Improvements in and connected with Secondary Galvanic Batteries.
Year: 1894

page_text: Date of Application, 19th Oct., 1894-Accepted, 23rd Mar., 1895
COMPLETE SPECIFICATION.
Improvements in and connected with Secondary Galvanic Batteries.
I, GEORG HÜBNER of Zellulose-Fabrik Chaussee, Gernsbach bei Baden, in the
Empire of Germany, 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 aud by the following statement:-
The object of this invention is to produce a filling material for electric
accumulators, and to provide an accumulator specially for the employment of
such filling material.
In order to produce the filling material cellulose is treated with a solution of
lead oxide dissolved in a large quantity of caustic alkali and sulphuret of carbon
is worked into the resulting thick mass. The slimy liquid thus obtained can be
applied direct for electric accumulators, or may be previously converted into a stiff
porous tissue by spontaneous decomposition. The decomposition of the liquid may
be facilitated by heating and oxidising the liquid. By the addition of a small
quantity of nitrated cellulose (which also dissolves in the liquid) and an alkaline
salt, the change of the liquid is facilitated very much and an almost untearable and
very effective filling material is produced.
The accumulators to which the new filling material is to be applied may be
constructed in the usual well known way, but preferably with a porous electrode
filled with the above described mass, with or without the addition of a suitable
proportion of powdered carbon, and placed in and insulated in a similar outer
electrode covered or surrounded with the active mass and filled with the electrolyte,
sulphuric acid for example.
The practical carrying out of the invention is best effected as follows:-
Into hot, strongly concentrated caustic alkali in which a sufficient quantity of
lead oxide is dissolved, is placed and stirred a large proportion (about 40 per cent.
of the oxide employed) of ordinary wood cellulose. As soon as the latter has
swollen up completely, and has become almost transparent, sulphuret of carbon is
introduced until a complete solution is effected and a gluey, slimy liquid results,
in which the dissolved lead oxide is combined and mixed with the cellulose.
This slimy mass forms the foundation for the accumulator, and is applied to the
electrodes and converted into a firm mass in the form of a porous tissue either by
heating to about 85° Centigrade, by oxidation by means of air, or by spontaneous
decomposition. In order to hasten the conversion and to produce an almost
untearable and very effective filling material one to one and a half per cent. of
nitrated cellulose with a half per cent. of an alkaline sulphate are added, whereby
the strength of the resulting tissue is immediately and considerably increased.
.
The active oxides adhere very firmly to this tissue, and they can be easily and
completely formed, because in consequence of the high porosity of the mass the
electrolyte is thoroughly absorbed thereby and the innermost parts thereof are
brought into action.
Lead plates, or sheet iron plates which have been made acid-proof and which
are covered with the above described. mass take up after the latter has been
changed into a tissue, a considerable quantity of current at the first charge, and
are consequently partly formed by such charge.
Or the gelatinous mass may be poured on to glass plates where it is converted
into sheets or tablets by the action of the air. These sheets or tablets are wrapped
round the electrodes and are fixed thereon by means of indiarubber rings.
On charging the accumulator the products resulting from the action of the

page_text: sulphuret of carbon on the caustic alkali separate out into the form of sulphurous
water so that they do not prejudice the action of the accumulator.
The best material for the electrodes is porous carbon, but lead plates or thin
sheet iron electrodes coated with lac containing powdered carbon and thus made
proof against the action of the electrolyte, may be employed although lead plates
are destroyed by continuous use.
The electrodes and accumulators may be put together in the usual way.
A. durable and practical form of accumulator is shown in section in the
accompanying drawing.
In a vessel a is placed a highly porous carbon cell b which is coated or enveloped
with the above described filling mass. In this cell is placed a smaller porous
carbon cell c standing on feet d of insulating material. This latter cell is filled
with the aforesaid filling mass (to which is added to make it a better conductor
a suitable quantity of powdered carbon). In order to hold the inner cell c
central, and to avoid short circuiting, it projects through a corresponding opening
in the cover e of the accumulator, which at the same time prevents the evaporation
of the electrolyte. The latter (dilute sulphuric acid in a liquid or gelatinous
condition) is placed in the space between the two electrodes. The clamps f and g
serve as conductors for the current.
Instead of fixing the clumping screw f direct to the inner carbon cell c a special
carbon rod c with clamp may be placed in the said cell as shown in dotted lines
in the drawing. By this means the charging current is obliged to pass through
the whole of the filling mass of the inner cell c which latter in that case serves
simply to hold firmly together the entire inner filling mass.
The accumulator above described is very suitable for transport in consequence
of its light weight as it is four or five times lighter than accumulators of the
ordinary construction, and although there is considerably less filling material
present than in the ordinary accumulator it is considerably better able to perform
work and is more effective, as the mass, in consequence of its high porosity, is
active not only at its surface but in its interior. The gradual corrosion and
destruction of the electrodes by the electrolyte which take place in the heavy lead
gratings and plates in general use, and the trouble in working caused thereby, are
all avoided by the use of this invention.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is
First. The process for producing a filling material for electric accumulators
which consists in treating cellulose with a solution of lead oxide in caustic alkali,
and introducing sulphuret of carbon, the slimy liquid thereby obtained being
either applied direct to the electrodes or previously converted into a stiff porous
tissue by heating, oxidation, or decomposition the conversion being facilitated, or
not, by the addition of nitrated cellulose and alkaline salt, substantially as
described.
Second. An accumulator adapted for the employment of the porous mass or
material herein described, which consists of a porous outer clectrode 6 covered with
or enveloped in the said porous mass or material, and filled with the electrolyte,
and a porous inner electrode c insulated from the outer electrode and filled with.
the said porous mass or material, and powdered carbon, substantially as described.
Dated this 18th day of October A.D. 1894.
G. HÜBNER,
Per W. H. Beck,
Agent.