Improvements in Secondary and other Electric Batteries.
Year: 1888

page_text: Date of Application, 10th Aug., 1888
Complete Specification Left, 8th May, 1889-Accepted, 15th June, 1887
PROVISIONAL SPECIFICATION.
Improvements in Secondary and other Electric Batteries.
I, HENRI PIEPER, of 12 Rue des Bayards, Liege, in the Kingdom of Belgium,
Manufacturer, do hereby declare the nature of this invention to be as follows :-
This Invention relating to galvanic elements for secondary electric batteries or
accumulators also applicable to primary batteries, has for its object increasing the
capacity and effective action of the electrolytic system the initial resistance opposed
to the chemical decomposition by which work is to be done being artificially increased
as hereinafter described. This artificial resistance is produced by the application of
a pressure which is considerably in excess of the atmospheric pressure and which is
maintained in the battery being produced either before or during the electrolysis.
In consequence of this method of operating the amount of energy stored in the
primary and secondary electrolysis is equal to the sum of the work of the affinities
in the ordinary atmospheric medium plus the work or force absorbed in counter-
balancing the artificial resistance. This internal pressure also prevents that abnormal
recombination of the separated elements which gives rise to the objectionable local
currents which are unavoidable in all known forms of accumulators worked in the
ordinary way. It also ensures the constancy and renders possible with the employ-
ment of porous electrodes to store up very considerable quantities of gases in their
pores either in liquid or in gaseous condition.
The artificial resistance can be produced by compressing air gases or other suitable
media in the space enclosing the elements or electrodes of the battery or by completely
filling the vessel containing the electrodes with liquid and hermetically closing it. In
the latter case the gas generated finds no room to expand owing to the complete or
almost complete incompressibility of the liquid and thus produces the pressure
required.
The effect of the pressure produced by either of these means is that the gases
resulting from the electrolysis are unable to escape at the electrodes but are compelled
to pass into the state of liquid when the pressure exceeds that required to liquefy the
gases.
In many cases the condensed gas becomes dissolved in the liquid whereby an
active depolarisation is obtained which to a certain extent favors the subsequent
reactions.
Gaseous chlorine which becomes liquid under a pressure of five atmospheres is well
suited for employment as a depolarizing gas for the purposes of this Invention. For
example in the case of an element consisting of a zinc plate and a carbon plate
immersed in a solution of chloride of zinc a very constant current is obtained when
the liquid contains chlorine in solution under pressure.
An accumulator can be formed with this element as follows. A carbon plate is
placed on the bottom of the vessel and a zinc plate is arranged over the carbon
plate both plates being immersed in a solution of chloride of zinc. The vessel
containing the plates and solution is placed in another vessel of metal or other
suitable material which is hermetically closed and into which air is forced under a.
pressure higher than that necessary to liquefy the chlorine that is to say nearly
5 atmospheres. The air may be compressed in the vessel containing the electrodes if
desired the external vessel being dispensed with. If a current be now caused to pass
from the carbon to the zinc chlorine is liberated at the carbon and metallic zinc
is, deposited on the zinc plate but as the pressure of the air is sufficient to cause
the direct liquefaction of the chlorine the latter passes into the liquid state as it is
generated and remains in contact with the carbon provided that the density of the

