Note: Descriptions are shown in the official language in which they were submitted.
S8
PRIOR A~T
Storage batteries and other energy conversion
systems in which one of the electrodes is a metal or metal
alloy which goes into solution during the production of
energy (discharge) and is redeposited during the storage
of energy (charge) are well known. Some employ metal-to-
metal couples such as nickel/cadmium or silver oxide/zinc
couples. Other energy conversion apparatus use halogen
or oxygen depolarized cathodes and consumable metal anodes
such as, for example, zinc, iron, lead, lithium, man~a-
nese, and the like. In many cases, these energy conver-
sion systems are recharged with the electrodes in place
by redepositing or partially redepositing the consumable
metal on the anode by applying an external potential to
the individual units or the entire energ~ storage system.
However, these batteries in practice are never completely
restored or recharged to their original state and become
progressively shorter-lived and must be out of use for
considerable time during recharging.
Various U.S. patents, such as Oswin, 3~436,270,
Rosansky, et al., 3,513,030, Fishman, 3,553,024, Loos,
et al., 3,708,345, and others, describe batteries with
anodes which are removable from and reinsertable into
an enclosing cathode chamber. The anodes are usually
of consumable metal, or consumable, compacted or sintered
metal powder, mounted on conducti~ve, porous metal supports
or screens of various metals such as nickel, iron, copper,
titanium, tantalum and alloys thereof. The removal and
insertion of the anodes of such prior art batteries into
the cathode chambers present problems because of shape
changes in the anode structure during recharging outside
2 -
mab/ ~k-
3~
the cathode chamber or envelope and because the electro-
lyte-impre~nated paper separators in the cathode chambers
are often torn or destroyed during removal or reinser-
tion of the recoated anodes.
THI S_ INVENTION
The anodes of this invention consists of rigid,
thin corrosion resistant metal support blanks, such as
titanium, tantalum, tantalum-coated titanium~ zirconium,
molybdenum, niobium, yttrium, tungsten or nickel, on
which the consumable electrode metal, such as zinc, is
deposited outside the cell, under the best conditions for
such deposition, ~nd the rigid anode support blank with
the consumable metal redeposited thereon is inserted into
the cell, opposite the cathode, and used until the con-
sumable metal is substantially all consumed, whereupon
the blank is removed from the cell and a new anode blank
with consumable metal thereon is inserted, while the used
blank is recoated with the consumable metal outside the
~0 cell.
Alternatively the consumable metal anode may
be removably mounted in supports on the cathode box and
when substantially consumed it may be removed from the
cathode box and a new consumably anode inserted in said
supports.
As zinc is the present preferred consumable
anode material, this invention will be described with
zinc as the exemplary anode, but it will be understood
that other consumable anodic materials, such as, for
example, iron, lithium, cadmium, or the like, are inclu-
ded in the scope of this invention and that this invention
applies to any energy conversion system .in which con-
.. -- 3 --
mab/~
r;3~358
sumable anodes are used.
The cathode is preferably a box-like s-tructure
of a metal resistant to corrosion in the particular elec-
trolyte used in the battery (i.e., titanium, tantalum,
tantalum-coated titanium, zirconium, molybdenum, niobium,
yttrium, tungsten or nickel), with a wall of sintered,
porous metal on one or more faces impregnated or acti-
vatèd with a catalyst, such as the platinum group metals,
including platinum black, platinum group metal oxides,
or other catalytic metal oxides such as perovskites,
delafossites, bronzes or spinel-type oxides. The acti-
vation of the sintered, porous metal wall is best effec-
ted by impregnating the degreased and slightly pickled,
porous metal wall with a solution of decomposable salts
of the catalytic metals, followed by heat treatment in
an oxidlzing or reducing atmosphere to decompose the
salts and deposite the catalytic oxides or metal on the
surfaces of the pores of the sintered wall.
The internal surface of the activated porous
~0 cathode, wall, that is, the surface towards the interior
of the bo~-like structure, is impregnated with a lipo-
phobic (e.g., hydrophobic) resin such as a polyethylene,
polypropylene, polytetrafluoroethylene, polychlorofluoro-
ethylene, various vinyl res`ins, and the like, in such a
way as to let the resin penetrate inside the pores for
a certain depth from the surface but without reaching
through the full thickness of the porous cathode. The
resin partially coats the surface of the pores near the
internal surface of the cathode and imparts hydrophobic
properties to the gas side layer of the porous cathode.
This effectively reduces flooding of the box-
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like structure by the electrolyte and facilitates main-
taining the three-phase boundary layer wi-thin the porous
sections of cathode.
