Betavoltaic power source including enclosure having pressure vent

Abstract

Various embodiments of a power source package are disclosed. The power source package includes an enclosure having an outer surface and an inner surface, where the enclosure includes a helium impermeable material; a betavoltaic power source disposed within an interior volume of the enclosure; and a pressure vent disposed on or at least partially in the enclosure and in fluid communication with the interior volume of the enclosure. The pressure vent is configured to vent at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

Description

Medtronic Ref. No. A0012900 WOO 1BETA VOLTAIC POWER SOURCE INCLUDING ENCLOSURE HAVING PRESSURE VENTThis application claims the benefit of U.S. Provisional Application No. 63 / 736,786, filed December 20, 2024, the disclosure of which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0001] This disclosure generally relates to a betavoltaic power source and more particularly to an implantable medical device that includes such betavoltaic power source.BACKGROUND

[0002] Power sources such as radiation particle power converters can convert energy from a radioactive source that emits high-energy electrons, e.g., beta particles, into electrical energy. The power converter can directly convert the energy of the high-energy electrons to electrical energy, i.e., current, by collecting electron-hole pairs that are formed by the high-energy electrons that are incident upon a semiconductor material of the power converter.

[0003] One such power source includes a radiation-emitting radioisotope and a plurality of semiconductor substrates. Each of the plurality of semiconductor substrates includes a junction for converting radiation particles to electrical energy, e.g., a p-n junction. The junction collects electron-hole pairs that are created within the semiconductor material caused by interaction between the nuclear radiation particles and the semiconductor material. Specifically, when a radiation particle of sufficient energy is incident upon the semiconductor material, electrons in the semiconductor material are excited into a conduction band of the semiconductor material, thereby creating electron-hole pairs. Electrons formed on an n side of a p-n junction are generally prevented from crossing the p-n junction due to the electric field that is created in a depletion zone, while the corresponding holes are swept across the p-n junction by the electric field. Electrons formed on the p side of the p-n junction are swept across the junction by the electric field while the corresponding holes are prevented from crossing the junction by the electric field. When the semiconductor material is connected to a load, electrons formed on the n side of the junction are swept across the junction from the p side via an anode and through a circuit connected to the power converter. The electrons that flow through the circuit then flow into the p side via a cathode, where they can recombine with holes from the original electron-hole pairs.

[0004] Other types of power sources that utilize radiation particles indirectly convert the particles by utilizing a phosphor layer disposed adjacent the radiation particle source. The phosphorMedtronic Ref. No. A0012900 WOO 1 absorbs the energy of the radiation particles and emits visible or invisible light, which is absorbed and converted into electricity by a photovoltaic device. While such indirect power sources may initially be less efficient than direct power sources, over time such indirect power sources have a higher efficiency and longer service life than that of at least some of the direct power sources.SUMMARY

[0005] The techniques of this disclosure generally relate to a power source package and a device that includes such power source package. The power source package can include a betavoltaic power source disposed within an interior volume of an enclosure. The package can also include a pressure vent disposed on or at least partially in the enclosure, where the vent is in fluid communication with the interior volume of the enclosure. The pressure vent can be configured to vent at least a portion of gas disposed or generated within the enclosure through the pressure vent to an external environment of the enclosure.

[0006] In one example, aspects of this disclosure relate to a power source package including an enclosure having an outer surface and an inner surfaces, a betavoltaic power source disposed within an interior volume of the enclosure, and a pressure vent disposed on or at least partially in the enclosure and in fluid communication with the interior volume of the enclosure. The pressure vent is configured to vent at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

[0007] In another example, aspects of this disclosure relate to an implantable medical device including a housing extending along a housing axis between a first end of the housing and a second end of the housing; an electronics module disposed within a first portion of the housing that is adjacent the first end of the housing; and a power source package disposed within a second portion of the housing that is adjacent the second end of the housing, where the power source package is electrically connected to the electronics module. The power source package includes an enclosure including an outer surface and an inner surface, where the enclosure defines the second portion of the housing, and a betavoltaic power source disposed within an interior volume of the enclosure; and a pressure vent disposed on or at least partially in the enclosure and in fluid communication with the interior volume of the enclosure. The pressure vent is configured to vent at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

[0008] In another example, aspects of this disclosure relate to a method including forming a power source package. Forming the power source package includes disposing a betavoltaic power source within an interior volume of an enclosure that includes an outer surface and anMedtronic Ref. No. A0012900 WOO 1 inner surface, disposing a pressure vent on or at least partially in the enclosure so that the vent is in fluid communication with the interior volume of the enclosure, and venting at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

[0009] All headings provided herein are for the convenience of the reader and should not be used to limit the meaning of any text that follows the heading, unless so specified.

