Anodes with corner and edge modified designs

• US 7,658,986 B2
• Filed: 05/30/2007
• Issued: 02/09/2010
• Est. Priority Date: 05/30/2007
• Status: Expired due to Fees

• Current Assignee: Kemet Electronics Corporation (Yageo Corporation)
• Original Assignee: Kemet Electronics Corporation (Yageo Corporation)
• Inventors: Thornton, Lance Paul, Bates, James C. Jr., Prymak, John, Qiu, Yongjian, Hahn, Randy S., Guerrero, Christian, Poltorak, Jeffrey
• Primary Examiner(s): XU, LING X
• Application Number:
  US11/807,765
• Publication Number:
  US 20080299371A1
• Time in Patent Office: 986 Days
• Field of Search: None
• US Class Current: 428/192
• CPC Class Codes: H01G 11/48 Conductive polymers
• CPC Class Codes: H01G 2/065 for surface mounting, e.g. chip capacitors
• CPC Class Codes: H01G 9/052 Sintered electrodes
• CPC Class Codes: H01G 9/15 Solid electrolytic capacitors H01G11/00 takes precedence
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y10T 428/24777 Edge feature
• CPC Class Codes: Y10T 428/24917 including metal layer
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/24999 Inorganic
• CPC Class Codes: Y10T 428/249991 Synthetic resin or natural rubbers

Abstract

Porous sintered anode bodies for capacitors formed from valve metals are treated by electrolysis to form a dielectric layer and coated with cathode layers. When standard parallelpiped shapes are used, cathode coverage at the edges and corners is non-uniform and failures occur at those locations. Rectangular prisms, obround prisms and cylindrical prisms are formed with transition surfaces at edges and corners, such as chamfers and curves, to enhance cathode layer uniformity. The transition surface greatly enhances the application of polymer slurries.

Claims

1. A porous anode body comprising a sintered anode in a form of a rectangular prism wherein at more than 5 intersections with each intersection of said interections being of at least two surfaces, said two surfaces meet at transition surfaces

wherein a transition surface at the intersection of two surfaces defined as XZ and YZ is defined by:

0.03 mm <

X″

<

0.5 X′

and

0.03 mm <

Y″

<

0.5 Y′

wherein X′

represent a length and Z′

represents a width of surface XZ;

wherein Y′

represent a length and Z′

represents a width of surface YZ;

XZ will deviate a distance X″

from a projected intersection of XZ and YZ, YZ will deviate a distance Y″

from said projected intersection.

2. The porous anode body according to claim 1 wherein the transition surfaces are substantially chamfers.

3. The porous anode body according to claim 1 wherein the transition surfaces are substantially curves.

4. The porous anode body according to claim 1 wherein said anode is selected from the group consisting of Al, Ta, Ti, Nb, Zn, Hf, W, mixtures, alloys, nitrides and suboxides thereof and NbO.

5. The porous anode body according to claim 1 wherein a transition surface at an intersection of three surfaces defined as XZ, XY and YZ is defined by:

0.03 mm <

X″

<

0.5 X′

0.03 mm <

Y″

<

0.5 Y′

and

0.03 mm <

Z″

<

0.5Z′

wherein X′

represent a length and Y′

represents a width of surface XY;

wherein XY will deviate a distance X″

from a projected intersection of XY, YZ and XZ at the intersection of XY and XZ;

YZ will deviate a distance Y″

from a projected intersection of XY, YZ and XZ at an intersection of XY and YZ; and

XZ will deviate a distance Z″

from a projected intersection of XY, YZ and XZ at an intersection of XZ and YZ.

6. The porous anode body according to claim 1 wherein all intersections of at least two surfaces are changed to create transition surfaces.

7. The porous anode body according to claim 6 wherein said anode is selected from the group consisting of Al, Ta, Ti, Nb, Zn, Hf, W, mixtures, alloys, nitrides and suboxides thereof and NbO.

8. The porous anode body of claim 1 further comprising a dielectric on said sintered anode and a conductive polymer on said dielectric.

9. The porous anode body of claim 1 wherein said rectangular prism further comprises at least one flute.

10. The porous anode body comprising a sintered anode in a form of a rectangular prism wherein at more than 3 intersections with each intersection of said intersections being of 3 surfaces said intersections are changed to create transition surfaces wherein a transition surface at an intersection of three surfaces defined as XZ, XY and YZ is defined by:

0.03 mm <

X″

<

0.5 X′

0.03 mm <

Y″

<

0.5 Y′

and

0.03 mm <

Z″

<

0.5 Z′

wherein X′

represent a length and Z′

represents a width of surface XZ;

wherein Y′

represent a length and Z′

represents a width of surface YZ;

wherein X′

represent a length and Y′

represents a width of surface XY;

wherein XY will deviate a distance X″

from a projected intersection of XY, YZ and XZ at an intersection of XY and XZ;

YZ will deviate a distance Y″

from a projected intersection of XY, YZ and XZ at an intersection of XY and YZ; and

XZ will deviate a distance Z″

from a projected intersection of XY, YZ and XZ at an intersection of XZ and YZ.

