Abstract: The performance of alkaline cells comprising a zinc anode and manganese dioxide cathode can be improved, especially in high power application, by applying thermal insulating material to the cell casing. The thermal insulation material can be conveniently applied between the cell label and casing. The thermal insulating material significantly reduces the overall heat transfer coefficient, Uo, for the cell. The insulation increases the internal temperature of the cell during discharge, resulting in better performance.

Abstract: The performance of alkaline cells comprising a zinc anode and manganese dioxide cathode can be improved, especially in high power application, by the addition of electrically conductive powders such as tin, copper, silver, magnesium, indium or bismuth to the anode mixture. The conductive powders are in physical mixture with the zinc particles. A preferred electrically conductive powder is tin powder. The alkaline cell to which the conductive powders are added preferably contain no added mercury and preferably are also essentially free of lead.

Abstract: An alkaline cell is disclosed having a cathode comprising manganese dioxide wherein the cathode is a semisolid during discharge of the cell. The cell has an anode comprising zinc and an electrolyte comprising potassium hydroxide. The semisolid cathode comprising manganese dioxide may be in the form of a putty or paste. The semisolid cathode reduces cathode polarization effects and results in increased manganese dioxide utilization (Amp-hr/g), particularly at high current drain, between about 0.5 and 2 Amp. The porosity of the cathode is between about 45% and 70%, and the volume ratio of electrolyte solution in the cathode to the solids in the cathode is at a value between about 0.7 and 2.3.

Abstract: A lithiated manganese dioxide for use in primary lithium electrochemical cells. The lithiated manganese dioxide is prepared by stepwise treatment with a liquid source of lithium cations that can include an aqueous solution of a lithium base or a low melting point lithium salt resulting in formation of a lithiated manganese dioxide product. Lithium cations in the lithium base or molten lithium salt can be ion-exchanged with hydrogen ions in the manganese dioxide crystal lattice and additional lithium ions reductively inserted into the lattice during subsequent heat-treatment to form the lithiated manganese dioxide product LiyMnO2−&dgr;. The primary lithium cell utilizing the lithiated manganese dioxide product as active cathode material exhibits increased operating voltage and enhanced high rate, low temperature, and pulse discharge performance compared with untreated manganese dioxide.

Abstract: A process is described whereby commercial manganese dioxide, for example, electrolytic manganese dioxide (EMD), is treated with ozone before it is utilized as cathode active material in an alkaline cell. The pretreatment of the manganese dioxide is accomplished by contacting manganese dioxide with ozone gas. Alternatively, the manganese dioxide may be treated with ozone while the cathode comprising said manganese dioxide is already in the cell casing. The treatment of the manganese dioxide improves the cell's open circuit voltage (OCV) and results in an increase in service life of the cell, particularly under high power application.

Abstract: A method of making lithium manganese oxide of spinel structure is disclosed. The method involves the step of prelithiating a manganese oxide by reacting it with lithium hydroxide or lithium salt and then reacting the prelithiated manganese oxide in a second step at elevated temperature, for example, with lithium carbonate to form a lithium manganese oxide spinel. The spinel product may be used advantageously in secondary (rechargeable) batteries. The spinel product may be admixed with a partially substituted nickelite, preferably, LiNi.sub.x Co.sub.1-x O.sub.2 (0.1<x<0.9) or LiNi.sub.x Mg.sub.1-x O.sub.2 (0.85<x<0.97) and mixtures thereof to form the active material for the positive electrode of a rechargeable lithium ion cell. A preferred mixture for the positive electrode of lithium ion cells comprises lithium manganese oxide spinel and LiNi.sub.x Co.sub.1-x O.sub.2 (0.1<x<0.9).

Abstract: An end cap assembly for an electrochemical cell, for example an alkaline cell, is disclosed comprising an exposed terminal end cap of single piece construction having a convoluted surface, an electrically insulating member and a metal support disk between the insulating member and the terminal end cap. The end cap assembly is inserted into the open end of the cell housing after the cell contents have been supplied. A portion of the end cap surface is a flat annular step which improves contact between the end cap and the electrically conductive portion of a condition tester for the cell which may be integrated into the cell label. The annular step is advantageously located at about right angle to the cell's longitudinal axis. The surface step is integral with the end cap and preferably located at about the same level as the shoulder of the cell housing at the end of the cell containing the end cap. The end cap assembly as a whole provides a tight seal for the cell.

Abstract: The invention is directed to a method of forming a pip protrusion at the closed end of a cylindrical casing of an electrochemical cell. The cell is preferably an alkaline cell having an anode comprising zinc, a cathode comprising manganese dioxide, and an alkaline electrolyte. The method of the invention is directed to forming the pip protrusion at the closed end of the casing so that the pip protrusion becomes an integral part of the casing. In an alkaline cell the pip protrusion becomes the cell's positive terminal. The method of the invention involves inserting cathode material into the casing through the open end thereof and then forcing an elongated plunger having a diameter less than the inside diameter of casing into the cathode material while providing means for preventing the cathode material form rising more than a predetermined level with the casing.