[0010] The terms “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims. Such terms will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements. The term “consisting of’ means “including,” and is limited to whatever follows the phrase “consisting of.” Thus, the phrase “consisting of’ indicates that the listed elements are required or mandatory and that no other elements may be present. The term “consisting essentially of’ means including any elements listed after the phrase and is limited to other elements that do not interfere with or contribute to the activity or action specified in the disclosure for the listed elements. Thus, the phrase “consisting essentially of’ indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present depending upon whether or not they materially affect the activity or action of the listed elements.

[0011] The words “preferred” and “preferably” refer to embodiments of the disclosure that may afford certain benefits, under certain circumstances; however, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the disclosure.

[0012] In this application, terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity but include the general class of which a specific example may be used for illustration. The terms “a,” “an,” and “the” are used interchangeably with the term “at least one.” The phrases “at least one of’ and “comprises at least one of’ followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

[0013] As used herein, the term “or” is generally employed in its usual sense including “and / or” unless the content clearly dictates otherwise.

[0014] The term “and / or” means one or all of the listed elements or a combination of any two or more of the listed elements.

[0015] As used herein in connection with a measured quantity, the term “about” refers to thatMedtronic Ref. No. A0012900 WOO 1 variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used. Herein, “up to” a number (e.g., up to 50) includes the number (e.g., 50).

[0016] Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0017] The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0018] FIG. l is a schematic block diagram of one embodiment of a power source package that includes a pressure vent.

[0019] FIG. 2 is a schematic perspective view of a portion of another embodiment of a power source package that includes a pressure vent.

[0020] FIG. 3 is a schematic perspective view of a portion of another embodiment of a power source package that includes a pressure vent.

[0021] FIG. 4 is a schematic cross-section view of another embodiment of a pressure vent that can be utilized with the power source package of FIG. 1.

[0022] FIG. 5 is a schematic cross-section view of another embodiment of a pressure vent that can be utilized with the power source package of FIG. 1.

[0023] FIG. 6 is a schematic perspective view of the pressure vent of FIG. 5.

[0024] FIG. 7 is a schematic cross-section view of another embodiment of a pressure vent that can be utilized with the power source package of FIG. 1.

[0025] FIG. 8 is a schematic cross-section view of another embodiment of a pressure vent that can be utilized with the power source package of FIG. 1.

[0026] FIG. 9 is a schematic cross-section view of another embodiment of a pressure vent that can be utilized with the power source package of FIG. 1.

[0027] FIG. 10 is a schematic side view of one embodiment of an implantable medical device that includes a power source package.

[0028] FIG. 11 is a schematic block diagram of the implantable medical device of FIG. 10.

[0029] FIG. 12 is a schematic cross-section view of the implantable medical device of FIG. 10.Medtronic Ref. No. A0012900 WOO 1

[0030] FIG. 13 is a schematic perspective view of an inner portion of an enclosure of the power source package of FIG. 10.

[0031] FIG. 14 is a schematic perspective view of an outer portion of the enclosure of the power source package of FIG. 10.

[0032] FIG. 15 is a schematic perspective view of another embodiment of a pressure vent that can be utilized with the implantable medical device of FIG. 10.

[0033] FIG. 16 is a schematic perspective view of the pressure vent of FIG. 15.

[0034] FIG. 17 is a schematic perspective view of another embodiment of an implantable medical device that includes a power source package.

[0035] FIG. 18 is a schematic cross-section view of the implantable medical device of FIG. 17.

[0036] FIG. 19 is a flowchart of one technique of manufacturing the power source package ofFIG. 1.DETAILED DESCRIPTION

[0037] The techniques of this disclosure generally relate to a power source package and a device that includes such power source package. The power source package can include a betavoltaic power source disposed within an interior volume of an enclosure. The package can also include a pressure vent disposed on or at least partially in the enclosure, where the vent is in fluid communication with the interior volume of the enclosure. The pressure vent can be configured to vent at least a portion of gas disposed or generated within the enclosure through the pressure vent to an external environment of the enclosure.