The electric coupling between each box-like
cathode element and the adjacent anode element is through
the electrolyte filling the spaces therebetween.
The electrolyte, held in a separate tank or
reservoir, is continuously circulated through the various
interelectrodic spaces in the battery by suitable dis-
tributor and collector pipes and/or conduits formed in
the walls of the plastic battery container.
The interior of each box-like element communi-
cates, by means of an inlet and an outlet port, respec-
tively, with the supply line and the exhaust line for
the cathode depolarizing gas (e.g., air, oxygen or
other depolarizing gas) which is circulated inside each
box-like element under superatmospheric pressure pre-
ferably slightly in excess of the pressure of the elec-
trolyte on the outside of the porous cathode structure.
~ During discharge of electricity from the
battery, the depolarizing gas such as oxygen or oxygen-
containing gas is contacted with the inside of the porous
cathode elements and the electrolyte contacts the out-
side of the cathode elements~ The gas pressure applied
internally to the activated porous cathode faces is
adjusted to the pressure of the electrolyte, so that
the electrolyte does not flood the pores o~ the cathode
elements and gas does not blow through into the elec-
trolyte. Aqueous alkaline electrolytes such as NaOH,
KOH and mixtures of KOH and RbOH are preferred ! but
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other electrolytes may be used.
With oxygen or air-depolarized cathodes and
zinc-coated anodes, the reaction within the cell can be
represented as:
At the cathode:
1/2 2 + H20 + 2e ~ 20H-
At the anode:
Zn + 20H- - --- > ZnO ~ H20 + 2e
Total cell reaction:
Zn -~ 1/2 2 - ~ ZnO
OBJECTS OF THE INVÆNTION
One of the objects of this invention is to
provide metal battery cells having consumable anodes
and gas-depolarized cathodes in box-like form in an inert
battery container, in which the cathodes in box-like
~0 form may be removed and replaced in the battery container
and the consumable portion of the anodes easily removed
and renewed outside the cell container and re-used in
the same or a similar cell container or in which only
the consumable portion of the anodes may be removed and
replaced without removing the box-like cathodes.
mab/ J
5~3
Another object is to provlde hollow, box-
like battery cell elements, of which the cathode is a
porous, gas-permeable, 02-reducing electrode and the
anode is consumable, replaceable zinc or other metal,
which can be removed and replaced in the same or a
dif~erent inert plastic battery container.
Another object is to provide a battery container
for removable and replaceable bipolar cell elements
having means to circulate electrolyte in the spaces be-
tween adjacent cell elements and gas through said shal-
low, box-like cathode elements to activa-te the battery.
Another ob~ect is to provide cathodes for
such battery cells having gas-permeable, oxygen-reducing
elements in which electrolyte and gas are contacted when
the battery is in operation.
Another object is to provide a bipolar gas-
depolarized battery with hollow, porous, ~inger or tube
shaped cathodes and solid or porous consumable anodes,
which anodes are removable and replaceable by other
~0 anodes when partially consumed ~y the chemical reactions
which take place in a battery.
.~ 7 -
5~
Another object is to provide a battery with
removable anodes and cathodes in which the anodes and
cathodes are guided by means in the battery casing so that
the anodes and cathodes do not contact each other during the
removal of either from the battery casing.
Another object is to provide a rugged battery with
no delicate parts or tearable envelopes which may be
damaged in replacing anodes, whereby consumable anodes ma~
be removed and replaced in the battery container without
damage to any other parts of the batteryO
Therefore, in accordance with the present invention
there is provided a battery com~rising an inert container
housing a plurality of hollow box-like cathode elements
and consumable metal anode elements in spaced relationship.
Each of the box-like cathode elements have at least one
gas-permeable, porous cathode in at least one wall and at
least one consumable metal anode separate from and removably
supported opposite the gas-permeable porous cathode. The
cathodes and anodes of adjacent elements are disposed in
~0 spaced facing relationship. The battery also comprises
means to maintain an electrolyte in the spaces between the
cathodes and anodes; means to feed a depolarizing gas
through the interior of the box-like cathode elements to the
porous cathodes, means for collecting precipitated material
below the anode and cathode elements and means to electrically
connect the cathode and anode elements to an external load,
the anode elements being removable and reinsertable in
the containers.
