Avx Corporation

James Steven Bates

Robert Hazen Pease

Andrew Paul Ritter

John L Galvagni

Mitchell D Weaver

Zebbie Lynn Sebald

Dirk H Dreissig

James Allen Fife

Lotfi Djebara

Gang Ning

Tomas Karnik

William A Millman

Richard Baker

Ed Jackson

A wet electrolytic capacitor is provided. The capacitor includes a planar anode formed from a pressed and sintered powder, a cathode that includes a metal substrate that is coated with an electrochemically-active material, and a working electrolyte in communication with the planar anode and cathode. The planar anode has a recessed portion formed in at least one of its surfaces. The capacitor also includes at least one restraint that is in contact with the recessed portion and has a shape that generally corresponds with a shape of the recessed portion. The recessed portion of the planar anode allows for stabilization of the planar anode with via a restraint without increasing the dimensions of the capacitor.

Wet electrolytic capacitor containing a recessed planar anode and a restraint

A wet electrolytic capacitor is provided. The capacitor contains an anode comprising an anodically oxidized pellet formed from a pressed and sintered powder, a cathode that contains a metal substrate coated with a conductive polymer, and a working electrolyte in communication with the anode and the cathode. The working electrolyte is in the form of a gel and comprises an ammonium salt of an organic acid, inorganic oxide particles, an acid, and a solvent system that comprises water. The working electrolyte has a pH value of from about 5.0 to about 8.0.

Wet electrolytic capacitor containing a gelled working electrolyte

A relatively thin planar anode for use in a wet electrolytic capacitor is provided. Through a combination of specific materials and processing techniques, the present inventors have surprisingly discovered that the resulting anode may possess a high volumetric efficiency, yet still be able to operate at a high voltage and capacitance, resulting in a capacitor with a high energy density. The anode is a pressed pellet formed from an electrically conductive powder that contains a plurality of particles (including agglomerates thereof) having a flake-like morphology. The present inventors have discovered that such a morphology can optimize packing density, which reduces the thickness of the anode and improves volumetric efficiency. Such particles can provide a short transmission line between the outer surface and interior of the anode and a highly continuous and dense wire-to-anode connection with high conductivity. The particles may also increase the breakdown voltage and help lower ESR.

Planar anode for use in a wet electrolytic capacitor

A wet electrolytic capacitor that contains a sintered anode positioned with an interior space of a metal casing is provided. The anode and metal casing are of a size such that the anode occupies a substantial portion of the volume of the interior space. More particularly, the anode typically occupies about 70 vol. % or more, in some embodiments about 75 vol. % or more, in some embodiments from about 80 vol. % to about 98 vol. %, and in some embodiments, from about 85 vol. % to 95 vol. % of the interior space. Among other things, the use of an anode that occupies such a large portion of the interior space enhances volumetric efficiency and other electrical properties of the resulting capacitor.

Volumetrically efficient wet electrolytic capacitor

A relatively thin planar anode for use in a wet electrolytic capacitor is provided. An anode leadwire is embedded within the anode and extends in a longitudinal direction therefrom. The wire may be formed from any electrically conductive material, such as tantalum, niobium, aluminum, hafnium, titanium, etc., as well as electrically conductive oxides and/or nitrides of thereof. To reduce the tendency of the leadwire to pull out of the anode due to stresses encountered during manufacturing (e.g., sintering) and/or use of the capacitor, the manner in which the wire is inserted is selectively controlled in the present invention. That is, at least a portion of the wire within the anode is bent at an angle relative to the longitudinal axis of the wire. This 'bend' reduces the ease to which the wire can be pulled out in the longitudinal direction after the anode is pressed and sintered.

Leadwire configuration for a planar anode of a wet electrolytic capacitor

A wet electrolytic capacitor that contains a hermetically sealed lid assembly is disclosed. More specifically, the lid assembly contains a lid (e.g., titanium) that defines an internal orifice. A conductive tube may extend through the orifice that is of a size and shape sufficient to accommodate an anode lead. An insulative material is also provided within the orifice to form a hermetic seal (e.g., glass-to-metal seal), such as between the conductive tube and the lid. The lid assembly also includes a liquid seal that is formed from a sealant material. The liquid seal coats a substantial portion of the lower surface of the lid and hermetic seal to limit contact with any electrolyte that may leak from the casing. To help achieve such surface coverage, the sealant material is generally flowable so that it can be heated during production of the capacitor and flow into small crevices that would otherwise remains uncoated.

Hermetically sealed wet electrolytic capacitor

A wet electrolytic capacitor that includes an anode, cathode, and an electrolyte is provided. The cathode contains a substrate and a coating overlying the substrate. The coating comprises a sintered body containing carbonaceous particles (e.g., activated carbon) and inorganic particles (e.g., NbO).

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Saco, ME, United States of America

James Steven Bates