Electrode stack for alkaline electrochemical cells

Abstract

In some embodiments, an electrochemical cell (200) may include: a container; electrodes disposed within the container and comprising a first set of electrodes and a second set of electrodes, where the first set of electrodes comprises one or more first electrodes (207) and the second set of electrodes comprises one or more second electrodes (205), and where the one or more first electrodes and the one or more second electrodes alternate within the stack, the first electrodes are not in contact with each other and the second electrodes are not in contact with each other; a set of separators (203, 204) comprising one or more separators disposed between the first set of electrodes and the second set of electrodes; an electrolyte solution disposed within the container; and a current collector disposed within the container.

Description

[0001] Cross - reference to related applications

[0002] This patent application claims priority to U.S. Provisional Application Serial No. 63 / 387,441, filed on December 14, 2022, the entire content of which is incorporated herein by reference. Technical field

[0003] The present invention generally relates to alkaline batteries, and more particularly, to alkaline batteries having electrodes arranged in a stacked configuration. Background art

[0004] Alkaline electrochemical single - cell batteries are commercially available. The sizes of the single - cell batteries are generally known as LR6 (AA), LR03 (AAA), LR14 (C), and LR20 (D). The single - cell batteries are cylindrical in shape, and this shape must conform to the size standards established by organizations such as the International Electrotechnical Commission. Consumers use the electrochemical single - cell batteries to power a variety of electrical devices, such as clocks, radios, toys, video games, film cameras that typically include a flash unit, and digital cameras. Such electrical devices have a wide range of discharge conditions, for example, from low power consumption (“low rate”) to relatively high power consumption (“high rate”). Due to the increasing use of high - power - consuming devices, there is a need for a battery with improved high - rate discharge performance. However, improvements in high - rate discharge performance may have a negative impact on low - rate discharge performance, or vice versa. Summary of the invention

[0005] Various different embodiments relate to an electrochemical single - cell battery, comprising: a container having a closed bottom end and an open top end; a sealing assembly fixed to the open top end of the container and closing the open top end; a stack comprising two or more sheet electrodes disposed within the container, wherein the two or more sheet electrodes comprise a set of one or more first electrodes and a set of one or more second electrodes, wherein the one or more first electrodes and the one or more second electrodes are alternately arranged within the stack; a set of separators comprising one or more separators disposed within the stack between each electrode; an electrolyte solution disposed within the container; and a current collector disposed within the container.

[0006] In some embodiments, the one or more separators of the electrochemical single cell include at least one first separator and at least one second separator, wherein the at least one first separator has a different composition from the at least one second separator. In some embodiments, the one or more first electrodes are anodes comprising a zinc material. In various different embodiments, the one or more second electrodes are cathodes comprising a manganese dioxide material. In some embodiments, the electrochemical single cell further includes a second electrode positioned at the bottom end of the stack adjacent to the closed bottom end of the container. In various different embodiments, the electrochemical single cell further includes a second electrode positioned at the top end of the stack adjacent to the open top end of the container. In some embodiments, each of the one or more second electrodes defines a central opening extending therethrough, and each of the one or more second electrodes further includes an insulating sleeve lining the central opening; wherein the current collector is a current collector pin extending through the center of the insulating sleeve. In various different embodiments, at least one of the one or more separators is fixed to each of the one or more first electrodes, and wherein the current collector pin extends through the center of the at least one separator fixed to each of the one or more first electrodes to electrically connect with the active material of the one or more first electrodes. In some embodiments, each of the one or more first electrodes includes a washer that electrically insulates the active material of the one or more first electrodes from the container, and wherein at least one of the one or more separators is fixed to the washer. In various different embodiments, each of the one or more second electrodes includes at least one separator; and wherein the insulating sleeve of each of the one or more second electrodes includes one or more insulating retaining rings that fix the at least one separator of each second electrode.

[0007] Certain embodiments relate to an anode for an electrochemical single cell, the anode comprising: an anode active material composition; an insulating washer having two open ends, wherein the insulating washer surrounds the anode active material; and an ion-permeable separator disk fixed to each open end of the insulating washer to seal the anode active material within the insulating washer.

[0008] In some embodiments, the anode active material comprises: particulate zinc suspended in an electrolyte gel; particulate zinc oxide; and dissolved zinc oxide. In various different embodiments, the insulating washer comprises a polymeric material. In some embodiments, the insulating washer includes: a cylindrical sleeve having a first open end and an opposite second open end; a first insulating collar fixed to the first open end, wherein the first separator is fixed to the first insulating collar; and a second insulating collar fixed to the second open end, wherein the second separator is fixed to the second insulating collar. In some embodiments, the first separator is adhered to the first insulating collar and the second separator is adhered to the second insulating collar.

[0009] Various different embodiments relate to a cathode that includes: a cathode active material composition formed in an annular shape that defines a central opening extending therethrough; a first ion-permeable separator on a first side of the cathode active material composition; a second ion-permeable separator on a second side of the cathode active material composition; an insulating sleeve positioned within the central opening, wherein: a first end of the insulating sleeve extends beyond the first ion-permeable separator and secures the first ion-permeable separator to the first side of the cathode active material composition; and a second end of the insulating sleeve extends beyond the second ion-permeable separator and secures the second ion-permeable separator to the second side of the cathode active material composition.

[0010] In some embodiments, the first ion-permeable separator and the second ion-permeable separator are planar and sidewalls of the cathode active material composition extending between the first side and the second side are exposed. In various different embodiments, the insulating sleeve includes a first insulating collar located within the center of a cylindrical opening of the cathode active material composition and a second insulating collar fixed to the first insulating collar. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present disclosure has been generally described, and now the present disclosure will be described with reference to the drawings, which are not necessarily to scale, and in which:

[0012] Figure 1 is a cross-sectional front view of an exemplary alkaline electrochemical single cell;

[0013] Figure 2A is a cross-sectional front view of an exemplary alkaline electrochemical single cell having an electrode stack configuration according to some embodiments;

[0014] Figure 2B is an x-ray image of an electrochemical single cell having a stacked electrode sheet configuration according to some embodiments;

[0015] Figure 3Ais a cross-sectional exploded view of an exemplary alkaline electrode group within an electrode stack configuration for an electrochemical single cell according to some embodiments;

[0016] Figure 3B is a cross-sectional exploded view of an exemplary cathode electrode sheet according to some embodiments;

[0017] Figures 4A - 4B is a cross-sectional exploded view of components of an exemplary anode electrode sheet according to some embodiments;

[0018] Figure 4C is a cross-sectional exploded view of components of an exemplary anode electrode sheet according to some embodiments;

[0019] Figure 5 is an exemplary estimation table of characteristics of an electrochemical single cell with a stacked electrode configuration according to some embodiments;

[0020] Figure 6 is a table of exemplary material compositions of an electrochemical single cell with a stacked electrode configuration according to some embodiments;

[0021] Figure 7 is a flow chart of an exemplary method of manufacturing an electrochemical single cell according to some embodiments; and

[0022] Figure 8 is another flow chart of an exemplary method of manufacturing an electrochemical single cell according to some embodiments. DETAILED DESCRIPTION

[0023] Various different embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some but not all embodiments are shown. In fact, the various embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals always refer to like elements. In the following description, various components may be identified as having specific values or parameters, however, these items are provided as exemplary embodiments. In fact, the exemplary embodiments do not limit the various aspects and concepts of the embodiments, since many comparable parameters, sizes, ranges, and / or values may be implemented. Terms such as "first", "second", etc., "main", "exemplary", "secondary / auxiliary", etc. do not denote any order, quantity, or importance, but are used to distinguish one element from another. Additionally, the terms "a", "an", and "the" do not denote a limitation of quantity, but rather denote the presence of "at least one" of the referenced item. For example, "an organic additive" may refer to two or more organic additives.

[0024] To the extent that the embodiments disclosed herein are not explicitly mutually inconsistent, each embodiment disclosed herein is considered applicable to each other disclosed embodiment. All combinations and sub - combinations of the various elements described herein are within the scope of the embodiments.

[0025] It should be understood that when a parameter range is provided, all integers and all ranges within that range, as well as their tenths, hundredths, thousandths, ten - thousandths, and hundred - thousandths are also provided by the embodiments. For example, “5 - 10%” includes 5%, 6%, 7%, 8%, 9%, and 10%; 5.0%, 5.1%, 5.2%....9.8%, 9.9%, and 10.0%; and 5.00%, 5.01%, 5.02%....9.98%, 9.99%, and 10.00%, and for example 6 - 9%, 7 - 10%, 5.1% - 9.9%, and 5.01% - 9.99%. As another example, “0.00001 - 1M” includes 0.00005 - 0.0001M and 0.001 - 0.01M.

[0026] As used herein, “about” in the context of a numerical value or range means within ±10% of the stated or claimed numerical value or range.

