SYSTEM AND METHOD FOR THERMOELECTRIC CHARGING OF A BATTERY

Abstract

The present invention provides an implantable medical device (10), such as a neural implant, a neural stimulator, a pacemaker, a defibrillator, a glucometer or a drug pump. The device (10) includes a battery (B) providing a supply of electric power for operation of the device, and a system (1) for thermoelectric charging or re-charging of the battery (B). The system (1) includes a field-sensitive component (2) configured and/or adapted for transducing a field of magnetic energy, microwave energy, ultrasound energy, and/or X-ray energy into heat; and a thermoelectric module (4) arranged and/or connected to interface with the field-sensitive component (2) for generating an electric potential from the heat transduced by the field-sensitive component (2). The thermoelectric module (4) is arranged in electrical connection with the battery (B) for applying the electric potential to the battery (B).

Claims

1. An implantable medical device, such as a neural implant, a neural stimulator, a pacemaker, a defibrillator, a glucometer or a drug pump, the device comprising: a battery providing a supply of electrical power for operation of the device, and a system for thermoelectric charging or re-charging of the battery, the system comprising: a field-sensitive component configured and/or adapted for transducing a field of magnetic energy, microwave energy, ultrasound energy, and/or X-ray energy into heat; and a thermoelectric module arranged and/or connected to interface with the field-sensitive component for generating an electric potential from the heat transduced by the field-sensitive component; wherein the thermoelectric module is arranged in electrical connection with the battery for applying the electric potential to the battery.

2. A device according to claim 1, wherein the field-sensitive component is adapted for transducing one or more of alternating current magnetic field (ACMF) energy, and microwave field (MWF) energy into heat.

3. A device according to claim 2, wherein the field-sensitive component comprises a plurality of particles adapted for transducing ACMF energy, and/or the MWF energy into heat.

4. A device according to claim 2, wherein the particles comprise or contain a ferro-magnetic material or one or more of haematite, magnetite, silicon carbide, graphite, for absorbing ACMF and/or MWF energy to be transduced into heat locally.

5. A device according to claim 1, wherein the particles comprise microparticles having a diameter in the range of about 10 microns to about 100 microns, and/or nanoparticles with a diameter in the nanometer range.

6. A device according to claim 1, wherein the particles comprise a plurality of molecular spring (MS) elements, including one or more of: decane, helicine or polyacetylene; and/or phase change materials (PCM), including one or more of: norbornadiene or titanium oxide.

7. A device according to claim 3, wherein the particles comprise an inert shell of resin or silicon or glass to enclose or encapsulate the particle.

8. A device according to claim 1, wherein the field-sensitive component comprises or contains a solid block, sheet, strip, or element of material for transducing the field of magnetic energy, micro-wave energy, ultrasound energy, and/or X-ray energy into heat, wherein the material is selected from the group comprising haematite, magnetite, silicon carbide, and graphite.

9. A device according to claim 1, wherein the thermoelectric module comprises two elements of dissimilar thermoelectric material, especially an n-type semiconductor element and a p-type semiconductor element, connected at their respective end regions, wherein at one end region the two elements are interconnected by and/or interface with the field-sensitive component and at an opposite end region the two elements are interconnected by and/or interface with a heat sink.

10. A device according to claim 1, wherein the thermoelectric module includes a cooling system, preferably including a cooling jacket and/or a cooling circuit, for maintaining and/or enhancing a temperature differential with respect to a side of the thermoelectric module heated by the field-sensitive component.

11. A device according to claim 10, wherein the cooling system includes a circuit for a coolant, wherein the cooling circuit provides single-phase or two-phase immersion cooling.

12. A device according to claim 10, wherein the active cooling system forms the heat sink at the opposite end region of the two elements of dissimilar thermoelectric material, especially an n-type semiconductor element and a p-type semiconductor element.

13. A device according to claim 1, wherein the thermoelectric module includes heat shielding for maintaining and/or enhancing a temperature differential to a side of the thermo-electric module heated by the field-sensitive component.

14. A device according to claim 13, wherein the heat shielding comprises locating the heated side of the thermoelectric module remote from the cool side.

15. An implantable medical device, such as a pacemaker, a defibrillator, or a drug pump, the device comprising: a battery providing a supply of electric power for operation of the device, and a system for thermoelectric charging or re-charging of the battery, the system comprising: a field-sensitive component configured and/or adapted for transducing a field of magnetic energy, microwave energy or ultrasound energy into heat; and a thermoelectric module arranged and/or connected to interface with the field-sensitive component for generating an electric potential from the heat transduced by the field-sensitive component, the thermoelectric module having a cooling system for maintaining a temperature differential with respect to a side of the module heated by the field-sensitive component; wherein the thermoelectric module is arranged in electrical connection with the battery for applying the electric potential to the battery.

