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US 5,686,204 AGranted
Gelling agent for alkaline electrochemical cells
AssigneeRayovac Corporation
InventorsPatricia S. Bennett, Kenneth H. Kenyon, Alane M. Boutelle, Janna L. Rose, Ronald J. Ekern, Randall L. Collien
Life of this patent
Estimating the term…
Abstract
A potassium polyacrylate superabsorbent polymer made by modified bulk polymerization and characterized as described herein is a superior gelling agent when provided at a suitable concentration in a gelled anode for an alkaline electrochemical cell. Suitable gelled anodes, alkaline electrochemical cells containing such gelled anodes, and methods for making and using same are also described.
Claims35
A gelled anode for use in an alkaline electrochemical cell, the gelled anode comprising:
- an aqueous alkaline electrolyte;
- an effective amount of a zinc powder;
- and
- a potassium polyacrylate superabsorbent polymer gelling agent formed by combining potassium acrylate and a polyvinyl monomer in a combined amount of 55 to 80 weight percent with water to form a monomer mixture then adding a polymerization initiator to the monomer mixture to initiate modified bulk polymerization of the monomer mixture.
1 more element
A gelled anode for use in an alkaline electrochemical cell, the gelled anode comprising:
- an aqueous alkaline electrolyte;
- an effective amount of a zinc powder;
- and
- a potassium polyacrylate superabsorbent polymer gelling agent characterized as a white, odor-free powder that is insoluble in the electrolyte and having a typical bulk density of 0.4, an absorption capacity of 27+10 grams of saline per gram, a maximal moisture content of 8%, 600 or fewer ppm of residual acrylate monomer, and a particle size distribution of between 135 and 850 microns.
1 more element
An alkaline electrochemical cell comprising:
- a positive current collector;
- a cathode in contact with the positive current collector;
- a gelled zinc anode inside the cathode, the anode comprising an aqueous alkaline electrolyte, an effective amount of a zinc powder, and a potassium polyacrylate superabsorbent polymer gelling agent formed by combining potassium acrylate and a polyvinyl monomer in a combined amount of 55 to 80 weight percent with water to form a monomer mixture then adding a polymerization initiator to the monomer mixture to initiate modified bulk polymerization of the monomer mixture;
- a separator between the cathode and the anode;
- and
- a negative current collector in electrical contact with the anode.
3 more elements
An alkaline electrochemical cell comprising:
- a positive current collector;
- a cathode in contact with the positive current collector;
- a gelled zinc anode inside the cathode, the anode comprising an aqueous alkaline electrolyte, an effective amount of a zinc powder, and a potassium polyacrylate superabsorbent polymer gelling agent characterized as a white, odor-free powder that is insoluble in the electrolyte and having a typical bulk density of 0.4, an absorption capacity of 27+10 grams of saline per gram, a maximal moisture content of 8%, 600 or fewer ppm of residual acrylate monomer, and a particle size distribution of between 135 and 850 microns;
- a separator between the cathode and the anode;
- and
- a negative current collector in electrical contact with the anode.
3 more elements
A method for forming a gelled anode, the method comprising the steps of:
- combining potassium acrylate and a polyvinyl monomer in a combined amount of 55 to 80 weight percent with water to form a monomer mixture;
- adding a polymerization initiator to the monomer mixture to initiate modified bulk polymerization of the monomer mixture to form a potassium polyacrylate superabsorbent polymer gelling agent characterized as a white, odor-free powder that is insoluble in the electrolyte and having a typical bulk density of 0.4, an absorption capacity of 27+10 grams of saline per gram, a maximal moisture content of 8%, 600 or fewer ppm of residual acrylate monomer, and a particle size distribution of between 135 and 850 microns;
- mixing together an aqueous alkaline electrolyte and the polymer gelling agent in suitable quantity to form a gelled electrolyte;
- mixing a suitable amount of a zinc powder into the gelled electrolyte to form a gelled anode.
1 more element
A method for forming an alkaline electrochemical cell, the method comprising the steps of:
- placing a cathode into a positive current collector open on one end so that the positive current collector contacts the cathode;
- introducing a separator so that the separator contacts the cathode;
- introducing a gelled anode comprising an aqueous alkaline electrolyte, an effective amount of a zinc powder, and a potassium polyacrylate superabsorbent polymer gelling agent characterized as a white, odor-free powder that is insoluble in the electrolyte and having a typical bulk density of 0.4, an absorption capacity of 27 grams of saline per gram, a maximal moisture content of 8%, 600 or fewer ppm of residual acrylate monomer, and a particle size distribution of between 135 and 850 microns, so that the gelled anode contacts the separator;
- and
- placing a negative current collector into the open end of the container so that the negative current collector contacts the gelled anode.
2 more elements
A method for discharging an alkaline electrochemical cell, the method comprising the steps of:
- providing an alkaline electrochemical cell having a positive terminal and a negative terminal, the cell comprising a gelled zinc anode comprising an aqueous alkaline electrolyte, an effective amount of a zinc powder, and a potassium polyacrylate superabsorbent polymer gelling agent characterized as a white, odor-free powder that is insoluble in the electrolyte and having a typical bulk density of 0.4, an absorption capacity of 27 grams of saline per gram, a maximal moisture content of 8%, 600 or fewer ppm of residual acrylate monomer, and a particle size distribution of between 135 and 850 microns;
- and
- providing a resistance between the positive terminal and the negative terminal.
Dependencies are inferred from the claim text.