Improvements in Electric Cells or Batteries.
Year: 1899

page_text: Date of Application, 21st Oct., 1899
Complete Specification Left, 13th July, 1900-Accepted, 1st Sept.. 1900
Date of Application, 21st Oct., 1899
Complete Specification Left, 13th July, 1900—Accepted, 1st Sept.. 1900
PROVISIONAL SPECIFICATION.
Improvements in Electric Cells or Batteries.
I, BENJAMIN WILLCOX, of 47, Lincoln's Inn Fields, in the County of London,
Patent Agent, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the Columbus Electricitatsgesellschaft,
Gescellschaft mit beschrankter Haftung, of Ludwigshafen-on-Rhine, in the Ger-
man Empire) to be as follows:-
The object of this invention is to provide an electric cell or battery of as
great constancy as that of Meidinger from which however the improved cell,
or battery, according to this invention, differs in presenting very slight internal
resistance and also in being capable of being used as a "dry" cell, or battery.
In a cell, or battery, according to this invention, a salt of mercury is employed
as a depolarizing material. The use of salts of mercury in electric cells, or
batteries, has been proposed before, but it has not hitherto proved possible to
provide a cell, or battery in which these salts are employed, which is suited for
other purpose
than the measurement of voltage for the reason that, owing to the
limited conducting power of the said salts, the internal resistance of the cell,
or battery, has risen to a very high degree, so that it was unfit for use to yield,
in a permanent manner currents of any appreciable value except for the aforesaid
purpose.
This invention obviates this drawback, and it mainly consists in making use
of a salt of mercury, not alone, but thoroughly mixed with powdered graphite,
or plumbago. By this admixture of graphite, or plumbago, to the salt of mercury,
the internal resistance of the cell, or battery, is (without any interference with
the depolarizing effect) so considerably reduced that a cell, or battery, provide:1
with this mixture, will furnish a current over twenty times more powerful
than that which could be supplied by a cell, or battery, of equal size, in which
a salt of mercury alone is used. The addition of graphite, or plumbago, also
prevents the mercury of the reduced salt from running off the carbon, as even
where reduction is carried to the maximum degree, the graphite or plumbago
finely divides such salt, so that it remains in close contact with the carbon and
continues to act in a permanent and uniform manner until its depolarizing power
is fully exhausted.
In practice, the invention may be carried out as follows:-
For the anode, zinc is used, while the cathode may consist of carbon, (charcoal),
platinum, or the like. The cathode is surrounded by the above mentioned
mixture which may be contained in a bag tied round the cathode.
The salt of mercury which is preferably used is calomel. The electrolyte may
consist of any suitable solution, preferably one containing chlorine. A cell, or
battery, thus constructed, when in practical operation, is apt to give rise to the
formation of hydrochloric acid in the mixture of graphite, or plumbago, and
calomel, which, while the cell, or battery, is at rest, is liable to exercise a decom-
posing action upon the zinc electrode. In order to obviate this, there should

