IMPROVEMENTS IN THE CONSTRUCTION OF SECONDARY BATTERIES
Year: 1882

page_text: LETTERS PATENT to Charles Vernon Boys of Wing near Oakham in the County
of Rutland for an invention of "IMPROVEMENTS IN THE CONSTRUCTION OF
SECONDARY BATTERIES"
"
PROVISIONAL SPECIFICATION left by the said Charles Vernon Boys at the
Office of the Commissioners of Patents on the 25th April 1882.
_CHARLES VERNON BOYS of Wing, near Oakham in the County of Rutland.
"IMPROVEMENTS IN THE CONSTRUCTION OF SECONDARY BATTERIES
My invention relates to Improvements in the construction of secondary batteries
whereby a considerable economy of time may be effected in the operation of
forming" such batteries whilst at the same time better results are obtained.
According to my invention in lieu of conting the lead plates of secondary
batteries with oxides or salts of lead, I coat metallic plates, or other supports with
a layer of finely divided lead produced in the manner next hereinafter described.
For this purpose I melt lead and pour it into a box or suitable receptacle in which
it may be gently moved until it begins to granulate. I then cause the box to be
violently shaken, by machinery or otherwise, so that the lead is thrown in all
directions in the box and reduced to a fine powder. When sufficiently cool the
powder is removed and sifted from larger particles. This lead dust may then bo
shaken up with a weak solution of mercury and washed with water. It is then
spread in layers on metallic plates, or other supports and compressed sufficiently
to make it bind together. The plates are then arranged so that they may lie in
a weak acid solution. Or in lieu of spreading the lead dust on plates or
supports as before mentioned, it may be consolidated so as to render an artificial
support unnecessary, the electrodes so prepared being used in a weak acid solution
as before.

page_text: "
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Vernon Boys in the Great Seal Patent Office on the
25th October 1882.
CHARLES VERNON BOYS of Wing near Oakham in the County of Rutland
"IMPROVEMENTS IN THE CONSTRUCTION OF SECONDARY BATTERIES
"
My said Invention relates to "improvements in the construction of secondary
batteries" whereby a considerable economy of time is effected in the operation of
" forming" such batteries whilst at the same time better results are obtained.
The Invention consists mainly in the use in the construction of secondary
batteries of electrodes formed by subjecting molten lead to agitation in a box or
receptacle until it is reduced to a fine state of division then coating the lead dust
_thus produced with mercury and finally compressing or consolidating the prepared
lead-dust so as to constitute the electrode. The improved-mode-of-reducing the lead
employed for the electrodes to a fine state of division may however be adopted
without coating the lead dust thus produced with mercury.
In carrying out my said Invention I proceed in the following manner videlicit.—
When operating on a small scale in order to reduce lead to a fine state of division
-I-employ-a-box--preferably made of wood which is of a convenient size to handle
and the bottom of which is by preference circular in shape and slightly-concave-
whilst the top is provided with a lid or cover Into this box I pour a suitable
quantity of lead in a molten condition and while the lead is still liquid and the
lid or cover remains open I give the box a gentle-circular-movement by hand_so_
as to keep the molten metal in a single pool in the middle of the box in order to
preserve uniformity of temperature throughout the mass. As soon as the metal
shows signs of solidification or crystallization I close down and secure the lid or
cover and shake the box either laterally or vertically with such force as to drive
the cakes of lead which are beginning to form against the sides and lid and bottom
of the box. The lead at this stage of the operation is in an exceedingly fragile
condition and by the act of shaking the box as hereinbefore described the lead is
reduced to the state of dust or fine powder which may be separated by sifting from
any coarser particles that may be intermixed with it Or if preferred I modify the
process in one of the following methods vizt.-
I remove the crucible or other vessel containing the molten lead from the
furnace and stir the said molten lead while in the crucible or other vessel until
it assumes the semi-solid condition before indicated when I immediately transfer
it to the box or receptacle before referred to and at once subject it to agitation as
hereinbefore described.
Or whilst the lead is in a molten condition in the crucible or other melting
vessel I take some coarse lead dust such for example as the coarser lead dust which
has been obtained by sifting from the finer lead dust in previous operations and
I intimately mix the same with the molten lead by stirring, adding sufficient of
the said coarser lead dust to convert the molten lead into the semi-solid condition
and I immediately transfer the lead in this condition to the box or receptacle
before referred to and at once subject it to agitation as hereinbefore described.
I sometimes place bars of wood or other suitable material across the upper part-
of the box the same having the effect of assisting in the comminution of the lead.
When it is required to produce the lead dust on a large scale I employ a box
similar to that hereinbefore referred to but of a capacity to receive such a quantity
of molten lead as it is desired to operate upon at one time and I provide mechanical
means for supporting the box whilst the first stage of the operation is being

