Improvements in or relating to Accumulator Plates for Secondary Batteries.
Year: 1897

page_text: Date of Application, 10th July, 1897-Accepted, 14th Aug., 1897
COMPLETE SPECIFICATION.
Improvements in or relating to Accumulator Plates for Secondary
Batteries.
I, ERNST WALDEMAR JUNGNER, of 7, Engelbrechtsgatan Stockholm, in the
Kingdom of Sweden, Candidate of Philosophy, 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 mechanical constructions in the form of grates bars and the like which
have lately been produced as electrodes for electric accumulators, have for their
main object to assure the strength of the electrodes, in which it has been en-
deavoured to retain the electrode metal and the filling material in unchanged
condition during the use of the accumulator. It has consequently been sought
to avoid the injurious action of the alterations of volume of the active mass during
the charging and discharging and to prevent the same from becoming detached
and falling down upon the bottom of the receptacle. This object has hitherto
been attained at the cost of other advantages. The electrode metal and the active
mass have been too much pressed together, whereby the surface of contact between
the electrolyte the metal and the active mass has become a relatively small one.
In addition to this such accumulators involve a relatively high cost, because so
much work must be devoted to the preparation and construction of the electrodes.
The object of the present invention is whilst retaining the advantage of great
firmness of the electrodes to render it possible to keep also the other advantages
of the same, and especially to retain a relatively large surface of contact between
the electrode metal the active mass and the electrolyte. At the same time the
cost of construction is reduced.
The invention is illustrated in the accompanying drawing in which a a¹ are two
metal plates between which the active mass m is spread in a thin layer by means
of rollers or in any other convenient manner. The metal plates a a¹ are perforated
with small glass close set holes h and are sewn together by means of a wire t with
stitches S arranged close to each other over the whole surface of the electrode.
The sewing is preferably effected by a machine and the wire may be either of
celluloid or of a suitable metal. In order to obtain larger capacity several such
sheets may be placed side by side with intervening layers of active material as
shown in Figure 2. Also the electrode may be folded in various ways as shown
in Figure 3 and Figure 4 in section. By this arrangement the filling material
keeps its position unaltered. It can suffer no injury by shocks or by the develop-
ment of gas. It can also not fall to the bottom and thereby cause short circuits
loss of capacity or the like. Moreover, on the alterations of volume of the mass
the connection between the metal and the mass is preserved. The construction of
the electrodes is moreover much simplified by the above-described arrangement.
In consequence of the great contact surface between the negative conductor the
active mass and the electrolyte the accumulator attains a relatively great capacity,
a small internal resistance, and a high efficiency so that it can support a relatively
strong charge and give a strong discharge current. The invention is therefore

page_text: specially valuable for travelling accumulators especially of larger size in which
the size of the abovementioned contact surface is one of the most important factors.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is:
In electrodes for electric accumulators the arrangement of two thin metal
plates a a perforated with fine and closely placed holes, having between them a
thin layer of active filling material m and sewn together over their whole surface
by wire with close stitches through both metal plates and thereby held firmly
together, for the purpose of retaining the active material in an unalterable position,
giving a great contact surface between the metal the active mass and the electrolyte
and permitting of a cheap preparation of the electrode substantially as described.
Dated this 7th day of July 1897.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.