Improvements in Secondary Voltaic Batteries.
Year: 1895

page_text: Date of Application, 21st Dec., 1895-Accepted, 1st Feb., 1896
COMPLETE SPECIFICATION.
Improvements in Secondary Voltaic Batteries.
I, LUDWIG EPSTEIN, of No. 28 Victoria Street, Westminster, in the County
of London, Electrical 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 :-
My invention relates to the construction and arrangement of a secondary voltaic
battery cell in such a manner as to obtain great electrical energy from comparatively
little weight, and to provide against short circuiting by fragments of the active
material, and loss of mercury from amalgamated plates.
Figs. 1 and 2 of the accompanying drawings are vertical sections on planes at
right angles to each other and
to
Fig. 3 is a plan, the cover supposed to be removed, of a secondary cell according
my invention.
Fig. 4 is a perspective view to an enlarged scale shewing one form of the casings
and troughs employed.
A indicates the positive plates which may be of any known kind. B indicates
the negative plates, which might be separate plates or may consist as shewn of
portions of a single sheet bent in zigzag form. In either case the negative
plates B are of known kind consisting of copper wire gauze electrolytically
coated with zinc and mercury amalgam. Around each of the positive plates A at
some distance from their surfaces is formed a porous casing C of nonconducting
material such as is not acted on by the exciting liquid. The walls of this casing
may be made in various ways. For instance each wall may consist of an open
framing or a perforated sheet of ebonite or the like on which is stretched
asbestos or other fabric; or it may consist of two perforated sheets of ebonite
or the like enclosing fabric between them. The casing extends some distance
below the plate A which is supported on wedge shaped bars D and the sides of the
casing have their lower parts which extend down beyond the plate A made without
perforation or with their perforations covered, there being thus formed under each
positive plate a quiescent chamber E which receives and retains such fragments of
active material as may drop off the plate. The fragments which may thus fall into
the chamber E being quite cut off by the non-conducting wall of the casing C from
contact with the neighboring negative plates, cannot effect short circuiting. The
lower edges of the negative plates B are held in troughs F of non-conducting
material, which receive such of the mercury as may during the action of the
battery separate itself from the zinc amalgam and descend along the surface of
the plates when the battery is charged, zinc is deposited on the negative plates
and the mercury then ascends from the troughs F to combine in amalgam with the
deposited zine.
The plates A and B, casings C and troughs F are all carried on an open framing G
under which is mounted a revolving agitator H. During the action of the battery,
this agitator being caused by any convenient motor to revolve either continuously
or from time to time produces currents of the exciting liquid which tend to render
it uniform throughout the cell.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is :-
J In a secondary voltaic battery casinos enclosing the positive plates and extending

page_text: below them, their walls being porous except in their lower parts substantially as and
for the purpose set forth.
2. In a secondary voltaic battery having negative plates coated with zinc and
mercury amalgam, troughs holding the lower edges of the negative plates substan-
tially as and for the purpose set.forth.
ABEL & IMRAY,
Agents for the Applicant.