[0038] Betavoltaic power sources that utilize tritium to provide beta particles that can be converted to electrical energy generate helium as the tritium decays. If the power source is disposed within a hermetic housing such as those utilized with implantable medical devices, then the generation of helium within the housing can cause an increase in an internal pressure of the housing. This internal pressure can degrade structural integrity of the housing, thereby potentially causing the housing to lose its hermeticity and allow fluids to enter the housing and damage electronic components and circuitry disposed therein.

[0039] One or more embodiments of the present disclosure can address the increase in pressure within a power source housing caused by the generation of helium that is a byproduct of the decay of the tritium of the power source. For example, a power source package of the present disclosure can include a pressure vent disposed on or at least partially in an enclosure of the package that is in fluid communication with an interior volume of the enclosure. The pressure vent can be configured to vent at least a portion of helium or other gases that are disposed or generated within the enclosure through the pressure vent to an external environment of theMedtronic Ref. No. A0012900 WOO 1 enclosure. By venting the helium, the internal pressure of the enclosure can be maintained at or below a pre-selected pressure, thereby helping to maintain structural integrity and hermeticity of the enclosure.

[0040] FIG. 1 is a block diagram of one embodiment of a power source package 10. The package 10 includes an enclosure 12 having an outer surface 14 and an inner surface 16. The package 10 also includes a betavoltaic power source 30 disposed within an interior volume 20 of the enclosure 12, and a pressure vent 22 disposed on or at least partially in the enclosure and in fluid communication with the interior volume of the enclosure. The pressure vent 22 is configured to vent at least a portion of helium generated within the enclosure 12 through the pressure vent to an external environment 24 of the enclosure. As used herein, the phrase “external environment” means an environment that is external to the interior volume 20 of the enclosure 12. In one or more embodiments, the external environment can be an environment within the human body within which the power source package 10 may be disposed as part of an IMD (e.g., IMD 600 of FIGS. 10-12). Further, in one or more embodiments, the external environment can include a housing of an IMD (e.g., housing 602 of IMD 600 of FIGS. 10-12). In one or more embodiments, the vent 22 can be configured to vent the at least a portion of helium generated within the enclosure 12 through the pressure vent to vent the portion out of the interior volume 20 of the enclosure.

[0041] The package 10 can be utilized to provide electrical energy to any suitable device or system, e.g., a medical device, an implantable medical device, electrical system, computer, smartphone, tablet, automobile, remote sensors, communication device, etc. For example, in one or more embodiments, one or more of the power source packages described herein can be utilized with any suitable implantable medical devices (IMDs), e.g., electrocardiogram (ECG) or cardiac monitors, sensors (such as glucose, pressure), implantable pulse generators (IPGs) (e.g., pacemakers, neurostimulators), implantable cardioverter defibrillators (ICDs, CRT -Ds), etc. Further, for example, one or more of the described power source packages 10 can be utilized with electronic devices that are external to the human body, e.g., EKG sensors, ECG sensors, oxygen sensors, glucose sensors, hearing aids, etc.

[0042] The enclosure 12 of the package 10 can take any suitable shape and have any suitable dimensions. In one or more embodiments, the enclosure 12 extends along an enclosure axis 2 between a first end 26 and a second end 28 of the enclosure. The enclosure 12 can further take any suitable shape in a plane substantially parallel to the enclosure axis, i.e., rectangular, cylindrical, elliptical, etc. The enclosure 12 can also take any suitable shape in a cross-sectionalMedtronic Ref. No. A0012900 WOO 1 plane that is substantially orthogonal to the enclosure axis 2, i.e., the same shapes described herein regarding the shape of the enclosure in the plane parallel to the enclosure axis.

[0043] The enclosure 12 can have any suitable helium permeability. As used herein, the phrase “helium permeability” means that that helium can pass through the material. The enclosure 12 can have a helium permeability of at least 0 and no greater than 10A(-12) ccSTD per (cmA2) area per mm thickness per cm HG pressure difference, where ccSTD is cubic-centimeters-at-standard- temperature-and-pressure. In one or more embodiments, the enclosure 12 can have a greater helium permeability so that the package 10 does not require a vent 22. In other words, the enclosure 12 can be configured to allow helium to permeate therethrough. In such embodiments, the enclosure 12 can have a helium permeability of greater than 10A(-12). In one or more of these embodiments, the enclosure 12 can have a helium permeability of greater than 10A(-8).