[0027] As used herein, “metal additive” refers to a metal - containing compound added to the electrolyte and / or cathode. Examples are metal salts and metal oxides. As used herein, “metal ion” refers to an ion of any element that can be considered a metal, which includes but is not limited to metals, transition metals (any element in Groups 3 - 12 of the periodic table, particularly any element in Groups 4 - 11), lanthanides, actinides, alkaline earth metals, and alkali metals. “Metal salt” refers to any salt formed by metal ions. “Metal oxide” refers to any compound containing metal ions and oxygen in the - 2 oxidation state. Examples of metals for metal salts, metal oxides, and metal ions applicable to the present invention include magnesium (Mg), barium (Ba), nickel (Ni), copper (Cu), aluminum (Al), and cerium (Ce).

[0028] As used herein, “improvement” with respect to specific capacity generally means an increase in specific capacity. Generally, an “improvement” in the properties or metrics of a material or an electrochemical single - cell means that the difference in the properties or metrics (compared to the properties or metrics of a different material or electrochemical single - cell) is such that the user or manufacturer of the material or single - cell would find it desirable (e.g., lower cost, longer duration, provide greater power, more durable, easier or faster to manufacture, etc.).

[0029] As used herein, “specific capacity” refers to the total amount of charge in an electrochemical single - cell when discharged at a specific rate. This is typically measured in ampere - hours.

[0030] As used herein, "runtime" refers to the length of time that an electrochemical single cell will be able to provide a useful voltage level or a voltage above the end voltage.

[0031] These embodiments will be better understood with reference to the accompanying drawings, which show various different embodiments of a cylindrical primary electrochemical single cell in front elevation cross - section. Figure 1 An exemplary primary electrochemical single cell is shown having a stud or barrel configuration and dimensions comparable to a conventional LR6 (AA) type alkaline single cell. Figures 2A - 2B and Figures 3A - 3B Details of another configuration are provided where the electrodes are configured in a stacked / layered sheet / electrode - sheet configuration. It should be understood that the embodiments described herein are applicable to alkaline (Zn / MnO2) and alkaline - P (Zn / MnO2 + other) primary single cell chemistries. The materials and designs of the components of the electrochemical single cell shown in the drawings are for illustrative purposes and may be replaced with other materials and designs, including secondary electrochemical single cell chemistries. The non - limiting embodiments described relate to an alkaline electrochemical single cell that includes manganese dioxide as an active material in the cathode.

[0032] In Figure 1 FIG. 14, an electrochemical single cell 1 is shown, which includes a container or can 10 having a closed bottom end 24, an open top end 22, and a sidewall 26 (e.g., a cylindrical sidewall) therebetween. The closed bottom end 24 includes a terminal cap 20 that includes a protrusion. The can 10 has an inner wall 16. In this embodiment, the positive terminal cap 20 is welded or otherwise attached to the bottom end 24. In one embodiment, the terminal cap 20 may be formed of plated steel, for example having a protruding nib in its central region. The container 10 may be formed of a metal such as steel, preferably nickel, cobalt, and / or other metals or alloys plated on the inside, or formed of other materials having sufficient structural properties compatible with the various inputs in the electrochemical single cell. A marking 28 may be formed around the outer surface of the container 10 and may be formed on the peripheral edges of the positive terminal cap 20 and the negative terminal cap 46, provided that the negative terminal cap 46 is electrically insulated from the container 10 and the positive terminal 20.

[0033] Disposed within the container 10 are a first electrode 18 (e.g., anode) and a second electrode 12 (e.g., cathode), with a separator 14 disposed therebetween. The first electrode 18 is disposed within a space defined by the separator 14 and a closure assembly 40 that is fixed to and closes the open end 22 of the container 10. The closed end 24, sidewall 26, and closure assembly 40 define a cavity in which the electrodes of the electrochemical cell are received. As will be described in more detail later in this disclosure, the first electrode 18 and the second electrode 12 may be stacked / layered in a vertical direction, where multiple separators 14 collectively embody a set of separators disposed between the first and second electrodes. In some embodiments, multiple first electrodes 18 and multiple second electrodes 12 may be stacked in a vertical direction in an alternating arrangement, with each separator 14 from the set of separators 14 disposed therebetween. In some embodiments, multiple first electrodes 18 and multiple second electrodes 12 may be stacked in a vertical direction in an alternating arrangement, with each separator 14 from the set of separators 14 disposed therebetween. For example, the stack may include a second electrode at the bottom of the stack, a separator, a first electrode, another separator, and then another second electrode, and the stack continues in this arrangement until the electrochemical cell is full or the stack reaches a desired height. It should be understood that in many other embodiments, the first electrode is at the bottom of the stack. This stacking / layering configuration and variations will be described in more detail later in this disclosure.

[0034] The closure assembly 40 includes a closure member 42 such as a gasket, a current collector 44, and a conductive terminal 46 in electrical contact with the current collector 44. The closure member 42 preferably includes a pressure relief port that will allow the closure member to rupture if the internal pressure of the electrochemical cell becomes too great. If the current collector 44 and the conductive terminal 46 are electrically insulated from the container 10 that serves as the current collector for the second electrode 12 (cathode), the closure member 42 may be formed from: a polymeric material or an elastomeric material such as nylon-6,6, an injectable polymer blend such as a polypropylene matrix combined with polyphenylene ether or polystyrene, or another material such as metal. In the illustrated embodiment, the current collector 44 is an elongate spike or spool-shaped member that extends into the first electrode 18 (anode). The current collector 44 is made of one or more metals or metal alloys such as copper or brass. In certain embodiments, some portions of the current collector 44 may be conductive electroplated spikes / rods having a metal or plastic core plated with one or more metals or metal alloys. Other suitable materials may also be used. The current collector 44 is inserted through a hole (e.g., a centrally located hole) in the closure member 42. In some embodiments, the electrodes 12 and 18 may be configured in an annular shape, and the current collector 44 may be disposed to pass through the center of the ring.

[0035] The first electrode 18 is preferably a negative electrode or an anode. The negative electrode comprises a mixture of one or more active materials, a conductive material, optionally solid zinc oxide, and a surfactant. The negative electrode may optionally comprise other additives such as binders or gelling agents, etc. Example anode compositions useful in the electrochemical single cells discussed herein are described in detail in U.S. Patent Publication No. 2023 / 0107037, which is incorporated herein by reference in its entirety.

[0036] Zinc is the primary active material for the negative electrodes of these embodiments. Mercury, aluminum, silicon, lithium, and magnesium may also be used in alternative embodiments. Preferably, the volume of the active material used in the negative electrode is sufficient to maintain the desired interparticle contact and the desired anode-to-cathode ratio (A:C).

[0037] Interparticle contact should be maintained during the service life of the battery. If the volume of the active material in the negative electrode is too low, the voltage of the single cell may suddenly drop to an unacceptable low value when the single cell powers a device. It is believed that the voltage drop is caused by a loss of continuity in the conductive matrix of the negative electrode. The conductive matrix may be formed by undischarged active material particles, electrochemically formed oxides, or a combination thereof. The voltage drop may occur after the oxides start to form but before a sufficient network is established to bridge between all the active material particles present.

[0038] The zinc suitable for these embodiments can be sourced from many different commercial sources under various different trade names such as BIA100, BIA115. Umicore S.A. in Brussels, Belgium is an example of a zinc supplier. In a preferred embodiment, the zinc powder typically has 25% to 40% fines less than 75 μm, preferably 28% to 38% fines less than 75 μm. Generally, a lower percentage of fines will not allow for the desired DSC service, and using a higher percentage of fines may result in increased gas evolution. The correct zinc alloy is required to reduce negative electrode gas evolution in the single cell and maintain the test service results.

[0039] A surfactant, which is a non-ionic surfactant or an anionic surfactant or a combination thereof, is generally present in the negative electrode. It has been found that adding zinc oxide alone increases the anode resistance during discharge, but the anode resistance can be mitigated by adding a surfactant. The addition of the surfactant increases the surface charge density of the solid zinc oxide and reduces the anode resistance.

[0040] An example of a surfactant is DISPERBYK-190 from BYK-Chemie GmbH, Wesel, Germany. Based on the total weight of the negative electrode, the surfactant is present in an amount sufficient to disperse solid zinc oxide, preferably in an amount of about 0.00064 wt% to about 0.20 wt% or more. It is believed that DISPERBYK-190 is a solution containing a water-soluble high molecular weight block copolymer, which block copolymer includes one or more functional groups, believed to include at least two different types of functional groups. The surfactant has anionic / nonionic characteristics due to its corresponding functional groups. Further, it is believed that the number average molecular weight of the block copolymer DISPERBYK-190 measured by gel permeation chromatography is greater than 1000. If a hydrophobic component is present in the electrode composition, its water solubility may be offset by the presence of the hydrophobic component. In one embodiment, the amount of the surfactant is about 10 ppm to about 100 ppm, preferably about 15 ppm to about 50 ppm, of the zinc used in the negative electrode. It is believed that DISPERBYK-190 does not contain any organic solvents and is thus suitable for aqueous systems. The acid value (in mgKOH / g) of DISPERBYK-190 is 10, and its density at 20 °C is 1.06 g / ml.

