Abstract: The present invention relates to electrochemical cells and to closure assemblies for aqueous alkaline electrolyte cells of the conventional cylindrical type. The closure assembly is for the negative terminal and comprises an internal cap disc in unsecured electrical contact with an internal cap ring. When pressure within the cell increases, for example due to gas generation by electrolysis of the electrolyte through abuse or overcharging, the cap disc moves away from the cap ring, breaking the electrical contact and disrupting the electrochemical circuit within the cell. This prevents further gas generation and pressure build-up, thereby preventing a failure of the internal blow out safety vent and escape of the corrosive electrolyte. In time, the pressure dissipates and the cap disc again makes contact with the cap ring, permitting the cell to be used again.

Abstract: In an improved rechargeable alkaline manganese cell that has a manganese dioxide cathode comprising pellets formed by pressing a cathode powder blend comprising a hygroscopic additive for increasing cumulative capacity, the sticky consistency of the pellets, which is un-desirable for continuous automated production is compensated for by the addition of up to 0.5% of a hydrophobic binder. This small amount leaves the cell performance substantially unimpaired, but provides the desired consistency for large-scale production. Further disclosed is an improved charge methodology for a rechargeable alkaline manganese cell wherein the charge current is pulsed at a voltage in excess of 1.65 V and the no-load cell voltage response is monitored at predetermined intervals. No charge current pulse is permitted to pass through the cell if the no-load voltage exceeds a threshold value. This results in increased utilization of the capacity of the cell while reducing the likelihood of damage to the cell due to overcharging.

Abstract: In an improved rechargeable alkaline manganese cell that has a manganese dioxide cathode comprising pellets formed by pressing a cathode powder blend comprising a hygroscopic additive for increasing cumulative capacity, the sticky consistency of the pellets, which is un-desirable for continuous automated production is compensated for by the addition of up to 0.5% of a hydrophobic binder. This small amount leaves the cell performance substantially unimpaired, but provides the desired consistency for large-scale production. Further disclosed is an improved charge methodology for a rechargeable alkaline manganese cell wherein the charge current is pulsed at a voltage in excess of 1.65 V and the no-load cell voltage response is monitored at predetermined intervals. No charge current pulse is permitted to pass through the cell if the no-load voltage exceeds a threshold value. This results in increased utilization of the capacity of the cell while reducing the likelihood of damage to the cell due to overcharging.

Abstract: In an improved rechargeable alkaline manganese cell that has a manganese dioxide cathode comprising pellets formed by pressing a cathode powder blend comprising a hygroscopic additive for increasing cumulative capacity, the sticky consistency of the pellets, which is un-desirable for continuous automated production is compensated for by the addition of up to 0.5% of a hydrophobic binder. This small amount leaves the cell performance substantially unimpaired, but provides the desired consistency for large-scale production. Further disclosed is an improved charge methodology for a rechargeable alkaline manganese cell wherein the charge current is pulsed at a voltage in excess of 1.65 V and the no-load cell voltage response is monitored at predetermined intervals. No charge current pulse is permitted to pass through the cell if the no-load voltage exceeds a threshold value. This results in increased utilization of the capacity of the cell while reducing the likelihood of damage to the cell due to overcharging.

Abstract: In an improved rechargeable alkaline manganese cell that has a manganese dioxide cathode comprising pellets formed by pressing a cathode powder blend comprising a hygroscopic additive for increasing cumulative capacity, the sticky consistency of the pellets, which is un-desirable for continuous automated production is compensated for by the addition of up to 0.5% of a hydrophobic binder. This small amount leaves the cell performance substantially unimpaired, but provides the desired consistency for large-scale production. Further disclosed is an improved charge methodology for a rechargeable alkaline manganese cell wherein the charge current is pulsed at a voltage in excess of 1.65 V and the no-load cell voltage response is monitored at predetermined intervals. No charge current pulse is permitted to pass through the cell if the no-load voltage exceeds a threshold value. This results in increased utilization of the capacity of the cell while reducing the likelihood of damage to the cell due to overcharging.

Abstract: Rechargeable galvanic cells are disclosed which comprise a manganese dioxide cathode, a zinc anode and a potassium hydroxide electrolyte wherein the cathode includes additive compounds to increase the cycle life and cumulative discharge capacity of the cell. The additives comprise at least a strontium compound and optionally a barium and/or calcium compound. Cells including the additive(s) desirably have an individual discharge capacity after 50 deep discharge-charge cycles of at least 0.100 Ah/gMnO2.

Abstract: In an improved rechargeable alkaline manganese cell that has a manganese dioxide cathode comprising pellets formed by pressing a cathode powder blend comprising a hygroscopic additive for increasing cumulative capacity, the sticky consistency of the pellets, which is un-desirable for continuous automated production is compensated for by the addition of up to 0.5% of a hydrophobic binder. This small amount leaves the cell performance substantially unimpaired, but provides the desired consistency for large-scale production. Further disclosed is an improved charge methodology for a rechargeable alkaline manganese cell wherein the charge current is pulsed at a voltage in excess of 1.65 V and the no-load cell voltage response is monitored at predetermined intervals. No charge current pulse is permitted to pass through the cell if the no-load voltage exceeds a threshold value. This results in increased utilization of the capacity of the cell while reducing the likelihood of damage to the cell due to overcharging.

Abstract: Rechargeable galvanic cells are disclosed which comprise a manganese dioxide cathode, a zinc anode and a potassium hydroxide electrolyte wherein the cathode includes additive compounds to increase the cycle life and cumulative discharge capacity of the cell. The additives comprise at least a strontium compound and optionally a barium and/or calcium compound. Cells including the additive(s) desirably have an individual discharge capacity after 50 deep discharge-charge cycles of at least 0.100 Ah/gMnO2.

