Rayovac Corporation

John David Burns

John Edward Oltman

Robert B Dopp

Michael J Root

Joseph Lynn Passaniti

Patrick J Spellman

Randall L Collien

Robert Adey

Cathode cans for use in air depolarized cells, and cells made with such cans. The side wall is stronger than the bottom wall, and has a smoother outwardly-disposed surface than the respective bottom wall surface. Strength, and thus hardness, of the side wall relates to strength, and thus hardness, of the bottom wall, as hardness of 130-185 relates, to hardness of 93-117, on the Vickers scale. Preferred hardness of the side wall is about 130 to 185; and of the bottom wall is about 93 to 117. The side wall is drawn, and an outwardly-disposed surface of the side wall is ironed. As ironed, the surface finish is related to surface finish of the bottom wall, at the same stage, as surface finish R of less than 2, preferably about 0.5 to about 1.5, microinches, is related to surface finish R of about 2 to about 5, preferably about 2.5 to about 4.5, microinches. Thickness of the side wall is generally up to about 85 percent as great as thickness of the bottom wall. In methods of forming cathode cans in a metal strip, a die has an initializing land, an inner side wall, a cavity inwardly of the inner side wall, and a lip between the initializing land and the inner side wall.

Air depolarized electrochemical button cell

This invention pertains to electrode cans and metal air electrochemical cells made with the electrode cans. The invention provides improvide structure, and methods for making the outer edge of the closed end of the can at the joinder of the closed end of the can with an side wall extinding from the closed end. A substantially flat portion of the outer surface of the closed end of the can extends outwardly of the inner surface of the side wall. The electrochemical cells are assembled using improved assembly methods. Button-type electrochemical cells made using the invention are free of the inward dishing common to especially cathode cans in such button cells.

Metal-air cathode can having reduced corner and electrochemical cells made therewith

Cathode cans for use in air depolarized cells, and cells made with such cans. The side wall is stronger than the bottom wall, and has a smoother outwardly-disposed surface than the respective bottom wall surface. Strength, and thus hardness, of the side wall relates to strength, and thus hardness, of the bottom wall, as hardness of 130-185 relates to hardness of 93-117, on the Vickers scale. Preferred hardness of the side wall is about 130 to 185; and of the bottom wall is about 93 to 117. The side wall is drawn, and an outwardly-disposed surface of the side wall is ironed. As ironed, the surface finish is related to surface finish of the bottom wall, at the same stage, as surface finish R,of less than 2, preferably about 0.5 to about 1.5, microinches, is related to surface finish R,of about 2 to about 5, preferably about 2.5 to about 4.5, microinches. Thickness of the side wall is generally up to about 85 percent as great as thickness of the bottom wall. In methods of forming cathode cans in a metal strip, a die has an initializing land, an inner side wall, a cavity inwardly of the inner side wall, and a lip between the initializing land and the inner side wall. Ratio of outer radius of the lip to inner radius of the lip is about 2/1 to about 8/1. Ratio of clearance between punch and die to thickness of the metal strip is about 0.5/1 to about 0.85/1, whereby moving the punch and metal strip into the cavity draws the metal, and irons the outer surface of the metal.

Method for making a cathode can from metal strip

This invention pertains to novel alkaline electrochemical cells having high drain capacities, especially cells having high drain rate capabilities at voltages of at least 1.1 volts for use in small appliances such as hearing aids. The anode includes anode material in the cells including potassium hydroxide, zinc powder, 0.02% to 0.5% of a reaction rate enabling compound selected from a compound of indium, cadmium, gallium, thallium, germanium, tin, or lead, with indium compounds being preferred. The anode material optionally further includes a low level of mercury, and preferably a surfactant comprising hydroxyethylcellulose. The cathode provides sufficient oxidative capability to oxidize the zinc at a sufficient rate to support the electrical drain demands on the cell. A cathode, in a preferred zinc air cell for a hearing aid, includes at least 5 air ports, evenly distributed over the surface of the bottom of the cathode can. Cells of the invention exhibit prolonged operation at relatively constant voltage over 1.1 volts, and relatively constant power output at a power density of at least about 210 milliwatts per square inch of the reaction surface area of the cathode assembly, for periods significantly longer than conventional cells of the same type.