[0041] In one embodiment, based on the total weight of the negative electrode, the negative electrode contains from about 0.2 weight percent (wt%) to 5 wt% of solid zinc oxide. In one embodiment, the negative electrode contains from about 1 wt% to 4 wt% of solid zinc oxide. In a preferred embodiment, the negative electrode contains from about 0.3 wt% to 1 wt% of solid zinc oxide. In a more preferred embodiment, the negative electrode contains about 0.66 wt% of solid zinc oxide.

[0042] In one embodiment, the solid zinc oxide is substituted to reduce its solubility. In one embodiment, a portion of the zinc in the solid zinc oxide is replaced by another cation. In one embodiment, the substituted solid zinc oxide has the formula Zn 1- x Y xO, where Y is at least one cationic substituent, and 0 < x ≤ 0.50. In one embodiment, the cationic substituent is selected from Mg, Ca, Bi, Ba, Al, Si, Be, Cd, Ni, Co, Sn, and Sr, and any combination thereof. In one embodiment, x is 0.01 - 0.40, or 0.02 - 0.35, or 0.4 - 0.30, or 0.05 - 0.25, or 0.10 - 0.20. In one embodiment, x ≥ 0.01, x ≥ 0.02, x ≥ 0.04, x ≥ 0.06, x ≥ 0.08, x ≥ 0.10, x ≥ 0.12, x ≥ 0.14, x ≥ 0.16, x ≥ 0.18, x ≥ 0.20, x ≥ 0.25, x ≥ 0.30, x ≥ 0.35, or x ≥ 0.40.

[0043] In one embodiment, a portion of the oxygen in solid zinc oxide is replaced by another anion. In one embodiment, the substituted solid zinc oxide has the formula ZnO 1-w A( 2w / z ), where A is at least one anionic substituent, 0 < w ≤ 0.50, and z is the charge of the anionic substituent. In one embodiment, the anionic substituent is selected from CO3 2- and PO4 3- , and combinations thereof. In one embodiment, w is 0.01 - 0.40, or 0.02 - 0.35, or 0.4 - 0.30, or 0.05 - 0.25, or 0.10 - 0.20. In one embodiment, w ≥ 0.01, w ≥ 0.02, w ≥ 0.04, w ≥ 0.06, w ≥ 0.08, w ≥ 0.10, w ≥ 0.12, w ≥ 0.14, w ≥ 0.16, w ≥ 0.18, w ≥ 0.20, w ≥ 0.25, w ≥ 0.30, w ≥ 0.35, or w ≥ 0.40. In one embodiment, the solid zinc oxide contains both cationic and anionic substituents.

[0044] In one embodiment, the aqueous electrolyte is an aqueous alkali metal hydroxide electrolyte and comprises an alkali metal hydroxide such as potassium hydroxide (KOH), sodium hydroxide (NaOH), etc., or a mixture thereof. Potassium hydroxide is preferred. Based on the total weight of the alkaline electrolyte, the alkaline electrolyte of the gel electrolyte for forming the negative electrode comprises an amount of alkali metal hydroxide of about 26 wt% to about 36 wt%, such as about 26 wt% to about 32 wt%, particularly about 26 wt% to about 30 wt%. An interaction occurs between the alkali metal hydroxide in the negative electrode and the added solid zinc oxide, and it has been found that less alkali metal hydroxide improves DSC service. An electrolyte with a lower alkalinity is preferred, but it may cause rapid separation of the electrolyte at the anode. An increase in the concentration of the alkali metal hydroxide creates a more stable anode but reduces DSC service. The concentration of metal ions in the electrolyte can be 0.1 - 20,000 ppm. In multiple alternative embodiments, the electrolyte can be neutral or salt-based, such as in a zinc-carbon primary battery.

[0045] Based on the total weight of the aqueous alkaline electrolyte solution, the aqueous alkaline electrolyte solution further comprises an amount of dissolved zinc oxide of about 1.5 wt% to 4 wt%.

[0046] As is well known in the art, a gelling agent is preferably used in the negative electrode, such as cross-linked polyacrylic acid, such as 940, which is available from Noveon, Inc., Cleveland, Ohio, USA. Carboxymethyl cellulose, polyacrylamide, and sodium polyacrylate are examples of other gelling agents suitable for alkaline electrolyte solutions. The gelling agent is desirable to maintain a substantially uniform dispersion of zinc and solid zinc oxide particles in the negative electrode. The amount of the gelling agent present is selected such that a lower electrolyte separation rate is obtained and the viscosity of the anode at the yield stress is not too high, otherwise it will cause problems with anode distribution.

[0047] Dissolved zinc oxide is present in the anode (preferably present in the anode by dissolving in the aqueous electrolyte solution) to improve plating on the nail-shaped current collector and reduce negative electrode gas evolution / degassing. The added dissolved zinc oxide is separate and different from the solid zinc oxide present in the anode composition. In one embodiment, based on the total weight of the negative electrode electrolyte solution, the amount of dissolved zinc oxide is preferably 3 - 4 wt%. In one embodiment, dissolved zinc oxide is present in the negative electrode electrolyte solution in an amount greater than 3 wt%. Soluble or dissolved zinc oxide typically has: a BET surface area of about 4 m 2 / g or less, which is measured using a Tristar 3000 BET surface area analyzer with multi-point calibration from Micrometrics after degassing the zinc oxide at 150 °C for 1 hour; and a particle size D50 (average diameter) of about 1 micron, which is measured using a CILAS particle size analyzer as described above.

[0048] Other components that may optionally be present in the negative electrode include, but are not limited to, gas evolution inhibitors, organic or inorganic corrosion inhibitors, electroplating agents, binders, or other surfactants. Examples of gas evolution inhibitors or corrosion inhibitors may include indium salts such as indium hydroxide, perfluoroalkylammonium salts, alkali metal sulfides, etc.

[0049] The negative electrode can be formed in a variety of different ways known in the art. For example, the negative electrode components can be dry blended and added to the monomer cell, the alkaline electrolyte can be added separately, or, as in a preferred embodiment, added using a pre-gelled negative electrode process.

[0050] In one embodiment, zinc and solid zinc oxide powder, as well as other optional powders except the gelling agent, are combined and mixed. Then, a surfactant is introduced into the mixture containing zinc and solid zinc oxide. A pre-gel containing an alkaline electrolyte, soluble zinc oxide, a gelling agent, and optional other liquid components is introduced into the surfactant, zinc, and solid zinc oxide mixture to further mix them to obtain a substantially homogeneous mixture before adding to the monomer cell. Alternatively, in another preferred embodiment, the solid zinc oxide is pre-dispersed in a negative electrode pre-gel containing an alkaline electrolyte, a gelling agent, soluble zinc oxide, and other desired liquids and co-blended for example about 15 minutes. Then the solid zinc oxide and the surfactant are added and the negative electrode is co-blended for an additional period of time, for example about 20 minutes. Based on the total weight of the negative electrode, the amount of the gel electrolyte used in the negative electrode is typically about 25 wt% to about 35 wt%, for example about 32 wt%. Based on the total volume of the negative electrode, the volume percentage of the gel electrolyte can be about 70%.