page_text: solution of chloride of zinc be less than that of the liquid chlorine. The aforesaid
arrangement of the plates can be reversed the zinc plate being placed below the
carbon. In this case the density of the solution must be greater than that of
the liquified chlorine in order that the latter may be sustained by the former.
When the electrodes are arranged in a vertical position the carbon electrode is
placed in a porous cell and the zinc plate is arranged externally to the latter so that
the liquiied chlorine is separated from the chloride and the liquids are prevented from
commingling. During the discharge or working this accumulator acts in the same
way as a primary element in which zinc is consumed and chlorine is employed as the
depolarizing agent. A carbon plate may be substituted for the zinc in which case
zinc is deposited on one of the carbons. Any suitable number of elements can be
combined or connected together in a hermetically closed vessel and the vessel is pro-
vided with a manometer to indicate the internal pressure.
Accumulators may also be constructed according to this Invention in which the
gases are simply compressed without being actually liquified such accumulators may
consist for example of two carbon plates immersed in water acidulated with sulphuric
acid. If this battery be charged while in communication with the atmosphere the
hydrogen and oxygen liberated pass away and the carbons absorb but an insignificant
quantity of these gases, but if the elements be placed in a closed receptacle charged
with air under a pressure of say 10 atmospheres for example the gases being, unable
to escape are largely absorbed in the pores of the plates whence they do not escape
until the pressure in the pores exceeds that of the compressed air. By these means
any desired quantity of gas may be stored in the electrodes by raising the pressure
at intervals when the gas shows a tendency to escape from the plates.
The pressure in the elements can also be modified by changing their temperature.
The pressure is regulated according to the electrolytic relationship of the compounds
employed and also according to the standard of charging. Thus for example any
desired electric charge can be maintained constant by maintaining the equivalent or
corresponding pressure. The discharge or working of the battery can also be
regulated or maintained at any desired standard by gradually reducing the internal
pressure that is to say the resistance to the progress of the recombination process.
Dated this 10th day of August 1888.
J. H. JOHNSON & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in Secondary and other Electric Batteries.
I, HENRI PIEPER, of 12 Rue des Bayards Liege in the Kingdom of Belgium,
Manufacturer, 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 Improvements in Galvanic Batteries, particularly secondary
Batteries or Accumulators.
The purpose of the invention is to increase the capacity and efficiency of the
electrolytic system, and this is effected by artificially increasing the opposing initial
resistance to the chemical decompositions by means of which the work is to be
stored up.
This artificial resistance consists in a pressure considerably exceeding that of the
atmosphere, which pressure is produced either before or during electrolysis and which
is maintained in the battery. As a consequence of this procedure, the energy stored
up in the primary and secondary batteries is made up of the sum of the initial work
of the chemical affinities in the atmospheric medium plus the work which must be
expended in order to neutralize the said artificial resistance. This increased internal
pressure forms furthermore an obstacle to the abnormal re-combinations of the

page_text: separated elements that give rise to the well-known parasite currents which it has
been impossible to avoid in accummulators as heretofore organized and worked.
The increased pressure furthermore insures constancy, and where porous electrodes
are used, renders possible the storage of very considerable quantities of gases within
said pores, either in a liquid fluid condition or in a elastic fluid condition.
The artificial resistance may be produced by compressing air in a space surrounding
the batteries; or by completely filling the vessel containing the electrode or electrodes
of the battery with liquid and hermetically sealing said vessel. In the latter case the
gas developed in the liquid (which latter becomes but slightly or not at all com-
pressed) finds no room for expansion and, therefore, produces the artificial resistance
(pressure).
The natural consequence of the artificial pressure produced in either of these ways
is that the gases developed by the electrolytic action cannot escape at the electrodes,
but are compelled to pass into the liquid condition as soon as the pressure is so great
that it exceeds the pressure necessary to be exerted to liquify said gases.
In many cases, the condensed gas dissolves in the liquid, whereby an active depolarisa-
tion ensues, which to a certain extent favors all subsequent reactions.
Of all depolarizing gases, gaseous chlorine, which becomes compressed to a liquid at
a pressure of somewhat less than five atmospheres, is the best adapted to the purposes
of this invention.
Thus, for instance, a battery consisting of a zinc and a copper plate immersed in a
zinc-chloride solution, makes a very constant galvanic battery, if the zinc-chloride
solution contains chlorine in solution under pressure.
From this battery, an accummulator can be obtained in the following manner: In
the bottom of the vessel, I place a carbon plate and above it a zinc plate, the whole
immersed in a zinc-chloride solution. This vessel is placed within an outer vessel of
metal or other suitable material which is herinetically sealed, and within which air is
then compressed at a pressure higher than that necessary to liquefy the chlorine-that
is, somewhat under five atmospheres.
I can however compress air direct in the vessel containing the electrodes; the
external vessel being dispensed with.
If now a current is passed from the carbon to the zinc, chlorine is given off at the
carbon pole, and metallic zinc is deposited upon the zinc plate; but as the pressure of
the air contained in the vessel suffices to produce the direct liquefaction of the
chlorine, the latter becomes liquid as it is generated, and remains in contact with the
carbon, provided that the concentration (density or specific gravity) of the zinc-chloride
solution employed be less than that of the liquefied chlorine.
The said arrangement of the plates can be reversed, the zinc plate being placed
beneath and the carbon plate above, in which case the density (specific gravity) of
the zinc-chloride solution employed must be greater than that of the liquefied
chlorine, so that the latter floats on top.
In case the electrodes are to be arranged vertically, the carbon electrodes are
placed in a porous cell and the zinc electrodes outside, so that the liquefying chlorine
remains separated from the zinc-chloride, and an admixture of the two fluids is
avoided. (During discharge or working, this accumulator acts like a primary battery,
in which the zinc serves for combustion, and the chlorine for depolarization.) I can
also substitute for the zinc plate a carbon plate; in this case, the zinc is deposited upon
one of the two carbon plates.
Any suitable number of elements can be combined in a hermetically closed vessel.
All connections are made before hand and the two outermost poles are attached to
two well-insulated buttons arranged on the receptacle. A manometer upon the
receptacle indicates constantly the pressure, which must never sink below that necessary
for the liquefaction of the generated gas.
In this case also, the plates may be arranged horizontally or vertically.
Accumulators may also be constructed according to this invention, by dispensing
with the use of compressed air, by hermetically closing the battery and by filling it

