IMPROVEMENTS IN THE MANUFACTURE OF SECONDARY BATTERIES OR ACCUMULATORS
Year: 1882

page_text: LETTERS PATENT to Farnham Maxwell Lyte of the Union Club, Trafalgar
Square, in the County of Middlesex for an Invention of "IMPROVEMENTS IN
LETTERS PATENT to Farnham Maxwell Lyte of the Union Club, Trafalgar
Square, in the County of Middlesex for an Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF SECONDARY BATTERIES OR ACCUMULATORS "
PROVISIONAL SPECIFICATION left by the said Farnham Maxwell Lyte at
the Office of the Commissioners of Patents on the 22nd September 1882.
FARNHAM MAXWELL LYTE of the Union Club, Trafalgar Square in the County
of Middlesex "IMPROVEMENTS IN THE MANUFACTURE OF SECONDARY BATTERIES
OR ACCUMULATORS
The electrodes of Secondary batteries when composed of porous carbon, a
network of carbon, or any built up form of carbon, or composed of built up lead
network or tissue, or any spongeous form of lead, appear hitherto to have presented
some inherent difficulties of construction. Firstly, owing to the porous nature of
the material of which the electrodes are constructed, they possess necessarily a
somewhat less amount of conductivity than if they were composed of the same
material in a more dense and coherent form. Secondly, such material being
obviously very fragile, will not bear rough handling or shaking of any kind.
.
To obviate these inconveniences, I construct the electrodes in two distinct parts,
viza central portion which may consist of porous carbon plate, a network of
carbon, or a built up tissue or network of carbon or some form similar to these,
woven or built up of lead and I surround such porous plates, networks, or tissues
of carbon or lead with a firmer and more solid frame preferably of carbon or lead
but which may be of any other suitable conducting material. This external frame
and the plates or tissue of carbon or lead are made separately, the plate or
tissue, &c, being introduced, adapted to, and fixed in the frame subsequent to their
manufacture.
The following example which is a description of a method of manufacturing a
frame of dense carbon in which is fixed a carbonised net, will better explain the
method of construction, but it should be understood that I do not limit myself in'
this respect.
A strong network of string or fibre twisted or otherwise, is first made, and the
stitch employed in its production may be the ordinary knitting stitch which forms,
a kind of open network well suited for my purpose, and composed of one continuous.
length of cord interlaced throughout. Any open-work tissue of string, cord, or
fibre may however be employed such as for instance that employed for rope or
cocoa nut fibre door mats. This network or tissue should be made so inuch larger
than the interior of the frame in which it is..to be fixed as will allow for the
shrinkage which always takes place during carbonization. The network or tissue

page_text: is then dipped in a strong solution of sugar, dried, and subsequently carbonized in
a closed box which may be of cast iron or other suitable material. It will now
form a tissue of carbon and by reason of the shrinkage which it will have under-
gone, will have become somewhat reduced in size. This shrinkage may be partially-
obviated and the density of the carbon of which the net is now composed, somewhat
improved by previously treating the string or fibrous material before immersion in
the syrup with a bath of sulphuric acid as in the manufacture of Gaines' parchment
paper. The carbonised network or tissue may be immersed in the syrup, dried,
and recarbonised several times successively until it acquires sufficient strength and
density to be handled without damage.
The frame of dense carbon is now separately made for the reception of this
tissue. This frame may be composed of a mixture of one part of very finely
pounded coke with two parts of very finely pounded coal moulded and compressed
in a mould, some suitable agglomerant being used to agglutinate the material, as
for instance, some thick syrup of sugar &c. The proportions will vary with the
coal used which, if of a very caking nature, may be considerably diminished in
proportion. After being moulded the frame may be dried in an oven or hot
chamber.
With a view to produce a frame of the densest possible carbon, it is advantageous
that the materials should be very finely ground, that the pressure in moulding
should be as great as possible, that the syrup should be as thick and dense as can
be, and that only so much syrup as will suffice to promote the cohesion of the
materials, should be employed. A convenient form of frame is rectangular, its sides
and ends being either of Ĺ section, or the frame having a rebate on the inside to
receive the carbonised tissue or network which is now placed in it, and luted into
the frame by means of a thick paste composed of the same material, viz, coke dust,
caking coal and sugar, of which the frame was made. This having been done, the
entire structure is placed in a close box or suitable vessel and submitted to
carbonization, again imbibed with syrup, dried, and recarbonized, and this repeated
several successive times.
In order to facilitate the absorption of the syrup by the carbon, a vacuum
apparatus may be used. The carbon frames so made are very suitable for the
reception of spongy lead.
In making electrodes of lead, I also form the central portion of a tissue or
network of lead. This may be either a woven, knitted, or netted fabric of lead or
lead wire, or a porous structure of lead, and I set this in a frame of lead or other
suitable conducting material which completely surrounds it as before. This central
or porous portion may be attached to the frame by grooving the interior of the
frame and inserting the porous central portion in the groove in which it may be
seized by compression, or it may be fixed by soldering or otherwise.
It should be noted that this mode of constructing. the plates or electrodes of
secondary batteries differs essentially from those batteries wherein solid plates of
carbon or lead corrugated or otherwise, and with or without holes, are used for
supporting the spongy lead or lead binoxide, and that by my Invention I ensure a
maximum of conductivity combined with strength of construction, lightness, and
a facility for packing the greatest possible quantity of the active material (spongy
lead, &c) into that part of the electrode where it will be the least exposed to
accident.
In order to better consolidate the frames if they are of carbon, and to destroy all
tendency to conduct away the electricity or short circuit the battery when set up,
whether the plates be of carbon, lead, or other material, I dip them on three of
their sides, i.e. the bottom and each of the sides, into melting sealing wax or lac or
paraffin, or some kind of nonconducting varnish or any suitable material capable of
forming a nonconducting varnish or coating. The top side is left unvarnished to
receive the clips or other means of attaching the conducting wires.

