An Improved Electrical Accumulator.
Year: 1897

page_text: Date of Application, 9th Dec., 1897-Accepted, 10th Sept., 1898
COMPLETE SPECIFICATION.
An Improved Electrical Accumulator.
I, PAUL BRANDT, of Naarssen, in the Kingdom of Holland, 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 follow-
ing statement:-
The subject of this invention is an electrical accumulator in the construction of
which lead-grids are dispensed with, while for the usual electrolyte consisting
of sulphuric acid there is substituted a paste of special composition; the new
accumulator being capable of being readily and quickly changed and safely dis-
charged without any short-circuiting, while at the same time the apparatus fitted
with it is free from the drawbacks attending the old constructions, and the
accumulator itself is enabled to continue fit for use for a longer period of time.
The invention will be best understood by reference to the accompanying draw-
ing in which one form of the improved accumulator is represented by way of
example.
Figure 1 is a longitudinal section, and
Figure 2 a top-view or plan of the accumulator.
The apparatus, the shape of which is optional, but is supposed to be square in
the present instance, mainly consists of a cell B of clay, placed in a vessel of
glass or other material and retained in position by means of cross-pieces K. The
interior of the vessel is divided by partitions of porous clay-which are made
sliding and removable into a number of compartments, such as F and H, which
are filled with the paste and serve for the reception of the electrodes. The elec-
trodes consist of lead combs D and L, which are provided with lugs E, G, project-
ing into the compartments alternately. Each of the lead-combs is bent in hook-
shape at one end and provided with a perforation J serving to connect together
the several cells. Now instead of receiving dilute sulphuric acid, the cells are
filled with a preparation consisting of a mixture of an alkaline sulphate with
a mixture of calcium oxalate or tartrate and sulphate of lime, which, together
with sulphuric acid and oxides or peroxides of lead (preferably litharge PbO)
are stirred or kneaded into a paste and filled into the several compartments.
The mass added to the lead oxide may for example consist of the following
constituents:
-
constituents:-
2 parts by weight magnesium sulphate.
4 parts by weight sodium sulphate.
16.5 parts by weight calcium oxalate.

page_text: To the paste thus produced, glycerine and butyric acid are superadded in order
to accelerate solidification, without its affecting the electrolytic process.
Now although in this accumulator the employment of lead-grids is avoided, its
cathodes nevertheless present a sufficiently wide surface to allow of the free motion
of the ions and impart considerable capacity to the accumulator-a capacity
being in fact almost equal to what it is in theory. The operation of moulding
the plates, moreover, is altogether omitted, and the accumulator owing to the
absence of a fluid electrolyte may readily be brought to the "charged" condition.
What causes the increased capacity of the accumulator, owing to which the
cathodes so formed prove to be more serviceable than grids of lead, is that the
oxygen arising from the composition of the sulphate, which is distributed through-
out the mass or volume of the paste, renders auch paste porous. The plates, at
the same time, are not acted upon in the same way as in the ordinary accumu-
lators, as the only part that is apt to wear away is the paste filled into the com-
partments, while the plate itself is affected but to a comparatively limited extent.
The charging of the battery may commence immediately after its erection is
completed and a full charge may be effected in about 15 hours without any special
periods of rest being required.
With this accumulator it is possible to avoid the objectionable local action of
the sulphuric acid upon the lead plates--an action which even in cells constructed
on Faure's principle is obviated only in a very incomplete mauner-that result
being attained because, most likely, its organic constituents take a share in the
reaction and because the lead-sulphate formed upon the positive plate im-
mediately combines with the calcium oxalate, whilst at the same time forming
"double salts" of lead, which, under the action of the current and of the oxygen
evolved from the sulphuric acid and sodium-sulphate, immediately decompose
again and in so doing for permanent peroxide of lead; while at the anode the
hydrogen literally given out in the process of decomposition of the organic acids
assists the formation of molecular lead.
In using this accumulator it is advisable to employ sulphuric acid of a strength
of 10° Beaume.
The novel construction renders the employment of grids unnecessary and
obviates the falling out of the paste from the grids, which where it happens is
so objectionable a feature and one so detrimentally affecting the operation of the
accumulator; and it also prevents the plates from warping and splitting. Besides
the erection of the apparatus itself is by this invention considerably simplified,
in us much as it does away with any necessity for ready made plates to be carried
or sent from one place to another. Owing to the avoidance of any secondary or
bye-effects, the capacity of the accumulator is also greatly enhanced, the result-
ing useful effect being about 97 per cent.
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. A process of manufacture of an electrical accumulator, mainly consisting
in forming an electrolyte of a mixture of alkali-sulphates and lead oxides with
sulphuric acid and calcium sulphate, also of organic lime-salts, the object being
without the employment of lead grids, to ensure a higher useful effect and to
avoid local action.
2. One form of carrying out the process referred to in the 1st Claim, mainly
consisting in the employment of butyric acid or any other organic acid and
glycerine in conjunction with alkaline sulphates, for the purpose of enhancing
the porosity of the paste without destroying its cohesion.
3. Apparatus for carrying out the process referred to in the 1st Claim, mainly
consisting of a cell of porous material which is divided into a number of chambera

page_text: or compartments by a corresponding number of sliding and removable partitions
of porous clay, such compartments serving for the reception of the electrodes.
Dated this 9th day of December 1897.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.