Improvements in the Manufacture and Production of Plates or Elements for Secondary Batteries or Electrical Accumulators.
Year: 1898

page_text: Date of Application, 13th Dec., 1898
Complete Specification Left, 7th Sept,, 1899—Accepted, 21st Oct., 1899
Improvements in the Manufacture and Production of Plates or
Elements for Secondary Batteries or Electrical Accumulators.
I, CAMILLE BRAULT, of 18 Quai de Clichy, Clichy, in the Republic of France,
Engineer do hereby declare the nature of this invention to be as follows: -
The object of my invention is to provide plates or elements for secondary
batteries or electrical accumulators, which though of small weight, possess a
high capacity of great solidity and strength.
Each plate or element is formed essentially of a number of small pieces
or tablets of agglomerated active material, or material to be rendered active,
firmly held between the bars of two grids of lead or of lead alloyed with antimony
made by casting stamping or other suitable means. They are formed of a
number of longitudinal and transverse bars triangular in cross section and
enclosing preferably rectangular spaces to be filled with the active material,
or material to be rendered active. Each plate or element is provided with
two grids, one grid has holes at the intersection of its bars, the other grid
having conical projections for entering the holes of the first grid.
The active material or material to be rendered active is prepared as follows:-
I make an intimate mixture of oxide of lead (litharge) with about. 10 per cent.
of sulphate of lime, or other alkaline salt or alkaline earth salt such for example
as sulphate, nitrate, or phosphate of sodium, potassium, lime, or magnesium.
When preparing the material for the negative plates I add to this mixture 1
to 3 per cent. of double chloride of platinum and mercury, or of chloride of
platinum, or of sulphate of mercury. After these materials have been well
mixed I work up or knead them in about 10 per cent. of distilled water in an
hermetically closed vessel, provided with two orifices, by which ammonia gas is
caused to pass through the material during the kneading, the gas entering by
one of the said orifices and passing out by the other.
Under the influence of the ammonia gas absorbed in part by the water con-
tained in the now pasty mass, the said mass gradually becomes hard and
commences to solidify. When this takes place I remove the material from the
vessel and I spread it in thin layers on tables or other supports and allow it
to dry in the air.
To hasten the drying a stream of dry cold air may be passed over the material
but the use of heat for this purpose should be avoided. When thoroughly dry
the material is pulverized (which may be done in an ordinary crushing mill)
and it is then ready for use in the manner hereinafter described.
Instead of using distilled water as aforesaid in forming the pasty mass I
may use a solution of ammonia and in this case it is unnecessary to submit
the paste to the action of the gaseous ammonia but a stream of dry air mav
be used instead or this may be dispensed with and the kneading be effected
in an open vessel but the operation then takes longer to perform. When the
material begins to solidify I withdraw it from the kneading vessel and dry
and pulverize it as hereinbefore described.
With the material so prepared I manufacture the plates or elements as
follows

page_text: In a rectangular mould I place a grid (formed with projections as aforesaid)
and I then place in the mould the powder prepared as hereinbefore described
and I level the surface of the powder and then I place a second grid (formed
with holes as aforesaid) in position over the first grid so that the holes in the
upper grid come over the projections on the lower grid; I then place an upper
part or cover accurately fitting the mould on the upper grid and the whole
is then subjected to strong pressure, so that the upper part or cover enters the
mould and forces the two grids into contact and causes the projections of the
lower grid to be rivetted into the openings of the upper grid. The spaces in
the grids are thus filled with tablets of strongly agglomerated material held
firmly between the bars of the grids. I may furnish the bottom of the mould
and the underside of the upper part or cover with points or projections of conical
or pyramidal shape, which by the compression, will leave indents, or impressions
on the corresponding sides of the blocks or tablets, and so increase the surface
of active material in contact with the electrolyte.
After the plate has been removed from the mould I place it in a bath of
water slightly acidulated with sulphuric acid and allow it to remain therein for
several hours; it is then removed and dried in the air.
To connect the plates together the positive and negative plates are soldered
respectively to two lead or equivalent bars constituting the two poles of the
secondary battery. This may be done in the ordinary manner.
To prevent contact between adjacent plates, I insert in the intervening spaces,
rods of glass, celluloid, or ebonite, or perforated and corrugated sheets of ebonite
or celluloid. The formation of the secondary battery is then completed in any
well known or suitable manner.
Dated th
1011
D
1
1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in the Manufacture and Production of Plates or
Elements for Secondary Batteries or Electrical Accumulators.
I, CAMILLE BRAULT, of 18 Quai de Clichy, Clichy, in the Republic of France,
Engineer, 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 provide plates or elements for secondary
batteries or electrical accumulators which though of small weight, possess a
high capacity and great solidity and strength.
Each plate or element is formed essentially of a number of small pieces,
or tablets, of agglomerated active material, or material to be rendered active,
firmly held between the bars of two grids of lead, or of lead alloyed with antimony
made by casting stamping or other suitable means. The grids are formed of a
number of longitudinal and transverse bars triangular in cross section and
enclosing preferably rectangular spaces to be filled with the active material,
or material to be rendered active. Each plate or element is provided with
two grids. One grid G¹ shewn in plan and cross section in Fig. 1 has holes a
at the intersection of its bars the other grid G2 (shewn in plan and cross section
in Fig. 2) having conical projections 6 for entering the holes a of the first grid.
The active material or material to be rendered active is prepared as follows:
I make an intimate mixture of oxide of lead (litharge) with about ten per cent.
of sulphate of lime, or other alkaline salt or alkaline earth salt such for example

