Hybrid battery power source for implantable medical use

• US 7,020,519 B2
• Filed: 04/04/2003
• Issued: 03/28/2006
• Est. Priority Date: 01/24/2003
• Status: Expired due to Fees

• Current Assignee: Gentcorp Limited
• Original Assignee: Gentcorp Limited
• Inventors: Greatbatch, Wilson, Deal, Jeffrey
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US10/407,916
• Publication Number:
  US 20040147972A1
• Time in Patent Office: 1,089 Days
• Field of Search: 607/5, 607/29, 607/34, 320/103
• US Class Current: 607/5
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 16/00 Structural combinations of different types of electrochemical generators
• CPC Class Codes: H01M 6/16 with organic electrolyte H01M6/18 takes precedence
• CPC Class Codes: H01M 6/5016 Multimode utilisation
• CPC Class Codes: H01M 6/5033 used as charging means for another battery
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A hybrid battery power source for implantable medical use provides a generally constant low internal resistance during discharge and avoids voltage delays of the type that develop as a result of run down-induced resistance increase in Li/SVO cells. The hybrid battery power source utilizes two batteries or cells, one being a primary cell of relatively high energy density and the other being a secondary cell of relatively low internal resistance that is rechargeable. The primary and secondary cells are connected in a parallel arrangement via a voltage boost/charge control circuit that is powered by the primary cell and adapted to charge the secondary cell while limiting charge/discharge excursions thereof in a manner that optimizes its output for high energy medical device use. The energy storage capacitors of the medical device in which the hybrid battery power source is situated are driven by the secondary cell. The primary cell is used to as an energy source for recharging the secondary cell.

Claims

1. A hybrid battery power source for implantable medical use, comprising:

a primary battery;

a secondary battery connected to receive power from said primary battery;

said secondary battery being adapted to power to an implantable medical device designed for high energy electrical stimulation of body tissue for therapeutic purposes; and

a charge control circuit powered by said primary battery and adapted to charge said secondary battery while limiting charge/discharge excursions thereof to a voltage range whose upper end is less than the maximum state of charge of said secondary battery and whose lower end is more than the minimum state of charge of said secondary battery, said upper end and said lower end of said voltage range being selected to minimize discharge capacity fade and internal resistance increase during service of said secondary battery.

2. A hybrid battery power source in accordance with claim 1, further including a voltage boost circuit that facilitates charging of said secondary battery at a voltage that is higher than a voltage output of said primary battery.

3. A hybrid battery power source in accordance with claim 2, wherein said voltage boost circuit comprises an inductive element.

4. A hybrid battery power source in accordance with claim 2, wherein said voltage boost circuit comprises a flyback transformer.

5. A hybrid battery power source in accordance with claim 1, wherein said charge control circuit includes a voltage comparator adapted to initiate charging when said secondary battery falls below a minimum reference voltage.

6. A hybrid battery power source in accordance with claim 1, wherein said charge control circuit includes a window voltage comparator adapted to initiate charging when said secondary battery falls below a minimum reference voltage and to terminate charging when said secondary battery is charged to a maximum reference voltage that is larger than said minimum reference voltage.

7. A hybrid battery power source in accordance with claim 1, wherein said primary battery is selected from the group consisting of lithium-carbon monofluoride batteries and lithium-silver vanadium oxide batteries, wherein said secondary battery is selected from the group consisting of lithium-ion batteries, and wherein said voltage range is 4.0–

3.8 volts.

8. A hybrid battery power source in accordance with claim 1, wherein said primary battery and said secondary battery are interconnected in parallel via said charge control circuit.

9. A hybrid battery power source in accordance with claim 1 wherein said charge control circuit is a pulse circuit adapted for variable pulse width or duty cycle control, thereby allowing it to operate over a range of voltages output by said primary battery.

14. An implantable medical device in accordance with claim 9, wherein said charge control circuit is a pulse circuit adapted for variable pulse width or duty cycle control, thereby allowing it to operate over a range of voltages output by said primary battery.

