Improvements in, and in the Manufacture of, Elements for Secondary Batteries.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in, and in the Manufacture of, Elements for Secondary
Batteries.
:―
I, DESMOND GERALD FITZ-GERALD, of 94, Loughborough Road, Brixton, S. W.,
Electrician, do hereby declare the nature of this Invention to be as follows:-
The object of my Invention is to construct a cheap, light, and durable secondary
battery or accumulator more particularly adapted for electrical locomotion.
According to my Invention I coat thin sheets of lead with electrolytically depo-
sited and mechanically consolidated crystalline spongy lead. The sheets of lead
so treated from which spongy lead elements are to be made may be about half
the thickness of the sheets from which the peroxide elements or plates are to be
made, the original thickness of the last mentioned sheets being, say, 50 mils. or
1/20th of an inch. I preferably first roughen both sheets either mechanically
or by coating them with a film of peroxide of lead, by making them anodes in a
suitable electrolyte, the layer of peroxide of lead being afterwards reduced to the
condition of spongy lead in order to ensure the adherence of the subsequently
deposited layers of spongy lead but this operation may be dispensed with if the
surface of the sheets is in a more or less oxidized condition.
The sheets are then electrolytically coated on one or both sides with layers of
spongy or porous lead, the weight (and approximately the thickness) of which,
regulated by the depositing current, is determined by the required capacity of
the elements per unit of surface. The sheets connected to the negative pole of a
source of electricity are made to pass between anode plates of lead in a solution of
a lead salt until a sufficient quantity of lead in a spongy form has been deposited
upon their surfaces. The crystals of lead thus loosely deposited upon the surfaces
of the sheet are consolidated by pressure between rollers through which the sheets
pass while still submerged in, or moistened by, the electrolyte and which may
serve to carry and guide the sheets between the anodes and which may be mounted
in a frame of wood or other material capable of being raised out of, and lowered
into, the tank. The pressure exerted by the rollers upon the plates should be
diminished as the thickness of the deposited layer increases. Instead of the lead
sheet being made to move between rollers these may be made to pass over the
surfaces of the sheet whilst the latter is stationary. Or instead of consolidating
the crystalline lead by rollers the plates, whilst immersed in the electrolyte, may
be subjected at intervals to pressure between plane surfaces. Ultimately the sheets
of lead, when sufficiently coated, may be passed through water and wound upon a
drum which should be kept immersed in water or moistened to avoid heating.
Theoretically, more lead should be deposited upon the sheet intended for the
manufacture of peroxide plates than upon that for the spongy lead plates. But
as peroxide of lead is always produced during the working of the battery at the
expense of the peroxide support, I prefer to deposit the same quantity of lead per
unit surface on both sheets and to use thicker sheets of lead for the peroxide
elements. From the coated sheets respectively, positive and negative elements of

page_text: any required size may be cut, preferably with a lug perforated for a wire to connect
the elements of like sign. Both kinds of elements may be allowed to become
slowly oxidized by the effect of exposure to the atmosphere. In the use of the
peroxide plates this oxidation economizes power expended in forming; in the case
of the other plates the oxide formed reduces the quantity of hydrogen evolved in
forming.
In portable batteries, and batteries for electrical locomotives, the distance
between the plates must be comparatively very small in order that the requisite
high rate of discharge and the minimum of weight may be obtained. To main-
tain constant this distance, and to obviate the risk of contact between the plates
by the effect of shocks and long-continued vibrations, an afluidic system in which
the plates are packed and rendered immovable by an absorbent material in fine
granules, alone or mixed with a pasty or gelatinous material, may be employed.
Or I may use as separator and distance-piece a plate of porous earthenware which
may be grooved vertically, or perforated, or both. Such plates need not neces-
sarily be of the same size as the elements but may be, so to speak, built up of plates
of much smaller size grooved, or perforated, or both.
T
11.
1100
A. M. & WM. CLARK,
Chartered Patent Agents, 53 Chancery Lane, London.
Improvements in, and in the Manufacture of, Elements for Secondary
Batteries.
I, DESMOND GERALD FITZ-GERALD, of 94, Loughborough Road, Brixton, S.W.,
Electrician, 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:-
The object of my Invention is to construct a cheap, light, and durable secondary
battery or accumulator more particularly adapted for electrical locomotion.
According to my Invention I coat thin sheets of lead with electrolytically
deposited and mechanically consolidated crystalline spongy lead. The sheets of
lead so treated, from which spongy lead elements are to be made, may be about
half the thickness of the sheets from which the peroxide elements or plates are to
be made, the original thickness of the last mentioned sheets being from, say, 50 mils.
or 1/20th of an inch, and upwards. After cleaning the sheets from grease, by
passing them through a bath or otherwise treating them with caustic alkali, I
preferably first roughen both sheets either mechanically by rolling between
roughened rollers for instance or by producing upon them an electrolytically
formed coating of peroxide of lead and then reducing the peroxide coating to the
condition of spongy lead, by first making the plates anodes and afterwards cathodes
in a suitable electrolyte. The object of so roughening the plates is in order to
ensure the adherence of the spongy lead subsequently deposited and consolidated
according to my Invention, but the preliminary operation of roughening the
sheets may be dispensed with if the surface of the sheets has become more or less
oxidized by exposure to the air. The sheets are then electrolytically coated on
both sides with spongy lead by being connected to the negative pole of a source
of electricity and being made to pass between anode plates of lead in a solution of
a lead salt until a sufficient quantity of lead in a spongy form has been deposited
upon their surfaces, the crystals of lead thus loosely deposited upon the surfaces
of the sheet being meanwhile consolidated continuously or intermittently by the