Abstract: An end cap seal assembly for an electrochemical cell such as an alkaline cell is disclosed. The end cap assembly comprises a convoluted end cap disk which may also function as a cell terminal and an underlying insulating disk also having a convoluted surface. The convoluted end cap disk has a downwardly extending wall with at least one aperture therethrough which preferably faces the ambient environment. The insulating disk has a downwardly extending wall forming a rupturable membrane which underlies and abuts the inside surface of the downwardly extending wall of the end cap. The rupturable membrane underlies and abuts the aperture in the downwardly extending wall of the end cap. When gas pressure within the cell exceeds a predetermined level the rupturable membrane pushes through said aperture and ruptures allowing gas to escape therefrom directly to the environment. A separate terminal plate may be welded to a portion of the top surface of the convoluted end cap.

Abstract: A current interrupt assembly for electrochemical cells is disclosed. The current interrupter assembly may be a self-contained, sealed unit which may be separately inserted into the cell during cell construction. Several current interrupt assemblies may be inserted in the cell. The current interrupter assembly has particular utility for thin rechargeable cells and when inserted in the cell forms a portion of the electrical pathway between a cell electrode and corresponding terminal. The current interrupt mechanism comprises a thin thermally responsive member preferably comprising a disk of a shape memory metal alloy having a curved surface. When cell temperature exceeds a predetermined value the disk deflects to cause a break in the electrical pathway within the assembly. The assembly may include therein a flexible electrically conductive member which forms a part of the electrical pathway within the assembly and which is physically responsive to deflection of the thermally responsive member.

Abstract: The invention is directed to a pressure activated current interrupt assembly for cells, particularly alkaline cells. The current interrupter is located at the closed end of the cell's housing. The current interrupter assembly comprises an electrically insulating member in proximity to the terminal at the closed end of the housing. The insulating member is in physical communication with a deflectable member formed from the cell's housing. When gas pressure within the cell builds up to exceed a predetermined value, the deflectable member deforms causing the insulating member to protrude beyond the extremity of said cell terminal, thereby preventing electrical contact between said terminal and the terminal of another cell or electrical device.

Abstract: A current interrupt mechanism for electrochemical cells is disclosed. A thermally activated current interrupt mechanism is integrated into an end cap assembly for an electrochemical cell. The thermally responsive mechanism preferably includes a free floating bimetallic disk or shape memory alloy member which deforms when exposed to elevated temperature causing a break in an electrical pathway within the end cap assembly. This prevents current from flowing through the cell and effectively shuts down an operating cell. The thermally responsive mechanism may include a heat producing electrical resistance means, preferably a Zener diode, to enhance thermal sensitivity. The end cap assembly may include a pressure responsive mechanism which ruptures when there is extreme gas pressure buildup. Gas is allowed to escape from the cell interior to the external environment through a series of vent apertures within the end cap assembly.

Abstract: An end cap assembly is disclosed for sealing the open end of a cylindrical alkaline cell housing preferably having a diameter less than the diameter of AAA size cells. The end cap assembly is preferably intended for sealing AAAA (LR61) size cylindrical alkaline cells. The end cap assembly comprises a terminal end cap, an insulating sealing disk underlying said end cap, and an elongated current collector penetrating through an aperture in said insulating sealing disk. At least a portion of the insulating sealing disk lies within the cell housing to seal the open end thereof. The terminal end cap is located outside of said housing. The end cap assembly may include an insulating washer between the terminal end cap and the cell housing. The terminal end cap and the insulating washer are stacked over the peripheral edge of the cell housing at the open end of the cell housing. The insulating washer electrically insulates the terminal end cap from the cell housing.

Abstract: A current interrupt assembly for electrochemical cells is disclosed. The current interrupter assembly may be a self-contained, sealed unit which may be separately inserted into the cell during cell construction. Several current interrupt assemblies may be inserted in the cell. The current interrupter assembly has particular utility for thin rechargeable cells and when inserted in the cell forms a portion of the electrical pathway between a cell electrode and corresponding terminal. The current interrupt mechanism comprises a thin thermally responsive member preferably comprising a disk of a shape memory metal alloy having a curved surface. The current interrupt mechanism may include a heat producing electrical resistance means, preferably a Zener diode in proximity to the thermally responsive member. When cell temperature exceeds a predetermined value the disk deflects to cause a break in the electrical pathway within the assembly.

Abstract: An end cap assembly for an electrochemical cell, for example an alkaline cell, is disclosed comprising an exposed terminal end cap of single piece construction having a convoluted surface, an electrically insulating member and a metal support disk between the insulating member and the terminal end cap. The end cap assembly is inserted into the open end of the cell housing after the cell contents have been supplied. A portion of the end cap surface is a flat annular step which improves contact between the end cap and the electrically conductive portion of a condition tester for the cell which may be integrated into the cell label. The annular step is advantageously located at about right angle to the cell's longitudinal axis. The surface step is integral with the end cap and preferably located at about the same level as the shoulder of the cell housing at the end of the cell containing the end cap. The end cap assembly as a whole provides a tight seal for the cell.