Year: 1886

page_text: Date of Application, 22nd June, 1886.
Complete Left, 22nd Mar., 1887.
Complete Accepted, 22nd Apr., 1887.
RESERV
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 53,
Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent Agents,
do hereby declare the nature of this Invention to be as follows:-
My Invention relates to secondary batteries, or electrical accumulators. I havo
found that the action of the battery, whatever may be its form or arrangement, is
considerably increased if the electrolytic liquid contains cadmium, or tin, in solution ;
owing to the fact that in charging the accumulator these metals are deposited upon
the electrode at the negative pole, and during discharge yield a better result than lead
or other metals. Cobalt, nickel, or bismuth, may also be similarly employed, but with
less advantage than cadmium or tin which are more electro-positive than lead, and
deposit more readily from acid solutions.
These metals may be employed in different forms, but the best results have been
obtained with the solutions hereafter mentioned, in which these inetals are
contained ;-
Water
Sulphuric acid
Sulphate of tin
900
Water
100
300
Sulphuric acid
Sulphate of cadmium
950
50
*300
With these solutions the metal deposits readily; it is barely attacked at all when
the circuit is open but it is attacked with great uniformity when the circuit is closed.
The addition of a little bi-sulphate of mercury to the above mentioned liquids renders
the action still more regular.
As the action of the electrodes at the negative pole is derived mainly from the tin
or cadmium which is deposited in charging, these electrodes may consist simply of
conductive plates of carbon, lead, copper, tin, or cadmium, either pure or alloyed with
other and less oxidizable metals.
My Invention further relates to the construction of the electrodes at the positive
pole, which I will describe with reference to the accompanying drawings.

page_text: Referring to Figure 1, a lead support, composed of a central rod C, a number of
longitudinal radial strips A, and a bottom plate B, is placed in a porous vase D, as
shown in Figure 3, and the spaces between the strips A are then filled with per-oxide
of lead, or other material capable of producing the same by oxidation, which is mixed
with a little water, slightly acidulated with sulphuric acid. Or, as shown in Figure 2,
the longitudinal radial strips of the support may be replaced by transverse or hori-
zontal, strips or discs or by spiral surfaces or by wires or points like a cylindrical
brush.
The electrode thus constituted enables the accumulator to be made in the form of
an ordinary battery by placing the porous vase thus prepared in a second vessel E of
glass (figure 4 for example) which contains the electrode F of the negative pole.
This electrode may be constituted by a simple plate or strip of lead, flat, corrugated, or
folded, which lines the bottom of the vessel, and surrounds the porous vase 1. This
plate or strip should be perforated with large holes as shown in Figure 5 (which
represents the development of the electrode) to permit the free circulation of the
liquid in which it is immersed, and which is the solution of tin or cadmium above
mentioned.
For large accumulators, I use water tight barrels in which I place a positive of
corresponding dimensions, or several small ones united together, of simple plates of lead
which line the bottom and surround the positive, form the electrode at the negative
pole on which the tin or cadmium is deposited in charging. Tin is better suited than
cadmium for accumulators with a porous cell as described, but cadmium is better for
those in which the electrodes are immersed directly in the liquid.
For the electrode at the negative pole, I may employ, in lien of lead, plates of
copper, nickel, or other metal less electro-positive than tin or cadmiums, as then these
metals are not attacked. I may also use plates of tin, or cadmium, directly by merely
employing water, plus 250 grammes of sulphuric acid per litre, as in that case sulphate
of tin, or cadmium is formed at the expense of the plates when the battery is
discharged.
To increase the duration of the electrodes at the positive pole, I have invented an
improvement which consists in protecting a part of the conducting surface of the
electrodes, by drawing, with an insulating varnish, vertical and horizontal, lines two
or three millimetres wide and about two millimetres apart. These lines form a reticu-
lated network which is protected from oxidation during a certain time, and which thus
increases the durability of the electrode. For this purpose, I may use a varnish made
with bitumen of Judea, gutta-percha, or other insulating materials; I may also use a
solution of platinum chloride in essence of lavender. In this case, the network having
been traced as above described, the metal is dried, and the platinum reduced by
submitting the electrode to the positive pole of a battery. The reduced platinum
preserves the subjacent metal from oxidation, and augments the duration of the
electrode.
To prevent the tangs of the electrodes from being attacked, and the liquids and salts
from creeping, as commonly happens, it is only necessary to envelop the tangs in
india-rubber tubes which dip just below the level of the liquid.
Dan:. 53. 1
T
1
A. M. CLARK.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Secondary Batteries or Accumulators."
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 53,
Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent Agents,
do hereby declare the nature of this Invention (a communication to me from abroad by
Antoine Edouard Peyrusson of Paris France) 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 improvements in Secondary Batteries or electrical accu-
mulators. The electrode at the negative pole is formed of a simple conducting plate
which may be of lead, copper, carbon, etc, immersed in one or other of the two
following acid solutions
Water
Sulphuric acid
Sulphate of tin
-
700
100
-
300
Water
Sulphuric acid
Sulphate of cadmium
700
50
300
Although the proportions may be varied, it is indispensable, in order to obtain good
results, that the cadmium solution should not contain more than 35% of sulphuric
acid including that which enters into the composition of the sulphate of cadmium,
while the sulphate of tin solution should not contain more than 45 % of sulphuric acid
including that entering into the composition of the sulphate of tin.
In charging the accumulator, the cadmium or tin of the solution is deposited on the
conducting plate or electrode, and if the liquid conforms to the prescribed conditions
the metal remains adherent in a pulverulent form while the circuit is open which
ensures the retention of electricity, whereas when the circuit is closed-that is to say-
when discharging the accumulator, the metals become rapidly attacked by the liquid
and re-dissolved. The great superiority of the electrodes thus constituted is due to
the combination of the following advantages
1st. Greater storage capacity, as the tin and cadmium in dissolving act throughout
their entire mass.
2nd. Better retention of the electricity, as these metals are not attacked in open
circuit in liquids of the composition above mentioned.
3rd. The electrodes do not require to be electrically "formed."
4th. The deposit of metal formed on the electrode in charging shews when they are
charged or whether they are run down which is impossible with ordinary accumulators.
5th. The accumulators develop a greater electro-motive force which, in the case of
cadmium, amounts to 2 volts 15 instead of 1 volt $5.
The electrodes at the positive pole of these accumulators are formed of blocks of
peroxide of lead with a conducting frame of lead distributed throughout the mass.
Electrodes of this kind possess great advantages, as compared with those made in the
form of plates, but they have the objection that their external surface is much nearer
to the opposite electrode than their central portion, so that in charging, the electricity
tends under the influence of the opposite electrode, to become condensed at the external
portions, the whole of the central portion being inactive, thus diminishing the storage
capacity of the accumulator. To neutralize this tendency of the electricity to accu-
mulate at the surface adjacent to the opposite electrode and distribute it uniformly