[0044] The enclosure 12 can include any suitable material, e.g., at least one of an inorganic material or an organic material. For example, the enclosure 12 can include at least one of glass (e.g., borosilicate glass (BSG), photo-imageable glasses (e.g., FOTURAN® or APEX®), soda lime glass), ceramic, sapphire, silicon, gallium nitride (GaN), and other semiconductor materials (indium gallium arsenide, gallium arsenide), metals (e.g., titanium, stainless steel, copper, palladium, silver), polymers, etc. In one or more embodiments, the enclosure 12 can include at least one of PEEK, LCP, or titanium. Further, the enclosure 12 can be an enclosure that prevents ingress of fluid or other contaminants into the interior volume 20 and / or egress of gas that is disposed in or generated in the interior volume. In one or more embodiments, the enclosure 12 can be a hermetic enclosure. In one or more embodiments, the enclosure 12 can be a near hermetic enclosure.

[0045] Disposed within the interior volume 20 of the enclosure 12 is the betavoltaic power source 30. Although described as a betavoltaic power source, the power source 30 can include any suitable power source that utilizes particles to generate electrical energy. Suitable betavoltaic power sources 30 include one or more of the embodiments of power sources described, e.g., in U.S. Patent Nos. 10,096,393; 10,811,157; 11,881,325; 10,290,757; 10,818,811; 10,580,544; and 11,189,390.

[0046] Power sources that utilize particles such as beta particles (i.e., a betavoltaic power source) include radioactive material that decays to provide the particles. The radioactive material is typically stored in a manner that maximizes the material’s storage density while at the same time minimizes losses caused by self-absorption within the material.

[0047] For example, betavoltaic power sources rely on beta particles, which are high energy electrons that are emitted from decaying radioactive material. While many beta emitting isotopesMedtronic Ref. No. A0012900 WOO 1 of various lifetimes and energies exist, isotopes that have a relatively low mass (to minimize selfabsorption) with reasonable half-lives and electron energies of less than what could cause damage in other materials used in the power source, e.g., 100 kiloelectronvolts (keV) or less, may be preferred. One such isotope is tritium (3H), which is an isotope of hydrogen and has an atomic mass unit of 3u, an approximate 12.3 year half-life, and peak energies of 18.6 keV.

[0048] The power source 30 can be electrically connected to one or more electronic components or circuitry 32 disposed on or at least partially in the enclosure 12 of the package 10. The electronic components 32 can include any suitable components or circuitry associated with controlling or regulating the power source 30, or storing electrical energy generated by the power source, e.g., and accumulator. Further, the electronic components 32 can be electrically connected to the power source 30 using any suitable technique. Although not shown, one or more electronic components 32 can be disposed on the outer surface 14 of the enclosure 12 or otherwise external to the enclosure and electrically connected to one or more components disposed within the enclosure using any suitable technique. For example, one or more feedthroughs can be disposed through the enclosure 12 that electrically connect external electronic components to the components 32 disposed within the enclosure.

[0049] Disposed on or at least partially in the enclosure 12 is the pressure vent 22. Although depicted as including a single pressure vent 22, the package 10 can include any suitable number of pressure vents. The pressure vent 22 can be disposed on or at least partially in any suitable portion or portions of the enclosure 12. In one or more embodiments, the pressure vent 22 extend through a wall 34 of the enclosure 12 between the outer surface 14 and the inner surface 16 of the enclosure. The pressure vent 22 is in fluid communication with the interior volume 20 of the enclosure 12 using any suitable technique. As used herein, the phrase “fluid communication” means that a fluid (e.g., gas) can pass through the pressure vent 22 between the interior volume 20 and the external environment 24.

[0050] The pressure vent 22 can take any suitable shape and have any suitable dimensions. Further, the pressure vent 22 can have any suitable thickness in a direction substantially orthogonal to the outer surface 14 of the enclosure 12 adjacent the vent.

[0051] The pressure vent 22 is configured to vent at least a portion of helium or other gas disposed or generated within the enclosure 12 through the pressure vent to the external environment 24 of the enclosure. In general, a pressure within the interior volume 20 of the enclosure 12 caused by generation of helium or other gases by the power source 30 can increase to values of at least 120 atm. The maximum pressure that can be generated depends upon a maximum tritium loading, which in turn depends upon the maximum power target for theMedtronic Ref. No. A0012900 WOO 1 betavoltaic power source along with the conversion efficiency. Such maximum loading increases as unoccupied or “dead” air space within the enclosure 12 is reduced by improving packaging efficiency.