[0051] In addition to the aqueous alkaline electrolyte absorbed by the gelling agent during the negative electrode manufacturing process, an additional amount of an aqueous solution of alkali metal hydroxide, i.e., "electrolyte shot / concentrate", "free electrolyte", or "alkaline electrolyte solution", is added to the monocell during the manufacturing process. The electrolyte concentrate can be incorporated into the monocell by placing it in a cavity defined by the positive electrode or the negative electrode or a combination thereof. The method for incorporating the electrolyte concentrate into the monocell is not critical as long as it comes into contact with the negative electrode, the positive electrode, and the separator. In one embodiment, the electrolyte concentrate is added both before and after adding the negative electrode mixture. In one embodiment, approximately 0.97 grams of a 29 wt% KOH solution is added as the electrolyte concentrate to an LR6 type monocell, and approximately 0.87 grams is added to the cavity of the separator liner before inserting the negative electrode. After inserting the negative electrode, the remaining portion of the 29 wt% KOH solution is injected into the cavity of the separator liner. In certain embodiments, the electrolyte concentrate contains an alkali metal hydroxide electrolyte (e.g., KOH). The alkali metal hydroxide electrolyte may have dissolved zinc oxide or zinc hydroxide. In certain embodiments, the alkali metal hydroxide electrolyte contains approximately 0.01 - 6.0 wt% dissolved zinc oxide. In some embodiments, the amount of dissolved zinc oxide equivalent contained in the electrolyte concentrate is greater than 0.1 wt%, greater than 0.2 wt%, greater than 0.3 wt%, greater than 0.4 wt%, greater than 0.5 wt%, greater than 0.6 wt%, greater than 0.7 wt%, greater than 0.8 wt%, greater than 0.9 wt%, greater than 1.0 wt%, greater than 1.1 wt%, greater than 1.2 wt%, greater than 1.3 wt%, greater than 1.4 wt%, greater than 1.5 wt%, greater than 1.6 wt%, greater than 1.7 wt%, greater than 1.8 wt%, greater than 1.9 wt%, greater than 2.0 wt%, greater than 2.1 wt%, greater than 2.2 wt%, greater than 2.3 wt%, greater than 2.4 wt%, greater than 2.5 wt%, greater than 2.6 wt%, greater than 2.7 wt%, greater than 2.8 wt%, greater than 2.9 wt%, greater than 3.0 wt%, greater than 3.1 wt%, greater than 3.2 wt%, greater than 3.3 wt%, greater than 3.4 wt%, greater than 3.5 wt%, greater than 3.6 wt%, greater than 3.7 wt%, greater than 3.8 wt%, greater than 3.9 wt%, greater than 4.0 wt%, greater than 4.1 wt%, greater than 4.2 wt%, greater than 4.3 wt%, greater than 4.4 wt%, greater than 4.5 wt%, greater than 4.6 wt%, greater than 4.7 wt%, greater than 4.8 wt%, greater than 4.9 wt%, greater than 5.0 wt%, greater than 5.1 wt%, greater than 5.2 wt%, greater than 5.3 wt%, greater than 5.4 wt%, greater than 5.5 wt%, greater than 5.6 wt%, greater than 5.7 wt%, greater than 5.8 wt%, greater than 5.9 wt%, greater than 6.0 wt%, greater than 6.1 wt%, greater than 6.2 wt%, greater than 6.3 wt%, greater than 6.4 wt%, greater than 6.5 wt%, greater than 6.6 wt%, greater than 6.7 wt%, greater than 6.8 wt%, greater than 6.9 wt%, greater than 7.0 wt%, greater than 7.1 wt%, greater than 7.2 wt%, greater than 7.3 wt%, greater than 7.4 wt%, greater than 7.5 wt%, greater than 7.6 wt%, greater than 7.7 wt%, greater than 7.8 wt%, greater than 7.9 wt%, greater than 8.0 wt%, greater than 8.1 wt%, greater than 8.2 wt%, greater than 8.3 wt%, greater than 8.4 wt%, greater than 8.5 wt%, greater than 8.6 wt%, greater than 8.7 wt%, greater than 8.8 wt%, greater than 8.9 wt%, greater than 9.0 wt%, greater than 9.1 wt%, greater than 9.2 wt%, greater than 9.3 wt%, greater than 9.4 wt%, greater than 9.5 wt%, greater than 9.6 wt%, greater than 9.7 wt%, greater than 9.8 wt%, greater than 9.9 wt%, greater than 10.0 wt%, greater than 10.1 wt%, greater than 10.2 wt%, greater than 10.3 wt%, greater than 10.4 wt%, greater than 10.5 wt%, greater than 10.6 wt%, greater than 10.7 wt%, greater than 10.8 wt%, greater than 10.9 wt%, greater than 11.0 wt%, greater than 11.1 wt%, greater than 11.2 wt%, greater than 11.3 wt%, greater than 11.4 wt%, greater than 11.5 wt%, greater than 11.6 wt%, greater than 11.7 wt%, greater than 11.8 wt%, greater than 11.9 wt%, greater than 12.0 wt%, greater than 12.1 wt%, greater than 12.2 wt%, greater than 12.3 wt%, greater than 12.4 wt%, greater than 12.5 wt%, greater than 12.6 wt%, greater than 12.7 wt%, greater than 12.8 wt%, greater than 12.9 wt%, greater than 13.0 wt%, greater than 13.1 wt%, greater than 13.2 wt%, greater than 13.3 wt%, greater than 13.4 wt%, greater than 13.5 wt%, greater than 13.6 wt%, greater than 13.7 wt%, greater than 13.8 wt%, greater than 13.9 wt%, or greater than 14.0 wt%.

[0052] In one embodiment, the electrolyte concentrate contains a metal additive and is a source of metal ions adsorbed onto a manganese dioxide-containing cathode. In one embodiment, the same metal additive present in the electrolyte concentrate is present in the electrolyte solution bound to the cathode. In one embodiment, the electrolyte concentrate has a different metal additive concentration than the cathode electrolyte solution. In an alternative embodiment, the electrolyte concentrate and the cathode electrolyte solution have the same concentration of metal additive. In one embodiment, the metal additive present in the electrolyte concentrate is not present in the cathode.

[0053] In one embodiment, at room temperature (~25 °C), the metal additive is insoluble or has very low solubility in the electrolyte solution. In one embodiment, the metal additive will have a solubility of less than 1×10 -x , where x is 10 - 75.

[0054] The second electrode 12, also referred to herein as the positive electrode or cathode, preferably comprises manganese dioxide (commonly referred to as EMD) as the electrochemically active material. The amount of EMD present is typically about 80 wt% to about 92 wt%, preferably about 81 wt% to 85 wt%, of the total weight of the positive electrode (i.e., manganese dioxide, conductive material, positive electrode electrolyte, and additives, including one or more organic additives, if present). The positive electrode is formed by combining and mixing the desired components of the electrode, then dispensing a quantity of the mixture into the open end of a container, and then using a ram / stamping machine to mold the mixture into a solid tubular configuration that defines a cavity within the container, into which the separator 14 and the first electrode 18 are subsequently disposed. As Figure 1 shown, the second electrode 12 has a ledge 30 and an inner surface 32. Alternatively, the positive electrode can be formed by pre-forming a plurality of rings from a mixture comprising EMD and optional additives and then inserting the rings into the container to form a tubular second electrode. Figure 1 The monomeric cell shown typically includes 3 or 4 rings.

[0055] The positive electrode may include other components such as a conductive material, e.g., graphite, which provides a conductive matrix substantially throughout the positive electrode when mixed with the EMD. The conductive material can be natural, i.e., mined, or synthetic, i.e., manufactured. In one embodiment, the single cell includes a positive electrode having an active material or oxide-to-carbon ratio (O:C ratio) ranging from about 12 to about 24. In one embodiment, the O:C ratio is in the range of about 12 - 14. An overly high oxide-to-carbon ratio reduces the resistance between the container and the cathode, which affects the overall single cell resistance and can potentially impact high rate testing, such as DSC testing, or higher cut-off voltages. Additionally, the graphite can be expanded or non-expanded. Graphite suppliers for alkaline batteries include Timcal America of Westlake, Ohio; Superior Graphite Company of Chicago, Illinois, USA; and Lonza Ltd. of Basel, Switzerland. Based on the total weight of the positive electrode, the conductive material is typically present in an amount of about 5 wt% to about 10 wt%. Too much graphite reduces the EMD input, thus reducing the single cell capacity; too little graphite increases the contact resistance between the container and the cathode and / or the overall cathode resistance. An example of an additional additive is barium sulfate (BaSO4), which can be obtained from Bario E.Derivati S.p.A. of Massa, Italy. Based on the total weight of the positive electrode, barium sulfate is typically present in an amount of about 1 wt% to about 2 wt%. Other additives can include, for example, barium acetate, titanium dioxide, binders such as coathylene, and calcium stearate.

[0056] In one embodiment, the cathode contains a metal additive in solid form. In one embodiment, the metal additive is present in the cathode as a solid at a concentration of 0.1 - 1000 ppm relative to the total mass of the cathode.

[0057] In some embodiments, the cathode may include a nickelate material as described in U.S. Patent No. 11,560,321, which is incorporated herein by reference in its entirety.

[0058] In one embodiment, a positive electrode composition (EMD), a conductive material, barium sulfate, and optionally one or more additives are mixed together to form a homogeneous mixture. During the mixing process, an alkaline electrolyte solution (such as a KOH solution of about 37% to about 40%, optionally containing one or more organic additives) is uniformly dispersed into the mixture, thereby ensuring a uniform distribution of the solution throughout the positive electrode material. The mixture is then added to a container and molded using a ram. The moisture within the container and the positive electrode are mixed before and after molding, and the components of the mixture are preferably optimized to allow for the molding of a high-quality positive electrode. Optimizing the mixing humidity allows for minimal spatter and flash during positive electrode molding due to wet mixing, and minimal flaking and excessive tool wear due to dry mixing. The optimization helps to achieve the desired high cathode weight. The moisture content in the positive electrode mixture affects the electrolyte balance of the entire single cell and has an impact on high-rate testing.