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.
22nd March 1883.
FARNHAM MAXWELL LYTE of the Union Club Trafalgar Square in the County
of Middlesex "IMPROVEMENTS IN THE MANUFACTURE OF SECONDARY BATTERIES
OR ACCUMULATORS."
The electrodes of secondary batteries when composed of porous carbon, a network.
of carbon, or any built up form of carbon, or composed of built up lead network or
tissue, or any spongeous form of lead, appear hitherto to have presented some
inherent difficulties of construction. Firstly, owing to the porous nature of the,
material of which the electrodes are constructed, they possess necessarily a some-
what less amount of conductivity than if they were composed of the same material.
in a more dense and coherent form. Secondly, such material being obviously very
fragile, will not bear rough handling or shaking of any kind.
To obviate these inconveniences, I construct the electrodes in two distinct
parts, viz-a central portion which may consist of porous carbon plate, a network
of carbon, or a built up tissue or network of carbon or some form similar to these
woven or built up of lead, and I surround such porous plates, networks, or tissues,
of carbon or lead with a firmer and more solid frame, preferably of carbon or lead,
but which, may be of any other suitable conducting material. This external frame
and the plates or tissue of carbon or lead are made separately, the plate or
tissue &c being introduced, adapted to, and fixed in the frame subsequent to their
manufacture.
The following example which is a description of a method of manufacturing
an electrode consisting of a frame of dense carbon in which is fixed a carbonised
net, will better explain the method of construction, but it should be understood.
that I do not limit myself in this respect.
A strong network of string or fibre, twisted or otherwise, is first made; the stitch-
employed in its production may be the ordinary knitting stitch which forms a kind
of open network well suited for my purpose, composed of one continuous length of
cord interlaced throughout. Any open work tissue of string cord or fibre may.
however be employed, such as for instance, that employed for rope or cocoa nut
fibre door mats. This network or tissue should be made so much larger than the.
interior of the frame in which it is to be fixed as will allow for the shrinkage,
which always takes place during carbonisation. The network or tissue is then by
preference dipped in a strong solution of sugar or other suitable hydrocarbon
dried and subsequently carbonised in a closed box which may be of cast iron or
other suitable material. It will now form a tissue of carbon and by reason of the
shrinkage which it will have undergone, will have become somewhat reduced in
size. This shrinkage may be partially obviated, and the density of the carbon of
which the net is now composed, somewhat improved by previously treating the
string or fibrous material before immersion in the syrup with a bath of sulphuric
acid, as in the manufacture of Gaines' parchment paper. The carbonised network
or tissue may be again immersed in the syrup, dried, and recarbonised several
times successively until it acquires sufficient strength and density to be handled
without damage.
The frame of dense carbon for the reception of this tissue is now separately
made. This frame may be composed of a mixture of 1 part of very finely:
pounded coke, with 2 parts of very finely pounded coal moulded and compressed

