Improvements in Electric Batteries.
Year: 1891

page_text: Complete opremation LL,
πουομιν
COMPLETE SPECIFICATION.
Improvements in Electric Batteries.
J, WALTER AMBUS CROWDUS, of Memphis, in the County of Shelby and
State of Tennessee, United States of America, Gentleman, do hereby declare the
nature of my invention for IMPROVEMENTS IN ELECTRIC BATTERIES, and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
This invention relates to two-fluid batteries, or those in which a porous diaphragm
or partition is used. Such batteries are subject to the disadvantages of the mixing
of the two solutions by osmotic action through the porous diaphragm and of the
high internal resistance due to the intervention of the porous diaphragm, which is
not in itself a conductor of electricity.
The object of my invention is to reduce to a minimum the internal resistance of
such batteries without increasing the osmotic effect, as would result from an effort
to reduce the internal resistance by making the porous diaphragm thinner or of
greater porosity.
To this end my invention consists in constructing the carbon negative plate of
the battery to constitute a portion of the porous partition or diaphragm separating
the two solutions. The remainder of the porous diaphragm consists of a plate of
unglazed earthenware, such as is commonly used in batteries; but this plate is
made very much thinner than heretofore, thereby reducing its electrical resistance.
The carbon plate is placed against and held to the earthenware plate, so that it
contributes in co-operation therewith to maintain the separation of the two liquids.
The osmotic action is thus equally well or in the case of a carbon plate of sufficient
thickness is even more effectually prevented than by the use of a simple carthen-
ware partition, as heretofore. At the same time the internal resistance is greatly
reduced, since only a portion of the thickness of the porous plate consists of non-
conducting earthenware, the remaining portion being made up of the electrically-
conducting carbon.
Figure of the accompanying drawings is a vertical transverse section of a
battery constructed according to my invention, the battery-jar being divided into
two compartments by a flat porous partition.
Fig. 2 is a vertical section in a plane at right angles to Fig. 1, as denoted by the
line 2 2.
Fig. 3 is a plan thereof.
Fig. 4 is a side view of the carbon plate removed.
Figs. 5 and 6 are respectively a plan and vertical mid-section of a modified form
of battery, wherein the porous partition is in the form of a cylindrical cup.
I will first describe the construction shown in Figs. 1 to 4, inclusive. The jar or
vessel A, which may be made of any suitable material-such as of wood permeated
with wax, for example-is divided by a porous partition B into two compartments a
and b, respectively, the former of which contains the electrolyte for the negative
plate and the latter that for the positive plate. The zinc or other positive plate C
is placed in the compartment b, preferably close to the partition B. The negative

page_text: plate consists of a plate of carbon D, placed against the partition B, which latter is
made of porous or unglazed earthenware. The plate D may be made of any
suitable porous carbon. It co-operates with the earthenware plate B in performing
the function of a porous diaphragm for separating the electrolytic solutions, thus
enabling the thickness of the earthenware plate B to be greatly reduced-say, for
example, to one-half its ordinary thickness-whereby the internal resistance of the
battery is proportionally lowered. The resistance of the earthenware plate B,
reduced by the electrolyte in its interstices, constitutes, practically, the sole
internal resistance of the battery, aside from the inevitable resistance of the
electrolyte. The resistance of the carbon plate D, with its contained electrolyte,
which is very low, is practically inappreciable, since the electrolytic action occurs
on the surface and within the interstices of the carbon plate, so that the
electric current is not compelled to traverse the entire thickness of this plate.
The extent to which the mixing of the electrolytic solutions occurs is dependent
upon the density of the carbon plate, (assuming the earthenware plate to be of
uniform density). Hence by making the carbon plate sufficiently dense I can
reduce the osmotic action to any desired extent. I prefer to use dense and
hard carbon, instead of soft and porous carbon, and to increase the osmotic
action to any extent desired by providing the carbon plate with one or more small.
holes, of such number and size as shall be suitable for the purpose, and that surface
of the carbon which is next to and in contact with the earthenware plate I form
with shallow channels or grooves, in order to expose between the plates a thin
stream of the negative electrolyte. This stream is caused to circulate upwardly by
the electrolytic action, thereby keeping the negative electrolyte in circulation.
The negative electrolyte thus introduced between the plates B and D reduces the
internal resistance of the battery and serves to check the osmotic mixing of the
positive and negative electrolytes, when the battery is open-circuited, by constituting
a third and partially neutral division. The perforations at the bottom and top are
designated by cd in Figs. 1 and 4, and the grooves or channels by ee in Figs. 4
and 3. The channels e e serve, also, to carry out at the top any disengaged gas,
removing it from the portion of the negative electrolyte which is inactive, since the
depolarization takes place only on that side of the carbon plate which is against the
earthenware plate.
I do not limit myself to the construction of the carbon plate with perforations
and channels, as this construction is not essential to my invention. A dense carbon
without perforations is best adapted to a battery designed to remain open-circuited
for long periods. The greater the work the battery has to do the freer must be
the circulation through the carbon plate, and hence for a closed-circuit battery to
give an active output the carbon plate, if it is not sufficiently porous, should be
perforated or otherwise treated, in order to increase the circulation to the proper
extent to produce the desired effect.
The terminal connections, with their respective plates or electrodes, may be made
in any known or suitable manner. The connections shown consist of binding-
posts, applied to one side of the jar and communicating through the side wall
thereof with their respective plates. One edge of the carbon plate may be electro-
plated with copper, as shown at g, and the positive binding-post screwed directly
into contact therewith or otherwise connected thereto. I have shown the positive
electrode or zinc plate C supported at its top by pegs and resting at its bottom
in a trough, containing mercury. This trough, if made of metal, may be formed
with a portion extending through the wall of the jar and connecting with the
negative binding-post.
The connection of the positive electrode to its binding-post through the medium
of a bath of mercury is not herein claimed, being made the subject of a separate
United States Patent application, Serial No. 347421 filed October 8, 1890.
Figs. 5 and 6 show a construction suitable for small batteries, wherein a cylindrical
jar A 'is used, within which is placed a curved sheet of zinc C, and within this a
porous 'cup B of earthenware, but thinner than the usual porous cup, and having a

