Improvements in and in the Construction of Soluble-metal Electrodes for Accumulators.
Year: 1896

page_text: Date of Application, 2nd Apr., 1896
Complete Specification Left, 3rd Dec., 1896-Accepted, 23rd Jan., 1897
Improvements in and in the Construction of Soluble-metal Electrodes
for Accumulators.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 322, High Holborn, in the County of Middlesex,
6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in the County of
Lancaster, and Lower Temple Street, Birmingham, in the County of Warwick,
Civil Engineer, do hereby declare the nature
the nature of this invention to be as
follows:-
The soluble-metal electrode for electric accumulators which forms the object of
the present application appertains to the class of electrodes formed by the galvano-
plastic deposit of a soluble metal zinc, cadmium or other equivalent or analogous
metal upon a base either of an insoluble or soluble metal serving as a support, but my
invention is distinguished from its predecessors in that anyone of the soluble metals
indicated such as zinc for instance is deposited by galvanic process upon a frame or
base of copper in such a manner as to cause it to adhere thereto by means of a
new manufacturing process which affords it all the advantages belonging to this
class of electrodes without retaining any of the drawbacks which have prevented
the general use of these elements however preferable in theory.
In the first place the said electrodes for which a support of lead or of zinc has
generally been adopted which receive the various galvanic deposits are of little
strength by reason of the flexibility in the support of lead and its fragility in the case
of zinc which becomes fragile under action of the current. A still more serious
drawback is that of the local actions the formation of parasitic couples of which
they are the location and which materially reduce the working power of the
accumulator.
Now my new process of forming the soluble metallic electrode admits not only of
the use of copper plates as a support and prevents entirely local action and formation
of parasitic couples, but it has also an extremely favourable influence upon the
galvanic deposition in that it is not attacked and only decomposes in proportion to the
discharge in order to reconstitute itself in the same manner during the charging.
The process of construction for carrying out the above described effect consists in
amalgamating before the galvanic deposition in a general manner of the supports
with soluble electrode metal, but especially a plate of copper intended to serve as the
support. When the supports are thus covered with a layer of mercury they are
plunged as electrodes in baths prepared for the deposition of zinc, cadmium and the
like. These galvanoplastic deposits have generally speaking the above indicated pro-
perties in relation to the very small action of the accumulator bath above mentioned,
but for the copper support the faculty of adhering somewhat to the same with all
the other advantages resulting from a copper support. It is possible to increase
moreover considerably the adhesion and the closeness of contact between the support
and the liquid metal such as mercury which serves to amalgamate then by means
of a special method of preparation consisting in depositing galvanoplastically upon

page_text: the support a layer of the same metal of which it is composed before the amal-
gamation in the liquid metal. Thus upon the copper support there would be deposited
a layer of copper galvanoplastically which would give it a very finely porous
surface. It is then amalgamated with mercury and afterwards the final coat of
soluble metal is applied as described above. The plates obtained by this process are
practically perfect for this kind of electrode.
If after the charging and discharging of the accumulator in which certain plates
act as negative electrodes beside positive electrodes of peroxide of lead they may
be enveloped in the permeable material described in another of my patents. The
new soluble electrode will have in addition to its special qualities that of an absolute
uniformity of material.
Dated the 2nd day of April 1896
W. P. THOMPSON & Co.,
Agents for the Applicant.
Improvements in and in the Construction of Soluble-metal Electrodes
for Accumulators.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 322, High Holborn, in the County of Middlesex,
6, Lord Street, Liverpool, and 5, Bank Street, Manchester, both in the County of
Lancaster, and Lower Temple Street, Birmingham, in the County of Warwick,
Civil 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:-
The soluble-metal electrode for electric accumulators which forms the object of
the present application appertains to the class of electrodes formed by the galvano-
plastic deposit of a soluble metal zinc, cadmium or other equivalent or analogous
metal upon a base either of an insoluble or soluble metal serving as a support, but
my invention is distinguished from its predecessors in that anyone of the soluble
metals indicated such as zinc for instance is deposited by galvanic process upon a
frame or base of copper in such a manner as to cause it to adhere thereto by means
of a new manufacturing process which affords it all the advantages belonging to this
class of electrodes without retaining any of the drawbacks which have prevented the
general use of these elements however preferable in theory.
In the first place the said electrodes for which a support of lead or of zinc has
generally been adopted which receive the various galvanic deposits are of little
strength by reason of the flexibility in the support of lead and its fragility in the
case of zinc which becomes fragile under action of the current. A still more
serious drawback is that of the local actions the formation of parasitic couples of
which they are the location and which materially reduce the working power of the
accumulator.
Now my new process of forming the soluble metallic electrode admits not only of
the use of copper plates as a support and prevents entirely local action and formation
of parasitic couples, but it has also an extremely favourable influence upon the
galvanic deposition in that it is not attacked and only decomposes in proportion to
the discharge in order to reconstitute itself in the same manner during the charging.
The process of construction for carrying out the above described effects consists in
amalgamating the supports in general and especially copper plates before the galvanic
deposition of soluble electrode metal. When the supports are thus covered with a
layer of mercury they are plunged as electrodes in baths prepared for the deposition
of zinc, cadmium and the like. These galvanoplastic deposits have generally speaking

page_text: the above indicated advantages in relation to the very small local action of the accumu-
lator bath above mentioned, and possess moreover in the case of the copper support
the faculty of adhering somewhat to the same with all the other advantages resulting
from a copper support. It is difficult to obtain satisfactory adhesion by the simple
amalgamation of ordinary copper but it is possible to increase considerably the adhesion
and the closeness of contact between the support and the liquid metal such as mercury
which serves to amalgamate it by means of a special method of preparation consisting
in depositing galvanoplastically upon the support a layer of the same metal of which
it is composed before the amalgamation with the liquid metal. Thus upon the copper
support there is deposited a layer of copper galvanoplastically which gives it a very
finely porous surface. It is then amalgamated with mercury and afterwards the final
coat of soluble metal is applied as described above. The plates obtained by this
process are practically perfect for this kind of electrode.
Although the electrodes thus prepared are quite perfect and durable when simply
immersed in the electrolyte, the mercury is still more certainly kept efficient if the
base of the electrodes be plunged into a layer of mercury which may moreover be of
very slight depth.
This layer of mercury may be spread over the bottom of the vessel which contains
the plates, or it may be contained in a narrow receptacle surrounding the base of each
electrode. This application is especially advantageous for electrodes of tubular form
such as shewn in vertical section in the accompanying drawing.
In this case, a block B of wood, ebonite or the like having an external rim ris
engaged in the end of the electrode E around which the said rim r forms a circular
groove which is filled with mercury. Into this groove the end of the amalgamated
electrode plunges and the same is thus entirely self-contained with relation to its
supplementary layer of mercury and prepared to be placed in the bath.
Having now particularly described and ascertained the nature of my said
invention as communicated to me by my foreign correspondent I declare that what
I claim is :-
1. The construction of soluble metal electrodes for accumulators characterised by
the galvanoplastic deposit of copper upon a plate of copper, the amalgamation of the
plate thus prepared, and the galvanoplastic deposit of a soluble metal such as zinc
cadmium or the like upon the plate thus prepared and amalgamated substantially as
and for the purposes described.
2. A tubular copper electrode closed at its base by a block of insulating material
forming a circular receptacle around the electrode and filled with mercury into which
the base of the amalgamated electrode is plunged substantially as herein before described
and shown in the accompanying drawing.
Dated this 3rd day of December 1896.
W. P. THOMPSON & Co.,
.322, High Holborn, London, W.C., Patent Agents for the Applicant.