Precision micro-hole for extended life batteries

• US 8,068,630 B2
• Filed: 11/26/2007
• Issued: 11/29/2011
• Est. Priority Date: 06/08/1999
• Status: Expired due to Fees

• Current Assignee: Insound Medical Incorporated (Sonova Holding AG)
• Original Assignee: Insound Medical Incorporated (Sonova Holding AG)
• Inventors: Baker, Ross, O'Hara, Tom, Gable, Richard
• Primary Examiner(s): Ensey; Brian
• Application Number:
  US11/945,149
• Publication Number:
  US 20080069386A1
• Time in Patent Office: 1,464 Days
• Field of Search: 381/312, 381/322, 381/323, 381/324, 429/27, 429/29
• US Class Current: 381/322
• CPC Class Codes: H01M 12/06 with one metallic and one gaseous electrode
• CPC Class Codes: H01M 50/107 having curved cross-section, e.g. round or elliptic H01M50/103, H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 50/119 Metals
• CPC Class Codes: H01M 50/121 Organic material
• CPC Class Codes: H01M 50/124 having a layered structure
• CPC Class Codes: H01M 50/128 with two or more layers of only inorganic material
• CPC Class Codes: H01M 50/129 with two or more layers of only organic material
• CPC Class Codes: H01M 50/14 for protecting against damage caused by external factors
• CPC Class Codes: H04R 2225/61 Aspects relating to mechanical or electronic switches or control elements, e.g. functioning
• CPC Class Codes: H04R 25/602 of batteries
• CPC Class Codes: H04R 25/603 of mechanical or electronic switches or control elements
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Various embodiments of the invention provide an enclosure for a metal-air battery assembly for an extended wear hearing aid. The enclosure includes a diffusion control element having a dimensional property configured for controlling oxygen and moisture diffusion into the metal-air battery assembly to maintain a minimum battery voltage when the hearing aid is operating and worn in an ear canal of a user over an extended period. In an embodiment, the enclosure can comprise a shell with a base end having an opening therein forming a cavity within the shell and a base cap for covering the opening of the base end. A diffusion element is disposed on the base cap. In an embodiment, the diffusion element comprises a laser drilled precision micro hole having an aspect ratio of least about four and a diameter in the range of about 10 to 15 microns.

Claims

1. A metal-air battery for an extended wear hearing aid, the battery comprising:

an air cathode assembly;

an anode assembly coupled to the air cathode assembly; and

an enclosure enclosing the air cathode assembly and anode assembly, the enclosure including a diffusion control element having a dimensional property configured for controlling oxygen and moisture diffusion into the metal-air battery to maintain a minimum battery voltage when the hearing aid is operating and worn in an ear canal of a user over an extended period, wherein the enclosure comprises a metal shell having at least one hole and wherein the diffusion control element comprises a polymer layer having a precision micro-hole formed therein and being arranged in series with the hole in the shell to control oxygen and moisture diffusion to the battery.

2. The battery of claim 1, wherein the shell of the enclosure comprises a base end having an opening therein forming a cavity within the shell and a base cap for covering the opening of the base end.

3. The battery of claim 2, wherein the at least one hole in the shell is disposed in the base cap and the polymer layer is laminated to the base cap with the micro-hole aligned with the hole in the cap.

4. The battery of claim 1, wherein the minimum battery voltage is in a range from about 1 volt to 1.3 Volts.

5. The battery of claim 1, wherein a current drain at which the minimum voltage is maintained is in range from about 40 A to 175 A.

6. The battery of claim 5, wherein a current drain at which the minimum voltage is maintained is in range from about 40 A to 90 A.

7. The battery of claim 1, wherein the diffusion control element is configured to control moisture diffusion into the battery to maintain a battery electrolyte concentration within a range sufficient to allow the battery to power the hearing aid.

8. The battery of claim 1, wherein at least a portion of the micro-hole is curved or non-linear.

9. The battery of claim 1, wherein the micro-hole is laser drilled.

10. The battery of claim 1, wherein the micro-hole has a length to diameter ratio such that the gas ingress into the battery is substantially diffusion controlled.

11. The battery of claim 10, wherein the micro-hole has a length to diameter ratio of at least about 4.

12. The battery of claim 1, wherein the precision micro-hole in the polymer layer has a diameter not greater than about 15 microns.

13. The battery of claim 1, wherein the polymer layer has a plurality of precision micro-holes.

14. The battery of claim 1, wherein the polymer layer and the metal shell comprise a metallized polymer.