15. An implantable medical device in accordance with claim 9, wherein said charge control circuit includes a voltage comparator adapted to initiate charging when said secondary battery falls below a minimum reference voltage.

16. An implantable medical device in accordance with claim 9, wherein said charge control circuit includes a window voltage comparator adapted to initiate charging when said secondary battery falls below a minimum reference voltage and to terminate charging when said secondary battery is charged to a maximum reference voltage that is larger than said minimum reference voltage.

17. An implantable medical device in accordance with claim 9, wherein said primary battery is selected from the group consisting of lithium-carbon monofluoride batteries and lithium-silver vanadium oxide batteries, and wherein said secondary battery is selected from the group consisting of lithium-ion batteries, and wherein said voltage range is 4.0–

3.8 volts.

18. An implantable medical device in accordance with claim 9, wherein said primary battery and said secondary battery are interconnected in parallel via said charge control circuit.

20. A method in accordance with claim 18, wherein secondary battery is charged at a voltage that is higher than a voltage output of said primary battery.

21. A method in accordance with claim 18, wherein said secondary battery is charged via pulse charging using variable pulse width or duty cycle control, thereby allowing said secondary battery to be charged over a range of voltages output by said primary battery.

22. A method in accordance with claim 18, wherein charging of said secondary battery is initiated when said secondary battery falls below a minimum reference voltage.

23. A method in accordance with claim 18, wherein said charging of said secondary battery is initiated when said secondary battery falls below a minimum reference voltage and terminated when said secondary battery is charged to a maximum reference voltage that is larger than said minimum reference voltage.

24. A method in accordance with claim 18, wherein said primary battery is selected from the group consisting of lithium-carbon monofluoride batteries and lithium-silver vanadium oxide batteries, wherein said secondary battery is selected from the group consisting of lithium-ion batteries, and wherein said voltage range is 4.0–

3.8 volts.

25. A method in accordance with claim 18, wherein said primary battery and said secondary battery are interconnected in parallel via a voltage boost/charge control circuit that performs said periodic charging of said secondary battery.

26. A method in accordance with claim 24, wherein said voltage boost/charge control circuit comprises a pulse control circuit and an inductive element.

27. A method in accordance with claim 24, wherein said voltage boost/charge control circuit comprises a pulse control circuit and a flyback transformer.

10. An implantable medical device for high energy electrical stimulation of body tissue for therapeutic purposes, comprising:

a pair of electrical contacts adapted to provide electrical stimulation to body tissue;

energy storage means adapted to provide electrical energy to said electrical contacts;

switching means adapted to periodically interconnect said energy storage means to said electrical contacts; and

a hybrid battery power source adapted to provide power to said energy storage means and including;

a primary battery;

a secondary battery connected to receive power from said primary battery and to provide power to said energy storage means; and

a charge control circuit powered by said primary battery and adapted to charge said secondary battery while limiting charge/discharge excursions thereof to a voltage range whose upper end is less than the maximum state of charge of said secondary battery and whose lower end is more than the minimum state of charge of said secondary battery, said upper end and said lower end of said voltage range being selected to minimize discharge capacity fade and internal resistance increase during service of said secondary battery.

11. An implantable medical device in accordance with claim 10, further including a voltage boost circuit that facilitates charging of said secondary battery at a voltage that is higher than a voltage output of said primary battery.

12. An implantable medical device in accordance with claim 10, wherein said voltage boost circuit comprises an inductive element.

13. An implantable medical device in accordance with claim 10, wherein said voltage boost circuit comprises a flyback transformer.

19. A method for powering an implantable medical device designed for high energy electrical stimulation of body tissue for therapeutic purposes, comprising:

providing a primary power source;

providing a secondary power source and connecting it to receive power from said primary power source;

connecting said secondary power source to power said implantable medical device; and

periodically charging said secondary battery by way of said primary battery while limiting charge/discharge excursions of said secondary battery to a voltage range whose upper end is less than a maximum state of charge of said secondary battery and whose lower end is more than a minimum state of charge of said secondary battery, said upper end and said lower end of said voltage range being selected to minimize discharge capacity fade and internal resistance increase during service of said secondary battery.