Improvements in Plates for Electric Accumulators.
Year: 1898

page_text: Date of Application, 28th Apr., 1898-Accepted, 18th June, 1898
COMPLETE SPECIFICATION.
Improvements in Plates for Electric Accumulators.
I, MAX BERNSTEIN, Proprietor of the Firm of Joh. Friedr. Wallmann & Co.,
of No. 74, Blumen Strasse, in the City of Berlin, in the German Empire, Patent
Agent, 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 subject of the present invention is a plate for electric accumulators, especially
for those used for driving vehicles, which can be kept charged during working by
such gas being supplied to the active material as is capable of renewing it. For
this purpose the plate is provided interiorily with a gas chamber.
An example of such an accumulator-plate, and of a cell containing several such
plates, is illustrated on the accompanying drawing.
Fig. 1 is a vertical section of the plate.
Fig. 2 a side view of same.
Fig. 3 a side view of a cell, the containing vessel being shown in section.
Fig. 4 is a plan view of the cell.
The accumulator-plate (Figs. 1 & 2) consists of two plates of lead a', a² having
longitudinal dove-tail grooves to receive the active material. The reverse sides
of these lead plates are turned towards each other, a small free space being left
between them. They are held together by means of a strip of lead b, soldered
air-tight to them, so that a chamber is formed, a small lead pipe c being soldered
onto the strip 6 to act as conduit. The plates a¹, a² are finely perforated on their
reverse side for the purpose of allowing gas contained in the chamber to penetrate
into the active material.
A cell formed of five such accumulator-plates is shown in Figs. 3 and 4, E
E3 Es being negative electrodes and EE positive.
The small lead pipes c of the plates E E³ E connect with the cross-pipe rl, and
the corresponding pipes c of the plates E³ E connect with a cross-pipe r, the
junctions being made by soldering.
In this way the electrodes of like polarity are arranged in parallel, their gas
chambers standing in connection with each other.
If now such an accumulator is formed and charged in the usual manner, lead
binoxide is formed on the positive electrode and pure lead on the negative.
On connecting up the accumulator to yield a current, however, oxygen, as is
well known, is given off at the negative electrode, converting the pure lead into
binoxide; whilst at the positive electrode hydrogen is evolved, reducing the lead
binoxide to monoxide.
If, however, by means of the tube l and the gas chamber, the plates E¹ E E³
are supplied with hydrogen, and similarly, by means of the tube r, the plates E³
E with oxygen, the action on the active material, of the gases given off during
the working of the cell can be counterbalanced by the gases mechanically con-
ducted to the plates. The accumulator can thus be kept charged as long as there
is hydrogen and oxygen in the reservoirs. The latter are of form suitable for
transit, for instance gas pressure cylinders.

page_text: From this it is clear that the capacity only depends upon the size of the cell
in so far as regards the attention which must be paid to the current-density per-
missible. A lengthened period of working necessitates no increase in the size of
the cell, but demands larger gas reservoirs. The gases, however, may be com-
pressed, so that the size of the reservoirs need not be unduly large.
The number of cells depends as ordinarily, upon the tension desired; they may
be connected up by means of strips of lead d (Figs. 3 & 4). The gas chambers of
like electrodes can be connected with each other by rubber tubing passed over the
ends of the pipes 2. Reducing valves are provided on the reservoirs in order
to regulate the supply to the gas chambers, of the gases contained under high
pressure in the reservoirs.
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:
An electric accumulator plate consisting of two separate plates of lead secured
in a lead frame, each lead plate having dove-tailed grooves formed on one side to
receive the active material, communicating by means of perforations with a central
passage or chamber left between the two plates, into which gas may be conducted
during working of the cell, for the purpose of continuous regeneration of the plate,
substantially as described.