Charging of Secondary Galvanic Batteries.
Year: 1888

page_text: Charging of Secondary Galvanic Batteries.
I, STANLEY CHARLES CUTHBERT CURRIE of 1719 Chesnut Street, Philadelphia
County of Philadelphia and State of Pennsylvania, United States of America,
Electrician, 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 has relation to indicators for accumulators or secondary batteries,
and has for its object the provision of novel means for indicating by a visual or
audible electrically operated signal when a battery is fully charged.
It is known that when an accumulator has received its full charge an ebullition of
the fluid therein takes place due to the fact that the elements of the battery have
absorbed all the gas they are capable of receiving, and the gas subsequently
generated, rises in the form of bubbles and escapes, thereby creating a fine spray or
mist upon the surface of the aforesaid fluid. This action is termed "sweating," and
is an indication that the battery is fully charged.
As the ebullition gradually increases in violence after it has started, the height to
which the spray rises above the surface of the fluid, also increases, and this increase
has been noted and acted upon when it is desired to surcharge the battery after
ebullition has commenced.
My invention consists in the provision of novel means for utilizing this ebullition
of the fluid contents of the battery to establish an electric circuit, through an
electrically operated visual or audible signal, thereby indicating that the battery is
charged.
My invention further consists in the novel construction, combination and
arrangement of parts hereinafter described, and specifically claimed.
In carrying my invention into effect, I arrange in proximity to the surface of the
fluid in the battery, a strip, rod, bar or section of a material either a non-conductor
of electricity, such as glass, vulcanite or india-rubber, or a section or piece of a

page_text: fibrous material, as a tape, string, or band of wool or other similar material, or a
section of a porous material, offering, under ordinary circumstances, considerable
resistance to the passage of an electric current as carbon; or a pair of elements
capable under the action of an exciting fluid, of producing an electric current, as,.
for instance, a piece of copper and a piece of zinc separated by a slip of felt, flannel,
paper or the like; the essential feature of the strip, rod bar section, or plural number
of such being that it or they shall normally present a high resistance to the passage
of an electric current, but when subjected to the action of the spray or moisture
arising from an accumulator, shall become a good conductor or a generator of
electricity as the case may be.
The said strip section or pair of elements, 1 interpose in an electric circuit con-
taining an electric bell, or an index hand, operated by the passage of an electric
current in its vicinity, in the manner of a galvanometer, or any other indicating or
signaling device, capable of being electrically operated.
As soon as the accumulator or secondary battery to which the above described device
is applied, becomes charged, the ebullition of the fluid of the same generates a spray
or mist which settles upon, or is absorbed into the resistance strip or section, and, as
the fluid in such batteries is acidulated water, provides a path, through or upon
the surface of the same for the passage of an electric current, which thereupon
operates the indicator.
The current for the operation of the indicator may be taken from the battery being
charged, or may be taken from a local battery, or may as before mentioned be
generated by the action of the moisture upon two elements, which may form the
resistance strip or section.
In practice, I have found that where the non-conducting or resistance strip or
section is used, there is considerable difficulty in drying the same after it has been
in use so as to render it fit for use a second time as the acidulated water deposited
by the spray, does not readily evaporate, and where the battery elements aro employed,
they speedily corrode, and have to be replaced. I have therefore devised a modifica-
tion of the above described device, which consists in attaching to the terminals of the
indicator circuit sections of a material practically noncorrosive, as lead or the like,
arranged in juxtaposition above the surface of the fluid in a battary, and so that the
moisture deposited by the spray will arrange itself in a drop or drops of water, which
will bridge the space between the sections of material and thus establish electrical
connection between the terminals of the indicator circuit.
:
While my invention is perfectly adapted to be applied to a single cell or battery,
I propose in practice generally to apply it to a number of cells, arranging the non-
conductor or resistance strips or sections of the several cells in series, and connecting
the terminal strips or sections to a single indicating device, so that all the batteries
in the set so arranged, must be fully charged before the indicator will act.
As it is generally desirable to charge an accumulator or secondary, battery for a
further period after the point has been reached where the ebullition begins, and as
has before been noted the height to which the spray rises increases as the cell is
overcharged. I am enabled, by altering the height of the non-conducting or
resistance strips or sections above. the fluid of the accumulator, or by altering the
size or shape of the same or by increasing the electro-motive force of the indicator
operating current, to readily pre-determine and regulate the amount of over charge
which the battery is to receive.
As the amount of liquid in the accumulator cells is apt to vary, I deem it advisable
to mount the non-conducting or resistance strips or sections adjustably upon a float
that will rest upon the surface of the fluid in the battery, so that any change in the
amount of fluid in the battery will not effect the relative position of the said strip or
section.
Referring to the accompanying drawing wherein Fig. 1, is a vertical sectional view
of a secondary battery or accumulator of the ordinary type, having my improvements
ap lied, Fig. 2, is a vertical sectional view of a number of such batteries, with the
non conducting or resistance strips or sections of the indicator appliance arranged in