Various other objects and advantages of the invention
will appear as this description proceeds~
Referring now to the drawings, which are for
illustrative purposes only and by which the principles of
this invention will be described~
~ 8 --
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3~B
Fig. 1 is a perspective view of a box-type
bipolar element,
Fig. 2 is an exploded view of four elements, namely
two intermediate bipolar elements and one cathodic and one
anodic end element,
Fig. 3 is a plan view of a battery container in
which bipolar elements are insertable and removable to
provide the desired number of cell units,
Fig. 4 is a sectional view approximately on the
line 4-4 of Fig. 3,
Fig. 5 is a sectional side view ~with parts omitted)
approximately on the line 5-5 of Fig. 7 of another embodiment
of a battery, with the anodes and cathodes each having
a
ms/~b
a double face so that, e~cept for the end elements,
the anodes and cathodes are active on both the front
and back faces thereof,
Fig. 6 is an exploded perspective view of two
cathode elements and two anode elements according to
Fig. 5 with electrical connections therebetween,
Fig. 7 is a sectional view along the line 3-3
of Fig. 5 showing ~he battery container into which the
anodic èlements, mounted on support plates, are inser-
table and removable to permit recoating of the anode
elements outside the battery container,
Fig. 8 is a part~sectional plan view of abattery container, in which the oxygen-depolarized ca-
thodes and the replaceable anodes of this invention are
shown,
Fig. 9 is an enlarged detail of the anode/
cathode structure of this embodiment,
Fig. 10 is a sectional plan view of another
embodiment of the invention, and
~0 Fig. 11 is a sectional view approximately on
the line 11-11 of Fig. 10.
Fig. l to 4 and 8 to 11 illu$trate b~polar em-
bodiments of the inyention and Figs. 5 to 7 illustrate
a monopolar embodiment.
As illustrated in Fi~ the replaceable bi~-
polar units are individual, vertical, shallow, box-
like cathode elements 1, of a valve metal, nickel,
stainless steel or the like, each consisting of an im-
perforate front portion 2 on which consumable anodes 5
g
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3i~5~
are mounted and ~-shaped top, bottom and side pieces
3, 3a and 3b, preferably formed from one piece of metal,
which form a frame for a porous, gas-permeable, cathode
4 formed o~ sintered, activated titanium or other val-
ve metal, or nickel or stainless steel impregnated
with catalytic materials such as the platinum group
metals, oxides of the platinum group metals, mixed
oxides thereof and other catalytic oxides such as spi-
nels, perovskites, delafossites, bronzes and the like.
The activated, sintered, porous cathode 4 is preferably
formed separately and welded into the frame formed by
the U-shaped parts 3, 3a and 3b.
The sintered, porous, gas-permeable cathode
elements 4 (and 32 and 34, Fig. 5, hereafter described)
are made of any corrosion-resistant metal, preferably
formed by sintering particles o~ the corrosion-resis-
tant metal by known techniques, such as those commer-
cially used to make metallic filter plates and tubes,
to obtain a structure with a porosity of 30% to 65%.
The sintered, porous cathode sections may be silicon or
a valve metal such as titanium, tantalum, tungsten
zirconium, niobium! hafnium, vanadium, yttrium, or
alloys thereof, nickel or stainless steel. The par-
ticles are preferably spherical and have a narrow size
distribution. Preferred size ranges in mesh number are
lO to 30, 30 to 50, 50 to 7Q and lO0 to 150~ wi~th the
preferred ranges being the coarser ones, such as lO
to 30 and 30 to 50. With these preferred particle size
ranges, the catalyst-impregnated and coated cathode o~
-- 10 --
mab/ c~
3~58
the invention retains a porosity of about 50% and a
very high permeability to both liquids and ~ases. Gas
pressure with reference to porosity is regulated so
that liquid electrolyte does not flood the pores of
the cathode and ~as does not blow through into the
electrolyte.
The surfaces of the sintered, porous cathodes
4 facing the inside of the cathode boxes, are pre-
ferably impregnated with a hydrophobic resin such as
a fluorocarbon resin, in order to make the inner cath- `
ode surface substantially impermeable to the aqueous
electrolyte while maintaining the side facing outwardly
unaltered as to its permeability to electrolyte. The
hydrophobic coating in conjunction with the positive
pressure exerted by the gas inside the box-like elements
1 substantially avoids percolation of electrolyte into
the box-like elements. However, draining means may be
provided in the box-like elements 1 to dispose of
minor or accidental flooding of the box-like elements.
~0 On the front wall 2 of the box-like bipolar
element 1, a consumable and replaceable anode 5 formed
of a sheet of zinc or other consumable anodic material
is removably mounted~ The anode sheet 5 is conductively
and mechanically connected to the imperforate wall 2
by means of spring clips 6, which are conveniently made
by welding suitably shaped strips of the metal along
the two vertical edges of the wall 2 and a horizontal
strip at the bottom of the two ~ertical strips. The
anode 5 can easily be inserted by simply slipping it
inside the vertical spring clips 6 until it engages
with the bottom clip. Removal of substantially
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consumed anodes is a simple and rapid operation. The
anodes 5 may be flat or corrugated sheets of solid
or porous zinc or other consumable metal.