11. The porous anode body according to claim 10 wherein the transition surfaces are substantially chamfers.

12. The porous anode body according to claim 10 wherein the transition surfaces are substantially curves.

13. The porous anode body according to claim 10 further comprising an anode lead projecting from a surface opposite to a surface intersecting 4 transition surfaces.

14. The porous anode body according to claim 10 wherein said anode is selected from the group consisting of Al, Ta, Ti, Zn, Nb, Hf, W, mixtures, alloys, nitrides and suboxides thereof and NbO.

15. The porous anode body of claim 10 further comprising a dielectric on said sintered anode and a conductive polymer on said dielectric.

16. The porous anode body of claim 10 wherein said rectangular prism further comprises at least one flute.

17. The porous anode body comprising a sintered anode in a form of a rectangular prism wherein at all intersections of two surfaces, said intersections are changed to create transition surfaces wherein a transition surface at an intersection of two surfaces defined as XZ and YZ is defined by:

0.03 mm <

X″

<

0.5 X″

and

0.03 mm <

Y″

<

0.5 Y′

wherein X′

represent a length and Z′

represents a width of surface XZ;

wherein Y′

represent a length and Z′

represents a width of surface YZ;

XZ will deviate a distance X″

from a projected intersection of XZ and YZ, YZ will deviate a distance Y″

from said projected intersection.

18. The porous anode body according to claim 17 wherein the transition surfaces are substantially chamfers.

19. The porous anode body according to claim 17 wherein the transition surfaces are substantially curves.

20. The porous anode body according to claim 17 wherein said anode is selected from the group consisting of Al, Ta, Ti, Zn, Nb, Hf, W, mixtures, alloys, nitrides and suboxides thereof and NbO.

21. The porous anode body of claim 17 further comprising a dielectric on said sintered anode and a conductive polymer on said dielectric.

22. The porous anode body of claim 17 wherein said rectangular prism further comprises at least one flute.

23. The porous anode body comprising a sintered anode in a form of an obround prism wherein at least one edge has been changed to create a transition surface wherein the transition surface at an intersection of two surfaces defined as XZ and YZ is defined by:

0.03 mm <

X″

<

0.5 X′

and

0.03 mm <

Y″

<

0.5 Y′

wherein X′

represent a length and Z′

represents a width of surface XZ;

wherein Y′

represent a length and Z′

represents a width of surface YZ;

XZ will deviate a distance X″

from a projected intersection of XZ and YZ, YZ will deviate a distance Y′

from said projected intersection.

24. The porous anode body according to claim 23 wherein the transition surface is substantially a chamfer.

25. The porous sintered body according to claim 23 wherein the transition surface is substantially a curve.

26. The porous anode body according to claim 23 wherein said anode is selected from the group consisting of Al, Ta, Ti, Zn, Nb, Hf, W, mixtures, alloys, nitrides and suboxides thereof and NbO.

27. The porous anode body according to claim 23 further comprising an anode lead projecting from a surface opposite to a surface intersecting at least one transition surface.

28. The porous anode body according to claim 23 wherein the intersection of all surfaces have been modified to create a transition surface.

29. The porous anode body according to claim 28 wherein said anode is selected from the group consisting of Al, Ta, Ti, Zn, Nb, Hf, W, mixtures, alloys, nitrides and suboxides thereof and NbO.

30. The porous anode body of claim 23 further comprising a dielectric on said sintered anode and a conductive polymer on said dielectric.

31. The porous anode body of claim 23 wherein said obround prism further comprises at least one flute.

32. The porous anode body comprising a sintered anode in the form of a cylindrical prism wherein an edge of at least one flat surface has been changed to create a transition surface meeting a requirement that 0.03 mm <

R<

r and 0.03 mm <

H<

h/2 wherein r and h are a radius and height of the cylindrical prism, respectively and R and H are distances cut back from an intersecting lines along r and h.

33. The porous anode body according to claim 32 wherein the transition surface is substantially a chamfer.

34. The porous anode body according to claim 32 wherein the transition surface is substantially curved.

35. The porous anode body according to claim 32 wherein said anode is selected from the group consisting of Al, Ta, Ti, Zn, Nb, Hf, W, mixtures, alloys, nitrides and suboxides thereof and NbO.

36. The porous anode body according to claim 32 wherein edges of both flat surfaces have been modified to create transition surfaces.

37. The porous anode body according to claim 36 wherein said anode is selected from the group consisting of Al, Ta, Ti, Zn, Nb, Hf, W, mixtures, alloys, nitrides and suboxides thereof and NbO.

38. The porous anode body of claim 32 further comprising a dielectric on said sintered anode and a conductive polymer on said dielectric.

39. The porous anode body of claim 32 wherein said cylindrical prism further comprises at least one flute.