An Improvement in Secondary Voltaic Batteries.
Year: 1892

page_text: Date of Application, 2nd Apr. 1892
Complete Specification Left, 29th Dec., 1892-Accepted, 4th Feb., 1893
PROVISIONAL SPECIFICATION.
An Improvement in Secondary Voltaic Batteries.
We, DAVID URQUHART of 17 Victoria Street, Westminster, Engineer, and
JAMES MILN SMALL, A.M.I.C.E. of 17 Victoria Street, Westminster do hereby
declare the nature of this invention to be as follows:-
Our invention relates to a simple and compact construction of secondary voltaic
battery which is of the following kind.
We take a number of lengths of lead wire each of which is helically twisted at
each end leaving a part in the middle untwisted which is bent so that the whole is
in the form of a U the helically twisted parts forming its limbs. One of these
twisted parts is gilded or coated with metal which is not oxidisable the other end
being left bare. Each of the helically twisted parts is packed with lead oxide or
other substance suitable for secondary batteries.
A number of cells are provided which may be in the form of test tubes of glass
or other non-conducting material in each of which are placed side by side a gilded
limb of one and the ungilded limb of another U these being prevented from
touching by an interposed strip of vulcanite or other non-conducting material.
These cells being charged with suitable electrolyte liquid the battery may be
formed in the usual way by passing an electric current through the wires and cells
and thereafter a reverse current will result from the action of the electrolyte
and oxides.
A number of the cells such as are above described may be mounted in a frame
which may be arranged to slide like a drawer into or out of a casing, the terminal
wires being connected to suitable contact screws outside.
Dated this 2nd day of April 1892.
ABEL & IMKAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
An Improvement in Secondary Voltaic Batteries.
We, DAVID URQUHART, of 17 Victoria Street, Westminster, Engineer, and
JAMES MILN SMALL, A.M.I.C.E. of 17 Victoria Street, Westminster, do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement :-
Our invention relates to a simple and compact construction of secondary voltaic
batteries which is of the following kind.
We take a number of lengths of lead wire each of which is helically twisted at
each end, leaving a straight part in the middle between the twisted parts, and we
bend each of these so as to form a U, the twisted parts forming the limbs. One of
these helically twisted limbs we gild or coat with a metal which is not oxidisable
or only very slightly oxidisable; the other limb we leave bare.
We pack or fill the spaces between the helical convolutions and sometimes also
the central spaces with lead oxide or other substance suitable for forming into
active material of a secondary battery.
A number of cells are provided which may be holes formed in a block of earthen-
ware or bored in a block of ebonite, but we usually prefer to use separate cells like
test tubes made of glass or other similar substance, as in this manner we obtain a
higher insulation between the cells.

page_text: '
In each cell we place the gilded or coated limb of one U and the bare limb of
another U, these being prevented from touching by an interposed strip of vulcanite,
or other non-conducting material, such as asbestos or silicate cotton which is not
affected by sulphuric acid.
The cells, being filled with a suitable electrolyte liquid, may be charged in the
usual way by passing an electric current through the wires and they will thereafter
give out a reverse current by the usual secondary action.
Fig. 1 of the accompanying drawings is an elevation and Fig. 1A is a plan of a
battery cell having in it the gilt or coated limb of one 'U and the bare limb of
another according to our invention.
One of the U's is shewn with its limbs filled with the lead oxide or other-active
material, the other U is shewn with its limb empty. A is a stopper of ebonite or
other suitable material which prevents accidental spilling of the electrolyte liquid.
Its sides are notched to admit the straight parts of the twisted wires. Bis a
small tube passing through the stopper to allow escape of gas.
After the stopper is placed, the openings through it, except the tube b, are filled
with melted paraffin wax.
C is a piece of caoutchouc tube drawn over the stopper and edge of the cell to
form a tight joint.
Figs. 2 and 24 shew a modification according to which the one limb of each U is
made with a helix of larger diameter than the other, the smaller helix of the one
being accommodated within the larger helix of the other. In this case the
stopper A is made in halves so that it can be inserted and treated with paraffin
wax after the electrodes have been placed in the cell.
1
1
Cells as above described, being very compact and highly insulated, are
especially applicable as portable testing batteries of high potential. For this
purpose, we mount the number of cells required, say for instance 50 for a battery.
giving 100 volts in a stand of wood, ebonite or glazed earthenware, which may
slide, like a drawer, into a suitable case provided with external terminals for the
connection of the wires to the instruments and with short internal leads to connect
these terminals to corresponding terminals on the sliding drawer.
When these batteries are made up in sets having a potential of more than
80 volts, we usually provide on the case a resistance so that the battery may be
charged in sections by simply connecting it to any continuous current circuit of
100 volts.
Fig. 3 shows diagrammatically the arrangement of the connections and resistance
in a battery of 50 cells.
Terminal 1 is connected to the negative electrode of the 1st cell. "Terminal 2 is
connected to one end of a resistance R the other end of which is connected between
'the 25th and 26th cell.
Terminal 3 is connected to the last cell.
A battery thus arranged can be charged in two sections by first connecting
terminal 1 to the negative wire and the terminal 2 to the positive wire of a
'continuous current circuit of 100 volts, thus charging the first half. The negative
wire is then shifted to terminal 2 and the positive wire to terminal 3 to charge
the second half. In each case the charging current has to pass through the
resistance R, which reduces it to the proper strength and protects the battery from
injury by a too powerful current.
The resistance R also acts as a protection in case of an accidental short circuit
between adjacent terminals.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, we would have it understood
that we do not claim generally gilding or coating with non oxidisable metal one
electrode but what we claim is :-
1. A pair of electrodes for a secondary battery consisting of a lead wire having
its end parts helically twisted one of these helices gilt or coated with non-

page_text: oxidisable metal, and both having their interstices filled with lead oxide or other
suitable material, the one helix of the wire forming the positive electrode of one
cell and the other forming the negative electrode of the next cell, substantially as
described.
2. The arrangement of sets of cells, having electrodes such as are above referred
to, in portable form with suitable connectious, substantially as described.
Dated this 23rd day of December 1892
ABEL & IMRAY,
Agents for the Applicants.