page_text: throughout the entire mass of the electrode and so increase the storage capacity of the
accumulator the arrangement represented in the accompanying drawings is adopted.
To this end, the conductive support of the electrode is made of the radiating form
shewn in figure 1, in which it is represented as composed of strips or blades A radi-
ating from a central rod or boss C and a bottom plate B. The radiating strips A are
necessarily much closer together near the centre than at the circumference, and as
this proximity reduces the electrical resistance at the central part, the electricity has a
tendency to pass in this direction instead of concentrating at the circumference to
which it is attracted by the proximity of the opposite electrode and under the influence
of these two counter attractions it becomes uniformly distributed throughout the
electrode.
If a lead support of the form shewn in Figure 1 be placed in a porous vessel and
the spaces between the radial strips A be entirely filled with a depolarizing agent,
such as peroxide of lead for example, the electrode will be active throughout its entire
mass and in which the electricity acts to the very centre, this result being unattainable
with electrodes of any other form whose conductive portions are not similarly
convergent, consequently less resistant towards the centre than at the circumference.
Not only is the storage capacity increased by the whole mass participating in the
action, but the electricity has less tendency to disengage spontaneously than when
concentrated at the surface as usual. Moreover, the durability of the electrode is
greater, as the edges of the conducting strips, instead of their flat surfaces, are
attacked. They can never get out of shape, and may be charged up to 5 or 6 ampères
per kilogramme without injury. There is no risk of short circuiting, or of damage
by transport from place to place, or shaking &c. and they can be easily replaced.
The strips A, instead of being longitudinal as in figure 1, can be spiral, as in
figure 2; or, instead of plates, wires or rods may be used like a cylindrical brush, as
in figuro 3, and the electrode, instead of being circular in cross-section, may be ellip-
tical, as in figure 4, or of other form, so long as the radial strips or points converge
or are closer together at the centre than at the circumference.
Figure 5 represents the complete battery, A being the outer vessel to contain the
liquid D of one or other of the compositions herein before specified, B the electrode
immersed therein, and C the other electrode as last described.
Having now particularly described and ascertained the nature of the said Invention
and in what manner the same is to be performed I declare that what I claim is ;-
1st. The employment, in an electric accumulator, of a liquid containing a solution
of sulphate of tin or sulphate of cadmium in combination and in contact with the
electrode at the negative pole as described.
2nd. In electric accumulators, the construction of electrodes of a central rod and
of plates, strips, wires, or points, radiating therefrom and being convergent or closer
together at the inner than at the outer part, as described and represented in figures 1
to 4 of the drawings.
A. MELVILLE CLARK.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.