PHASE CHANGE MATERIAL AS A DYNAMIC HEAT SINK FOR TRANCUTANEOUS ENERGY TRANSMISSION SYSTEMS

• US 20140233184A1
• Filed: 02/20/2014
• Published: 08/21/2014
• Est. Priority Date: 02/21/2013
• Status: Active Grant

• Current Assignee: LivaNova USA, Inc. (LivaNova Plc)
• Original Assignee: Cyberonics, Inc
• Inventors: Thompson, David L., Gaw, Shan E., Stewart, Jeffrey B., Rodriguez, John E., Ritrivi, Charles A., Ramesh, Rajesh, Lewis, Eric M.
• Granted Patent: US 9,537,344 B2
• Time in Patent Office: Days
• US Class Current: 361/692
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/6569 Fluids undergoing a liquid-gas phase change or transition, e.g. evaporation or condensation heat pipes H01M10/6552
• CPC Class Codes: H01M 2010/4278 Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller
• CPC Class Codes: H01M 2220/30 Batteries in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method and system for management of thermal energy produced during transcutaneous energy transmission to provide power to energize implanted medical devices. A phase changing material (PCM) acts as a heat sink to absorb thermal energy generated during the energy transfer process. The PCM can be thermally coupled to tissue proximate to an implanted medical device, enabling heat generated within the implantable device to be absorbed. The generation of heat during the energy transfer process is primarily caused by eddy currents induced in the implantable device by the magnetic flux produced by the energy transfer system. The PCM can also be used to absorb heat generated by the device producing the magnetic flux that is used to transcutaneously transfer electrical power to recharge a rechargeable power source or energize the implanted medical device.

Claims

1. A transcutaneous energy transfer system for providing power to an implanted device, the system comprising:

a strap having opposing first and second ends;

an external charging device mounted on the first end of the strap, the external charging device having a primary induction coil and a surface configured to face the implanted device to provide energy from the primary induction coil to the implanted device, the primary induction coil defining an inner volume at a center of the primary induction coil;

a cooling system mounted on the second end of the strap, the cooling system having an air inlet and an air outlet; and

a tubing extending between the first and second ends of the strap, an interior lumen of the tubing fluidly communicating with the inner volume of the external charging device and at least one of the air inlet and the air outlet of the cooling system.

2. The system of claim 1, further comprising a fan disposed within at least one of the external charging device and the cooling system.

3. The system of claim 1, further comprising at least one of a control interface, a display, and a battery in signal communication with at least one of the external charging device and the cooling system.

4. The system of claim 1, further comprising a phase change material disposed at the first end of the strap in thermal communication with the external charging device.

5. The system of claim 4, wherein a phase transition point of the phase change material is less than a predetermined temperature, the predetermined temperature being a temperature at which tissue damage can occur from a timed exposure to a heat generated by at least one of the external charging device and the implanted device, the time exposure being a time over which energy is provided to the implanted device.

6. The system of claim 5, wherein the external charging device and an enclosure containing the phase change material each have external surfaces configured to define an alignment with each other.

7. The system of claim 5, wherein the phase change material is a composite of a plurality of phase change materials, each of the plurality of phase change materials having a different temperature at which a phase change occurs.

8. A transcutaneous energy transfer system for providing power to an implanted device, the system comprising:

a strap having opposing first and second ends;

an external charging device mounted on the first end of the strap, the external charging device having a primary induction coil and a surface configured to face the implanted device to provide energy from the primary induction coil to the implanted device;

an enclosure in thermal communication with the external charging device, the enclosure configured to contain a phase change material as the phase change material transitions from a first phase to a second phase;

a cooling system mounted on the second end of the strap, the cooling system having a reservoir configured to contain the phase change material in the first phase; and

a tubing extending between the first and second ends of the strap, an interior lumen of the tubing fluidly communicating with the reservoir of the cooling system and the enclosure to allow a flow of the phase change material in the first phase from the reservoir to the enclosure.

9. The system of claim 8, wherein the enclosure includes an exit port configured to allow the egress of the phase change material in the second phase from the enclosure.

10. The system of claim 8, further comprising at least one of a fan and an impeller disposed within at least one of the reservoir, the tubing, and the enclosure.

11. The system of claim 8, further comprising at least one of a control interface, a display, and a battery in signal communication with at least one of the external charging device and the cooling system.

12. The system of claim 8, wherein a phase transition point of the phase change material is less than a predetermined temperature, the predetermined temperature being a temperature at which tissue damage can occur from a timed exposure to a heat generated by at least one of the external charging device and the implanted device, the time exposure being a time over which energy is provided to the implanted device.

13. The system of claim 8, wherein the external charging device and the enclosure containing the phase change material each have external surfaces configured to define an alignment with each other.

14. The system of claim 8, wherein the phase change material is a composite of a plurality of phase change materials, each of the plurality of phase change materials having a different temperature at which a phase change occurs.

15. The system of claim 9, wherein the enclosure defines a tortuous pathway extending between the tubing and the exit port.

16. The system of claim 9, wherein the enclosure defines a pathway extending between the tubing and the exit port, at least a portion of the pathway having a semicircular configuration.

17. A method of cooling an external charging device configured to be disposed on the skin of a human body, the method comprising:

delivering a flow from one side of the body to the other via a tubing, the flow including at least one of an airflow phase change material and a liquid phase change material; and

cooling a surface of the external charging device with the flow.

18. A method of cooling an external charging device configured to be disposed on the skin of a human body, the method comprising:

thermally engaging an exterior surface of the external charging device with an external surface of an enclosure containing a phase change material;

cooling the external charging device as the phase change material transitions from a first phase to a second phase; and

thermally disengaging the external charging device from the enclosure after receiving an indication that the phase change material is in the second phase.

19. The method of claim 18, further comprising:

operating at least one of a fan and an impeller to cause a flow of the phase change material through the enclosure.

20. The method of claim 18, wherein the phase change material is a composite of a plurality of phase change materials, each of the plurality of phase change materials having a different temperature at which a phase change occurs.