Cryogenic grinding of tantalum for use in capacitor manufacture

Patent metadata

Field	Value
Publication number	US-2016336115-A1
Application number	US-201615220345-A
Country	US
Kind code	A1
Filing date	Jul 26, 2016
Priority date	Jun 29, 2012
Publication date	Nov 17, 2016
Grant date	—

Abstract

An electrolytic capacitor comprising an anode comprised of cryogenically milled anode material is described. The cryogenic milling process prepares the active anode material for anode fabrication. The capacitor further comprises a casing of first and second casing members secured to each other to provide an enclosure. A feedthrough electrically insulated from the casing and from the casing and extending there from through a glass-to-metal seal, at least one anode electrically connected within the casing, a cathode, and an electrolyte. The cathode is of a cathode active material deposited on planar faces of the first and second casing members.

First claim

What is claimed is:

1 . A method of fabricating a capacitor comprising the following steps:
a) providing a case having first and second casing members; b) applying a cathode active material to a first face wall of the first casing member and a second face wall of the second casing member; c) providing an anode active material comprising the following steps:
i) providing a base anode material;
ii) providing a milling instrument;
iii) positioning the base anode material within the milling instrument;
iv) cooling the base anode material to a temperature below −150° C.; and
v) milling the base anode material to an average particle diameter of less than 5 mm;
d) forming the anode active material into an anode and positioning the anode within the first casing member; e) securing the second casing member to the first casing member such that the cathode active material faces the anode within the case; and f) filling the case with an electrolyte.

2 . The method of claim 1 including selecting the base anode material from the group consisting of tantalum, aluminum, titanium, niobium, zirconium, hafnium, tungsten, molybdenum, vanadium, silicon, germanium, alloys, and mixtures thereof.

3 . The method of claim 1 including milling the base anode material to an average particle diameter from about 0.5 μm to about 3 μm.

4 . The method of claim 1 including milling the base anode material to an average particle length from about 5 μm to about 25 μm.

5 . The method of claim 1 including milling the base anode material to an average particle surface area from about 0.3 m 2 /g to about 0.6 m 2 /g.

6 . The method of claim 1 including milling the base anode material to a bulk density from about 1 g/cc to about 3 g/cc per ASTM specification B212.

7 . The method of claim 1 including selecting the milling instrument from the group consisting of an attritor mill, a jet mill, a vibratory mill, a ball mill, and a hammer mill.

8 . The method of claim 1 including adding milling media with the base anode material within the milling instrument prior to the cooling step.

9 . The method of claim 1 including providing a feedthrough having opposing proximal and distal terminal lead ends and positioning the feedthrough within an opening of a sidewall of the casing such that the proximal terminal lead end resides within the case and the distal terminal lead end resides outside the case.

10 . The method of claim 9 including electrically connecting the anode to the terminal lead proximal end.

11 . The method of claim 1 including selecting the cathode active material of an oxide, a nitride, or a carbon nitride from the group of metals consisting of ruthenium, cobalt, manganese, molybdenum, tungsten, tantalum, iron, niobium, iridium, titanium, zirconium, hafnium, rhodium, vanadium, osmium, palladium, platinum, nickel, lead, alloys, and mixtures thereof.

12 . A method of preparing an anode active material for incorporation within a capacitor, the method comprising the following steps:
a) providing a base anode material; b) providing a milling instrument; c) positioning the base anode material within the milling instrument; d) cooling the base anode material within the milling instrument to a temperature below −150° C.; and e) milling the base anode material to an average particle diameter of less than 5 μm.

13 . The method of claim 12 including selecting the base anode material from the group consisting of tantalum, aluminum, titanium, niobium, zirconium, hafnium, tungsten, molybdenum, vanadium, silicon, germanium, alloys, and mixtures thereof.

14 . The method of claim 12 including milling the base anode material to an average particle diameter from about 1 μm to about 2 μm.

15 . The method of claim 12 including milling the base anode material to an average particle length from about 5 μm to about 25 μm.

16 . The method of claim 12 including milling the base anode material to an average particle surface area from about 0.3 m 2 /g to about 0.6 m 2 /g.

17 . The method of claim 12 including milling the base anode material to a bulk density from about 1 g/cc to about 3 g/cc per ASTM specification B212.

18 . The method of claim 12 including selecting the milling instrument from the group consisting of an attritor mill, a jet mill, a vibratory mill, a ball mill, and a hammer mill.

19 . The method of claim 12 including adding milling media with the base anode material within the milling instrument prior to the cooling step.

20 . The method of claim 12 including fabricating the anode active material into a capacitor anode.

Assignees

• Greatbatch Ltd

Inventors

• Kaiser Donald F
• Thiebolt William C
• Hahl Jason T

Classifications

• B02C19/186 Primary

  Use of cold or heat for disintegrating (B02C4/44, B02C7/17, B02C11/08 take precedence) · CPC title

• H01G9/0029 Primary

  Processes of manufacture · CPC title

• H01G9/145

  Liquid electrolytic capacitors (H01G11/00 takes precedence) · CPC title

• H01G9/042

  characterised by the material (H01G11/22 takes precedence) · CPC title

• H01G9/06

  Mounting in containers · CPC title