16. (canceled)

17. A system for thermoelectric charging or re-charging of a battery in a device for deployment in an inaccessible location, such as an implantable medical device, the battery providing a supply of electrical power for operation of the device, the system comprising: a field-sensitive component configured and/or adapted for transducing a field of magnetic energy, microwave energy, ultrasound energy, and/or X-ray energy into heat; and a thermoelectric module arranged and/or connected to interface with the field-sensitive component for generating an electrical potential from the heat transduced by the field-sensitive component; wherein the thermoelectric module is arranged in electrical connection with the battery for applying the electrical potential to the battery.

18. A system according to claim 17, wherein the field-sensitive component is for transducing one or more of alternating current magnetic field (ACMF) energy and microwave field (MWF) energy into heat.

19. A system according to claim 18, wherein the field-sensitive component is comprised of a material adapted for transducing ACMF energy and/or the MWF energy into heat, the material comprising a plurality of particles suited or adapted for transducing ACMF energy and/or the MWF energy into heat.

20. A system according to claim 19, wherein the particles comprise or contain ferro-magnetic material or other metamaterials, especially one or more of haematite, magnetite, silicon carbide, graphite, for absorbing ACMF and/or MWF energy to be transduced into heat.

21. A system according to claim 19, wherein the particles comprise microparticles having a diameter in the range of about 10 microns to about 100 microns, and/or naked microparticles or nanoparticles with a diameter in the nanometer range.

22. A system according to claim 19, wherein the particles comprise a plurality of molecular spring (MS) elements, including one or more of: decane, helicine or polyacetylene; and/or phase change materials (PCM), including one or more of: norbornadiene or titanium oxide.

23. A system according to claim 17, wherein the field-sensitive component comprises or contains a solid block, sheet, strip, or element of material adapted for transducing the field of magnetic energy, micro-wave energy, ultrasound energy, and/or X-ray energy into heat, wherein the material is selected from the group comprising haematite, magnetite, silicon carbide, and graphite.

24. A system according to claim 17, wherein the thermoelectric module includes an n-type semiconductor element and a p-type semiconductor element connected at their respective end regions, wherein at one end region the two elements are interconnected by and/or interface with the field-sensitive component and at an opposite end region the two elements are interconnected by and/or interface with a heat sink.

25. A system according to claim 17, wherein the thermoelectric module includes an active cooling system, including a cooling jacket or a cooling circuit, for maintaining and/or enhancing a temperature differential to a side of the thermoelectric module heated by the field-sensitive component.

26. A system according to claim 25, wherein the active cooling system forms a heat sink at the end region of the n-type and p-type semiconductor elements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a more complete understanding of the invention and advantages thereof, exemplary embodiments of the invention are explained in more detail in the following description with reference to the accompanying drawing figures, in which like reference signs designate like parts and in which:

[0026] FIG. 1 is a schematic side view of a system according to a preferred embodiment of the invention, showing application of ACMF and/or MWF energy;

[0027] FIG. 2 is a schematic side view of a system according to another embodiment of the invention, showing application of field energy;

[0028] FIG. 3 is a schematic side view of a system according to a further embodiment of the invention, showing application of field energy;

[0029] FIG. 4 is a schematic side view of a system according to yet another embodiment of the invention, showing application of field energy; and

[0030] FIG. 5 is a flow diagram that schematically represents a method of charging a battery in an IMD according to an embodiment of the invention.

[0031] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate particular embodiments of the invention and together with the description serve to explain the principles of the invention. Other embodiments of the invention and many of the attendant advantages will be readily appreciated as they become better understood with reference to the following detailed description.

[0032] It will be appreciated that common and/or well understood elements that may be useful or necessary in a commercially feasible embodiment are not necessarily depicted in order to facilitate a more abstracted view of the embodiments. The elements of the drawings are not necessarily illustrated to scale relative to each other. It will also be understood that certain actions and/or steps in an embodiment of a method may be described or depicted in a particular order of occurrences while those skilled in the art will understand that such specificity with respect to sequence is not actually required.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] With reference firstly to FIG. 1 of the drawings, a system 1 for wireless charging and recharging a battery B in an implantable medical device 10 is shown schematically. The system 1 comprises a field-sensitive component 2 configured and/or adapted for transducing a field F of applied energy, especially radio-frequency alternating current magnetic field (ACMF) energy, and/or microwave field (MWF) energy into heat. In this regard, the field-sensitive component 2 contains a dense packed array of ferro-magnetic particles 3 adapted for transducing ACMF energy and/or MWF energy into heat.

