IMPROVEMENTS IN SECONDARY BATTERIES
Year: 1884

page_text: I, ERNEST GEORGE DORNBUSCH, of 35 Stapleton Hall Road, Crouch Hill, London,
in the County of Middlesex, Electrician, do hereby declare the nature of my
invention for IMPROVEMENTS IN SECONDARY BATTERIES" to be as follows:--
.
A
In "Faure's" and other secondary batteries in which the electrodes are enclosed
in, or separated, by means of felt, flannel, or other suitable absorbent material, the
"active material" (consisting of a salt of lead) is liable to penetrate through this
absorbent material, and appearing on the outer surface thereof establish short
circuits between the two electrodes forming the secondary couple.
The object of my invention consists primarily of making use of this penetration
of the "active material" through the interstices of the felt, flannel, or other suit-
able material employed, in such a way that such material, viz., felt, flannel, etc.,
may become & carrier or support of the "active material" aforesaid.
"
"
Í employ lead plates of suitable thickness, the one to form the support of the
anode (charging) being considerably thicker than that to form the cathode
(charging), such plates being slit into strips from a short distance from one edge
right down to the opposite edge. Each plate is placed in the fold of a doubled
piece of felt, flannel or other suitable absorbent material which will not be affected
by the passage of an electric current or the acid used when the electrodes are used
in the battery, such material being cut into strips in the same manner as the plates.
A strip of felt, flannel or other suitable material is then interwoven backwards and
forwards, over and under the strips of the covered plate, until the end of such
strips is reached, when the felt or flannel is again passed round the plate so as to
cover the spaces left exposed when it was passed over and under the strips, such
passage for this purpose being preferably in a direction at right angles to the
former.
The strip and the cover of flannel or felt before being applied as described, are
first impregnated with a salt of lead which is caused to fill up the interstices
between the fibres of the material in any suitable manner, and after being placed
on the sheet of lead, the whole is dipped into a paste of the salt of lead (formed as
hereinafter described), so as to complete the filling up of the interstices. The plates
are then inserted into bags or envelopes of felt or fannel (either prepared as
described or not) when the salt of lead can be reduced to a metallic state by making

page_text: the plates the cathodes in an electrolytic bath, or the plates, without being so
reduced, inay be immediately placed in the cell they are intended to be used in,
and the one peroxidized and the other reduced by charging as is well understood.
In the former case the cathodes (charging) are then ready for use, while those to
form the anodes (charging) have the metallic lead carried by the felt or flannel first
peroxidized in the usual manner.
The salt of lead I prefer to use for impregnating the felt or flannel is minium or
red lead mixed with water, but I may use litharge or other suitable salt for this
purpose.
Pressure may be applied during the preparation of the plates so as to cause a more
perfect contact between the lead plate and its covering of felt or flannel prepared
as described. The felt or flannel is preferably folded so as to form two or more
thicknesses of material.
The principal advantages of my improved plates are that the contact is greatly
improved, as the active material carried by the felt will always be kept in intimate
contact with the centre plate in both the anode and cathode, and be prevented
from falling away from the same, and the plates forming the supports of the
electrodes, more especially that intended for the anode (charging), being very thick,
the secondary couple will last for a very lengthened period.
The plates are placed in separate compartments formed in a box or case by par-
titions preferably of wood or porous earthenware, such, partitions being pierced with
inverted V shaped perforations running through the thickness of the partitions
parallel with the side edges thereof, whereby any particles of metal which may
become detached from the felt or flannel covering the plates will have great
difficulty in passing from one plate to another, and the chances of short circuiting
will be very greatly diminished if not entirely removed.

page_text: I, ERNEST GEORGE DORNBUSCH, of 35 Stapleton Hall Road, Crouch Hill, London,
in the County of Middlesex, Electrician, do hereby declare the nature of iny
invention for "IMPROVEMENTS IN SECONDARY BATTERIES" and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
7
In "Faure's" and other secondary batteries in which the electrodes are enclosed
in, or separated, by means of felt, flannel, or other suitable absorbent material, the
"active material" (consisting of a salt of lead) is liable to penetrate through this
absorbent material, and appearing on the outer surface thereof establish sliort
circuits between the two electrodes forming the secondary couple. This is, there-
fore, a great defect in such cells.
My invention consists primarily in making use of this penetration of the "active
material" through the interstices of the felt, flannel or other material employed, in
such a way that the latter may becoine a carrier or support of the "active
material" aforesaid.
""
"
I prepare the flannel, felt, asbestos cloth, or other suitable material not affected
by the passage of an electric current, nor by the acid employed in the cell, by
impregnating it with a salt of lead, which is caused to fill up the interstices between
the fibres of the material in any suitable manner. The salt of lead I prefer to use
is minium (red lead), which I mix with water until a paste is formed of about the
consistency of cream. The flannel, felt, asbestos cloth, or other suitable material is
then placed in this mixture and subjected to violent and continuous motions until
the salt of lead has reached and filled up all the interstices in the material used.
The method of forming the electrodes is illustrated in Figs. 1, 2, 3, and 4, of the
accompanying drawing.
;
As conducting supports I employ lead plates A of suitable thickness, the one to
form the support of the anode (charging) being considerably thicker than that to
form the cathode (charging). These plates are shown inore clearly in Fig. 4, which
represents such plates before the felt or other material has been applied thereto, and
in which it will be seen that each plate is cut into strips A¹ from a short distance
from one edge right down to the opposite edge.
In Figs. 1, 2 and 3, the method of applying the prepared felt or other material to
the plates A is shown. Each plate is placed in the fold of a doubled piece of felt
or other suitable material B, prepared as above described, and cut into strips in the
same manner as the plates. A narrow strip C of the felt or other material, also
prepared as described, is then interwoven backwards and forwards, over and under
the strips of the covered lead plate, until the end of the strips of the latter is
reached. The spaces which are necessarily left bare after this first operation is
completed, are then filled in (as shown by the dots marked D) with a paste formed
by mixing red lead with water as above described; but of a thicker consistency
than that which is used for impregnating the absorbent material; in short, of such
a consistency, that it may with the greatest convenience be applied with a small