page_text: be added, to the mixture of graphite, or plumbago, and calomel, a body capable
of absorbing, or holding, the hydrochloric acid, while current is being derived
from. the cell, or battery, the substance best suited to this purpose being finely
divided chalk, which is thoroughly mixed with the graphite, or plumbago, and
calomel.
In preparing this mixture, equal parts, by weight, of graphite, or plumbago,
and calomel can be used, and about 5 per cent. of chalk be added.
A cell, or battery, so constructed will have an internal resistance approximately
equal to that of the Leclanché cell, and it will not rise in any appreciable degree
at the time of the discharge. Its constancy; or uniformity, equals that of an
accumulator and an electro-motive force of 1.12 volts. can be obtained from it.
As the reducing salt of mercury does not flow off the carbon, but, even when
brought to the extreme state of reduction, continues in close uniform contact
with the cathode, this cell, or battery, may, after having once been exhausted,
be regenerated in a certain degree by means of current supplied from an ex-
ternal source so that, within limits, it may be utilised as an accumulator.
As this cell, or battery, contains one fluid only that acts as an electrolyte,
and as the substances used remain unvarying during the state of rest, it affords
the advantage, highly important from a practical point of view, that it may
be utilized as a dry cell, or battery, in the well-known manner.
The described cell, or battery, affords a portable source of a considerable
amount of current of constant electro-motive force, capable of use, say, for light-
ing purposes, or for driving small motors, thereby supplying a want which has
long been felt in practice.
Dated this 21st.
of October 1800
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agenis.
Improvements in Electric Cells or Batteries.
I, BENJAMIN WILLCOX, of 47, Lincoln's Inn Fields, in the County of London,
Patent Agent, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the Columbus Electricitatsgesellschaft,
Gescellschaft mit beschrankter Haftung, of Ludwigshafen-on-Rhine, in the Ger-
man Empire) and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement:-
The object of this invention is to provide an electric cell or battery of con-
stancy, as great as that of Meidinger from which however the improved cell or
battery according to this invention differs in presenting very slight internal
resistance and also in being capable of being used as a dry" cell or battery.
The cell or battery to which this invention relates is of the kind wherein salt
of mercury in admixture with carbon is employed as a depolarizing agent.
The use of salts of mercury in electric cells or batteries owing to the limited
conducting power of the said salts, causes the internal resistance of the cell,
or battery, to rise to a very high degree so as to be unfit for use to yield in a per-
manent manner currents of any appreciable value, and to overcome this objection
it has been proposed to use carbon in admixture with the salt of mercury and
certain electric cells or batteries are known wherein for the purpose of producing
more powerful currents a mixture of a salt of mercury and carbon is employed
for example that of A. Schanschieff described in the Specification of Letters
Patent 68708+.

page_text: In these cells the salt used is the protosulphate of mercury and it is mixed
with graphite or plumbago held together with paraffin as an agglutinant.
A cell so formed on account of the solubility of the protosulphate of mercury
and of the high degree of resistance of the electrode due to the use of paraffin
will not supply constant currents of any appreciable value.
Parkhurst describes in the Specification of a Patent No. 269454 granted in
the United States of America a cell in which a salt of mercury (chloride of
mercury) is used in combination with carbon and black oxide of manganese.
In this cell however as in the other cells in which a salt of mercury and carbon
have been used free chloride of hydrogen forms and exercises an injurious action
and prejudicially affects the durability of the cell.
According to this invention chloride of mercury (calomel) is employed as
the salt of mercury, and the carbon may be of any suitable kind such as finely
divided graphite or plumbago or charcoal; no other material having an electrical
effect is employed in this depolarizing mixture but there is added to it an
electrically indifferent body capable of absorbing or holding hydrochloric acid
while current is being derived from the battery: the substance best suited for
this purpose being finely divided chalk which is thoroughly mixed with the
calomel and carbon.
In preparing this mixture equal parts by weight of the carbon and of the
calomel may be used and about five per cent. of the chalk be added.
In practice the cathode may be of carbon or platinum for example and it may
be placed in a bag tied round the said cathode and filled with the aforesaid
mixture, the electrolyte used being preferably a chloride of zinc solution while
zinc serves as an anode.
The addition of chalk or the like to the depolarizing material has the effect
of destroying the hydrochloric acid forming in the operation of the battery as a
result of the reduction of the calomel without injuriously affecting the hydrogen
holding property of the calomel which is wholly reduced to pure metal, down to
the stage of exhaustion of the cell so that the internal resistance of the cell
becomes lower rather than higher. Owing to the fact that the reduced calomel
remains enclosed in the carbon in the condition of very finely divided metal,
the cell may, similarly to an accumulator, be regenerated in a certain degree by
means of current supplied from an external source. The cell being capable of
being arranged as a dry cell which is durable for practical purposes, is an
advantage of the highest importance.
The electro motive force of this cell is from 1'07 to 1'10 volts. while its internal
resistance is approximately equal to that of the Leclanché cell. At a constant
voltage currents sufficient for illumination or for driving small motors can be
derived from this 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 I
claim is:
In electric cells or batteries wherein calomel intimately mixed with carbon
alone is employed as a depolarizing agent the admixture with the calomel and
carbon of an electrically indifferent neutralizing body such for example as
powdered chalk to avoid the formation of free hydrochloric acid in the depolarizer
as hereinbefore explained.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.