page_text: series, Fig. 5, a vertical sectional view of a battery, with a modified form of resistance
or non-conducting strip or section, and Fig. 4, a plan view of an accumulator having
my improved indicating device in position thereon, the latter being shown with a
resistance strip or section consisting of two metallic elements, insulated from one
another by an interposed piece of fibrous material. A, designates the outer casing of
the battery; B, B, the metallic plates or elements thereof, and C. C the
surface of the fluid in the same. D, designates a float arranged in the battery, and
supported upon the fluid of the same, and E, Figs. 1, 2 and 3, a strip or section of
glass, india rubber, wood, carbon or other non-conducting or high resistance material,
supported by, and adjustable upon uprights d, d, rising from said float; suitable
shields dd surrounds the standards d, d, so as to prevent the deposit of moisture
upon the strips or sections E immediately adjoining said standards. The strip or
section E, is connected by a wire e with one terminal of an electric circuit F. in which
is interposed an indicating device G, and which connects with the plates B, of the
battery A, and the other end of said section E, is connected by a wire f, to a conductor H,
leading from plates B¹
As shown in Fig. 2, where several of the strips or section E, are shown in position
in as many batteries A, A, A, it will be observed that the strips or sections E, are in
series upon an electric circuit K, in which is interposed a single indicator, and a local
battery L. In this case all the sections E, must become coated with moisture before
the indicator will act.
In Fig. 3, the strip or section E, is shown as being suspended from the edge of the
battery by hooks gig, the float D, being dispensed with. In this figure the strip or
section E, is shown as being hollow and containing a spiral wire i, and by passing an
electric current through this wire so as to heat the same, I am enabled to almost
immediately disperse the moisture from the surface of the strip E, after it has been in
action, thereby rendering it fit for immediate application to another accumulator, or
another charge indication.
In Fig. 4, the resistance section is composed of two elements, which inay be, for
instance, copper and zinc, separated by a strip of porous material, as felt or paper, and
one of said clements is connected to one terminal of the electric circuit K, while the
other element is connected to the other terminal of the same circuit. It is to be
noted that with this arrangement, the current for the operation of the indicator is
furnished by the metallic clements which- when the ebullition of the finid in the
accumulator takes place are acted upon by the exciting moisture deposited, and
become a battery, thus dispensing with the necessity of employing a local battery, or
other source of electric supply.
OPERATION.
The parts being constructed and arranged as above described, operate as follows.
When the accumulator has become charged, and ebullition of the fluid begins, the
spray thrown up by the escaping bubbles of gas, moistens the surface of the strip.or
section E, and serves to conduct the electric current between its terminals e, f, where-
upon the indicator is set in operation, and serves to notify the overseer that the
battery is fully charged.
The adjustability of the strip or section E, renders it possible to determine the
extent of time the battery is to be subjected to surplus charging after ebullition has
begun.
The device shown in Fig. 4, operates in substantially the same manner as that
shown in Figs. 1, 2 and 3 that is to say the moisture from the fluid of the accu-
mulator, forms the medium of electric connection between the previously insulating
terminals of the electric circuit, but in this case the necessity of an outside source of
electric supply for the indicator circuit, is dispensed with, as the elements of the
resistance section when moistened, generate sufficient current to work the indicator.
The modification hereinbefore referred to is illustrated in Figs. 5, 6, 7, 8 and 9
Fig. 5, being a vertical sectional view of a secondary battery with the modified form
of indicator, Fig. 6, a top view of the same, and Figs. 7, 8 and 9, diagrams

