IMPROVEMENTS IN SECONDARY BATTERIES
Year: 1882

page_text: LETTERS PATENT to Farnham Maxwell-Lyte of the Science Club Savile Row
in the County of Middlesex for an invention of "IMPROVEMENTS IN
SECONDARY BATTERIES."
PROVISIONAL SPECIFICATION left by the said Farnham Maxwell-Lyte
at the Office of the Commissioners of Patents on the 21st March 1882.
FARNHAM MAXWELL LYTE of the Science Club, Savile Row in the County of
Middlesex "IMPROVEMENTS IN SECONDARY BATTERIES."
One of the chief points of the various criticisms with which the existing forms
of the Planté, Faure, and other secondary batteries are assailed, is that the Lead
Binoxide formed on the Anodes when these batteries are being charged (these
anodes becoming cathodes during discharge) is formed and retained in immediate
contact with metallic lead supports, and that this contiguity of the binoxide is
liable to induce a discharge of its excess of oxygen into the subjacent metallic
surfaces, the battery having in consequence during repose a tendency to exhaust
itself spontaneously and to run down. Another defect has been noted in the too
slight thickness of the films of spongy lead formed on the surfaces of the lead plates
inore especially in the Planté form of secondary battery. This has been partially
remedied in the Faure accumulator by coating the plates with red lead or lead
oxides.
I however propose to remedy both these inconveniences and while, by the
method I am about to describe, I render secondary batteries more stable and
permanent by avoiding the contiguity of the binoxide with the metal beneath it,
I increase the EM F obtainable from any given volume or weight of battery by
thickening to any required extent the spongy metal, thus increasing the storage
capacity, I also do away once for all with any lead supports, substituting for
these other inert and inoxidable conducting surfaces,
Several of the insoluble or only slightly soluble salts of lead (among which may
more especially be cited the Haloid Lead Salts such as the chloride, &c) are readily
fusible and may be cast in moulds, and if allowed to solidify, the cakes of lead salt

page_text: .
thus formed may be reduced to the metallic state if placed at the cathode of any
suitable and sufficiently powerful electro generator and immersed in a proper
electrolytic fluid. A. porous, more or less coherent, mass of spongy metallic lead of
any required size or form may be thus produced. Plates or other suitably formed
castings of fusible lead salts having been made and reduced to the condition of such
spongy metal, form a material eminently suited for the construction of secondary
batteries or accumulators of electric energy, such plates or masses being of course
producible of any requisite thickness or form. When such plates of spongy lead
are attached to the anode of an electric generator, another plate being attached to
the cathode, and the whole is immersed in a suitable electrolytic solution (e, g. dilute
sulphuric acid) the anode plate becomes rapidly converted into a mass of lead
binoxide and that, far more speedily than the sheets of lead used in the Planté or
other accumulators, the spongy lead presenting a larger extent of oxidizable
surfaces.
Accumulators may be constructed with such porous lead plates, and instead of
plates, other shapes may be produced such as cylinders, prisms, &c; such an
arrangement presents some remarkable advantages for but a small weight and
quantity of lead may thus be made to yield a large proportion of electro-motive
force. Of course prisms, plates, or cylinders of such fusible lead salts may be
readily cast on central cores of wire or any other form of suitable conducting
material, or the fused lead salt may be run into a network of wire or porous carbon
plates, prisms, or cylinders may be imbibed with the said fused lead salts and the
said salts subsequently electrolysed as already described so that the porous lead
may become deposited actually within the pores of the carbon, or the lead salts
may be suspended and fixed in the solid state within the pores of any other
suitable porous medium so as to agglutinate the plates so to speak and prevent
them from being disintegrated and destroyed by the successive oxidations and
reductions to which they have to be exposed. Like results may be also obtained
by forming plates, cylinders or prisms of the lead salts by compression in place of
fusion, such plates &c, being subsequently electrolysed as already mentioned or any
suitable porous conducting material such as porous carbon, wire network, &c,
having been saturated with a soluble lead salt, this may be converted within the
pores of such support into a suitable haloid or other insoluble or sparingly soluble
salt of lead by immersion in suitable saline solutions such as soluble chlorides,
sulphates &c and the lead within the pores of the support may be then electrolysed
into spongy lead Or even the soluble lead salt may be electrolysed direct into
metallic lead without being rendered first insoluble Lead binoxide may also be
formed direct within the interstices of such porous material by first of all intro-
ducing the lead salt fused or otherwise and then immersing the whole in a solution
of bleaching powder or other suitable oxidising solution.
In any case the plates, cylinders or prisms may be arranged as desired but
forming as they do a material of the utmost porosity combined with coherence,
they may be interspaced easily while kept at the least necessary distance apart
thereby avoiding as far as may be, internal resistance in the arrangement. If
thought desirable such plates, prisms or cylinders as above described may be
reduced electrically to the state of spongy lead by merely being placed for a certain
period in contact with metallic zinc and may be then washed and subsequently
built up into secondary batteries. Of course the plates or prisms of reduced lead
whether made from the cast blocks of lead salts, from the pressed blocks, or from
the imbibed porous carbon or other material and whether such lead plates or
prisms have been previously oxidised to the condition of binoxide or not, may be
built up into compact batteries with separating diaphragins of porous paper, felt,
cloth, plaster, or other suitable material between them as in the Faure, Planté, and
other secondary batteries.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Farnham Maxwell-Lyte in the Great Seal Patent Office on
the 21st September 1882.
FARNHAM MAXWELL LYTE of the Science Club, Savile Row, in the County of
Middlesex "IMPROVEMENTS IN SECONDARY BATTERIES."
One of the chief points of the various criticisms with which the existing forms of
the Planté, Faure, and other secondary batteries are assailed, is that the lead
binoxide formed on the anodes when these batteries are being charged (these
anodes becoming cathodes during discharge) is formed and retained in immediate
contact with metallic lead supports, and that this contiguity of the binoxide is
liable to induce a discharge of its excess of oxygen into the subjacent metallic
surfaces, the battery having in consequence during repose, a tendency to exhaust
itself spontaneously and to run down. Another defect has been noted in the too
slight thickness of the films of spongy lead formed on the surfaces of the lead
plates, more especially in the Planté battery. This has been partially remedied in
the Faure accumulator by coating the plates with red lead or lead oxides. I
however propose to remedy both these inconveniences, and while, by the method I
ain about to describe, I render secondary, batteries more stable and permanent,
I also increase the electro motive force obtainable from any given volume or
weight of battery, by thickening to any required extent the spongy metal, thus
increasing the storage capacity. I also do away altogether with any lead supports-
substituting for these other inert and inoxidizable conducting surfaces.
Several of the insoluble or only slightly soluble salts of lead (among which may
more especially be cited the Haloid Lead Salts such as the chloride &c) are readily
fusible and may be cast in moulds, and if allowed to solidify, the cakes of lead salt
thus formed may be reduced to the metallic state if placed at the cathode of any
suitable and sufficiently powerful electro generator and immersed in a proper
electrolytic fluid. A porous, more or less coherent, mass of spongy metallic lead of
any required size or form may be thus produced. I have discovered that plates, or,
other suitably formed castings of fusible lead salts, having been made of any
requisite thickness or form and reduced to the condition of such spongy metal, are
eminently suited for the electrodes of secondary batteries or accumulators of electric
energy. When such plates of spongy lead are attached to the anode of an electric
generator, another plate being attached to the cathode, and the whole is immersed
in a suitable electrolytic solution (e.g. dilute sulphuric acid) the anode plate
becomes rapidly converted into a mass of lead binoxide, and that, far more speedily
than the sheets of lead used in the Planté or other accumulators, the spongy lead
presenting a larger extent of oxidizable surfaces.
Accumulators may be thus constructed with porous lead plates or electrodes but
instead of plates other shapes may be produced such as cylinders, prisms or
fragments &c; such an arrangement presents some remarkable advantages, for, but a
small weight and quantity of lead may thus be made to yield a large proportion of
electro motive force.
Of course prisms, plates, or cylinders of such fusible lead salts may be readily
cast on central cores or stems of wire or any other suitable conducting material, or
the fused lead salt may be run into a network of wire, or porous carbon or porous
carbon plates, prisms, or cylinders may be imbibed with the said fused lead salts,
and the said salts subsequently electrolysed as already described so that the porous
lead may become deposited actually within the pores of the carbon, or the insoluble
or sparingly soluble lead salts may be suspended and packed or interstratified in