Suitable extractors may be provided which,
engaging with holes (not shown) in the top portion
of the zinc sheets, will facilitate the removal opera-
tion.
Both the anodes 5 and the porous cathodes 4
are smaller in size than the overall dimensions of the
box~like elements 1, so that inoperative edge portions
are provided around the box-like elements 1 which fit
into slots or other spacers 11 provided in the battery
container described below.
Inlets 7 and outlets 8 are provided for intro-
ducing depolarizing gas and maintaining the required
gas pressure inside the hollow, box-like elements 1.
` Other means beside the spring clips shown
in Fig. 1 may be provided to connect the consumable
anodes 5 mechanically and electrically to the box-like
structures. For example, a thermoplastic, electrically
conductive cement may be used for spot-bonding the
sheets 5 to the wall 2 of the box-like elements. How-
ever, the use of clips is preferred because the con-
sumable anodes can be removed and reinserted without
- removing the box-like elements from the container of
the battery, thus reducing the time necessary for
"recharging" the battery.
Fig. 2 is an exploded view of four bo~-like
elements 1 showing them in their eleckrical series
spatial disposition. Each cathode 4 faces the anode
5 of the adjacent element.
- 12 -
mab/ Cl`
3~
The first element A of the series has an im-
perforate wall in place of the cathode 4, has an anode
5 carried in clips 6 thereon and is connected to the
negative terminal of the battery which becomes the posi-
tive pole when the battery is connected to an external
load. Similarly, the last element D, which has a cathode
4 and does not carry an anode is connected to the posi~
tive pole of the battery. Two bipolar elements s and C
are operatively inserted between the two terminal (half-
cell) elements A and D, but any number of bipolar ele-
ments may be so inserted to provide the desired battery
voltages.
The bipolar element B has its porous cathode 4
(visible in the cutout corner of element B) facing the
anode 5 of the terminal element A and its anode 5 facing
the porous cathode 4 (not visible) of the ad~acent bi-
polar element C, and so on.
The gas inlets 7 and outlets 8 of elements ~,
C and D communicate with a distribution manifold and an
~0 exhaust manifold whereby air, oxygen or other depolar-
i2ing gas is circulated into these box-like elements
under a regulatable pressure.
Fig. 3 is a sectioned plan view of a battery
container made of inert material such as plastic, hard
rubber or the like, and provided with spaced slots 11
or other spacing means, into which the box-like elements
1 axe inserted. The slots or spacing means 11 do not
extend to the bottom of the container 10, so that there
is a space 16 for circulation, drainage, etc., of the
electrolyte below the elements 1.
mab/(~
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When the elements 1 are inserted in the spaced
slots 11, spaces 12 are formed between the porous cathode
4 of each element and the anode 5 of the next adjacent
element 1.
Instead of slots 11 iIl the side walls of con-
tainer 10, the elements 1 may be provided with lugs on
each side which rest on the top of the side walls of
container 10 and suspend the elements 1 at the desired
depth in the container.
The walls of the container 10 are provided
with conduits 13 and 14 communicating with each of the
interelectrodic spaces 12 by conduits 13a and 14a.
During operation, electrolyte contained in a separate
tank or reservoir is circulated into the spaces 12, con-
duits 13 and 14 being used, respectively, as inlet and
outlet for the electrolyte. The terminal element A
is electrically connected to the negative terminal
post 24 of the battery and the opposite terminal ele-
ment tnot shown in Fig. 3) is connected to positive ter-
minal post 25 of element D shown in Fig. 2.
Fig. 4 is a sectional view of the battery along
the line 4-4 of Fig. 3. The box-like elements 1 shown
in this figure have inoperative bottom portions 15 ex-
tending for a certain distance below the bottom clips
6, which delimit the operative portion of the anode
element. The bottom portions 15 extend preferably for
a length corresponding to 3 to 5 times the interelec-
trodic distance between a cathode 4 and an anode 5
(that is, the width of spaces 12 of Fig. 3). This
inoperatlve bottom portion 15 has the function of
elongating the electric path for any by-pass current
-- 1~ --
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throu~h electrolyte in the space 16.
In a modification, the slots 11 could extend
to the bottom of the container 10 to eliminate the space
16. In this instance, the bipolar elements do not need
an enlarged inoperative bottom portion 15 as shown in
Fig. 4, but could be dimensioned as shown in Figs. 1
and 2.