[0059] One of the parameters used by single cell designers to characterize a single cell design is the ratio of the electrochemical capacity of one electrode to the electrochemical capacity of the opposing electrode, such as the ratio of the anode (A) to the cathode (C), i.e., the A:C ratio. For an LR6 type alkaline primary battery that uses zinc in the negative electrode or anode and MnO2 in the positive electrode or cathode, the A:C ratio can be greater than 1.32:1, such as greater than 1.34:1, particularly 1.36:1 for a stamped positive electrode. The A:C ratio of a ring-molded positive electrode can be lower, such as from about 1.3:1 to about 1.1:1. In some embodiments, the cathode can be ring-molded.

[0060] A separator 14 is provided to separate the first electrode 18 from the second electrode 12. The separator 14 maintains a physical dielectric separation between the electrochemically active material of the positive electrode and the electrochemically active material of the negative electrode and allows ions to be transported between the electrode materials. Additionally, the separator acts as a wicking medium for the electrolyte and acts as a collar to prevent fragmented portions of the negative electrode from contacting the top of the positive electrode. The separator 14 can be a layered ion-permeable nonwoven fibrous fabric. Typical separators generally include two or more layers of paper. Traditional separators are typically formed by preforming the separator material into a cup-shaped basket and subsequently inserting it below the cavity defined by the second electrode 12 and the closed end 24 and any positive electrode material thereon, or by forming a basket during single cell assembly by inserting two rectangular separator sheets into the cavity such that the materials are rotated 90° relative to each other in angle. Traditional preformed separators are typically made from a nonwoven fabric sheet rolled into a cylindrical shape that conforms to the inner wall of the second electrode and has a closed bottom end.

[0061] Example alkaline electrochemical single cell having stacked / layered electrodes

[0062] A cell with a high anode / cathode interface area can have better high-rate performance (e.g., longer runtime of a high-discharge device). However, an electrochemical single cell with a high interface area requires a correspondingly high separator surface area to keep the anode and cathode electrically isolated. Due to the increased volume resulting from the larger surface area of the separator material included, the remaining volume of the active materials of the anode and cathode in an electrochemical single cell with an increased interface area between the electrodes (compared to the Figure 1 conventional wound / bobbin-style / coaxial wound single cells described and illustrated in

[0063] Compared with the conventional "cylindrical" design of an electrochemical single cell, the exemplary stacked electrode single cell configuration described herein includes sheet electrodes (e.g., cylindrical, square, rectangular, and / or other shapes). The sheet electrodes have an outer perimeter shaped to fit within a single cell can (e.g., a circular outer perimeter that fits within a cylindrical single cell). The sheet electrodes have a dual interface between adjacent electrodes; that is, each sheet electrode can be separated from another electrode (using a separator) at the top or bottom of the electrode. As a specific example, the anode electrode can be positioned such that the cathode electrode is disposed on either side of the anode electrode (above and below the anode electrode), and the cathode electrode together with the anode electrode is disposed on either side of the cathode electrode (above and below the cathode electrode). Multiple sheet electrodes can be located within the single cell to fill the single cell can. As an example, two electrodes (e.g., one anode and one cathode), three electrodes (e.g., two cathodes and one anode), four electrodes, five electrodes, six electrodes, seven electrodes, and / or the like can be disposed within the single cell can. The height of the sheet electrodes can be determined by the total number of electrodes to be positioned within the single cell can so as to maximize the amount of active material within the electrodes placed within the single cell. For example, the sheet electrodes of a single cell in which 5 sheet electrodes are positioned are taller than the sheet electrodes of a single cell in which 7 sheet electrodes are positioned (for single cells of the same size and shape). As discussed in more detail herein, each sheet electrode includes an insulating component to insulate the electrode active material from the current collector of the opposite polarity. For example, the cathode electrode sheet includes an insulating component positioned centrally (e.g., a centrally positioned insulating sleeve and / or an insulating guard ring lined with a centrally positioned hole extending through the cathode) to insulate the cathode active material from the centrally positioned anode current collector (e.g., a current collector pin extending along the central axis of the single cell). The anode electrode sheet includes an annular insulating component located on the outer perimeter of the anode electrode sheet (e.g., an annular washer positioned around the outer perimeter of the anode electrode sheet and / or one or more caps / fittings secured to the annular washer) to insulate the anode active material from the single cell can that serves as the cathode current collector. A disk-shaped separator is further provided to separate the anode active material and the cathode active material from each other.

[0064] Although these sheet electrodes require additional non-active materials within the single cell (e.g., additional separator materials, insulating components not present in cylindrical single cells, etc.), the increased surface area between the electrodes compared to cylindrical single cells helps the active material within the electrodes to discharge more completely during high-speed discharge, and thus the theoretical capacity of a single cell having stacked electrode sheets is higher than that of a cylindrical single cell having the same electrode active material composition.

[0065] These configurations can also be distinguished from other example single cell configurations, such as the "jelly roll" type single cell, which may require metal foil current collectors to prevent diffusion. Compared with the "cylindrical" and "jelly roll" type single cells, the configurations described in the present disclosure may also include electrodes with reduced thickness.

[0066] Figures 2A - 4C An electrode configuration for an electrochemical single cell (a sheet electrode within an electrode stack including two or more electrodes) is shown, which Figure 1 compared with the cylindrical single cell shown, has an increased interfacial area (amount of active material per unit volume) between the anode and the cathode. Specifically, Figure 2A is a schematic view of a cross-sectional view of an electrochemical single cell cut along the vertical central plane of the electrochemical single cell. Figure 2B is an x-ray view of an exemplary electrochemical single cell having the configuration described herein. Figures 3A - 4C Schematic and exploded views of the anode component and the cathode component (also referred to herein as electrode "sheets") are shown, which can be positioned in an electrochemical single cell in a stacked electrode configuration. In the stacked electrode configuration shown in the figure, each electrode is embodied as an annular "sheet" within the stack. As previously mentioned, in certain embodiments, other electrode sheet shapes may be provided to accommodate other electrochemical single cell shapes. These sheet electrodes are stacked within the electrochemical single cell can (e.g., alternating between anode electrode sheets and cathode electrode sheets along the height of the electrode stack within the electrochemical single cell). Adjacent electrodes are separated from each other by one or more layers of separator material (e.g., separator paper provided as a separator disk, which can be fixed as part of one or more electrodes). In certain embodiments, the number of anode electrodes is the same as the number of cathode electrodes, but in other embodiments, the number of anode electrodes may be different from the number of cathode electrodes.

[0067] It should be understood that the drawings shown and described in the present disclosure are illustrative, and some components (including but not limited to separators, cans, and current collectors) have been removed for clarity and to highlight the various components of the disclosed embodiments. Additionally, the active material composition / composition of each of the anode, cathode, current collector, separator sheet, can, and other components Figure 1 described can be used in Figures 2A - 4C embodiments. For example, when various electrodes are mentioned in the description of Figures 2A - 4C the description of the first electrode 18 (e.g., anode) and the second electrode 12 (e.g., cathode) from the previous part of the present disclosure - including their composition / composition - can be applied to Figures 2A - 4C the first and second electrodes shown and described.

[0068] Now refer toFigures 2A - 4C , in some embodiments, an electrochemical single cell 200 is provided. Figures 2A - 2B A view of the assembled single cell 200 with a sheet-like electrode stack therein is shown, while Figures 3A - 3B an exploded view shows a single cathode electrode sheet for placement in the stack of the single cell 200 to illustrate the various components of the cathode electrode sheet according to various embodiments. Figures 4A - 4C An exploded view shows an exemplary anode electrode sheet for placement in the electrode stack of the single cell 200 according to certain embodiments.

[0069] In some embodiments, the single cell 200 includes a plurality of first electrodes 207 (anodes) and a plurality of second electrodes 205 (cathodes) stacked and arranged within the single cell 200. In some embodiments, the plurality of first electrodes 207 may be collectively referred to as a group of first electrodes, and the plurality of second electrodes 205 may be collectively referred to as a group of second electrodes. At least Figures 2A - 2B such a stacked arrangement can be seen therein, where the stack alternates between the first electrode 207 and the second electrode 205. Similarly as Figures 2A - 2B shown, the second electrode 205 (cathode) is disposed at the bottom of the stack, while the first electrode 207 (anode) is disposed at the top of the stack. In some embodiments, the first and second electrodes 207, 205 may be disposed within a can 210, and the can 210 serves as a current collector and is in conductive contact with each second electrode 205 (via the exposed sidewall of the second electrode 205). Thus, the second electrode 205 may contact the inner wall of the can, while the first electrode 207 may be insulated from the inner wall of the can 210 (e.g., by an anode gasket 201, as will be described later). In some embodiments, the first and second electrodes 207, 205 may have an annular shape within the cylindrical single cell 200. In some embodiments, a current collector 209 may be disposed within the single cell 200 and is in conductive contact with each first electrode 207. In some embodiments, the current collector 209 may be disposed within a central opening extending through the center of each second electrode 205 (while being electrically insulated from the cathode material by an insulating collar as described herein) and the anode. In some embodiments, the current collector 209 may be configured such that it does not extend into (or completely through) the second electrode 205 at the bottom of the stack.

