IMPROVEMENTS IN SECONDARY BATTERIES
Year: 1881

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS IN SECONDARY
BATTERIES." A communication from abroad by Nicolas de Kabath, of Paris,
Branco
PROVISIONAL SPECIFICATION left by the said William Clark at the Office
of the Commissioners of Patents on the 19th September 1881.
WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex, Patent
Agent. "IMPROVEMENTS IN SECONDARY BATTERIES." [A communication from
abroad by Nicolas de Kabath, of Paris, France.]
Plante's secondary battery as hitherto constructed is capable of storing only a
very limited quantity of electricity per unit of surface of the electrode. This
proportion of electricity depends on the thickness of the layer of binoxide of lead
(Pb O) deposited on the positive plate, and of that of the spongy lead in powder
(Pb) deposited on the negative plate. As the thickness of these layers is necessarily
very restricted, since they fall off if a certain thickness be exceeded, the accu-
mulating capacity of the apparatus is consequently limited, and the employment of
Plante's battery as heretofore constructed is therefore subordinated to a given limit
which cannot be exceeded without danger of destroying the apparatus.
The construction and preparation of Plante's battery is a long and delicate
operation requiring scrupulous attention, especially as regards the layers of binoxide
of lead (Pb O'), and of lead (Pb). To prepare the apparatus for work it is
indispensable to employ a current of limited intensity, but as constant as possible
during the whole time of preparation (which requires 6 or 7 days), otherwise the
layers of lead instead of each forming a uniform and homogeneous mass will be
divided into layers of different thicknesses, and consequently become more readily
detached from the electrodes.
The object of this Invention is to avoid these objections, and to furnish an
apparatus for accumulating or storing electricity in which the layer of binoxide of
lead with which the positive plate becomes coated and that of spongy lead with

page_text: which the negative plate becomes coated, as the elements by which the accu-
mulation is effected may be of great thickness as compared with those of the Planté
battery without the possibility of becoming detached from the plates, and thereby
arresting the accumulation.
These layers may be properly formed whatever may be the variation of the
current, and but a relatively short time is required for their formation.
To construct the apparatus of this Invention I take a sheet of lead a half a
millimetre in thickness (Figure 1), which I moisten with sulphuric acid (H2SO4)
slightly concentrated in order to form upon its surface a thin layer of sulphate of
lead (Pb SO). I prepare in the same way other plates of lead of about 1/10th of a
millimetre in thickness. I cover the plate a with these thin plates b, suitably
prepared, as shown by way of example in Figure 1 of the accompanying Drawings,
so that their extremities are placed upwards in the apparatus in order to permit of
the escape of the gases generated when the apparatus is charged. The plates thus
arranged are enveloped in one or more thicknesses of artificial parchment c
according to the internal resistance desired. This parchment plays a triple rôle ;
it serves to hold together the plates, it increases the internal resistance of the
battery, and it serves to insulate from one another the compound plates or
electrodes. The plates thus combined may be of any suitable form; for example,
they may be of either of the flat or corrugated forms, shown in Figures 2 and 3.
The plates thus prepared are grouped in the accumulator, as shown in Figure 4.
The number of pairs of electrodes of the accumulator is unlimited, and they may
be arranged either parallel to one another or in the transverse direction so as to
act for quantity or tension.
The whole of the pairs are enclosed in a parchment sheet whose joins as well as:
those of the wrappers of the electrodes are made with a solution of guttapercha in
chloroform. The whole is then placed in a lead box d (Figure 4) whose sides are
also covered with thin sheet lead, since in the working of the accumulator they act
in combination with an uneven number of electrodes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Clark in the Great Seal Patent Office on the 17th March
1882.
WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex, Patent
Agent.
"IMPROVEMENTS IN SECONDARY BATTERIES." A communication from
abroad by Nicolas de Kabath, of Paris, France.
Plante's secondary battery as hitherto constructed is capable of storing only a
very limited quantity of electric energy per unit of surface of the electrode. This
proportion of electric energy depends on the thickness of the film or layer of
binoxide of lead (Pb O²) formed on the anode, and of that of the spongy lead in
powder (Pb) formed on the kathode. As these layers are necessarily of very
limited thickness (since they fall off if they exceed a certain depth) the accu-
mulating capacity of the apparatus is consequently limited, and the employment of
Plante's battery as heretofore constructed is therefore restricted by limits which
cannot be exceeded without danger of destroying the apparatus.
The "formation" of Planté's battery is a long and tedious operation requiring
scrupulous attention to the production of the films or layers of binoxide of lead and
of spongy lead. To prepare the apparatus for work it is indispensable to employ
a current of low intensity but as constant as possible during the whole time of
"formation" (which requires 6 or 7 days), otherwise the layers of lead instead of
being uniform and homogeneous will split up or divide into films of different
thicknesses easily detachable from the electrodes.
The object of this Invention is to avoid these objections, and to construct an
apparatus for accumulating or storing electric energy in which the layers of
binoxide of lead and of spongy lead with which the anode and kathode become
conted may be of great thickness as compared with those of the Planté battery
without liability of becoming detached.
These layers are properly formed in a relatively short time notwithstanding
variations of the current, and the electrodes are so arranged as to present a large
extent of surface in a small compass and of little weight.
In order that the Invention may be more readily understood, I have illustrated
the construction of this improved accumulator in the accompanying Drawings, and
will proceed to describe it with reference thereto.
I take as a support a sheet of lead a (Figure 1) half a millimetre in thickness,
which I moisten with dilute sulphuric acid (H2SO4) in order to form upon its
surface a thin layer of sulphate of lead (PbSO.); I also prepare in the same way
other thin plates or lamina of lead b, about 1/4 of a millimetre in thickness. I
then cover the plate a with these thin plates 6 when suitably prepared by folding
them around it, as shown by way of example in Figure 1 of the accompanying
Drawings, so that their extremities are upwards in the cell in order to permit of
the escape of the gases generated in charging. The plates thus arranged are
enveloped in one or more thicknesses of artificial parchment c according to the
internal resistance desired. This parchment holds together the plates or lamina
composing the electrode, increases the internal resistance of the battery, and serves
to insulate from one another the composite electrodes. The plates thus combined
may be of any suitable form; for example, they may be of either of the flat or
corrugated forms, shewn in Figures 2 and 3.
The composite electrodes may also be made of a combination of corrugated or
undulated strips or plates and of flat strips or plates, arranged alternately as seen,

page_text: surrounded by an envelope of parchment paper or other analogous material, and
placed in a lead box or cell covered interiorly with thin sheets of lead, prepared in
a similar manner to and acting in combination with the electrodes, the whole
substantially as described with reference to Figure 11 of the Drawings.
In witness whereof, I, the said William Clark, have hereunto set my hand
and seal, this Seventeenth day of March, in the year of our Lord One
thousand eight hundred and eighty two.
TUM CLARK
1