However, the box-like bipolar elements 1 pre-
ferably do not extend to the bottom of the container 10
but a space 16 is left between the bottom of the bipolar
elements 1 and the bottom of the container 10. In this
spaGe 16, solid precipitated oxides of the dissolved
anodic metal can collect without interfering with the
electrodic areas.
When the battery is being recharged by the in-
sertion of new anode sheets 5, the electrolyte is drained,
together with precipitated oxides through a suitable
valve draining nozzle 26 in the bottom of the container
10 .
The gas inlets 7 and outlets 8 of the box-like
elements 1 are respectively connected through couplings
17 to a gas distributor pipe 18 and to an exhaust col-
lector pipe 19.
A fan or compressor 20 and throttling valves
21 in the inlet line 22 and the exhaust line 23 co-
operate to maintain the desired gas pressure inside the
box-like elements 1 of the battery. A cover 9 is pro-
vided to avoid electrolyte splashing outside the
battery container and the electrolyte in the battery
is kept at approximately the level 27 indicated in
Fig, 4.
.~
- 15 -
,
S~
During operation, air, 2' 02-enriched or other
depolarizing gas is passed into the interior of the bi-
polar elements 1 by means of the fan 20 (Fig. ~), or
other air or gas-circulating means, and is exhausted
under the control of the throttling valve 210 A certain
constant, positive gas pressure is maintained inside
the elements in order to prevent percolation of the
electrolyte through the porous cathodes 4 and to esta-
blish a three-phase boundary inside the thickness of the
porous cathodes. The pressure varies with the porosity
and permeability characteristics of the activated por-
ous cathode and is adjusted so that the electrolyte
does not flood the pores of the cathode 4 and the gas
does not blow through into the electrolyte.
Zinc is the preferred anode material. However,
any electroconductor used in metal oxygen cells, such
as metals, metalloids, alloys and heavy metal salts, may
be used. The anodes 5 are prefera~ly solid metals, but
porous anodes or part-porous and part-solid anodes may
be used. The anodes may be flat, slightly curved or
corrugated sheets. The anode material must be chemically
reactive with the electrolyte and must be more electro-
positive than oxygen. Alkaline electrolytes such as
NaOH, KOH, mixtures of KOH and RbOH and the like, may
be used.
When the battery is connected with an external
load current flows through the electrolyte contained in
the interelectrodic spaces 12 to the zinc anodes 5 and
through each conductive, box-like bipolar element 1 to
the cathode 4 of the same element, and through the elec-
trolyte contained in the next interelectrodic space to
the zinc anode of the next adjacent bipolar elem~nt, and
- 16 -
mab/ ~
3~S8
so on to the positiv~ terminal elem~n-t 25 of the battery,
which is connected to the external load.
In order to reduce current by-pass through the
electrolyte contained in the bottom space 16 of the
battery container, the space 16 may be partly filled
with insulating packing material such as broken ceramic
tubes, etc.
In the embodiment illustrated in Figs. 5 to 7,
individual, vertical, shallow, box-like elements 31
(similar to elements 1 of Figs. 1 and 2) of a valve
metal, nickel, stainless steel or the like, form cathode
elements each having a porous front and rear cathode
portion 32 and 34, respectively, mounted in a U-section
rectangular frame comprising top, bottom and side pieces
` 33, 33a, 33b and 33c (Fig. 6), preferably formed from
one piece of metal. The rectangular cathode portions
32 and 34 are formed of sintered, activated titanium or
other valve metal, or nickel or stainless steel impreg-
~ nated with catalytic materials such as the platinum group
metals, oxides of the platinum group metals, mixed oxides
thereof and other catalytic oxides such as spinels,
perovskites, delafossites, bronzes and the like. The
cathode portions 32 and 34 are preferable welded into
the frame formed by the u-shaped parts 33, 33a, 33b and
33c.
The inner faces of the sintered cathode portions
32 and 34 are preferably impregnated with a lipophobic
(e.g., hydrophobic) resin, such as a fluorocarbon resin,
in order to make the cathode substantially impermeable
to the aqueous electrclyte from the outside, while main-
taining unaltered its permeability to gases from the in-
mab/ ~'
1~3i~5~3
side. The hydrophobi~ coating, in conjunction with ~he
positive pressure exerted by the gas inside the box-
like elements 31, substantially avoids the percolation
of the electrolyte into the box-like elements. How-
ever, draining means may be provided in the box-like
elements to dispose of minor or accidental flooding of
the box-like elements.