page_text: the solid state within the pores or ramifications of any other suitable porous con-
ducting medium só as to agglutinate the plates, so to speak, and prevent them
from being disintegrated and destroyed by the successive oxidations and reductions
to which they have to be exposed.
I may also imbibe any suitable porous conducting material such as porous
carbon, wire network, &c, with a soluble lead salt, and convert the latter within
the pores of such support into a suitable haloid or other insoluble or sparingly
soluble salt of lead by immersion in suitable saline solutions such as soluble
chlorides, sulphates, &c, the lead within the pores of the support being subsequently
electrolysed into spongy lead.
The plates, cylinders, or prisms may be arranged as desired, but forming as they
do a composite substance of great porosity combined with coherence, they may be
interspaced easily while kept at the least necessary distance apart, thereby
avoiding as far as may be, internal resistance in the battery.
If thought desirable such plates, prisms, or cylinders as above described may be
reduced electrically to the state of spongy lead by merely being placed for a certain
period in contact with metallic zinc, and may be then washed and subsequently
built up into secondary batteries.
The plates or prisms of reduced lead, whether made from the cast blocks of lead
salts, or from the imbibed porous carbon or other material (whether such lead
plates or prisms have been previously oxidised to the condition of binoxide or not)
may be built up into compact batteries with separating diaphragms of porous
paper, felt, cloth, plaster, or other suitable material between them as in the Faure,
Planté, and other secondary batteries.
Having described the nature of my Invention and the manner of performing the
same, I declare that what I claim as my Invention to be protected by the lierein-
before in part recited Letters Patent is.
1st. The manufacture of electrodes for secondary batteries of insoluble or but
slightly soluble lead salts fused and cast into plates, fragments, or masses of any
desired form, or upon conducting cores or supports, substantially as specified, the
said salts being reduced to the metallic state by electrolysis and the battery
constituted, as usual, by reoxidation of one of the poles.
2nd. In the manufacture of electrodes for secondary batteries, the introduction
of the said insoluble or but slightly soluble salts of lead within the pores or
ramifications of a wire network or porous carbon support by fusion or packing
substantially as specified.
3rd. In the manufacture of electrodes of secondary batteries, the production of
the insoluble or sparingly soluble salts of lead by double decomposition within the
pores of a porous conducting medium as specified.
In Witness whereof I the said Farnham Maxwell Lyte have hereunto set my
hand and seal this twentieth day of September, A.D. 1882.