Rechargeable battery

• US 6,265,100 B1
• Filed: 02/23/1998
• Issued: 07/24/2001
• Est. Priority Date: 02/23/1998
• Status: Expired due to Term

• Current Assignee: VARTA Microbattery GmbH (VARTA AG)
• Original Assignee: Research International Incorporated
• Inventors: Passerini, Stefano, Saaski, Elric W., Owens, Boone B.
• Primary Examiner(s): Brouillette, Gabrielle
• Assistant Examiner(s): ALEJANDRO, RAYMOND
• Application Number:
  US08/942,963
• Time in Patent Office: 1,247 Days
• Field of Search: 381/322, 381/323, 381/324, 381/328, 381/330, 381/137, 381/135, 381/133, 381/127, 429/163, 429/164, 429/175, 429/176, 429/94, 429/161, 429/209, 429/186
• US Class Current: 429/163
• CPC Class Codes: H01M 10/0431 Cells with wound or folded electrodes H01M10/045 takes precedence
• CPC Class Codes: H01M 10/30 Nickel accumulators H01M10/34 takes precedence
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H01M 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• CPC Class Codes: H04R 2225/31 Aspects of the use of accumulators in hearing aids, e.g. rechargeable batteries or fuel cells
• CPC Class Codes: H04R 25/602 of batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A contactless rechargeable hearing aid system in which a rechargeable hearing aid may be optically or inductively recharged by an optical or an inductive recharger. The optically rechargeable hearing aid may have a dual purpose optical fiber that may act as a light conduit for the recharging light, and that may also act as a draw string for the hearing aid. The rechargeable hearing aid may use a high energy nickel metal-hydride rechargeable battery or a high energy, high voltage lithium based rechargeable battery, in conjunction with a DC to DC voltage regulating circuit for converting the rechargeable battery'"'"'s declining DC output voltage to the fixed DC input voltage needed by the hearing aid'"'"'s audio related circuitry. The DC to DC voltage regulating circuit may also help to present a supply impedance that matches the input impedance of the audio related circuitry in the hearing aid. The rechargeable battery may have an alternately folded cell stack, a spiral wound cell stack or an accordion folded cell stack, in order to provide, in a minimized volume, the large anode, cathode and electrolyte areas that may be needed to reduce the rechargeable battery'"'"'s output impedance, in order to help reduce internal resistance losses during use of the battery.

Claims

1. An improved lithium based rechargeable battery;

wherein said battery has an external volume of less than about 10 cubic centimeters;

wherein said battery comprises a housing means, an alternately folded cell stack, and positive and negative electrical connections for said alternately folded cell stack;

wherein said housing means is for holding said alternately folded cell stack and is for providing said positive and negative electrical connections for said alternatively folded cell stack;

wherein said alternately folded cell stack comprises a cathode, an anode, and layers of electrolyte;

wherein said cathode and said anode are folded alternately over each other to form alternate layers of said cathode and said anode;

wherein one of said layers of electrolyte is located between, and separates, an adjacent pair of said alternate layers of said cathode and said anode;

wherein said housing means comprises an entire external surface having an entire external surface area;

wherein said entire external surface comprises at least one pair of parallel external faces that are at least generally parallel with respect to each other;

wherein each said pair of parallel external faces has a respective combined external parallel surface area; and

wherein a ratio of a largest said respective combined external parallel surface area to a difference between said entire external surface area and said largest said respective combined external parallel surface area is greater than about 0.5.

2. The battery according to claim 1, wherein said external volume of said battery is less than about 1 cubic centimeter.

3. The battery according to claim 1, wherein said battery has an output impedance in the range of about 1-10 ohms.

4. The battery according to claim 2, wherein said battery has an output impedance in the range of about 1-10 ohms.

5. The battery according to claim 1, wherein said housing means comprises a base having a base shape;

wherein said cathode comprises a strip of material comprising a pair of adjacent cathode elements and a cathode neck joining said pair of adjacent cathode elements;

wherein said pair of adjacent cathode elements have a maximum width;

wherein said cathode neck has a maximum width;

wherein said maximum width of said cathode neck is substantially less than said maximum width of said pair of adjacent cathode elements;

wherein said anode comprises a strip of material comprising a pair of adjacent anode elements and an anode neck joining said pair of adjacent anode elements;

wherein said pair of adjacent anode elements have a maximum width;

wherein said anode neck has a maximum width;

wherein said maximum width of said anode neck is substantially less than said maximum width of said pair of adjacent anode elements;

wherein said alternate layers of said cathode and said anode in said alternately folded cell stack comprise said pair of adjacent cathode elements and said pair of adjacent anode elements folded alternately over each other; and

wherein each of said adjacent cathode elements and said adjacent anode elements have a respective shape that is at least similar to said base shape.

6. The battery according to claim 2, wherein said housing means comprises a base having a base shape;

wherein said cathode comprises a strip of material comprising a pair of adjacent cathode elements and a cathode neck joining said pair of adjacent cathode elements;

wherein said pair of adjacent cathode elements have a maximum width;

wherein said cathode neck has a maximum width;

wherein said maximum width of said cathode neck is substantially less than said maximum width of said pair of adjacent cathode elements;

wherein said anode comprises a strip of material comprising a pair of adjacent anode elements and an anode neck joining said pair of adjacent anode elements;

wherein said pair of adjacent anode elements have a maximum width;

wherein said anode neck has a maximum width;

wherein said maximum width of said anode neck is substantially less than said maximum width of said pair of adjacent anode elements;

wherein said alternate layers of said cathode and said anode in said alternately folded cell stack comprise said pair of adjacent cathode elements and said pair of adjacent anode elements folded alternately over each other; and

wherein each of said adjacent cathode elements and said adjacent anode elements have a respective shape that is at least similar to said base shape.

