Improvements in or relating to Electrodes for Primary and Secondary Batteries.
Year: 1893

page_text: Date of Application, 26th Aug., 1893-Accepted, 7th Oct., 1893
COMPLETE DIECIFICATION,
Improvements in or relating to Electrodes for Primary and
Secondary Batteries.
A communication from RUDOLPH THEODOR ERNST HENSEL, of Dresden, in the
Empire of Germany, Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered 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 present invention relates to the production of clectrodes for primary and
secondary batteries which require no separate core for the active mass, nor any
internal conductor, and consist entirely of active metallic salts or oxides with or
without the addition of suitable cementing agents.
No exact
The electrodes are formed from active metallic salts or oxides-e.g. they may be
made from red lead oxide (Pb,O) stirred with sulphuric acid, till it forms a stiff
paste, which is then under high pressure compressed and dried in moulds.
quantitative relation between the metallic salt employed and the medium used as
solvent can be given-the mixture need only be so chosen that the paste is stiff
enough to assume any plastic shape. Hence the process is a purely empiric one.
Gelatine or silicates are added in at most-only small percentage.
After drying the electrodes are covered with a coating of such substances as will
by the force of their chemical affinity support them while being handled, but which
on the other hand are decomposed or dissolved on the making of the current-so
that when the current is made the electrodes lose their coatings. This coating may
be produced by either rubbing the electrodes over with or dipping them into a
solution of the substances in question or in any other suitable manner.
For the production of such a coating sodium silicate (soluble glass) or other
soluble silicate may be used to advantage-also gelatine and other glue materials;
or gelatine and soluble glass may be used together, a suitable mixture being one
part of gelatine to four parts of silicate.
Specially suitable coatings are obtained by dipping the electrodes in a metallic
bath, in which case however the metal chosen must be soluble in the electrolyte
employed (sulphuric acid) e.g. an alloy of tin.
As regards the shape of such electrodes they should not be smooth-but fluted
furrowed, undulated or zigzag shaped, ribbed or perforated, for the purpose of
obtaining in proportion to their weight an active surface as large as possible.
Specially adapted forms are represented in the accompanying drawings.
The electrodes represented in Figures 1-3 are substantially zigzag shaped in
transverse section. By a corresponding shaping of the moulds parallel ribs and
grooves are formed on the body of the electrodes by means of which its active
surface is rendered much larger than that of the ordinary flat ones of the same
size, for it is not only the two parallel wall surfaces but also the sides of the
grooves and ribs that are active. Another no less noteworthy advantage of these
electrodes is that the ribs serve to render them stiffer and that a substantially
greater durability is thus attained. The ribs running in one direction may be met
crosswise by other ribs as is indicated in Figure 4. In Figure 5 the electrode
has the form of a wafer-iron (honeycombed) by which the same end is attained.
All these shapes may of course be modified and combined into many other
forms.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner
the same is to be performed, I declare that what I claim is :-
1
1. The production of electrodes for primary or secondary batteries without
a separate core entirely from a plastic mass of metallic salts or oxides acting as
electrolytes with the addition, if necessary, of cementing agents such mass being
compressed in suitable moulds under a high pressure substantially as specified.
2. The method of protecting such electrodes from falling to pieces before the
making of a current or from mechanical injuries during their handling by dipping
the freshly formed and dried electrodes into a solution of soluble silicates gelatine
melted metals and like substances or rubbing the electrodes over with such coating
or applying it in any other suitable manner-such coating substances being
dissolved or otherwise destroyed by the making of the electric current substantially
as described.
3. Shaping electrodes formed in the above described manner so as to provide
their surfaces with ribs grooves undulations or any other forms of excavation or
perforations substantially as and for the purpose specified.
Dated this 26th day of August 1893
W. P. THOMPSON & BOULT,
London, Nottingham, Liverpool, and Manchester,
Agents for the Applicant.
W. P. THOMPSON & BOULT,
London, Nottingham, Liverpool, and Manchester,
Agents for the Applicant.