page_text: entirely with liquid; for, in such case, the gas freed at the electrode or electrodes
finds no room for expansion (because the liquid can only be compressed very slightly
or not at all) and becomes liquid as it is generated.
By conducting the electrolysis under pressure I can also obtain accummulators in
which the gas generated is present not actually liquified but merely in a compressed
condition.
Let us assume the accummulator to consist of two porous carbon electrodes which
are immersed in water acidulated for instance with sulphuric acid. If now the battery
be charged in the open air, the liberated hydrogen and oxygen would escape at once
into the air, and. the carbon plates would absorb only very little of either gas. If,
however, place this accumulator within a closed receptacle, filled with air com-
pressed under a pressure of, for instance, ten atmospheres, the gases can no longer
escape, but become absorbed in notably increased quantity by the porous plates and
only begin to escape from the latter when their pressure within the pores exceeds the
external pressure, that is, that of the compressed air. In accordance with this method
of procedure I can store up in a given electrode as much gas as I desire, provided
only I permit the electrolysis to be completed in a vessel in which air may be kept
compressed under an equivalent or higher pressure.
As soon as the electrodes begin to allow gas to escape, the charging is complete ;
if I thereupon increase the surrounding pressure, I can continue the charging until
counterbalancing of the two pressures ensues; and so forth.
The pressure in the batteries can also be modified by changing their temperature.
According as the electrolytic relationship of the compounds used varies, so varies
also the pressure to be employed. Furthermore, said pressure varies in each separate
case according to the chosen rate or standard of charging. Thus for instance, I can
maintain every electric charging constant by maintaining an equivalent or higher
counter-pressure. Furthermore, I can regulate the rate to be observed in discharge,
by gradually diminishing the interned artificial pressure, that is, the resistance to the
progress of the re-combination process.
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 :
1. The method of increasing the capacity of primary and secondary batteries and
effecting their depolarization, which consists in maintaining within the battery fluid,
gases under pressure; substantially as described.
2. The method of preventing all evolution of free gas at the electrodes of secondary
batteries, which consists in liquefying said gas within the battery by pressure, as
generated, whereby the greatest possible quantity of gas is compressed within the
smallest possible space; substantially as described.
3. The method of maintaining in a battery gases under pressure, which consists in
maintaining above the surface of the battery fluid, a compressed body of air or other
elastic fluid; substantially as described.
4. The method of maintaining in a compound battery made up of several cells, gases
under a uniform pressure in all the cells, which consists in maintaining above the
surfaces of the battery fluids of said cells a body of compressed air or other elastic
fluid common to all; substantially as described.
5. The method of increasing the storage capacity of secondary battery electrodes,
which consists in subjecting the battery during the charging operation to pressure
until the gases generated enter in large quantities into the pores of the electrodes,
either in a liquid fluid condition or an elastic fluid condition; substantially as
described.
6. The method of maintaining constant the rate of charging secondary batteries,
which consists in maintaining therein constantly a pressure equivalent to or:greater
than that necessary to liquefy the gases as generated; substantially as described.
7. The method of regulating the rate of discharge of secondary batteries wherein

page_text: gases are held under pressure, which consists in gradually diminishing said pressure
thereby removing the obstacle to re-combination to the extent desired; substantially
as described.
J. H. JOHNSON & Co.,
Agents.