7. The battery according to claim 5, wherein said base shape and said shape of each of said adjacent cathode elements and said adjacent anode elements are all at least substantially circular.

8. The battery according to claim 6, wherein said base shape and said shape of each of said adjacent cathode elements and said adjacent anode elements are all at least substantially circular.

9. The battery according to claim 5, wherein each of said adjacent cathode elements and said adjacent anode elements comprises a respective top face and a respective bottom face;

wherein two of said layers of electrolyte are located, respectively, adjacent said top and bottom faces of at least one of said adjacent cathode elements and said adjacent anode elements;

wherein said two layers of electrolyte have a shape that is at least substantially the same as said shape of said at least one of said adjacent cathode elements and said adjacent anode elements; and

wherein said two layers of electrolyte have edges which are heat sealed together in said shape that is at least substantially the same as said shape of said at least one of adjacent cathode elements,and said adjacent anode elements.

10. The battery according to claim 6, wherein each of said adjacent cathode elements and said adjacent anode elements comprises a respective top face and a respective bottom face;

wherein two of said layers of electrolyte are located, respectively, adjacent said top and bottom faces of at least one of said adjacent cathode elements and said adjacent anode elements;

wherein said two layers of electrolyte have a shape that is at least substantially the same as said shape of said at least one of said adjacent cathode elements and said adjacent anode elements; and

wherein said two layers of electrolyte have edges which are heat sealed together in said shape that is at least substantially the same as said shape of said at least one of adjacent cathode elements and said adjacent anode elements.

11. An improved lithium based rechargeable battery;

wherein said battery has an external volume of less than about one cubic centimeter;

wherein said battery comprises a housing means, a spiral wrapped cell stack, and positive and negative electrical connections for said spiral wrapped cell stack;

wherein said housing means is for holding said spiral wrapped cell stack and is for providing said positive and negative electrical connections for said spiral wrapped cell stack;

wherein said spiral wrapped cell stack comprises a cathode, a first layer of electrolyte, an anode, and a second layer of electrolyte;

wherein said cathode, said first layer of electrolyte, said anode, and said second layer of electrolyte are wound on top of each other to form concentric, alternating layers of said cathode, said first layer of electrolyte, said anode, and said second layer of electrolyte;

wherein said cathode and said anode are separated by said first and second layers of electrolyte;

wherein said housing means comprises an entire external surface having an entire external surface area;

wherein said entire external surface comprises at least one pair of parallel external faces that are at least generally parallel with respect to each other;

wherein each said pair of parallel external faces has a respective combined external parallel surface area; and

wherein a ratio of a largest said respective combined external parallel surface area to a difference between said entire external surface area and said largest said respective combined external parallel surface area is greater than about 0.5.

12. The battery according to claim 11, wherein said battery has an output impedance in the range of about 1-10 ohms.

13. The battery according to claim 11, wherein said anode comprises a strip of material having an end;

wherein said spiral wrapped cell stack has an axis;

wherein said battery further comprises an anode rod secured to said end of said anode;

wherein said anode rod is located on said axis of said spiral wrapped cell stack; and

wherein said spiral wrapped cell stack is wrapped around said anode rod.

14. The battery according to claim 13, wherein said housing means comprises a can and a cover for said spiral wrapped cell stack;

and wherein said anode rod is an integrally formed part of said cover.

15. The battery according to claim 13, wherein said housing means comprises a can and a cover for said spiral wrapped cell stack;

and wherein said anode rod is secured to said cover.

16. The battery according to claim 11, wherein said cathode comprises a strip of material having an end;

wherein said spiral wrapped cell stack has an axis;

wherein said battery further comprises an cathode rod secured to said end of said cathode;

wherein said cathode rod is located on said axis of said spiral wrapped cell stack; and

wherein said spiral wrapped cell stack is wrapped around said cathode rod.

17. The battery according to claim 13, wherein said housing means comprises a can and a cover for said spiral wrapped cell stack;

and wherein said cathode rod is integrally formed as part of said cover.

18. The battery according to claim 13, wherein said housing means comprises a can and a cover for said spiral wrapped cell stack;

and wherein said cathode rod is secured to said cover.

19. An improved lithium based rechargeable battery;

wherein said battery has an external volume of less than about one cubic centimeter;

wherein said battery comprises a housing means, an accordion folded cell stack, and positive and negative electrical connections for said accordion folded cell stack;

wherein said housing means is for holding said accordion folded cell stack and is for providing said positive and negative electrical connections for said accordion folded cell stack;

wherein said accordion folded cell stack comprises a cathode, an anode, and a layer of electrolyte located between said cathode and said anode;

wherein said layer of electrolyte separates said cathode and said anode;

wherein said cathode and said anode are accordion folded over each other;

wherein said housing means comprises an entire external surface having an entire external surface area;

wherein said entire external surface comprises at least one pair of parallel external faces that are at least generally parallel with respect to each other;

wherein each said pair of parallel external faces has a respective combined external parallel surface area; and

wherein a ratio of a largest said respective combined external parallel surface area to a difference between said entire external surface area and said largest said respective combined external parallel surface area is greater than about 0.5.

20. The battery according to claim 19, wherein said battery has an output impedance in the range of about 10-20 ohms.