[0070] In some embodiments, the first electrode 207 may have as previously described with respect to Figure 1The composition of the anode 18 described above. In some embodiments, the first electrode 207 may include a zinc active material disposed in an electrolyte concentrate. In some embodiments, the first electrode 207 may be contained within an anode gasket 201 to electrically insulate the first electrode 207 from the can 210. In some embodiments, the anode gasket 201 may be annular and have an interference fit with the can 210 to achieve a secure fit. In some embodiments, the anode gasket 201 may be made of a thermoplastic material such as polypropylene or nylon. Additionally, the anode gasket 201 may be pressed against a separator (discussed below) to prevent leakage of electrode material around the edge of the separator, which could create a short circuit between adjacent anodes and cathodes.

[0071] Figures 4A - 4C An alternative embodiment of the anode gasket 201 is shown in accordance with certain embodiments. In an embodiment including a cross-sectional view ( Figure 4A ) and an exploded view ( Figure 4B ) of Figures 4A - 4B , the anode gasket 201 includes a sleeve 221 (e.g., a cylindrical sleeve) surrounding the outer periphery of anode material (not shown). Insulating retaining rings 222 are fixed to both ends of the sleeve 221, with an inner portion of the insulating retaining ring extending into the interior of the sleeve. The insulating retaining rings 222 may be made of the same material as the sleeve 221. The insulating retaining rings 222 may be frictionally fit into the interior of the sleeve such that the outer surface of the inner portion of each insulating retaining ring 222 is in frictional contact with the inner surface of the sleeve 221. As shown, the insulating retaining rings 222 also include an outer portion having a diameter that at least substantially matches the outer diameter of the sleeve 221. The insulating retaining rings 222 are further characterized by at least substantially flat end faces against which a separator disc 223 (comprising separator material as described herein) is fixed (e.g., adhered using an adhesive). The resulting anode electrode sheet 207 is sealed within the sleeve 221, the insulating retaining rings 222, and the separator disc 223. As described herein, during the assembly of the electrochemical cell 200, the separator disc 223 may be pierced by a nail collector 209 to electrically connect the anode material within the anode electrode sheet 207 to the negative terminal of the electrochemical cell 200.

[0072] Figure 4C A cross-sectional view of another alternative embodiment of the anode gasket 201 is shown in accordance with certain embodiments. As Figure 4CAs shown, the anode gasket 201 includes an anode cup 225 (e.g., a cylindrical anode cup), an anode cap 226 (e.g., a cylindrical anode cap) fixed (e.g., frictionally fixed, adhered, and / or in a similar manner) to the anode cup 225 to form the anode gasket 201, and spacer disks 223 fixed to opposite open ends of the anode gasket 201. In the illustrated embodiment, the anode cup 225 defines a cylindrical outer surface having a hollow interior. The hollow interior is defined by a stepped inner surface having a wider portion and a narrower portion. The narrower portion has an inner surface parallel to the inner surface of the wider portion. The narrower portion defines the first open end of the anode gasket 201 against which the spacer disk 223 is fixed (e.g., adhered).

[0073] The anode cap 226 may be formed of the same material as the anode cup 225 (e.g., an insulating material). Although not drawn to scale in Figure 4C the illustrated embodiment, the anode cap 226 defines at least a substantially uniform cylindrical inner surface. The diameter of the inner surface is at least substantially equal to the diameter of the inner surface of the narrower portion of the anode cup 225. The outer surface of the anode cap 226 defines a stepped profile that is securely mounted within the wider portion of the anode cup 225. The anode cap 226 has a length that fits within the anode cup 225 such that at least the substantially uniform cylindrical inner surface of the anode cap is positioned adjacent to the narrower portion of the anode cup 225 to jointly define at least a substantially continuous inner surface of the anode gasket 201 around the anode material. As shown, the spacer disk 223 is fixed (e.g., adhered) to the open end of the anode cap 226 to seal the anode material within the anode gasket 201.

[0074] In some embodiments, the second electrode 205 may have the composition of the cathode 12 as previously referenced Figure 1 as described. In some embodiments, as shown in the exploded view in Figures 3A - 3B the second electrode 205 may be an assembly that includes electrode sheets 208 along with one or more ion-permeable separator sheets 203, 204 (including a first ion-permeable separator sheet and a second ion-permeable separator sheet having a composition different from that of the first separator) disposed on both sides (top and bottom) of the electrode sheet 208, and a centrally located insulating collar (specifically, a two-piece insulating collar including a convex insulating collar and a concave insulating collar 202, 206) that separates the second electrode 205 from the current collector 209. As shown, the second electrode 205 has an exposed sidewall (extending between the separator sheets at the top and bottom of the second electrode 205) such that when the sheet-like second electrode 205 is placed within the single cell can, the active material within the cathode is in electrical contact with the single cell can that serves as the cathode current collector.

[0075] In some embodiments, the electrode sheet 208 can be a cathode electrode sheet 208. In some embodiments, the one or more separator sheets 203, 204 can be part of a set of separators including multiple separator sheets 203, 204. In certain embodiments, separator sheet 203 is the first separator sheet and separator sheet 204 is the second separator sheet. The first separator sheet 203 and the second separator sheet 204 can comprise the same separator material (having the same separator composition) or can comprise different separator materials (having different separator compositions). Like the anode gasket 201, opposite sides of the insulating sheath can be pressed against the separator to further seal against short circuits around the separator layer between adjacent electrodes. In some embodiments, the insulating collar 202, 206 can be the separator material and the second electrode 205 can be sealed within the separator sheets 203, 204, which would render the insulating collar 202, 206 unnecessary.

[0076] In some embodiments, the insulating collar 202, 206 can be electrically insulating between the first electrode 207 and the second electrode 205. In some embodiments, the insulating collar 202, 206 can assist in guiding the insertion of the current collector 209; that is, the current collector 209 can be disposed through the inner bore of the insulating collar 202, 206. In some embodiments, the insulating collar 202, 206 can frictionally engage the outer surface of the current collector 209; in a number of other embodiments, the current collector 209 can be disposed through the inner bore of the insulating collar 202, 206 such that a space / gap is left between the inner surface of the insulating collar 202, 206 and the outer surface of the current collector 209.

[0077] As Figure 3B shown, the cylindrical sleeve 232 can be positioned within the central perforation of the electrode sheet 208 and the insulating collar 231 can be secured inside the central sleeve 232 (e.g., by an adhesive or friction fit). The insulating collar 232 can have a diameter-expanded end portion that extends radially outward beyond the cylindrical outer surface of the sleeve 232. These diameter-expanded end portions can be configured to cover at least a portion of the separator sheet 203 (disc-shaped separator sheet 203) positioned at opposite ends of the electrode sheet 208 to secure the separator sheet 203 to the electrode sheet 208. As shown, the electrode sheet 208 has an exposed cylindrical outer surface that, when the electrode sheet 208 is placed in an electrochemical single cell, is in electrical contact with the inner surface of the electrochemical single cell can.

[0078] In some embodiments, the separator sheets 203, 204 may be provided only on one side of the electrode sheet 205. For example, with respect to the second electrode 205 on the bottom of the electrode stack within the single cell 200, the electrode sheet 208 for this bottom second electrode 205 may have separator sheets 203, 204 provided only on the "top" side of the cathode electrode sheet 208 (the side that interfaces with the first electrode 207). In such a configuration, the bottom side of the second electrode 205 may be in electrical contact with the single cell can 210 that serves as a current collector.

[0079] In some embodiments, the convex and concave insulating retaining rings 202, 206 may be interlocked, and the interlock length may vary to allow for a range of thicknesses of the electrodes 205, 207. In some embodiments, as previously described in the present disclosure, the electrode sheet 208 may comprise a cathode material.

[0080] In some embodiments, the separator sheets 203, 204 may be paper discs that serve as electrical insulators and are ion-conductive. The separator sheets 203, 204 may be annular with a central hole. In some embodiments, the separator sheet 203 adjacent to the first electrode 207 may be a different material from the other separator sheet 204. In some embodiments, the separator sheets 203, 204 may be composed of a variety of different materials, including non-woven paper having a composition of cellulose and PVA fibers, double-layer paper having a higher density side, and / or cellophane.

[0081] In some embodiments, one or more of the separator sheets 203, 204 may be disposed within the anode gasket 201 and prevent the anodic active material from leaking between the various components of the single cell 200 and causing a short circuit (e.g., when contacting the cathodic active material or the cathode current collector).