Removable and replaceable, consumable anodes
35 are carried on non-consumable, lightweight support
sheets 36, of, for example, titanium, titanium coated
with tantalum, nickel or other suitable metal, which are
fitted into slots or other spacing means 37 in an in-
sulating, plastic battery case 40. The consumable
portions 35 of zinc or other consumable anodic material
may be electroplated on the support sheets 36, or welded,
riveted, rolled, secured by thermoplastic, electrically
conductive cement, or otherwise attached on the support
sheets. Suitable extractor tools engaging in holes
(not shown) in the top portion of the support sheets
~0 may be provided to facilitate the removal and reinser-
tion of the support sheets in the slots 37.
The consumable portions of the anodes 35 are
smaller in size than the overall dimensions of the sup-
port sheets 36, so that inoperative edge portions are
provided around the support sheets which fit into the
slots 37 in the battery container.
Inlets 38 for the electrolyte and outlets 39
are provided with branches 38a and 39a for introducing
and circulating electrolyte through the battery con-
tainer.
- 18 -
mab/~
~t5~35~
Conventional electrolytes, including the alkaline mater-
i~ls such as sodium hydroxide, potassium hydroxide,
Mixtures of potassium and rubidium hydroxide and the
like, may be used. Acid electrolytes, including sul-
furic acid, phosphoric acid and hydrochloric acid can
be employed. Depending upon the particular electrolyte
used, different anode materials can be selected.
Box-like cathode elements 30A, 30B, 30C to 30D
(Fig. 5) are mounted in slots 41 in the battery case 40
with each sintered cathode 32 and 34 ~acing double faced
anodes 35 on the adjacent support sheet 36, except for
the first (cathode) and last (anode) element. The
first element, 30A, of the series, has an imperforate
end wall (in place of the sintered, porous portion 34
of the other elements,) which imperforate end wall is
adjacent an end wall of the battery case 40O Similarly,
facing the last element 30D is a single anode face 35
on a support sheet 36 and which does not carry a zinc
anode on its other face. The last support sheet 36
~0 ~its into a slot 37 at the opposite end of the battery
case from the element 30A. Intermediate cathode ele-
ments 30B, 30C, and so forth, each have porous, sintered
cathodes 32 and 34 welded therein, and between each of
the intermediate cathode boxes, a support sheet 36 having
replaceable, consumable anodes 35 on each side thereof,
is inserted.
Any number of anode and cathode elements may
be inserted between the two terminal elements.
The element 30B has its porous cathode 32 facing
one side of the zinc anode between elements 30B and 3QC,
-- 19 --
mab/ ;'1-~
3~5~3
and its ca~hode 34 facing the ~inc anode 35 betw~en
elements 30A and 30s, and so on throughout the cell to
the end element 30D.
The container 40 is preferably made of inert
material such as a plastic and its spaced slots 37, 41
do not extend to the bottom of the container 40 so that
the anode support sheets 36 and the cathode elements
31 do not extend to the bottom of container 40 but
are spaced from the botto~ of the container so that the
electrolyte can circulate in the electrolyte spaces
and below the anode and cathode elements and can be
drained through the drain opening 42 when desired.
When the cathode elements 31 are in the slots
41 and the support sheets 36 each with two anode faces
35 are in slots 37, spaces 43 are formed between the
porous cathodes 32 and 34 and the anode faces 35 through
which the electrolyte circulates. The electrolyte,
contained in a separate tank or reservoir, is circulated
into the spaces 43, conduits 38 and 39 being used as
inlet and outlet, respectively, for the electrolyte.
Fig. 6 is an exploded view of two box-like
cathode elements 31 and anodes 35 on support sheets
36, showing the elements in their electrical series
spatial relationship. The cathode boxes 31 are con-
nected together by leads 44 leading to the positive
terminal (not shown) of the battery, and the anode
support sheets 36 are connected by projecting lugs
- 20 -
mab/,~
~3~35~
36a and l~ads 45, to each other and to the negative
terminal of the battery, to which terminals the con-
nections to the load are made. This embodiment oper-
ates as a monopolar battery.
The gas inlets 46 and outlets 47 of each box-
like cathode element 31 are connected, respectively,
through couplings 48 and 48a to a gas distributor pipe
49 and to an exhaust collector pipe 50. A fan or com-
pressor 51 in the inlet line 52 and a throttling valve
53 in the exhaust line 53a cooperate to maintain the
desired gas pressure inside the box-like elements 31
of this battery. A cover 54 is provided to avoid elec-
trolyte splashing outside the battery container and
the electrolyte in the battery is kept at approximately
the level 55 indicated in Fig. 7.