page_text: pressure of rollers between which the sheets are caused to pass while still moistened
by the electrolyte, these rollers also serving to carry the sheet between the anodes
when the operation of depositing the spongy lead is performed on the moving
sheet. The pressure exerted by the rollers upon the plates should preferably be
greatest at the commencement of the operation and should be diminished as the
thickness of the deposited layer increases so as to obtain a gradually diminishing.
density towards the surface of the layer. The weight (and approximately the
thickness) of the layer of spongy lead thus deposited and consolidated is determined
by the required capacity of the elements per unit of surface and depends on the
intensity of the current and the duration of the operation. Ultimately the
sheets of lead, when sufficiently coated, may be passed through water and wound
upon a drum which should be kept immersed in water or moistened to avoid
heating.
Theoretically, more lead should be deposited upon the sheet intended for the
manufacture of peroxide plates than upon that intended for use as spongy lead
plates. But as, during the working of a lead accumulator, the support of the⚫
peroxide element becomes itself gradually peroxidized I prefer to deposit the same
quantity of lead per unit surface on both sheets and to use thicker sheets of lead
for the peroxide elements. From the coated sheets elements of any required size
may be cut preferably with a lug for purposes of connection. These elements
whether intended for use as positive or negative clements may be allowed to become
slowly oxidized by the effect of exposure to the atmosphere, with the object in
the case of elements to be formed into peroxide plates of economizing power
expended in "forming" and in the case of spongy lead plates to avoid the evolu-
tion of a large quantity of hydrogen in "forming."
For the purpose of carrying the process into effect I may employ apparatus
such as that illustrated in the accompanying drawings wherein Figure 1 is a cross
section of an electrolytic tank and rollers continuously depositing and consoli-
dating the spongy lead and Figure 2 is a part cross-section and Figure 3 a part
sectional elevation of an apparatus for depositing the spongy lead and consoli-
dating it at intervals.
In Figure 1 A is the sheet of lead to be operated on, made into an endless form
by its ends being "burned" together after the sheet has been passed around a
drum B and beneath pressing rollers C and around the upper one D of a pair of
anodes D D. The drum B and pressing rollers C have peripheries of hard wood
and are mounted above an electrolytic tank E in which the pendent bight of the
lead sheet is immersed, the rollers being journalled in spring-pressed bearings so
as to constantly consolidate the electrically deposited and still moist layer of spongy
lead, as the sheet is caused to travel round through the bath by the revolution of
the main drum to the axis of which power is applied. The upper anode D) is a
sheet of lead fixed to a support plunging into the bath and carried by cheeks
attached to the cover of the tank in which the shafts of the drum B and rollers C
are mounted so that by raising the cover by means of suitable tackle the drum
rollers and anode D will all be raised together to permit of placing the sheet in
position, burning together its ends, and lowering it into the tank or of removing
it from the tank when the operation is completed. The lower anode D¹ is also a
sheet of lead fixed in the bottom of the tank with a sufficient space between it
and the upper anode for the passage of the pendent bight of the sheet the anodes
being of such form as to be substantially equi-distant from the sheet at all points.
The anodes are connected together and with the positive pole of the source of cur-
rent by any suitable means, the sheet A being made the cathode by being con-
nected with the negative pole through spring contacts F bearing against the
margin of the sheet.
In Figures 2 and 3 the lead sheets A to be coated with spongy lead are held in
guides in the tank between anode plates D of lead, and the consolidation of the
deposited layer is effected from time to time by means of a pair of rollers C mounted
in spring-pressed bearings in a frame H adapted to travel along the edges of the

page_text: tank so as to be brought into position over the plate to be rolled, the plate being
provided with lateral lugs a for engagement by hooks on counterweighted cords
passing round overhead pulleys and adapted to be passed down within the frame H
so as when attached to the plate to raise it up to the bite of the rollers C and sup-
port it against buckling or falling over as it is raised up through the rollers by
the revolution of the latter in the operation of rolling the plate.
The gearing for traversing the frame along the tank and retaining it in posi-
tion whilst rolling, may be of any suitable kind, a leading screw G being shewn.
The electrical connection with the plates whilst in the bath may be with the lugs a
by means of any suitable binding screw or other detachable connections.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. The herein described method of coating lead sheets with electrolytically
deposited and mechanically consolidated crystalline spongy lead by subjecting the
sheet whilst still moistened by the electrolyte, to the pressure of rollers substan-
tially as specified.
2. The herein described method of coating lead sheets with electrolytically
deposited and mechanically consolidated crystalline spongy lead by causing the
endless sheet to travel continuously between anodes in the electrolytic bath and at
same time subjecting it whilst still moistened with the electrolyte, to pressure of
'rollers so as to simultaneously deposit and consolidate the spongy lead upon the
shect substantially as specified.
1005
A. M. & WM. CLARK,
Chartered Patent Agents, 53 Chancery Lane, London.