[0082] In some embodiments, a sealant (e.g., an adhesive) may be used to improve the anodic seal / blocking between the separator sheets 203, 204 and the anode gasket 201.

[0083] In some embodiments, the single cell 200 may include a current collector gasket 212, which may be a gasket as described at least with reference to Figure 1 and the related description. In some embodiments, the gasket 212 may be a plastic gasket having a safety venting feature configuration. In some embodiments, the current collector gasket 212 and the anode gasket 201 fit closely together to enclose the first electrode 207 at the top of the electrode stack. In some embodiments, the single cell 200 may further include an electrolyte concentrate, which is dispensed into the single cell 200 and into the centers of the annular electrode sheets 207, 205 to saturate each separator sheet 203, 204 and fill the excess irregular space below the current collector gasket 212.

[0084] Figure 5 This is a table showing different exemplary configurations of components of a stacked electrode embodiment of an LR6 electrochemical single cell. These are merely examples, and in some embodiments, electrode sheets of other sizes, other numbers of electrode sheets, etc. may be used. In some embodiments, as Figure 2A shown, the stack may have a second electrode 205 at the bottom of the stack and a first electrode 207 at the top of the stack. In some embodiments, there may be four second electrodes and four first electrodes disposed in the single cell 200, with a total of eight electrodes and seven separator interfaces between adjacent first electrodes 207 and second electrodes 205. The number of electrodes in the stack within the single cell 200 can be increased to improve the rate performance of the single cell 200, but this may have a trade-off that affects the performance of other areas. For example, increasing the number of electrodes within the single cell requires reducing the height of each electrode sheet. As described herein, a change in the electrode height may result in a corresponding change in the height of the insulating guard ring and the gasket. Although an increase in the number of electrode sheets of the electrodes correspondingly increases the interfacial area between the anode and the cathode within the single cell, an increase in the number of electrode sheets of the electrodes requires an increase in the amount of separator material within the single cell, thereby reducing the volume of the single cell available for the active material. This may result in an increase in high-rate performance but a decrease in low-rate performance (due to a reduction in the active material in the single cell).

[0085] Still referring to Figure 5 , the second column shows a control single cell (e.g., a single cell having a cylindrical configuration as Figure 1 shown). The remaining columns provide details of exemplary single cells with separator increments of three, five, seven, and nine separated first and second electrode sheets 207, 205, where the first electrode 207 includes an anode active material and the second electrode 205 includes a cathode active material. The left column shows various characteristics of the electrochemical single cell and its components (e.g., total electrode height, total wet paper thickness, interfacial surface area, etc.), and their associated rows show how these properties vary according to the configuration / arrangement of the electrodes and separators within the single cell. The bottom row shows the percentage of anode utilization during discharge for each configuration / arrangement. It should be noted that the value of anode utilization is estimated based on a function of the number of electrodes in the stack. However, at least as Figure 5 shown, increasing the number of separator increments (thereby increasing the interfacial surface area) is calculated to increase the anode utilization to 100% for nine separator increments. Compared to the reference single cell, increasing the number of separator increments is also calculated to reduce the cathode capacity.

[0086] Figure 5The table shown also describes other predicted characteristics of various electrochemical single cells having a stacked electrode sheet configuration. For example, increasing the number of separator sheets results in a corresponding decrease in the height of electrodes 205, 207 such that electrodes 205, 207 can be assembled within single cell 200. In some embodiments, the electrodes may have the same height, while in many other embodiments, the electrodes within a single single cell 200 may have different heights. In some embodiments, the electrodes may all have a central hole (e.g., to accommodate a current collector). This configuration simplifies manufacturing. In many other embodiments, the bottommost electrode (e.g., the cathode electrode sheet) may not have a central hole. As another example, the total wet volume of the separators may increase with an increase in the total number of separator increments.

[0087] Figure 6 Another table summarizing certain characteristics of electrochemical single cells is shown, the electrochemical single cells including electrode sheets of the electrodes described herein. Six example single cell designs (Examples 1-6) are summarized and compared to a conventional cylindrical single cell design summarized as a control example. In Figure 6 , Example 1 describes a single cell design using 7 cathode electrode sheets; Example 2 describes a single cell design using 5 cathode electrode sheets; Example 3 describes a single cell design using 7 cathode electrode sheets; Example 4 describes a single cell design using 7 cathode electrode sheets; Example 5 describes a single cell design using 14 cathode electrode sheets; and Example 6 describes a single cell design using 14 cathode electrode sheets. Each of single cell Examples 1-4 utilized an anode electrode sheet having the "cup & lid" design as shown and described in Figure 4C . Each of single cell Examples 5-6 utilized an anode electrode sheet having the "sleeve" design as shown and described in Figures 4A - 4B . Single cell Example 5 includes zinc foil attached to a zinc current collector stud, as detailed in U.S. Application No. 15 / 057,639, filed November 21, 2022, the contents of which are incorporated herein by reference in their entirety. Figure 6Shows the volume of the internal components of an electrochemical single cell, the maximum diffusion length of the active materials in the anode and cathode, and the interfacial area between the anode and cathode within each electrochemical single cell. As shown, each of the single cell embodiments 1-6 has a smaller anode diffusion length compared to the anode diffusion length of a conventional cylindrical single cell (the values shown in the table are provided as a percentage comparison to the conventional cylindrical single cell design). Each of the single cell embodiments 1 and 3-6 has a smaller cathode diffusion length compared to the conventional cylindrical single cell design. Additionally, each of the single cell embodiments 1 and 3-6 has a higher interfacial surface area compared to the conventional cylindrical single cell design. Compared to the conventional cylindrical single cell design, the single cell embodiment 2 has a higher cathode capacity and anode capacity.

[0088] Example method of manufacturing an alkaline electrochemical single cell having a stacked electrode

[0089] Figure 7 Is a flow chart illustrating an example method of manufacturing an alkaline electrochemical single cell having a stacked electrode. These example methods are provided to manufacture an electrochemical single cell 200 having a stacked electrode as described herein.

[0090] As Figure 7 shown, the manufacturing method 300 may include a step 302 of inserting a first cathode (including separator material, cathode electrode sheet, and convex and concave insulating retaining rings) into the electrochemical single cell. In some embodiments, the first cathode may be assembled before being inserted into the electrochemical single cell. The cathode electrode sheet may comprise cathode material pressed into the final shape of the cathode electrode sheet. The separator material may be paper disks placed on opposite sides of the cathode electrode sheet. In some embodiments, the cathode electrode sheet and separator may be annular and have a central hole. The convex and concave insulating retaining rings may be inserted into the central holes of the annular cathode electrode sheet and separator material. The convex and concave insulating retaining rings together with the separator may seal the first cathode to prevent the anode material from infiltrating and contacting the cathode. When the first cathode is inserted into the electrochemical single cell in step 302, the active material of the cathode electrode sheet may contact the can, such that the can functions as a cathode current collector. Additional steps before inserting the cathode into the electrochemical single cell may include applying a sealant to the separator material and / or insulating retaining rings of the cathode to further seal the cathode.

[0091] Method 300 may also include a step 304 of inserting an annular washer into the electrochemical single cell, where the washer is configured to receive the anode material within its open interior. In some embodiments, when the washer is inserted into the electrochemical single cell, the bottom edge of the washer may bear against the top surface of the first cathode. Thus, the washer may sandwich the separator material between the washer and the cathode electrode sheet, which may prevent the anode material from leaking into the cathode (and vice versa). The washer may frictionally engage the inner wall of the can and engage with the cathode such that the cathode bears against the bottom of the can. In some embodiments, the top edge of the washer may support a second cathode, which, as described below, may be inserted into the single cell. When the second cathode is inserted into the single cell, the separator material of the second cathode may be sandwiched between the cathode electrode sheet and the washer, which again prevents any anode material from leaking into the cathode (and vice versa).

[0092] Method 300 may include a step 306 of providing a second cathode (with separator material) to the electrochemical single cell. Like the first cathode, the second cathode may be pre-assembled before being inserted into the electrochemical single cell, similar to the assembly of the first cathode. Method 300 may include a step 308 of inserting a second washer into the electrochemical single cell, the second washer being configured to receive the anode material. The insertion of the second washer in step 308 may be substantially the same as the insertion of the first washer in step 304. Steps 302, 304, 306, and 308 may be repeated as needed to insert additional cathodes and washers.

[0093] Method 300 includes a step 310 of providing (e.g., extruding) the anode through the central hole of the insulating collar and into the electrochemical single cell. As discussed herein, since the central hole of the insulating collar is electrically insulated from the cathode material, the anode material can be extruded through the central hole of the cathode without the risk of creating a short circuit. Method 300 may then include a step 312 of inserting an anode current collector (e.g., a nail) through the aligned central holes of the insulating collar into the electrochemical single cell. Inserting the anode current collector through the central hole of the cathode enables the anode current collector to make electrical contact with the anode material in each anode material layer within the stacked electrode single cell. In some embodiments, method 300 may allow an electrolyte concentrate to be inserted into the single cell 200 while still allowing the trapped air to escape from the single cell 200.