page_text: performed by hand as first hereinbefore mentioned and also for actuating the box
during the second stage of the operation in such a manner as to imitate the
motions of the hand when working on a small scale. These objects may bo
accomplished in various ways but I have found it convenient to support the box
during the first stage of the operation by suspending it by a connecting rod and
crank from a rotary crank shaft whence a vertical reciprocating notion may be
imparted for performing the second stage of the operation.
An arrangement suitable for producing mechanically the required motion is
shown in sectional elevation in the drawing annexed hereto in which A is the
box a a lids of the same secured by spring fasteners b, b; c, c rods which may
extend across the inside of the box, B a radius rod secured at one end to the
bottom of the box A and jointed at its opposite end to a bracket d, from which it
may be detached on the withdrawal of the pin e. Ca crank on a rotary crank
shaft jointed to a connecting rod D the bifurcated arms of which are carried
down one at each side of the box and attached at their lower ends to a transverse
rod g forming part of the radius rod B.
The apparatus is operated in the following manner videlicit :-
Assuming the box A to be suspended at its centre from the crank shaft with
the radius rod B disconnected from its bracket & and the molten lead to have been
poured in while the box is in such a position that the lead will accumulate in the
middle, the box is then caused to rock gently by hand until the lead shows signs
of crystallizing. The box is next connected by the radius rod B to the bracket d
in such a manner that the box whilst prevented from moving laterally shall be
capable of movement vertically and the open lid or cover being closed and secured
and the crank shaft put in motion the box is suddenly thrown into a violent state
of agitation whereby the lead is immediately broken up into the condition of dust
or fine powder. The motion of the apparatus is then arrested and the box being
tilted the lead is projected onto screens for the separation of the dust from any
larger particles which may be intermixed with it.
It is obvious that any equivalent apparatus may be substituted for the apparatus
herein before referred to for carrying out this part of my said Invention. And
further that if the lead is reduced to the semi-solid condition in the crucible or
other melting vessel as hereinbefore described the agitation of the box A must be
commenced as soon as the semi-solid lead has been placed therein.
I consider it advisable to perform all these operations near the mouth of a fluo
which opens into depositing chambers so that any excessively fine lead dust which
might injure the health of the workmen may be carried away and deposited to be
afterwards collected.
The lead having been reduced to the condition of dust or fine powder is then
agitated in a weak solution of nitrate or other soluble salt of mercury for the
space of say about five minutes. A solution composed of about twenty grains of
nitrate of mercury to one quart of water is found suitable for the purpose. The
exact strength of the solution is however not very material but I have usually
found that when using stronger solutions greater rapidity in the mixing is necessary
than when weaker solutions are employed.
I then take the "amalgamated" lead dust (that is the lead dust coated with
mercury) and place the same in a large jar or other suitable vessel and allow a
stream of water preferably warm to flow on to it the said amalgamated lead dust
being well stirred or agitated so that every part of it may be thoroughly washed.
This washing process removes any soluble salts or acid that may remain mixed
with the lead dust after the amalgamating process and which would tend to
impair the efficiency of the battery constructed of the said amalgamated lead dust.
The liquid remaining after the agitation with the inercurial solution may be
decanted and poured into vessels in which zinc scrap is placed for the purpose of
recovering any lead or mercury left in the solution.
I then place a sufficient quantity of the amalgamated and washed lead dust to
form one plate of a battery in a metal or other rigid frame of the shape the

page_text: finished plate is to assume the said frame resting on a flat plate and into the
frame I place an easily fitting plunger. In the lead dust near one end I embed a
piece of lead (by preference previously amalgamated) which projects some distance
from the mass of lead dust the said projecting piece of lead being employed_for
making electrical connections A suitable recess is formed in the frame to allow
this piece of lead to project I then transfer the whole to a hydraulic or other
suitable press and compress the lead dust into a firm plate or cake after which I
invert the frame and press the plunger through it thus removing the compressed
plate with its leaden connection from the frame. I prefer to compress the lead
dust while in a damp condition and after compression and removal from the frame
to allow it to dry when it becomes quite firm which condition it retains when in
use in a battery. The lead dust should be subjected to sufficient pressure to cause
its firm adherence when in the form of plates or cakes of any desired shapo. If
preferred the embedded lead piece can be dispensed with and the lead dust
compressed onto a binding screw or other electrical connection such screw or
connection being by preference amalgamated. Plates or cakes thus prepared
which form the electrodes are adapted to the receptacle for containing the weak
acid solution usually employed as in the ordinary manner and the batteries are
afterwards formed" by the passage of an electric current in the usual and well
known way.
Having now described and particularly ascertained the nature of my said-
Invention and the best methods with which I am acquainted of carrying the same
into effect I would observe in conclusion that I do not claim in the construction
of secondary batteries the use of finely divided lead except when the lead employed
is reduced-to-a-fine-state-of-division in the manner hereinbefore described nor do I
claim the use of mercury for amalgamating or coating-in-mass-the-metallic plates
or electrodes of secondary batteries-nor the cousulidation under pressure of metallic
-matter_to_form the plates or electrodes of secondary batteries but what I consider
to be novel and original and therefore-claim-as-the-Invention secured to me by
the herein before in part recited Letters Patent is :-
First In the construction of secondary batteries, the use of electrodes formed
of finely divided lead amalgamated, that is coated with mercury, while in a state
of division and compressed or consolidated, substantially as herein before described.
Second-In the construction of Secondary batteries, the use of finely divided
lead reduced to such finely divided condition by the means substantially as herein-
before described.
In witness whereof I the said Charles Vernon Boys have hereunto set my
hand and seal this twenty third day of October One thousand eight
hundred and eighty two.