can be varied so as to get
the maximum efficiency for the smallest weight.
The surfaces of the electrodes may be amalgamated.
The above method is preferably applied to secondary batteries of the Plantò
type, where the electrodes are of lead.
But it may be also applied to secondary batteries where the electrodes are of
metals other than lead, or to any batteries where it is desirable to give very large
surface to the electrodes, or either of them.
If the component, other than the metal of which the electrode is to be formed,
is itself not a metal, so that the two do not form an alloy, a similar method is
employed. The mixture is formed by any suitable means into electrodes of suitable
shape, and the other component is then removed from the metal (wholly or
partially) by the action of water, acids, or other chemical re-agents, or by heat,
or by electrolysis. The various subsidiary treatments given above can also be
applied to this method so far as the nature of the substances permits.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Rookes Evelyn Bell Crompton and Desmond Gerald Fitz-Gerald
in the Great Seal Patent Office on the 25th May 1882.
ROOKES EVELYN BELL CROMPTON, of Mansion House Buildings, Queen Victoria
Street, in the City of London, Engineer, and DESMOND GERALD FITZ-GERALD, of
No. 6, Ackerman Road, Brixton, in the County of Surrey, Electrician.
"IMPROVEMENTS IN GALVANIC BATTERIES AND ELECTRO-CHEMICAL ACCUMU-
LATORS."
This Invention relates to the construction of the electrodes of galvanic batteries,
especially of the type known as secondary batteries or electro-chemical accu-
mulators. In these batteries it is desirable to increase as much as possible the
surface of the electrodes, and sometimes to give to them a structure which permits
of large quantities of gas being occluded or retained at or near the surface.
We accomplish this by giving to the electrodes a highly porous structure, and
otherwise extending their surface in the following manner: The electrode is inado
of a mixture or alloy of lead and some other substance capable of being extracted
and removed therefrom by the action of water, acids, or other chemical agents, or by
heat, or by electrolysis
When by fusion, compression, or otherwise the mixture has been made into a
shape suitable for the electrode, the foreign substance is removed wholly or
partially by some of the means herein before referred to, and the lead of the
electrode is left with a porous structure which greatly increases the surface
exposed to the electrolyte when it is made to form part of a secondary battery.
The method which we prefer to use is to take an alloy of lead and some suitable
metal, such as sodium, potassium, or zine, or a compound alloy of lead with two of
the above substances. The alloys of lead and sudium may be cheaply made by
exposing a mixture of litharge and carbonate of soda to a strong heat in a covered
crucible, and a similar plan may be adopted to procure the alloy of lead and
potassiuin, but in general the alloys are most conveniently made by fusing together
lead and the other component inetals.
These alloys may be cast into the desired shape, but if they are malleable or
ductile they may be rolled out or pressed into plates of the form required, or drawn
out into wires, which may be coiled in any convenicut shape to form electrodes,
either or both "wire" or plate being treated as before described so as to leave the
lead as a porous structure.
These plates or wires may be used either naked or covered with silk, cotton, or
other suitable substance to prevent contact.
We also form compound electrodes by covering a plate of some suitable metal
with plates of some of the alloys above spoken of.
Such compouud electrodes may also be made by immersing a plate of such a
metal into the alloy while in a state of fusion, or into an amalgain of such an alloy.
Similarly by covering a cylinder of some suitable metal with one of the above
mentioned alloys, which is ductile, and drawing out the bar so formed, a compound
wire may be made with an outer covering of the alloy.
In all cases, after the electrode is formed or has been made into a shape
sufficiently near to the form it will have in the battery, the component or
components of the alloy other than lead are wholly or partially removed by one of
the methods hereinbefore referred to. If it is to be removed by electrolysis, this is
effected by making the plate the anode of a depositing cell.
The method to be chosen for removing the other component depends on its
bature. If it be soluble in water or any acid or other chemical reagent which
does not attack lead, the removal will be effected by exposing it to the action of

page_text: water or of such acid or reagent, but if it be a metal it will generally be found to
bo most easily removed by electrolysis.