page_text: cylinder or carbon D fitted within it and constituting the negative electrode. This
carbon cylinder may be perforated, as shown at ed in Fig. 6, and may be formed
on its outer side with grooves, as shown at ee in Fig. 5.
I am aware that carbon alone has been used as a porous cup in single-fluid
batteries, having a solid depolarizer within it, as in chloride-of-ammonia batteries.
Attempts have also been made to use a carbon porous cup in two-fluid batteries.
I make no claim to such construction. That which is characteristic of my battery
is the use of a porous carbon diaphragm, combined and co-operating with an
earthenware or non-conducting porous partition, joined together in any suitable
manner. The actual contact of the two plates at all points not essential. My
invention is also characterized by the use of means for changing the circulation
through and between the porous inediums.
In lieu of forming grooves or channels on the side of the carbon next the carthen-
ware plate, the two plates may be slightly separated to leave room for the
circulation of a thin film of the liquid between them.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
:―
1. In an electric battery, the combination, with a battery-jar and a non-conducting
porous partition dividing it into two chambers for the respective electrolytes, of a
conducting porous partition arranged against and co-operating with the non-con-
ducting partition, whereby the thickness and resistance of the latter may be
reduced without increasing the osmotic mixing of the electrolytes.
2. In an electric battery, the combination, with a battery-jar and a non-conducting
porous partition dividing it into two chambers for the respective electrolytes, of a
positive electrode in one of said chambers and a negative electrode in the other,
consisting of a conducting porous partition arranged against and co-operating with
the non-conducting partition in separating the electrolytes.
3. In a two-fluid battery, the porous partition consisting of a plate of porous
non-conducting material and a plate of porous carbon, arranged together to
co-operate in separating the electrolytes.
4. In an electric battery, the combination, with a battery-jar and a non-conducting
porous partition dividing it into two chambers for the respective electrolytes, of a
positive electrode in one of said chambers and a negative electrode in the other,
consisting of a plate of porous carbon arranged against and co-operating with the
non-conducting partition, and provided with chambers or passages additional to its
porous interstices for admitting the electrolyte in a predetermined volume through
the carbon and into contact with the non-conducting plate, whereby the electrolytic
circulation may be increased to any desired extent beyond the capacity of the
natural porosity of the carbon.
5. In a two-fluid battery, the porous partition consisting of a plate of porous non-
conducting material and a plate of porous carbon arranged against it, and formed
to admit a circulation of a thin stream or film of the electrolyte between it and the
non-conducting plate.
6. In a two-fluid battery, the porous partition consisting of a plate of porous non-
conducting material and a plate of porous carbon arranged against it, having
perforations through it and grooves or chambers on its side next the non-conducting
plate to admit a circulation of the electrolyte between them.
7. In a two-fluid battery, the porous partition consisting of a plate of porous
non-conducting material, and a negative electrode consisting of a plate of porous
carbon arranged against it and formed to admit a stream or film of the electrolyte
to circulate between it and the non-conducting plate.
Dated this 1st day of dunil 1901
F. W. BARKER,
Applicant's Agent.