Vent for cylindrical electrochemical batteries

A method of venting pressure from an axially extending electrochemical cell of the type having a container defining an interior, a cathode chamber housing a cathode disposed in the interior, an anode disposed within the interior and separated from the cathode via an ionically permeable separator, a vent extending between the interior and an ambient environment, and a gasket disposed adjacent the container to seal the vent, the method comprising the steps of:

• (A) generating internal cell pressure that exceeds a predetermined pressure threshold;
• (B) in response to step (A), biasing the gasket axially downstream away from the container;
• (C) in response to step (B), removing the seal formed between the gasket and the container;
• and
• (D) in response to step (C), venting pressurized cell contents into the ambient environment via the vent.

A size AAA electrochemical cell disposed in an ambient environment having a negative terminal end, comprising:

• (a) a cylindrical container having an upstanding sidewall presenting an inner and outer surface and a terminal end proximal the negative terminal end of the cell, wherein the container defines an interior container void;
• (b) an annular cathode ring disposed within the container void and presenting an inner peripheral sidewall;
• (c) an ionically permeable separator disposed adjacent the inner peripheral sidewall of the cathode ring and defines a central void;
• (d) an anode disposed in the central void;
• (e) a negative current collector electrically connected to the anode and closed at its axially outer end by a negative endplate;
• and
• (f) a vent placing the container void in fluid communication with the ambient environment;
• and
• (g) a gasket extending radially from the negative current collector to the container sidewall, wherein the negative terminal end defines a negative terminal void disposed between the gasket and the endplate, wherein the negative terminal void has a volume substantially within the range of 0–0.03 cubic centimeters.

A size AA electrochemical cell disposed in an ambient environment having a negative terminal end, comprising:

• (a) a cylindrical container having an upstanding sidewall presenting an inner and outer surface and a terminal end proximal the negative terminal end of the cell, wherein the container defines an interior container void;
• (b) an annular cathode ring disposed within the container void and presenting an inner peripheral sidewall;
• (c) an ionically permeable separator disposed adjacent the inner peripheral sidewall of the cathode ring and defines a central void;
• (d) an anode disposed in the central void;
• (e) a negative current collector electrically connected to the anode and closed at its axially outer end by a negative endplate;
• and
• (f) a vent placing the container void in fluid communication with the ambient environment;
• and
• (g) a gasket extending radially from the negative current collector to the container sidewall, wherein the negative terminal end defines a negative terminal void disposed between the gasket and the endplate, wherein the negative terminal void has a volume within the range of 0–0.09 cubic centimeters.

A size C electrochemical cell disposed in an ambient environment having a negative terminal end, comprising:

• (a) a cylindrical container having an upstanding sidewall presenting an inner and outer surface and a terminal end proximal the negative terminal end of the cell, wherein the container defines an interior container void;
• (b) an annular cathode ring disposed within the container void and presenting an inner peripheral sidewall;
• (c) an ionically permeable separator disposed adjacent the inner peripheral sidewall of the cathode ring and defines a central void;
• (d) an anode disposed in the central void;
• (e) a negative current collector electrically connected to the anode and closed at its axially outer end by a negative endplate;
• and
• (f) a vent placing the container void in fluid communication with the ambient environment;
• and
• (g) a gasket extending radially from the negative current collector to the container sidewall, wherein the negative terminal end defines a negative terminal void disposed between the gasket and the endplate, wherein the negative terminal void has a volume within the range of 0–0.4 cubic centimeters.

A size D electrochemical cell disposed in an ambient environment having a negative terminal end, comprising:

• (a) a cylindrical container having an upstanding sidewall presenting an inner and outer surface and a terminal end proximal the negative terminal end of the cell, wherein the container defines an interior container void;
• (b) an annular cathode ring disposed within the container void and presenting an inner peripheral sidewall;
• (c) an ionically permeable separator disposed adjacent the inner peripheral sidewall of the cathode ring and defines a central void;
• (d) an anode disposed in the central void;
• (e) a negative current collector electrically connected to the anode and closed at its axially outer end by a negative endplate;
• and
• (f) a vent placing the container void in fluid communication with the ambient environment;
• and
• (g) a gasket extending radially from the negative current collector to the container sidewall, wherein the negative terminal end defines a negative terminal void disposed between the gasket and the endplate, wherein the negative terminal void has a volume substantially within the range of 0–1.1 cubic centimeters.

An electrochemical cell having a negative terminal end, comprising:

• (a) a cylindrical container having an upstanding sidewall presenting an inner and outer surface and a terminal end proximal the negative terminal end of the cell, the container defining a vent extending therethrough;
• (b) an annular cathode ring disposed within the container, the cathode ring having an inner peripheral sidewall;
• (c) an ionically permeable separator having an outer surface disposed adjacent the inner peripheral sidewall of the cathode ring and an inner surface defining a central cylindrically shaped void, the container inner surface and the separator outer surface defining a cathode chamber;
• (d) an anode disposed in the central cylindrically shaped void;
• (e) a negative current collector electrically connected to the anode and closed at its axially outer end by a negative endplate;
• and
• (f) a gasket that extends radially from the negative current collector to the container sidewall, wherein the container is crimped about the gasket to provide a seal therebetween that is removed when internal cell pressure exceeds a predetermined threshold to enable electrolyte to flow out of the cell, the gasket sealing the vent when the internal cell pressure is less than the predetermined threshold, the seal being removed when the internal cell pressure is greater than the predetermined threshold.