[0034] The system 1 furthermore comprises a thermoelectric module 4 arranged and connected to interface with the field-sensitive component 2 for generating an electric potential ΔV from heat transduced by the particles 3 of the field-sensitive component 2. The thermoelectric module 4 comprises a thermoelectric element 5 of a p-type semi-conductor material having positive charge carriers, and a thermoelectric element 6 of an n-type semiconductor material having negative charge carriers. Both the thermoelectric elements 5, 6 are connected (i.e. thermally conductively and preferably also physically) at one of their respective end regions with the field-sensitive component 2. In particular, at their one end region, both the n-type and p-type semiconductor elements 5, 6 are interconnected by and interface with the field-sensitive component 2 and, at an opposite end region, those semiconductor elements 5, 6 are interconnected by and interface with a heat sink 7. In this way, a temperature differential is created between the opposite end regions of the thermo-electric elements 5, 6 to generate the electric potential ΔV when the magnetic or micro-wave energy field F is applied to the field-sensitive component 2. The thermoelectric module 4 will usually include some internal resistance R.sub.i (optionally a variable resistance) and is arranged for electrical connection with the battery B at an output 8, preferably via a switchable electrical connection (not shown), for applying the electric potential ΔV to the battery B. It will be noted that, while the end region of the n-type and p-type thermoelectric elements 5, 6 are in thermally conductive connection or contact with the heat sink 7, those end regions are electrically isolated from the heat sink 7, e.g. via electrically insulating end sheets or pads 9, and electrically connected separately, e.g. via circuit wiring, to the output 8.

[0035] The nature of the particles 3 is such that they can transduce externally applied energy waves in an ACMF or MWF into heat to generate the thermal gradient which can then be converted into electricity by the Seebeck effect, hence producing a wireless re-charging of the battery. The heated field-sensitive component 2 would need to be well thermally insulated from the patient's body tissues to prevent thermal injury. To this end, thermal shielding may be employed. The system 1 is designed to generate an electric current via the Seebeck effect that can then be used to charge the contacted battery B in the IMD 10, as shown in FIG. 1. In this context, it will be noted that a resistance R.sub.L is just a simplified representation of the operational load applied to the battery B within the IMD 10. Further innovations such as shielding, insulation, spatial rearrangement, and/or incorporation of new materials, such as conducting polymers or metamaterials, into system 1, battery B and/or implanted device 10 to facilitate safe and effective re-charging are contemplated, as will be described later.

[0036] This embodiment of the invention relies on the application of a radiofrequency alternating current magnetic field, a microwave field, and/or an ultrasonic field to deliver energy specifically to the particles 3 in the implanted thermoelectric generator (TEG) of system 1. These energy fields F should be focussed as much as possible onto the field-sensitive component 2 to minimise collateral tissue damage by extraneous energy; for example, Joule heating of normal tissue by an ACMF. A number of electromagnetic coil geometries could be used to produce a uniform ACMF that encompasses an implanted TEG, including Helmholtz and Maxwell coils, pancake coils of various geometries, a simple solenoid or electromagnetic coils having soft iron cores wound with copper wire, such as a Halbach array. The configuration of the ACMF applicator would depend on the location of the TEG system 1. For example, if the TEG system 1 were located in an arm of the patient and connected by wiring to the IMD elsewhere in the body, a simple solenoid applicator head of a field generator (not shown) could accommodate the arm and apply an ACMF safely. If the TEG system 1 were located in the thorax or abdomen of the patient, then pancake coils in an applicator head of a field generator (not shown) sited above and below the supine patient could apply the ACMF.

[0037] Referring now to FIG. 2 of the drawings, a system 1 for wireless charging and/or recharging a battery B in an implantable medical device or other device 10 to be located in an inaccessible position is shown schematically. The system 1 of this embodiment is very similar to the system of FIG. 1 with a field-sensitive component 2 configured and/or adapted for transducing a field F of applied energy, such as ACMF energy and/or MWF energy, into heat. To this end, the field-sensitive component 2 contains densely packed ferro-magnetic material or particles 3 for transducing ACMF energy and/or MWF energy into heat. The system 1 furthermore includes a thermoelectric module (TEG) 4 arranged and connected interfacing with the field-sensitive component 2 for generating an electric potential ΔV from heat transduced by the material 3 of the field-sensitive component 2. To this end, the thermoelectric module 4 has a thermoelectric element 5 of p-type semi-conductor material with positive charge carriers, and a thermoelectric element 6 of n-type semiconductor material with negative charge carriers. The thermoelectric elements 5, 6 are elongate and are connected thermally, and preferably also physically, at one of their respective end regions with the field-sensitive component 2. At their opposite end regions, those semiconductor elements 5, 6 are interconnected by and interface with a heat sink 7 for creating a temperature differential between opposite end regions of the thermo-electric elements 5, 6 to generate an electric potential ΔV when the energy field F is applied to the field-sensitive component 2. A difference with this embodiment is a cooling arrangement 11 provided at the heat sink 7. In particular, the heat sink 7 has an active cooling system that includes a cooling jacket or cooling circuit 11 for circulating a coolant C to the end regions of the n-type and p-type semiconductor elements 5, 6; for example, via an inlet 12 and an outlet 13 of the cooling jacket 11. In this regard, the coolant C could be a dielectric liquid which is introduced at inlet 12 and absorbs heat from the end regions of the n-type and p-type semiconductor elements 5, 6 at the heat sink 7. This causes the liquid to change phase into a vapour conducting heat away from the elements 5, 6. When the vapour cools and loses heat as it circulates away from the outlet 13 of the TEG 4, it re-condenses into a liquid for circulating back to the inlet 12.

