Method and apparatus for high voltage aluminum capacitor design

• US 7,224,575 B2
• Filed: 07/15/2005
• Issued: 05/29/2007
• Est. Priority Date: 07/16/2004
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Sherwood, Gregory J.
• Primary Examiner(s): Thomas; Eric W.
• Application Number:
  US11/182,707
• Publication Number:
  US 20060023400A1
• Time in Patent Office: 683 Days
• Field of Search: 361/503, 361508-509, 361516-521, 361/522, 361528-529, 607/5
• US Class Current: 361/508
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: H01G 9/0032 formation of the dielectric layer
• CPC Class Codes: H01G 9/10 Sealing, e.g. of lead-in wires
• CPC Class Codes: Y10T 29/43 Electric condenser making
• CPC Class Codes: Y10T 29/435 Solid dielectric type

Abstract

Structure and method providing a capacitor connected to a component, including a capacitor stack made from one or more substantially planar cathode layers, one or more substantially planar anode layers, one or more substantially planar separator layers, and a solitary electrolyte. Additionally, the capacitor includes a case with a first aperture sized for passage of the capacitor stack and a second aperture, and one or more conductors connecting the capacitor stack to the component, with at least one conductor passing through the second aperture of the case, the at least one conductor sealingly connected to the second aperture. Further, the capacitor case is filled with a solitary electrolyte, and the capacitor stack is adapted to deliver to electronics from about 5.3 joules per cubic centimeter of capacitor stack volume to about 6.3 joules per cubic centimeter of capacitor stack volume, at a voltage of between about 465 volts to about 565 volts.

Claims

1. A capacitor for connection to a component, comprising:

a capacitor stack, including;

one or more substantially planar cathode layers;

one or more substantially planar anode layers having a dielectric thickness less than 1200 nanometers and formed using a process comprising;

forming a hydrous oxide layer on the anode layers;

anodizing the anode layers in a bath containing an aqueous solution of boric acid and phosphate;

passing the anode layers through a borax solution; and

reanodizing the anode layers in boric acid phosphate electrolyte,

one or more substantially planar separator layers; and

a unitary electrolyte;

a case with a feedthrough hole and a first aperture sized for passage of the capacitor stack;

a lid sealingly substantially conforming to the first aperture and sealingly connected to the first aperture; and

a feedthrough assembly connected to the capacitor stack and passing through a second aperture of the case and sealingly connected to the feedthrough hole,

wherein the case is filled with the unitary electrolyte, and the capacitor is adapted to deliver to the component from about 5.3 joules per cubic centimeter of capacitor stack volume to about 6.3 joules per cubic centimeter of capacitor stack volume, at a voltage of between about 465 volts to about 620 volts.

2. The apparatus of claim 1, wherein the capacitor stack is adapted to deliver an electrical pulse to the component at between approximately 490 volts and approximately 540 volts.

3. The apparatus of claim 2, wherein the capacitor stack is adapted to deliver an electrical pulse at approximately 515 volts.

4. The apparatus of claim 1, wherein the capacitor stack is adapted to deliver from about 5.5 joules per cubic centimeter of capacitor stack volume to about 6.1 joules per cubic centimeter of capacitor stack volume.

5. The apparatus of claim 4, wherein the capacitor stack is adapted to deliver about 5.8 joules per cubic centimeter of capacitor stack.

6. The apparatus of claim 1, wherein the capacitor stack includes from about 16 substantially planar cathode layers to about 22 substantially planar cathode layers, and from about 52 substantially planar anode layers to about 64 substantially planar anode layers, and one or more substantially planar separator layers.

7. The apparatus of claim 6, wherein the capacitor stack includes approximately 20 substantially planar cathode layers, and approximately 58 substantially planar anode layers.

8. The apparatus of claim 1, wherein the anode includes anode foils comprising an aluminum substrate at least partially encased in an aluminum oxide (Al₂O₃).

9. The apparatus of claim 8, wherein the aluminum oxide is formed at between approximately 600 volts and approximately 760 volts.

10. The apparatus of claim 1, wherein the cathode includes an aluminum substrate and a titanium coating.

11. The apparatus of claim 10, wherein the titanium coating is between approximately 0.5 nanometers and approximately 6.0 nanometers thick.

12. The apparatus of claim 1, wherein the capacitor stack has a mass of between approximately 10.7 grams and approximately 11.8 grams.

13. The apparatus of claim 1, wherein the anode has a capacitance of between approximately 0.70 and approximately 0.85 microfarads per square centimeter when charged at approximately 550 volts.

14. The apparatus of claim 1, wherein the anode and cathode layers include at least one member of the group including aluminum, tantalum, hafnium, niobium, titanium, and zirconium.

15. The apparatus of claim 1, wherein a plurality of anode connection members define a first surface, and a plurality of cathode connection members define a second surface, and the feedthrough assembly is connected to the first surface.

16. The apparatus of claim 1, wherein the capacitor case is electrically conductive.

17. The apparatus of claim 16, wherein a conductor connects the capacitor case to the cathode of the capacitor stack.

18. The apparatus of claim 17, wherein a terminal is connected to the case and is adapted for connection to the component.

19. The apparatus of claim 1, wherein a plurality of anode connection members define a first surface, and a plurality of cathode connection members define a second surface, and the feedthrough assembly is connected to the second surface.

20. The apparatus of claim 19, wherein a conductor connects the capacitor case to the second surface of the capacitor stack.