Laser drilling of metal foils for assembly in an electrolytic capacitor

Patent metadata

Field	Value
Publication number	US-9969030-B2
Application number	US-201615153369-A
Country	US
Kind code	B2
Filing date	May 12, 2016
Priority date	May 12, 2016
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A capacitor and methods of processing an anode metal foil are presented. The capacitor includes a housing, one or more anodes disposed within the housing, one or more cathodes disposed within the housing, one or more separators disposed between an adjacent anode and cathode, and an electrolyte disposed around the one or more anodes, one or more cathodes, and one or more separators within the housing. The one or more anodes each include a metal foil that includes a first plurality of tunnels through a thickness of the metal foil in a first ordered arrangement, the first ordered arrangement being a close packed hexagonal array arrangement, and having a first diameter, and a second plurality of tunnels through the thickness of the metal foil having a second ordered arrangement and a second diameter greater than the first diameter.

First claim

What is claimed is:

1. A method of forming tunnels through a metal foil for use in an electrolytic capacitor, comprising:
stretching a sheet of metal foil around a cylindrical body;
pulsing a beam of light, at a first beam spot towards a portion of the metal foil stretched around the cylindrical body to form a tunnel through a thickness of the metal foil;
pulsing the beam of light at a second beam spot towards another portion of the metal foil to form another tunnel through the thickness of the metal foil, the second beam spot being displaced from the first beam spot in a first direction across the sheet of foil stretched around the cylindrical body; and
moving the sheet of metal foil in a second direction around the cylindrical body, the second direction being substantially perpendicular to the first direction.

2. The method of claim 1 , wherein the metal foil is an aluminum foil or a tantalum foil.

3. The method of claim 1 , wherein said beam of light is a beam of light having a top hat spatial profile and further comprising:
generating, using a laser source, an initial beam of light having a substantially Gaussian spatial profile; and
converting, the initial beam of light into the beam of light having the top hat spatial profile.

4. The method of claim 3 , wherein the beam of light having the top hat spatial profile includes a plurality of beams of light each having a top hat profile.

5. The method of claim 4 , wherein the pulsing steps comprise pulsing, the plurality of beams of light at a plurality of said first and second beam spots, the first and second beam spots being arranged linearly in the first direction.

6. The method of claim 1 , comprising moving a laser head in the first direction between the first beam spot and the second beam spot, the beam of light being emitted from the laser head.

7. The method of claim 1 , wherein the pulsing comprises pulsing the beam of light at the first beam spot or the second beam spot at a power density greater than 7.8×10 8 W/cm 2 .

8. The method of claim 1 , comprising moving the beam of light from one beam spot to a subsequent beam spot and pulsing the beam of light at each beam spot until a length of the metal foil has been traversed, wherein the moving the sheet of metal foil occurs after the length of the metal foil has been traversed.

9. A method of processing a metal foil for use in an electrolytic capacitor, comprising:
securing a sheet of metal foil on a rotary actuator;
rotating the sheet of metal foil using the rotary actuator about an axis substantially normal to a major surface of the sheet of metal foil;
pulsing a beam of light at a first beam spot towards the rotating sheet of metal foil, such that successive beam pulses are received at different locations circumferentially on the metal foil; and
pulsing the beam of light at a second beam spot towards the rotating sheet of metal foil, the second beam spot being radially displaced from the first beam spot.

10. The method of claim 9 , wherein the metal foil is an aluminum foil or a tantalum foil.

11. The method of claim 9 , wherein said beam of light is a beam of light having a top hat spatial profile and further comprising:
generating, using a laser source, an initial beam of light having a substantially Gaussian spatial profile;
converting the initial beam of light into the beam of light having the top hat profile.

12. The method of claim 9 , wherein the pulsing comprises pulsing the beam of light at a pulse rate between 10 picoseconds and 100 femtoseconds.

13. The method of claim 9 , wherein the rotating comprises rotating the sheet of metal foil between 1000 and 2000 revolutions per minute.

14. The method of claim 8 , comprising moving a laser head in a radial direction between the first beam spot and the second beam spot, the beam of light being emitted from the laser head.

15. The method of claim 9 , wherein the pulsing comprises pulsing the second beam of light at the first beam spot or the second beam spot at a power density greater than 7.8×10 8 W/cm 2 .

Assignees

• Pacesetter Inc

Inventors

• Hemphill Ralph Jason
• Bowen David R
• Erickson Kurt J
• Fernstrom Peter

Classifications

• H01G9/008 Primary

  Terminals · CPC title

• H01G9/042

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

• H01G9/02

  Diaphragms; Separators · CPC title

• B23K2203/10

  Operations & Transport · mapped topic

• B23K26/083

  Devices involving movement of the workpiece in at least one axial direction · CPC title