[0038] Referring to FIGS. 3 and 4 of the drawings, further embodiments of a system 1 for wireless charging and/or recharging a battery B in an implantable medical device or other device 10 designed/intended for an inaccessible location is shown schematically. The system 1 of these embodiments is very similar to the system of FIG. 2 and again includes an active cooling arrangement 11 at the heat sink 7. These two embodiments illustrate schematically the manner in which the system 1 may be configured such that the field-sensitive component 2 is located physically spaced from the cool side of the TEG 4—i.e. from the end regions of the n-type and p-type semiconductor elements 5, 6 at the heat sink 7. To this end, the elongate semiconductor elements 5, 6 of the TEG 4 are designed with a geometry selected to provide a spacing or separation between both an area of incidence of the field energy F to the field-sensitive component 2 and thermal shielding or isolation of the cool side of the TEG 4—i.e. of the end regions of the n-type and p-type semiconductor elements 5, 6 at the heat sink 7. In this way, the chances of an inadvertent and undesired heat transfer to the end regions of the n-type and p-type semiconductor elements 5, 6 at the heat sink 7 can be reduced or minimised.

[0039] With reference to FIG. 5 of the drawings, a flow diagram is shown to illustrate schematically the steps in a method of charging a battery according to the invention using the system 1 of the embodiments described above with reference to any one of FIGS. 1 to 4. In this example, the invention is employed in an implantable medical device (IMD) 10, such as a neural implant, a pacemaker, a defibrillator, a glucometer, or a drug pump. The IMD 10 has a battery B that provides a supply of electric power for operation of the IMD. In this regard, the first box i of FIG. 5 represents the step of arranging a field generator adjacent to and/or around a body of the patient in which the IMD is implanted. The field generator may comprise an array of coils or electromagnets for generating an electromagnetic field, especially an alternating current magnetic field (ACMF), and/or a magnetron for generating a microwave energy field (MWF). The second box ii of FIG. 5 represents a step of activating the field generator to apply the ACMF energy and/or the MWF energy to the field-sensitive component 2 of the system 1 in the patient's body, whereby the material or particles 3 packed in that component 2 transform or transduce that energy field F into heat. The third box iii of FIG. 5 represents the step of generating an electric potential ΔV from heat transduced by the field-sensitive component 2 via the thermoelectric module 4 connected to interface with the field-sensitive component 2. The final box iv in FIG. 5 of the drawings represents the step of applying that electric potential ΔV to the battery B to effect the charging or re-charging, typically by electrically connecting an output 8 of the thermoelectric module 4 with the battery B, for example by switching (not shown).

[0040] Although specific embodiments of the invention are illustrated and described herein, it will be appreciated by persons of ordinary skill in the art that a variety of alternative and/or equivalent implementations exist. It should be appreciated that each exemplary embodiment is an example only and is not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0041] It will also be appreciated that the terms “comprise”, “comprising”, “include”, “including”, “contain”, “containing”, “have”, “having”, and any variations thereof, used in this document are intended to be understood in an inclusive (i.e. non-exclusive) sense, such that the process, method, device, apparatus, or system described herein is not limited to those features, integers, parts, elements, or steps recited but may include other features, integers, parts, elements, or steps not expressly listed and/or inherent to such process, method, device, apparatus, or system. Furthermore, the terms “a” and “an” used herein are intended to be understood as meaning one or more unless explicitly stated otherwise. Moreover, the terms “first”, “second”, “third”, etc. are used merely as labels, and are not intended to impose numerical requirements on or to establish a certain ranking of importance of their objects. In addition, reference to positional terms, such as “lower” and “upper”, used in the above description are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee in the appropriate context.