P. R. Mallory Co.

Duracell Inc.

Michael J Smith

Franciszek J Przybyla

Ronald J Book

Charles Markin

Marian Wiacek

John P Mathews

In a sealed galvanic cell having an anode, cathode, and cylindrical can into which the principal components of the cell are assembled, a sealing and insulating member at the top end of the cathode can is provided which is held in sealing relationship to the can by a crimp formed over the top edge thereof. The sealing and insulating member has a circular rim formed at its periphery in at least one of the top and bottom surfaces, the diameter of the sealing and insulating member being substantially the same as the inside diameter of the can above a bead which is formed near the top edge thereof. At least a portion of the thickness of the peripheral material of the member is stressed by the crimp in an amount greater than the elastic limit of the material, and at least another portion of the thickness of the peripheral material of the sealing and insulating member is stressed in an amount less than the elastic limit. The stressed portion is at the top or bottom of the periphery of the member. When the can is sealed by crimping over the member, a change of elevation of at least the central portion of the sealing and insulating member may occur, or inward flexing of the peripheral rib may occur, or both.

Galvanic cell and sealing and insulation member therefor

A metal-air battery usually comprises a plurality of air-depolarizable cells within a battery case. The present invention provides that the battery case has a vent and a vent cover, where the vent cover is associated with an electrical actuator so as to open only when the battery is supplying electrical power to a load. In this manner, the metal-air battery is open to the atmosphere only when it is operating, and consequently is open to the possibility of harsh ambient conditions such as very high or very low ambient relative humidity, prolonged carbon dioxide exposure, and so on; and as a consequence, a long operating life for the battery which operates only intermittently during that life can be expected. In general, the vent cover is a flexible element which may either be a bimetal element or one having an elastic memory, and is biased to the vent-closed position but is associated with an electrically powered actuator so that, upon actuation of the battery to supply power to its own load, the vent cover actuator operates to cause movement of the vent cover to the vent-opened position. The source of electrical power for the vent cover actuator may be the battery itself, or it may be an auxiliary primary cell. Where the vent cover comprises a bimetal element, it is preferably an electrothermal actuator having a feeder element physically secured to the bimetal element.

Metal-air battery having electrically operated air access vent cover

A gas-depolarizable galvanic cell is provided having restricted gas access to the cathode. The cell is generally a metal-air cell, and may particularly be a button cell suitable for use in electronic watches, hearing aids and the like. The restricted gas access to the cathode comes either by way of a very small aperture in the cell container, or in an additional barrier layer placed within the cell. The cross-sectional area of the gas passageway is less than the projected area of the gas passageway through the thickness of the container or additional barrier layer; and may be formed by piercing or punching but more particularly by exposing the container or the material of the additional barrier layer to a laser beam.

Metal-air depolarized cell having restricted gas passageway

A gas-depolarizable galvanic cell in which restricted gas and water vapor access to the gas-depolarizable cathode is provided by interposing a gas and moisture impermeable barrier in the gas communication path and carefully controlling the size of holes or openings in the barrier so as to restrict the gas flow rate past the barrier.

Metal-air depolarized cell with restricted water vapor access

A self sealing microporous membrane of utility especially in electrochemical cells of the gas-depolarized type comprising a microporous polymer membrane of a density range between about 0.7 and 1.9 grams per centimeter embodies a pressurized sealing zone of maximum density and zero porosity. Such pressurized zone is located to provide a seal against leakage of electrolyte.

Growing community of inventors

Mississauga, Canada

Michael J Smith