page_text: in a mould, some suitable agglomerant, as for instance, some thick syrup of sugar
being used to agglutinate the material. The proportions will vary with the coal
used which, if of a very caking nature, may be considerably diminished in
proportion. After being moulded the frame may be dried in an oven or hot
chamber before carbonising.
With a view to produce a frame of the densest possible carbon, it is advan-
tageous that the materials should be very finely ground, that the pressure in
moulding should be as great as possible, that the syrup should be as thick and
dense as can be, and that only so much syrup as will suffice to promote the
cohesion of the materials,. should be employed. Care should be taken that no
alkaline salts are used or are contained in the materials, and especially that the
sugar should be. of good quality. A convenient form of frame is rectangular, its
sides and ends being either of L section or having a rebate on the inside to receive
the carbonised tissue or network which is now placed in it and luted into the
frame by means of a thick paste composed of the same materials (viz :-coke dust,
caking coal, and sugar) of which the frame was made. This having been done
the entire structure is placed in a close box or suitable vessel immersed in carbon
dust and submitted to carbonization. It is afterwards again saturated with syrup,
dried and recarbonised; this recarbonization may be repeated several successive
times.
In order to facilitate the absorption of the syrup or of a soluble salt of lead by
the carbon, a vacuum apparatus may be used, that is to say, the carbon plates or
frames so formed may be put into a suitable apparatus by which the air naturally
contained in them may be exhausted so that a solution of syrup or of a soluble
salt of lead may be absorbed into them so as to fill the space previously occupied
by the air.
"
The carbon electrodes so made are very suitable for the reception of solutions of
lead salts which may be subsequently reduced to the form of spongy lead. The
frame itself may if desired be protected from this action by varnishing it with a
nonconducting varnish. In making electrodes of lead, I also form the central
portion of a tissue or network of lead. This may be either a woven, knitted, or
netted fabric of lead or lead wire or a porous structure of lead, and I set this in a
frame of lead or other suitable conducting material which completely surrounds it
as before. This central or porous portion may be attached to the frame by grooving
the interior of the frame and inserting the porous central portion in the groove in
which it may be seized by compression, or it may be fixed by soldering or other-
wise. When I form the electrodes of lead I prefer in some cases to form them by
casting the porous lead or by autogenous soldering instead of by grooving or by
inserting a central porous plate as before described.
It should be noted that this mode of constructing the plates or electrodes of
secondary batteries differs essentially from those batteries wherein solid plates of
carbon or lead corrugated or otherwise and with or without holes are used for
supporting the spongy lead or lead binoxide, and that by my Invention I ensure a
maximum of conductivity combined with strength of construction lightness and
a facility for packing the greatest possible quantity of the active material (spongy
lead, &c) into that part of the electrode where it will be the least exposed to
accident.
In order to better consolidate the frames if they are of carbon and to destroy all
tendency to conduct away the electricity, or short-circuit the battery when set up,
whether the frames be of carbon, lead, or other material, I dip them on three of
their sides, i.e. the bottom and each of the sides into melted sealing wax or lac or
paraffin, or some kind of nonconducting varnish or any suitable material capable
of forming a nonconducting varnish or coating. The top side is or may be left
unvarnished to receive the clips or other means of attaching the conducting wires
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as my Invention to be protected by the
herein before in part recited Letters Patent is.

page_text: 1st The manufacture of electrodes of secondary batteries with a central portion
composed of a porous carbon plate, or a built up tissue or network of carbon or
lead fixed in an external frame of dense carbon or lead or other conducting
material, substantially as herein described.
2nd The herein described process of manufacturing the central portion of an
electrode constructed as described in the first claim, consisting in carbonising a
network of string, cord, or fibre, substantially as specified.
•
3rd In a secondary battery having one or both electrodes constructed as herein
described and specified in the first claim, the mode of insulating their external
frames to prevent the conducting away of the electric current or short circuiting
of the battery, by dipping them into melted sealing wax or lac or paraffin, or some
other nonconducting substance or coating, as hereinbefore specified.
In Witness whereof I the said Farnham Maxwell Lyte have hereunto set
my hand and seal this twenty first day of March, A.D 1883.
M
I VTL