[0094] Figure 8 is a flowchart showing a second example method of manufacturing an electrochemical single cell with a stacked electrode.

[0095] As Figure 8As shown, the cathode electrode sheet and the anode electrode sheet are constructed before being inserted into the electrochemical single cell. Specifically, step 601 represents constructing a plurality of cathode electrode sheets, and step 602 represents constructing a plurality of anode electrode sheets. The cathode electrode sheet is constructed by forming a cathode disk having a central through-hole. The cathode disk can be formed by pressing the cathode material into the desired shape of the cathode disk. The separator is placed at opposite planar ends of the cathode disk while keeping the cylindrical sidewall of the cathode disk exposed. As Figures 3A - 3B shown, then an insulating collar (and / or sleeve) of insulating material is inserted into the central through-hole to insulate the cathode material from the anode current collector pin that is later inserted through the central through-hole and to secure the separator material to the planar surface of the cathode electrode sheet. As described above, the insulating collars (and / or sleeves) are fixed to each other to secure the separator material to the surface of the cathode material.

[0096] Referring to step 602, the anode electrode sheet is constructed by placing the anode material inside a sealed anode electrode sheet, as Figures 4A - 4C shown. In embodiments where the anode material is a flowable material (e.g., a gel), the anode material can be extruded or otherwise provided into an anode sleeve 221 having a sealed end (e.g., the separator material is sealed to one end of the sleeve 221). Once the anode material has been provided into the sleeve 221, the open end of the sleeve can be sealed by fixing a separator to the open end of the sleeve to produce a fully sealed anode electrode sheet.

[0097] Referring again to Figure 8 , the electrochemical single cell is constructed by stacking the cathode and anode electrode sheets inside the electrochemical single cell. As shown in step 603, the cathode electrode sheet is first inserted into the electrochemical single cell, and subsequently, as shown in step 604, the anode electrode sheet is inserted. Steps 603 - 604 are repeated until the desired number of cathode electrode sheets and anode electrode sheets are inserted into the electrochemical single cell. It should be understood that although Figure 8 shows that the cathode electrode sheet is first inserted into the electrochemical single cell, it should be understood that in many other embodiments, the anode electrode sheet can be inserted first.

[0098] As shown in step 605, once the desired number of assembled cathode electrode sheets and anode electrode sheets are inserted into the electrochemical single cell, the anode current collector pin is inserted through the center of the electrodes. The current collector pin extends through the central through-hole in the cathode electrode sheet within the insulating retaining ring and / or sleeve of the cathode electrode sheet to electrically insulate the current collector pin from the cathode active material. The current collector pin pierces the sealed anode electrode sheet by extending through the separator sheets on each side of the anode electrode sheet. The current collector pin extends from the top of the electrochemical single cell and extends at least into the anode electrode sheet first inserted into the single cell (the lowest anode electrode sheet in the electrochemical single cell). For those electrochemical single cells having cathode electrode sheets on the inner surface of the bottom of the electrochemical single cell, the cathode electrode sheets do not need to extend into the insulating central opening of the bottommost cathode electrode sheet. In such an embodiment, the distal end of the anode current collector pin is located in the lowermost anode electrode sheet in the electrochemical single cell.

[0099] Then, the open top end of the electrochemical single cell is sealed with a sealing assembly that includes a gasket and a negative terminal electrically connected to the anode current collector.

[0100] Although numerous embodiments have been shown and described in detail above, such showings and descriptions are to be considered illustrative or exemplary and not restrictive. It should be understood that changes and modifications can be made by those of ordinary skill in the art within the scope and spirit of the appended claims. Multiple embodiments include any combination of features from different embodiments described above and below.

[0101] Multiple embodiments are further described by the following illustrative and non-limiting examples, which provide a better understanding of the embodiments and their many advantages. The following examples are included to illustrate the preferred embodiments. Those skilled in the art should understand that the techniques disclosed in the following examples represent techniques used in the embodiments to function well in the practice of the embodiments and thus can be considered to constitute a preferred mode of their practice. However, according to the present disclosure, those skilled in the art should understand that many changes can be made to the specific embodiments disclosed without departing from the spirit and scope of the embodiments and still obtain the same or similar results.

[0102] Benefiting from the foregoing description and the teachings given in the associated drawings, those skilled in the art to which the present disclosure pertains will think of many modifications and other aspects of the present disclosure set forth herein. Accordingly, it should be understood that the present disclosure is not limited to the specific aspects disclosed, and the modifications and other aspects are intended to be included within the scope of the appended claims. Although specific terms are used herein, they are used only in a general and descriptive sense and not for purposes of limitation.

Claims

1. An electrochemical single cell, comprising: A container having a closed bottom end and an open top end; A sealing assembly fixed to the open top end of the container and closing the open top end; A stack including two or more sheet electrodes disposed within the container, wherein the two or more sheet electrodes include a set of one or more first electrodes and a set of one or more second electrodes, and Wherein the one or more first electrodes and the one or more second electrodes are alternately arranged within the stack; A set of separators, including one or more separators disposed within the stack between each electrode; An electrolyte solution disposed within the container; And A current collector disposed within the container.

2. The electrochemical single cell according to claim 1, wherein, The one or more separators include at least one first separator and at least one second separator, wherein the at least one first separator has a different composition from the at least one second separator.

3. The electrochemical single cell according to claim 1, wherein, The one or more first electrodes are anodes containing a zinc material.

4. The electrochemical single cell according to claim 3, wherein, The one or more second electrodes are cathodes containing a manganese dioxide material.

5. The electrochemical single cell according to claim 4, including a second electrode positioned at the bottom end of the stack adjacent to the closed bottom end of the container.

6. The electrochemical single cell according to claim 5, including a second electrode positioned at the top end of the stack adjacent to the open top end of the container.

7. The electrochemical single cell according to claim 1, wherein, Each of the one or more second electrodes defines a central opening extending therethrough, and each of the one or more second electrodes further includes an insulating sleeve lining the central opening; and Wherein the current collector is a current collector pin extending through the center of the insulating sleeve.

8. The electrochemical single cell according to claim 7, wherein, Each of the one or more first electrodes has at least one of the one or more separators fixed thereto, and the current collector pin extends through the center of the at least one separator fixed to each of the one or more first electrodes to electrically connect to the active material of the one or more first electrodes.

9. The electrochemical single cell according to claim 8, wherein, Each of the one or more first electrodes includes a washer that electrically insulates the active material of the one or more first electrodes from the container, and the at least one of the one or more separators is fixed to the washer.

10. The electrochemical single cell according to claim 7, wherein, Each of the one or more second electrodes includes at least one separator; and Wherein the insulating sleeve of each of the one or more second electrodes includes one or more insulating retaining rings that fix the at least one separator of each second electrode.

11. An anode, comprising: An anode active material composition; An insulating washer having two open ends, wherein the insulating washer surrounds the anode active material; And An ion-permeable separator disk fixed to each open end of the insulating washer to seal the anode active material within the insulating washer.

12. The anode according to claim 11, wherein, The anode active material comprises: Granular zinc suspended in an electrolyte gel; Granular zinc oxide; and Dissolved zinc oxide.

13. The anode according to claim 11, wherein, The insulating washer comprises a polymeric material.

14. The anode according to claim 11, wherein, The insulating washer includes: A cylindrical sleeve having a first open end and an opposite second open end; A first insulating collar fixed to the first open end, wherein the first spacer is fixed to the first insulating collar; and A second insulating collar fixed to the second open end, wherein the second spacer is fixed to the second insulating collar.

15. The anode according to claim 14, wherein, The first spacer is adhered to the first insulating collar, and the second spacer is adhered to the second insulating collar.

16. A cathode comprising: A cathode active material composition formed in an annular shape that defines a central opening extending therethrough; A first ion-permeable separator on a first side of the cathode active material composition; A second ion-permeable separator on a second side of the cathode active material composition; An insulating sleeve positioned within the central opening, wherein: A first end of the insulating sleeve extends beyond the first ion-permeable separator and secures the first ion-permeable separator to the first side of the cathode active material composition; A second end of the insulating sleeve extends beyond the second ion-permeable separator and secures the second ion-permeable separator to the second side of the cathode active material composition.

17. The cathode according to claim 16, wherein, The first ion-permeable separator and the second ion-permeable separator are planar, and sidewalls of the cathode active material composition extending between the first side and the second side are exposed.

18. The cathode according to claim 16, wherein, The insulating sleeve includes a first insulating collar located within the center of a cylindrical opening of the cathode active material composition and a second insulating collar fixed to the first insulating collar.

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