page_text: bricklayer's trowel. The surfaces of the plate A being now without projections or
depressions, the felt or other material is again passed round and round the plate, as
shown at C, each successive 'pass' overlapping its predecessor by about one-eighth
to one-quarter the width of the strip, until the whole plate is covered. This
winding round and round the plates is preferably made at right angles to the
former passing of the strip C, as shown.
The plates are then inserted into bags or envelopes of flannel, felt, asbestos cloth,
or other suitable material (either prepared as above described or not) when the salt
of lead can be reduced to a metallic state by making the plates the cathodes in an
electrolytic bath, or the plates, without being so reduced, may be immediately
placed in the cell they are intended to be used in, and the one per-oxidized and the
other reduced by charging as is well understood. In the former case the cathodes
(charging) are then ready for use, while those to form the anodes (charging) have
the metallic lead carried by the felt or other material first peroxidized in the usual
manner.
Moderate pressure may be applied during the preparation of the plates, especially
after the salt of lead has been reduced to a metallic state, in order to cause a more
perfect contact between the lead. plate and its now metallized covering. This
operation, however, is not essential for the successful action of the plates.
The felt, flannel or other material, may be folded so as to form a thicker coating
of active material, when necessary. Sometimes I dispense with the first fold of
material round the plates.
The principal advantages of my improved plates are (1) that the contact is
greatly improved, as the active material carried by the felt or other material, will
always be kept in intimate contact with the centre plate in both the anode and
cathode, and be prevented from falling away from the same, and (2) that the plates
forming the supports of the electrodes, more especially that intended for the anode
(charging), being very thick, the chances of 'buckling' are altogether removed, and
the secondary couple will last for a very lengthened period.
■ I prefer to place the plates in separate compartments formed in a box or cell E
(as shown in the plan view Fig. 5) by partitions F of wood, porous earthenware, or
other suitable material. Figs. 6 and 7 are detail views of the partitions F, which
in order to make the internal resistance of the cell small, are pierced with inverted
V-shaped perforations F¹, running through the thickness of the partitions parallel
with the edges thereof. It will be seen that when using porous earthenware for
instance, by perforating the partitions in this way the chance of "short circuiting"
the couple is in no way increased, while the internal resistance is materially
reduced.
I prefer, also, to raise my plates a small distance from the bottom of the box or
cell E in which they are used, by means of inverted V-shaped pieces of wood G
placed about 3 or 4 inches apart, and running the whole length of the box or cell
in a direction at right angles to the width of the plates. The plates in Figs. 1 and 2
are shown resting upon or supported by three such blocks G.
The plates are placed in the cell E, positive and negative alternately in the usual
way, the former (the positive) having all their ears or lugs A² on one side of the
cell, and the latter (the negative) having all their lugs or ears A' on the other side
of the cell. Each lug or ear is pierced with a hole of any suitable diameter.
Between all the adjacent lugs are placed pieces of stout lead tubing H, having an
internal diameter the same as that of the holes through the lugs, and of a length
exactly equal to the distance between such lugs, when the plates are in their proper
position. Two rods of iron or other hard metal I and I¹, are passed through the
lugs and all the pieces of lead tubing between them, one rod on each side of the
cell, that is, one for the positive plates and one for the negative plates, each rod
being provided with a head I3 at one end, while a nut 13 is screwed on to the other
end, for the purpose of tightening up the whole. The advantages of this method
are that a plate can be removed from the cell and another substituted, if necessary,

page_text: with very little trouble, and that by such method the plates are secured rigidly in
position. Good contact may be relied upon if the lugs and also the ends of the
tubes are well cleaned before passing the rod through and screwing up.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The use in the construction of electrodes for secondary batteries of flannel,
felt or other suitable absorbent material prepared substantially in the manner and
for the purpose herein set forth.
2. The use in the cells of secondary batteries of partitions of wood, porous
earthenware, or other suitable material, having inverted V-shaped perforations,
substantially as and for the purpose herein set forth..
Dad his oth 1