Electrochemical cell anode and high discharge rate electrochemical cell

This invention pertains to electrode cans and metal air electrochemical cells made with the electrode cans. The invention provides improved structure, and methods for making the outer edge of the closed end of the can at the joinder of the closed end of the can with an side wall extending from the closed end. A substantially flat portion of the outer surface of the closed end of the can extends outwardly of the inner surface of the side wall. The electrochemical cells are assembled using improved assembly methods. Button-type electrochemical cells made using the invention are free of the inward dishing common to especially cathode cans in such button cells.

Metal-air cathode can having reduced corner radius and electrochemical

This invention pertains to novel electrochemical metal air cells having improved closed circuit voltage characteristics. The improved voltage characteristics are illustrated at a constant load of 51 ohms. The closed circuit voltage during an initial placement into use of the cell of the invention has a decreased voltage drop relative to prior art cells, and recovers to a higher voltage. For example, the closed circuit voltage of the metal air cell drops to a minimum voltage during the first 20 seconds of initial placement into use. The minimum voltage is no more than 22% less than the initial open circuit voltage. This voltage drop is less than the voltage drop of other known metal air cells at 51 ohms. Metal air cells of the invention recover, during the first minute of use, to a closed circuit voltage of at least 79% of the initial open circuit voltage. The value of the open circuit voltage of the metal air cell of the invention is preferably about 1.43 volt.

Low mercury, high discharge rate electrochemical cell

This invention pertains to novel alkaline electrochemical cells having high drain capacities, especially cells having high drain rate capabilities at voltages of at least 1.1 volts for use in small appliances such as hearing aids. The anode includes anode material in the cells including potassium hydroxide, zinc powder, 0.02% to 0.5% indium as indium compound separate from the zinc powder, optionally a low level of mercury, and preferably a surfactant comprising hydroxyethylcellulose. The cathode provides sufficient oxidative capability to oxidize the zinc at a sufficient rate to support the electrical drain demands on the cell. A cathode, in a preferred zinc air cell for a hearing aid, includes at least 5 air ports, evenly distributed over the surface of the bottom of the cathode can. Cells of the invention exhibit prolonged operation at relatively constant voltage over 1.1 volts, and relatively constant power output at a power density of at least about 210 milliwatts per square inch of the reaction surface area of the cathode assembly, for periods significantly longer than conventional cells.

This invention pertains to alkaline electrochemical cells, typically to metal-air cells of the button-type. Non-reactive elements of cells of the invention are thinner than corresponding non-reactive elements of prior art cells. Such elements can be made thinner because of improved structures of such elements. The anode can is made from a metal strip structure having a higher steel content. The cathode can has a modified temper, which improves relative stiffness and rigidity while retaining sufficient ductility. The seal disposed between the anode can and the cathode can is made thinner. Structure of the corner of the cathode can between the bottom and the side wall is improved. By so reducing the thicknesses of non-reactive elements of the cell, and thus the volume occupied by such non-reactive elements, the fraction of the cell devoted to holding electrochemically reactive anode material therein is increased, with corresponding increase in the milliampere hour capacity of the cell.

High energy density metal-air cell

Tempered thin-walled cathode can

This invention pertains to alkaline electrochemical cells, typically to metal-air cells of the button-type. Non-reactive elements of cells of the invention are thinner than corresponding non-reactive elements of prior art cells. Such elements can be made thinner because of improved structures of such elements. The anode can is made from a metal strip structure having a higher steel content. The cathode can has a modified temper, which improves relative stiffness and rigidity while retaining sufficient ductility. The seal disposed between the anode can and the cathode can is made thinner. Structure of the corner of the cathode can between the bottom and the side wall is improved. By so reducing the thicknesses of non-non-reactive elements of the cell, and thus the volume occupied by such non-reactive elements, the fraction of the cell devoted to holding electrochemically reactive anode material therein is increased, with corresponding increase in the milliampere hour capacity of the cell.

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Durham, United Kingdom

John David Burns