page_text: illustrating the action of the liquid deposited on the sections which are connected with
the terminals of the indicator circuit and in said figures, A2, designates an accu-
mulator or secondary battery and B2, the liquid contained therein. C³, designates a
piece of non-conducting material, as glass, ebonite or the like, which rests upon the
top of the battery A², and is formed with two openings c², c², through which pass
strips of lead D2, D³, that are bent around on top of and fastened to a block of non-
-conducting material F2, that rests upon the piece C², screw cups d², e², upon the ends
of sections D, E, serve to receive the terminals of an electric conductor G
forming a circuit containing a battery H2, and an indicator 12, which may be a visual
or audible signal of any known or desired construction operable by means of an
electric current. Beneath the strip (2, the sections D2, E2, are bent toward each
other, and are brought close together at their ends but without touching, and the end
of section D, which serves to collect the moisture, is mado considerably longer than
that of section E³. The ends of both aro slanted so that, as the fluid deposited by the
spray accumulates, it will run down the ond of section D³, and after bridging the
space between the sections for a brief interval, will run down the end of section E³,
to a point, thereon, and will then drop off into the battery.
The different positions of the drop or globule are illustrated in Figs. 7, 8 and 9.
In Fig. 7, the moisture is shown collecting in small globules along the slanting
portion of section D. In Fig. 8, the small globules have accumulated and formed a
drop of sufficient size to bridge or span the space between the sections D, and E², and
in this condition the electric circuit is completed through the drop and the indicator
thereupon thrown into action, for as long a period as the drop spans or bridges the
space, which period may be nicely determined and regulated by increasing or
diminishing the distance between or the area of the sections D², E².
After the indicator has been brought into action as above described, the drop of
fluid descends to the end of section E as shown in Fig. 9, and eventually falls into
the battery.
This action is repeated from time to time as the drops accumulate, until the
operator removes the indicator appliances from the battery.
The principle advantages of the invention above described are that the apparatus
may be removed from a battery or accumulator after having been in use, and
immediately applied to another, without the necessity of waiting for the sections to
dry, and being practically non-corrosive, the sections will last for an indefinite period.
The terminals of the circuit being upon the upper side of the non-conducting strip,
are out of reach of the spray and fluid from the battery, and hence there is no
danger of an accidental completion of the indicator circuit.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is.
1st. In an accumulator indicator, the combination with an accumulator or secondary
battery, containing a fluid, an electric circuit normally incompleto, and an indi-
cating device in said circuit, of one or more strips or sections of material interposed
in said electric circuit, and arranged in proximity to the surface of the said fluid,
whereby ebullition of the latter will cause a deposit of moisture upon the said
material and complete said circuit, substantially as and for the purpose described.
a
2nd. In an accumulator or secondary battery indicator; the combination with
battery of that class containing a fluid, of normally incomplete electric circuit, an
indicating device in said circuit, and terminal points or pieces, normally electrically
disconnected and adjustably supported above tlie fluid in the said battery, substan-
tially as and for the purpose described.
3rd. In an indicator for accumulators or secondary batteries; the combination with
a battery of that class, containing a conducting fluid, and a float resting on said
fluid, of an electric circuit containing an indicating device, and having terminal
points normally electrically disconnected, the latter being supported upon said float,
substantially as described.

page_text: 4th. In an indicator for accumulators or secondary batteries; the combination of
an electric circuit, and an indicator interposed in said circuit, with terminal points
normally electrically disconnected, and also interposed in said circuit, and a coil of
wire arranged in the vicinity of said terminal points, and adapted to be heated for the
purpose of evaporating moisture from the same when desired, substantially as
described.
5th. In an indicator for accumulators or secondary batteries; the combination with
à plural number of such batteries, an electric circuit, and an indicating device,
arranged in said circuit, of a plural number of pairs of terminal points normally
electrically disconnected arranged in series in said circuit, and each said pair of
terminals being appropriated to a different battery cell whereby all the latter must be
charged before said indicator will be brought into action, substantially as described.
6th. In an indicator for accumulators or secondary batteries, the combination with
a normally incomplete electric circuit, containing an indicator of two sections of
material connected one to each terminal of said circuit, arranged with their ends in
juxtaposition and at an angle to a horizontal position, so that moisture accumulating
on the surface of one of the sections will assemble in drops and bridge the space
between the sections, substantially as described.
7th. In an indicator of accumulators or secondary batteries, the combination with
the strip C having holes c, c, of the conducting sections D, E, having each one end
screwed upon top of said strip, and their other ends passed through said holes and
brought into juxtaposition beneath said strip, substantially as described.
8th. In an indicator for accumulators or secondary batteries; the combination of a
non-conducting strip, adapted to be placed on top of the battery casing, with two
sections of practically non-corrosive material, having each one end secured to said
strip, and their other ends in proximity, and an electric circuit of which said sections,
form the terminals, substantially as described.
Dated this Third day of December 1888