When tha battery is connected with an externai
load, air, 2' 02-enriched or other depolarizing gas
is passed into the interior of the elements 31 by means
of the fan 51 (Fig. 7) or other air or gas-circulating
means, and i5 exhausted under the control of the throt-
tling valve 53. A certain constant, positive pressure
is maintained inside the porous cathode boxes 31 in
order to prevent percolation by the electrolyte through
the porous cathode faces 32 and 34 and for establish-
ing a three-phase boundary inside the thic~ness of the
porous cathode faces 32 and 34. The pressure applied
varies with the porosity and permeability characteris-
tics of the activated porous cathode faces and is ad-
justed so that the electrolyte does not flood the pores
of the cathodes 32 and 34 and the gas does not blow
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y
~-~` mab/~¦~
58
through into the electrolyte.
During operation, current flows, through
the electrolyte contained in the interelectrodic spaces
43, from the porous cathodes 32 or 34 to the zinc anode
faces 35.
In order to reduce current by-pass through
the electrolyte contained in the bottom space 56 of the
battery container, the space 56 may be partly filled
with insulating packing material such as broken ceramic
1~ tubes, etc.
Fig. 8 illustrates a plurality of shallow,
box-like bipolar anode/cathode elements with removable
and replaceable anodes, disposed inside an insulating
plastic battery container 61 provided with gas inlets
62 leading into the interiors 63 of the hollow bipolar,
box-like elements 64. The container 61 is provided
with a removable cover (not shown), electrical con-
nections (not shown) to and from the terminal anodes
and cathodes and gas outlets 65. The inlets 62 and
outlats 65 are provided with valves 66 and 66a by which
the gas pressure inside the cathodes may be controlled.
Container 61 is provided with slots or other spacing
means 61a into which the hollow, box-like elements 64
are fitted. Hollow cathode fingers 68 forming the pas-
sages for the depolarizing gas are supported Erom faces
64a of the elements 64, and anodes 69 are supported by
the elements 64 between the cathode fingers 68.
Fig. 9 shows in greater detail the construc-
tion of the bipolar elements 64 and the hollow cathode
fingers 68. The depolarizing gas entering the hollow
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-
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bipolar elements 64 flows through openings 67 i.nto the
base of tapered fingers 68 formed o~-er the major
part of their surfaces of corrosion resistant, porous
and gas-permeable metal such as spherical particles of
sintered valve metal having a porosity of about 50%,
impregnated with an oxygen-reducing catalyst such as
the platinum group metals, including platinum black,
platinum group metal oxides, and other catalytic metal
oxides such as perovskites, delafossites, bronzes,
spinel-type oxides and the like, as previously des-
cribed. These catalysts are capable of reducing 1/202
to OH-, which reacts with the zinc of anodes 69 accor-
ding to the reaction given above. This reaction pro-
duces zinc oxide, some of which remains in solution
in the electrolyte and some of whlch precipitates as
znO particles, which remain in the electrolyte until
the electrolyte is discharged from th.e battery during
replacement of the zinc anodes 69 to "recharge" the
battery.
One side of the anodes 69 fits into insula-
ting guides 70 mounted on side 64a of the hollow bi-
polar elements 64 and the other side fits into con-
ducting metal clips 71 and 71a mounted on the opposite
element 64. Clips 71 and 71a provide support for and
electrical contact between anodes 69 and the bipolar
elements 64. The opposite faces of elements 64 are
connected by edges 72 shown in Fig. 8.
mab/ r 1~
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The elements 64 with the ho]low cathode ~in-
gers 68 are preferably assembled in succession in con-
tainer 61 (from left to right) as cell units 60A, 60B,
60E, etc. The first cell unit 60A is a cathode half-
cell ad~acent the left wall of container 1. It is
connected to the positive terminal of the battery.
The last element 64 at the right of the battery is an
anode half-cell; it is of similar box-configuration to
the other elements 64 but has no gas inlets/outlets
and has imperforate walls. It is connected to the
negative terminal of the battery. To assemble the
battery, the anodes 69 for cell unit 60A are inserted
in the insulating guides 70 and the element 64 of cell
60B is then assembled with the clips 71-71a pushed over
the right side of anodes 69 to make electrical contact
with the anodes of cell 60A. The same procedure is
followed for the assembly of each cell until the
desired number of cell units i5 assembled and placed
in the container 61 and the terminal elements are con-
~0 nected into the load circuit. For replacement of the
anodes 69 in a given cell of the assembled battery,
the battery electrolyte is drained, the cell units
are removed from the container 61 and the anodes re-
quiring replacement are pulled apart; the partially
consumed anodes 69 are removed from the insulating
guides 70 and the specific cell units, 60A, 60B, 60E,
etc. are reassembled with the clips 71 and 71a grip-
ping the right-hand edge of anodes 69 to restore elec-
tricàl contact of all the cell units. Alternatively,
3~ only the anodes 69 are remo~ed and replaced by new
anodes, using a special tool therefor.