page_text: as sulphate, nitrate, or phosphate of sodium, potassium, lime, or magnesium.
When preparing the material for the negative plates I add to this mixture 1
to 3 per cent. of double chloride of platinum and mercury, or of chloride of
platinum, or of sulphate of mercury.
After these materials have been well
mixed I work up or knead them in about 10 per cent. of distilled water in an
hermetically closed vessel, provided with two orifices, by which ammonia gas is
caused to pass through the material during the kneading, the gas entering by
one of the said orifices and passing out by the other.
Under the influence of the ammonia gas absorbed in part by the water con-
tained in the now pasty mass, the said mass gradually becomes hard and
commences to solidify. When this takes place I remove the material from the
vessel and I spread it in thin layers on tables or other supports and allow it
to dry in the air.
To hasten the drying a stream of dry cold air may be passed over the material
but the use of heat for this purpose should be avoided. When thoroughly dry
the material is pulverised (which may be done in an ordinary crushing mill)
and it is then ready for use in the manner hereinafter described.
Instead of using distilled water as aforesaid in forming the pasty mass I
may use a solution of ammonia and in this case it is unnecessary to submit
the paste to the action of the gaseous ammonia but a stream of dry air may
be used instead or this may be dispensed with and the kneading be effected
in an open vessel but the operation then takes longer to perform. When the
material begins to solidify I withdraw it from the kneading vessel and dry
and pulverise it as hereinbefore described.
With the material so prepared I manufacture. the plates or elements as
follows:-
In a rectangular mould M (Fig. 3) I place a grid G2 (formed with projec-
tions 6 as aforesaid) and I then place in the mould the powder prepared as herein-
before described, and I level the surface of the powder and then I place the
second grid G (formed with holes a as aforesaid) in position over the first grid G2
so that the holes in the upper grid come over the projections on the lower grid;
I then place an upper part or cover N, accurately fitting the mould M, on the
upper grid G¹ and the whole is then subjected to strong pressure, so that the
upper part or cover enters the mould and forces the two grids into contact and
causes the projections 6 of the lower grid to be rivetted into the openings a
of the upper grid as shewn in Fig. 4. The spaces in the grids are thus filled
with tablets P of strongly agglomerated material held firmly between the bars
of the grids. I may furnish the bottom of the mould and the underside of the
upper part or cover with points or projections of conical or pyramidal shape
which, by the compression, will leave indents, or impressions, on the corresponding
sides of the blocks, or tablets, and so increase the surface of active material in
contact with the electrolyte.
After the plate has been removed from the mould I place it in a bath of
water slightly acidulated with sulphuric acid and allow it to remain therein for
several hours; it is then removed and dried in the air.
To connect the plates together the positive and negative plates are soldered
respectively to two lead or equivalent bars constituting the two poles of the
secondary battery. This may be done in the ordinary manner.
To prevent contact between adjacent plates, I insert in the intervening spaces
rods of glass, celluloid or ebonite or perforated and corrugated sheets of ebonite
or celluloid. The formation of the secondary battery is then completed in any
well known or suitable manner.
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 preparation for the positive plates or elements of secondary batteries

page_text: or electrical accumulators of active material or material to be rendered active
by submitting a moistened mixture of litharge and of a salt of an alkali or of
an alkaline earth to the action of ammonia gas, well kneading the mixture,
allowing the product to dry and then reducing it to powder.
2. The preparation for the positive plates or elements of secondary batteries
or electrical accumulators of active material or material to be rendered active
by kneading a dry mixture of litharge and a salt of an alkali, or of an alkaline
earth, with a solution of ammonia, allowing it to dry after kneading, and then
reducing it to powder.
}
3. The preparation for the negative plates or elements of secondary batteries
or electrical accumulators of active material or material to be rendered active
by adding to the materials constituting the mixture for the said plates or elements
as aforesaid a salt of platinum or of mercury or a double salt of the said metals.
4. The manufacture of a plate or element for secondary batteries or electrical
accumulators by compressing the active material or material to be rendered
active in a powdered state and prepared as described between two grids of lead.
Dated this 7th day of September 1899.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.