Capacitor having textured pellet and method for making same

• US 6,191,936 B1
• Filed: 04/12/1999
• Issued: 02/20/2001
• Est. Priority Date: 04/12/1999
• Status: Expired due to Fees

• Current Assignee: Vishay Sprague Inc. (Vishay Intertechnology Incorporated)
• Original Assignee: Vishay Sprague Inc. (Vishay Intertechnology Incorporated)
• Inventors: Webber, Dean A., Van Voorhis, John E.
• Primary Examiner(s): Kincaid, Kristine
• Assistant Examiner(s): THOMAS, ERIC W
• Application Number:
  US09/289,995
• Time in Patent Office: 680 Days
• Field of Search: 361/523-529, 361/531-533, 29/250.3
• US Class Current: 361/528
• CPC Class Codes: H01G 9/052 Sintered electrodes

Abstract

A pellet for use in a capacitor includes a rectangular body formed from compressed and sintered particles of conductive material. The body has an exterior surface which is textured to form a plurality of indentations therein. The profile of the textured surface in cross section is selected from the group including essentially of a curved profile, a sine shape profile, a rectangular shaped profile, a U-shaped profile, and a V-shaped profile.

Claims

1. A pellet for use in a capacitor, comprising:

a rectangular body comprised of compressed and sintered particles of conductive material, said body having an exterior surface;

said exterior surface having a textured portion comprising a plurality of indentations therein;

said indentations having a depth of from 0.254 mm to 0.508 mm;

said indentations having a width of from 0.254 mm to 0.508 mm.

2. A pellet according to claim 1, where said indentations comprise a plurality of elongated channels.

3. A pellet according to claim 2 wherein each of said channels has a profile in cross section which is selected from the group consisting essentially of a curved profile, a sine shaped profile, a rectangular shaped profile, a U-shaped profile, and a V-shaped profile.

4. A pellet according to claim 2 wherein said elongated channels are parallel to one another.

5. A pellet according to claim 2 wherein said plurality of elongated channels include a first group of channels which are parallel to one another and a second group of channels which are parallel to one another but are not parallel to said first group of channels.

6. A pellet according to claim 1, wherein said indentations are formed in said exterior surface of said body during sintering and compressing of said conductive particles to form said body.

7. A pellet according to claim 6, wherein said indentations comprise a plurality of elongated channels.

8. A pellet according to claim 7, wherein each of said channels has a profile in cross section which is selected from the group consisting essentially of a curved profile, a sine shaped profile, a rectangular shaped profile, a U-shaped profile, and a V-shaped profile.

9. A pellet according to claim 7, wherein said elongated channels are parallel to one another.

10. A pellet according to claim 7, wherein said plurality of elongated channels include a first group of channels which are parallel to one another and a second group of channels which are parallel to one another but are not parallel to said first group of channels.

11. A capacitor comprising:

a body comprised of compressed and sintered particles of conductive material, said body having an exterior surface;

said exterior surface having a textured portion comprising a plurality of indentations therein;

a lead electrically connected to said body;

a conductive cathode coating at least partially covering said body;

a first dielectric material electrically insulating said particles of conductive material from said conductive cathode coating;

a second dielectric material covering at least a portion of said cathode coating;

said indentations having a width of from 0.254 mm to 0.508 mm;

said indentations having a depth of from 0.254 mm to 0.508 mm.

12. A pellet for use as an anode in a solid capacitor, comprising:

a rectangular body comprised of compressed and sintered particles of conductive material, said body having an exterior surface;

said exterior surface having a textured portion therein;

said textured portion comprising a plurality of indentations therein;

said indentations having a depth of from 0.254 mm to 0.508 mm;

said indentations having a width of from 0.254 mm to 0.508 mm.

13. A pellet according to claim 12, wherein said indentations comprise a plurality of elongated channels.

14. A pellet according to claim 13, wherein each of said channels has a profile in cross section which is selected from the group consisting essentially of a curved profile, a sine shaped profile, a U-shaped profile, and a V-shaped profile.

15. A pellet according to claim 13, wherein each of said channels has a profile in cross section which is selected from the group consisting essentially of a curved profile, a sine shaped profile, a rectangular shaped profile, a U-shaped profile, and a V-shaped profile.

16. A pellet according to claim 13, wherein each of said channels has a width of from 0.254 mm to 0.508 mm.

17. A pellet according to claim 12, having a top surface, a bottom surface, and four side surfaces, wherein three or more of said surfaces have said indentations.

18. A pellet according to claim 12, having a top surface, a bottom surface, and four side surfaces, wherein one or more sides has five or more indentations.

19. A pellet according to claim 12, wherein said indentations being sufficient in number to cause said exterior surface to define a first surface area of said body approximately 30 percent larger than the same exterior surface being flat and completely free from said indentations.

20. A pellet for use as an anode in a solid capacitor, comprising:

a rectangular body comprised of compressed and sintered particles of conductive material, said body having an exterior surface comprising;

a top surface, a bottom surface, and a plurality of side surfaces;

said plurality of side surfaces being textured by a plurality of indentations increasing the surface area of said side surfaces;

said indentations being sufficiently small in depth and width to cause said side surfaces and said top and bottom surfaces to define a first volume of said body approximately the same as a second volume defined by said top, bottom, and side surfaces being flat and completely free from said indentations.

21. A pellet according to claim 20, wherein said indentations comprise a plurality of elongated channels.

22. A pellet according to claim 21, wherein each of said channels has a profile in cross section which is selected from the group consisting essentially of a curved profile, a sine shaped profile, a U-shaped profile, and a V-shaped profile.

23. A pellet according to claim 21, wherein each of said channels has a profile in cross section which is selected from the group consisting essentially of a curved profile, a sine shaped profile, a rectangular shaped profile, a U-shaped profile, and a V-shaped profile.

24. A pellet according to claim 21, wherein each of said channels has a width of from 0.254 mm to 0.508 mm.

25. A pellet according to claim 20, having a top surface, a bottom surface, and four side surfaces, wherein three or more of said surfaces have said indentations.

26. A pellet according to claim 20, having a top surface, a bottom surface, and four side surfaces, wherein one or more sides has five or more indentations.

27. A pellet according to claim 20, wherein said indentations being sufficient in number to cause said exterior surface to define a first surface area of said body approximately 30 percent larger than the same exterior surface being flat and completely free from said indentations.

28. A pellet for use as an anode in a solid capacitor comprising:

a rectangular body comprised of compressed and sintered particles of conductive material, said body comprising a top exterior surface, a bottom exterior surface, and four exterior side surfaces;

said four exterior side surfaces all being textured by a plurality of indentations;

wherein said indentations have a width of from 0.254 mm to 0.508 mm and a depth of from 0.254 mm to 0.508 mm.

29. The capacitor body of claim 28, further comprising:

a lead electrically connected to said body;

a conductive cathode coating at least partially covering said body;

a first dielectric material electrically insulating said particles of conductive material from said conductive cathode coating;

a second dielectric material covering at least a portion of said conductive cathode coating.