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The cathode fingers 68 may be slightly tap~red
to facilitate assembly and disassembly and each may be
one tapered finger extending from top to bottom of the
cell units 60A, 60s, etc., or a vertical row of round,
or conical projections extending from the faces 64a.
The tapered interelectrodic gap between the cathode
fingers 68 and the anodes 69 is shown exaggerated for
better illustration.
During operation, electric current yenerated
by the chemical reactions described above flows from
the anodes 69 through clips 71 and 71a to the elements
64, through the connections 72 at each end of elements
64 to the faces 64a, through the cathode fingers 68
and via the electrolyte to the anodes 69 of each ele-
ment of the battery. Current will continue to ~low
as described, as long as oxygen is supplied to the
cathode fingers 68 from the hollow elements 64 and the
anodes 69 remain unconsumed. When one or more of the
anodes 69 is consumed, or substantially consumed, the
~0 supply of oxygen-containing gas to the elements 64 is
stopped, the electrolyte is drained from the cell and
the partially consumed anodes are replaced with new
anodes.
Figs 10 and 11 illustrate a modification of
the embodiment illustrated in Figs. 8 and 9, in which
the container 73 has slots or spaces 61a into which
the anode/cathode assemblies (similar to 64, 68 and
69 of Figs. 8 and 9) are removably fitted. The walls
of container 73 are provided with conduits 74 and 75
which con~unicate by channels 74a and 75a with the
electrolyte spaces between the anodes 76 cathode
~ 25 -
3~S8
fingers 78. The anodes 76, of zinc or other consumable
metal, are mounted on a support consisting of a series
of spaced, non-consumable supporting blades or fingers
76a, mounted on or cast integrally with a supporting
backplate 77. The zinc anodes 76 are plated or other-
wise secured on the blades or fingers 76a. Alterna-
tively, pre-formed zinc sheets can be secured on the
blades 76a, or these blades may be in the form of hooks
on which pre-formed zinc plates are suspended. The
1~ blades 76a and bac}cplate 77 may be made of titanium,
nickel or other non-corroding metal. The supporting
blades 76a with the consumable metal supported thereon,
extend between hollow, porous cathodes 78a in fingers
78. The supporting backplate 77 is removably secured
by clips 79, conducting cement or other meansl to the
impervious wall 80 of box-like elements 81, through
which 2 or 02-containing gas flows through passages 82
into the hollow, porous cathode fingers 78, which are
constructed similarly to the fingers 68 of Figs. 8 and
The depolarizing gas is preferably conducted
into and out of the gas passage 81 by vertical conduits
83 and 84 connected by slip joints 85 to a gas inlet
pipe 86 and an exhaust pipe 87.
During operation, air 2' or 02-enriched gas
is passed into the interior of elements 81 through
conduits 83 by a pump 89 (Eig. 11) or other gas-cir-
culating means, and is exhausted through passages 87
by conduits 84, 90. The pressure in elements 81 is
controlled by valves 91. A removable cover 92 on the
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_ ~, , I -
~3i~5~
battery container 73 prevents splashing and spillage
from the battery. The electrolyte level is maintained
at approximately the level of line 93. A space 94 below
the electrode bank permits free communication between
the electrolyte spaces and a drain valve 95 permits
the container 73 to be drained of electrolyte and ac-
cumulated oxide of the consumable anodes, when desired.
The cells of this invention have many advan-
tages over prior-known cells. The cell elements can
be assembled and the cells remain idle until current is
needed by the system, at which time the cells may be
quickly activated by supplying electrolyte to the
anode/cathode-containing spaces between elements and
supplying an oxygen-containing gas to the hollow,
porous cathodes to start the reactions described above.
Deactivation of the cell during periods in which no
electric power is required from the cell requires only
that gas flow to the cell be discontinued and the elec-
trolyta drained during the period of idleness or periods
of anode replacement.
A common feature of the described embodiments
is that the consumable metal anodes are mounted on non-
consumable metal supports, the consumable metal anodes
being removable from the battery container either alone
(as in Figs. 1-4, and Figs. 8-9) or together with their
supports (as is necessary in Figs. 5-7 and Figs. 10-11
and optional in Figs. 1-4 and Figs. 8-9).
The consumable anodes may thus be quickly re-
moved and replaced with new or recoated consumable
anodes without contacting the cathodes during removal
and reinsertion of the anodes so that there is no damage
to the cathode element.
ï~ - 27 -
3i~58
While specific embodiments of this invention
have been described to illustrate the principles there-
of, it will be understood that the invention may be
embodied in other forms, sizes and shapes and that this
invention is not limited to the specific forms used to
illustrate it.
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