Abstract: A method of manufacturing an anode composition for use in an electrochemical cell in which the anode comprises an electrochemically active material, the method comprising the steps of mixing the electrochemically active material with an alkaline electrolyte solution, an organic surfactant, an indium compound, and a gelling agent, such that the indium compound or a portion thereof is added in an alkaline environment. In one embodiment, the surfactant is added after the electrolyte.

Abstract: A method of manufacturing an anode composition for use in an electrochemical cell in which the anode comprises an electrochemically active material, the method comprising the steps of mixing the electrochemically active material with an alkaline electrolyte solution, an organic surfactant, an indium compound, and a gelling agent, such that the indium compound or a portion thereof is added in an alkaline environment. In one embodiment, the surfactant is added after the electrolyte.

Abstract: A rechargeable alkaline manganese (RAM) battery or battery pack comprising an overcharging protection circuit that allows the RAM battery or battery pack to be charged using a charging circuit designed for use with a different type of rechargeable battery, for example a NiCd or NiMH rechargeable battery. The battery of the present invention is particularly advantageous as a replacement battery for use in devices having an embedded charging circuit designed for use with NiCd or NiMH batteries. The overcharging protection circuit may be provided in a battery pack that allows the individual RAM cells to be removed and replaced. Alternatively, the overcharging protection circuit may be installed in the device itself. When the battery pack is provided as original equipment in an electronic device, an activation key may be provided that prevents discharge of the batteries before the device is used.

Abstract: The invention described herein is directed to a method of manufacturing an anode composition for use in an electrochemical cell, in which the anode comprises an electrochemically active material, the method comprising the steps of mixing the electrochemically active material with an alkaline electrolyte solution, an organic surfactant, an indium compound, and a gelling agent, such that the indium compound or a portion thereof is added in an alkaline environment.

Abstract: In an improved rechargeable alkaline manganese cell that has a manganese dioxide cathode comprising pellets formed by pressing a cathode powder blend comprising a hygroscopic additive for increasing cumulative capacity, the sticky consistency of the pellets, which is un-desirable for continuous automated production is compensated for by the addition of up to 0.5% of a hydrophobic binder. This small amount leaves the cell performance substantially unimpaired, but provides the desired consistency for large-scale production. Further disclosed is an improved charge methodology for a rechargeable alkaline manganese cell wherein the charge current is pulsed at a voltage in excess of 1.65 V and the no-load cell voltage response is monitored at predetermined intervals. No charge current pulse is permitted to pass through the cell if the no-load voltage exceeds a threshold value. This results in increased utilization of the capacity of the cell while reducing the likelihood of damage to the cell due to overcharging.

Abstract: The invention described herein is directed to a method of manufacturing an anode composition for use in an electrochemical cell, in which the anode comprises an electrochemically active material, the method comprising the steps of mixing the electrochemically active material with an alkaline electrolyte solution, an organic surfactant, an indium compound, and a gelling agent, such that the indium compound or a portion thereof is added in an alkaline environment.

Abstract: Rechargeable galvanic cells are disclosed which comprise a manganese dioxide cathode, a zinc anode and a potassium hydroxide electrolyte wherein the cathode includes additive compounds to increase the cumulative discharge capacity of the cell thereby increasing its cycle life. The additives consist of a) barium or strontium compounds, and mixtures thereof, and b) titanium, lanthanum, yttrium, cerium, zinc, calcium, tin or magnesium compounds, and mixtures thereof.

Abstract: A cylindrical electrochemical cell includes a cathode, an anode, a cylindrical separator, coaxial with the cell, for electrically separating the cathode and anode, and a cup seal at an end of the separator for electrically separating the anode and cathode and maintaining an ionic connection therebetween. The cup seal is comprised of one or more first layers of a micro-porous or a non-porous membrane, or a combination thereof, and one or more second layers of a porous membrane and wherein the seal overlaps at least a portion of the separator.

Abstract: The zinc active powder for a mercury-free rechargeable electrochemical cell is coated with a surfactant, and separately with an aqueous solution of indium sulphate. Without any subsequent filtering, washing or drying, the powder is assembled into an electrochemical cell. The cell can include a hydrogen recombination catalyst in contact with the electrochemically active material of the cathode.

Abstract: A rechargeable manganese dioxide/zinc cell is provided, where the cell has high capacity, high volumetric and gravimetric energy densities, high cycle life, and is capable of continued charge-discharge cycles following an overdischarge. The cell has an aqueous electrolyte, with the usual solute of potassium hydroxide, but the solute may also be a mixture of zinc chloride and ammonium chloride. The electrode balance as determined by the ration of the theoretical discharge capacity of the zinc and the theoretical one electron discharge capacity of the manganese dioxide ranges from greater than 65% up to 110%. On the 15th discharge, a cell of the present invention will deliver a discharge capacity of at least 20% of the discharge capacity delivered on the first discharge. A cell according to the present invention is capable of continued charge-discharge cycles after overdischarge or voltage reversal.

Abstract: Low mercury or mercury free primary or secondary alkaline manganese dioxide-zinc cell that comprises a manganese dioxide cathode with a manganese dioxide active material and a conductive powder. The active material and powder are uniformly mixed and pressed to form a porous cathode body. The cell further comprises a gelled zinc anode, a separator between the cathode and the anode, and an alkaline electrolyte. The anode gel comprises a modified starch as a gelling agent capable of releasing hydrogen gases developed during slow corrosion of zinc in the anode.A hydrogen recombination system can be used in the cell to limit inside pressure within permitted limits by recombining the evolved hydrogen.