A salt, such as ammonic sulphate in powder, may be brought into admixture
with lead in a state of subdivision and dissolved out by water. Chalk or magnesia
in similar admixture would be dissolved out by an acid. Metals removed preferably
by electrolysis.
We also in some cases perforate the electrodes so as to give still greater surface,
and to reduce the weight even to the extent of making the electrode take the form
of a grating or strainer.
It is not necessary that the two electrodes of the battery should be alike in sizo
or perforations, but these can be varied so as to get the maximum efficiency for
the smallest weight.
The surfaces of the electrodes may be amalgamated.
The above method is preferably applied to secondary batteries of the Plante type
where the electrodes are of lead. But it may be also applied to secondary batteries
where the electrodes are of metal other than lead, or to any batteries where it is
desirable to give very large surface to the electrodes or either of them.
If the component, other than the metal of which the electrode is to be formed,
is itself not a metal, so that the two do not form an alloy, a similar method is
employed, but as has been above stated, it will rarely be found to be removeable
by electrolysis.
The mixture is formed by any suitable means into electrodes of suitable shape
and the other component is then removed from the metal (wholly or partially) by
the action of water, acids, or other chemical agents, or by heat. The various
subsidiary treatments given above can also be applied to this method so far as the
nature of the substances permits.
It is not necessary that the mixture of the metal of the electrode and the other
component should be obtained by fusion. It is often convenient to obtain it by
intimate mechanical mixture of the materials in a finely divided state, sufficient
cohesion being obtained by consolidating them under pressure or by heating them
to such a temperature that a pasty condition is obtained, or by a combination of
the two methods.
More than one of the various methods above described may in some cases bo
advantageously employed in the preparation of the same electrode. For instance
it may be found convenient to commence by removing the other components or
one of them by heat from the outer surface and continuing the operation by a
chemical reagent or by electrolysis, or both.
When we use manganese dioxide (Mn O*) as the other ingredient in the mixture
with finely divided lead, the electrode containing lead and dioxide of manganese
should first be made a cathode in order to reduce the manganese dioxide to a
lower degree of oxidation. Afterwards it may be made an anode in order to
dissolve out the manganese as sulphate, the electrolyte being dilute sulphuric acid.
We are aware that it has been proposed though not known to us or to the
public, or published in any way within this realm prior to the date of our
Patent, save so far as its being contained in a Provisional Specification of
earlier date than this Patent, viz., that granted to Henry Edward Newton
on the 25th day of June 1881, and No. 2782, to employ electrolysis to
the preparation of electrodes by removing thereby the tin from an alloy of
lead and tin. We therefore do not claim generally the use of electrolysis in the
preparation of electrodes for removing one component from an alloy, nor do we
claim the use of an alloy of lead and tin for such purpose. Moreover we havo
found that tin is very unsuitable for the purposes described on account of the
extreme difficulty of extracting the whole of it thoroughly by electrolysis, and it
is necessary so to do to prevent the formation of crystals or aggregations of metal
which lead to sbort circuiting.
But what we do claim as our Invention is as follows:-
First. The method of obtaining in an electrode a porous structure offering large

page_text: surface by the removal through solution, chemical action, or heat, of a component
originally brought into a condition of intimate admixture or combination with
the perimaneut component of the electrode, substantially as herein before
set forth.
Second. The preparation of porous electrodes by the removal through electrolysis
of sodium, potassium, zinc, cadmium, iron, antimony, copper, or silver, from
mixtures or alloys of one or more of these metals with lead, substantially as
herein described.
Third. The construction of electrodes by the compression of mixtures
containing lead in a subdivided state together with a component or com-
ponents to be removed by solution or otherwise, substantially as hereinbofore
Bet forth.
In witness whereof, I, the said Rookes Evelyn Bell Crompton, have hereunto
set my hand and seal, this Twenty third day of May, in the year One
thousand eight hundred and eighty two.
Witness,
ROOKES EVELIN BELL CRUMPTUN. (LS.)
ALFRED GEORGE BROOKES,
59, Chancery Lane,
London.