Multiple anode high energy density electrolytic capacitor

• US 5,963,418 A
• Filed: 03/18/1998
• Issued: 10/05/1999
• Est. Priority Date: 05/02/1997
• Status: Expired due to Fees

• Current Assignee: CM Components Incorporated
• Original Assignee: CM Components Incorporated
• Inventors: Greenwood, John M. Jr., Weatherup, Oakland J., Harwood, Van Ness Jr.
• Primary Examiner(s): Kincaid, Kristine
• Assistant Examiner(s): Dinkins, Anthony
• Application Number:
  US09/040,903
• Time in Patent Office: 566 Days
• Field of Search: 361/500, 361/502, 361/508-509, 361/511-512, 361/516, 361/517, 361/520, 361/524, 361/528-530, 361/531-533, 361/535, 361/538, 29/25.03
• US Class Current: 361/508
• CPC Class Codes: H01G 9/055 Etched foil electrodes

Abstract

A multiple anode capacitor (10) having offset terminal leads or strips which maximizes capacitance achieved per volume occupied by the capacitor. More specifically, the invention including a multiple anode aluminum electrolytic capacitor including a cylindrical casing (42), a header (45) crimped to the open end of the casing, the header including a primary anode terminal (41) and a primary cathode terminal (44). Disposed within the casing is a wound or coiled capacitor body (28) having plural anode foils (11, 12, 13), a capacitor foil (14), and dielectric paper separator layers (15, 16) disposed between the cathode and the anodes. In a preferred embodiment, three juxtapositioned anode foils are used, the foils being made from a high purity porous aluminum foil. In addition, each of the dielectric paper separator layers is formed of two kraft capacitor tissue papers (15a, 15b, 16a, 16b). Leads, or terminal strips, are attached to each of the anode or cathode foils, the attaching section of each of the leads being offset from the other attaching sections (21a, 22a, 23a, 24a) when the foils are wound together. The leads of the anode foils are connected to the primary anode terminal and the lead of the cathode foil is connected to the primary cathode terminal. A suitable electrolyte (47) permeates the wound capacitor body.

Claims

1. A multiple anode high energy density electrolytic capacitor comprising:

a cylindrical housing having a primary anode terminal and a primary cathode terminal;

a first paper separator layer comprising a strip of electrolytic tissue paper;

a cathode layer comprising a strip of aluminum foil, said cathode layer located adjacent said first paper separator layer and having a cathode terminal strip affixed transversely to said cathode foil strip;

a second paper separator layer comprising a strip of electrolytic capacitor tissue paper, said second paper separator layer located adjacent said cathode layer;

a first anode layer comprising a strip of aluminum foil, said first anode layer located adjacent said second paper separator layer and having a first anode terminal strip affixed transversely to said first anode foil strip;

a second anode layer comprising a strip of aluminum foil, said second anode layer located adjacent said first anode layer and having a second anode terminal strip affixed transversely to said second anode foil strip, said second anode terminal strip is offset with respect to said first anode terminal strip; and

,

a third anode layer comprising a strip of aluminum foil, said third anode layer located adjacent said second anode layer and said first paper separator layer and having a third anode terminal strip affixed transversely to said third anode foil strip, said third anode terminal strip is offset with respect to both said first anode terminal strip and said second anode terminal strip;

wherein said first paper separator layer, said cathode layer, said second paper separator layer, said first anode layer, said second anode layer, and said third anode layer are all in contact with an electrolyte and are rolled into a cylindrical shape within said housing and said cathode terminal strip is connected to said primary cathode terminal and said first anode terminal strip, said second anode terminal strip and said third anode terminal strip are all connected to said primary anode terminal.

2. The multiple anode high energy density capacitor as recited in claim 1 wherein said first anode foil and said third anode foil are porous.

3. The multiple anode high energy density capacitor as recited in claim 2 wherein said second anode foil is non-porous.

4. The multiple anode high energy density capacitor as recited in claim 1 wherein said first, second and third anode foils are porous.

5. A high energy density electrolytic capacitor comprising:

a cylindrical housing dimensioned for retaining a rolled laminate containing a cathode layer, an anode layer and separator layers;

a primary anode terminal and a primary cathode terminal;

said cathode layer, comprising an elongate strip of aluminum foil and having a primary cathode terminal strip affixed transversely to the foil strip;

said anode layer, comprising three elongate strips of roughened porous aluminum foil arranged in adjacent layers, each strip of porous aluminum foil having a primary anode terminal strip affixed transversely thereto, said anode layer arranged adjacent said cathode layer and being separated from said cathode layer by said separator layers;

a separator layer comprising an elongate strip of electrolytic capacitor separator material arranged adjacent to and between said cathode layer and said anode layer;

each of said cathode layer, separator layers and anode layer being in contact with an electrolyte and rolled into said cylindrical housing, said cathode terminal strip being connected to said primary cathode terminal and said anode terminal strips being connected to said primary anode terminal;

wherein each of said three elongate porous aluminum foil strips comprising said anode layer has a minimum porosity, measured by air flow, of about 0.5 cc/sec-cm² -atm, and a foil surface area, measured by capacitance, of at least about 0.2 μ

F per square centimeter.

6. A capacitor of claim 6 wherein a separator layer comprises two layers of separator material.

8. A capacitor of claim 6 wherein said roughened porous aluminum foil of said anode layer has a capacitance of at least about 0.4 μ

F per square centimeter and said cathode layer has a capacitance of from about 5 to about 30 μ

F per square centimeter.

7. A capacitor of claim 7 wherein said capacitor separator material comprises a kraft tissue paper.

9. A high energy density layered electrolytic capacitor comprising:

at least two anode layers having terminals offset with respect to one another;

a cathode layer having a terminal;

at least two electrolytic separator layers separating said anode layers from said cathode layer;

a housing containing said at least two anode layers, said cathode layer, and said at least two separator layers; and

, an electrolyte contained within said housing.