[0052] In one or more embodiments, the pressure vent 22 can be configured to maintain the internal pressure within the enclosure 12 at or below any suitable threshold pressure. In one or more embodiments, the threshold pressure can be selected so that integrity of the enclosure 12 is maintained. In one or more embodiments, the threshold pressure can be equal to 40 atm. In one or more embodiments, threshold pressure can be equal to 10 atm over ambient atmosphere.

[0053] The pressure vent 22 can have any suitable helium flux. As used herein, the phrase “helium flux” means the mass or quantity of helium passing through the vent per unit time. The flux (delta mgas) / (delta t) = PA(delta p) / l, where (delta mgas) / (delta t) is the flux or transmission rate across a barrier, P is the permeability, A is the area of the barrier, delta p is the partial pressure differential across the barrier, and 1 is the thickness of the barrier. As a result, the flux will be a function of the design and materials and will change linearly with delta p.

[0054] As mentioned herein, the pressure vent 22 can be disposed in any suitable portion or portions of the enclosure 12. For example, in one or more embodiments, the pressure vent 22 can be disposed in the first end 26 of the enclosure 12. Further, in one or more embodiments, the pressure vent 22 can be disposed in the second end 28 of the enclosure. In one or more embodiments, the proper pressure vent 22 can be disposed in a sidewall 35 of the enclosure 12.

[0055] The pressure vent 22 can be disposed in the sidewall 35 of the enclosure 12 so that the pressure vent is circumscribed or surrounded by the wall of the enclosure. For example, FIG. 2 is a schematic side view of another embodiment of a power source package 100. All design considerations and possibilities described herein regarding power source package 10 of FIG. 1 apply equally to power source package 100 of FIG. 2 unless stated otherwise. As shown in FIG.2, a vent 122 is disposed in a sidewall 135 of an enclosure 112 of the package 100. The vent 122 is circumscribed by the enclosure 112, i.e., portions 136 of the enclosure completely surround the vent. In other words, the pressure vent 122 is similar to a window disposed through the sidewall 135 of the enclosure 112.

[0056] Further, the vent can be disposed on or at least partially in the enclosure so that the vent is disposed between two or more portions of the enclosure. For example, FIG. 3 is a schematic perspective view of another embodiment of a power source package 200. All design considerations and possibilities described herein regarding the power source package 10 of FIG.1 apply equally to the power source package 200 of FIG. 3 unless stated otherwise. A pressure vent 222 is disposed between a first portion 238 and a second portion 240 of an enclosure 212 ofMedtronic Ref. No. A0012900 WOO 1 the package 200 so that the pressure vent along with the first portion and the second portion formed the enclosure. The enclosure 212 of FIG. 3 can be formed using any suitable technique. In one or more embodiments, the pressure vent 222 can be connected to the first portion using any suitable technique, and the second portion 240 can be connected to the pressure vent using any suitable technique. In one or more embodiments, the pressure vent 222 takes the shape of the ring that forms part of a cylindrical housing or enclosure 212 along with the first and second portions 238, 240.

[0057] Returning to FIG. 1, the pressure vent 22 can include any suitable configuration so that it is configured to vent at least a portion of helium or other gas disposed or generated within the enclosure 12 through the pressure vent to the external environment 24 of the enclosure. For example, FIG. 4 is a schematic cross-section view of one embodiment of a pressure vent 322 that can be utilized with the power source package 10 of FIG. 1. All design considerations and possibilities described herein regarding the pressure vent 22 of FIG. 1 apply equally to the pressure vent 322 of FIG. 4 unless stated otherwise. The pressure vent 322 includes a cover 342 disposed over a portion 344 of the wall 34 of the enclosure 12 of the package 10 of FIG. 1. In one or more embodiments, the portion 344 of the wall 34 can have a thickness that is less than a maximum thickness of the wall of the enclosure. The reduced thickness of portion 344 can be formed using any suitable technique, e.g., etching, ablation, laser ablation, stamping, etc.

[0058] The cover 342 can take any suitable shape and have any suitable dimensions such that it can occlude the portion 44 of the wall 34. Further, the cover 342 can include any suitable material, e.g., glass. A thickness of the cover 342 can be selected to provide the desired helium flux of the vent 322. In one or more embodiments, the thickness of the cover 342 can be at least 40 microns and no greater than 500 microns. Further, the cover 342 can be disposed in any suitable configuration relative to the portion 44 of the wall 34 having reduced thickness. For example, the cover 342 can be disposed on the outer surface 14 of the enclosure 12. Further, for example, the cover 342 can be disposed on the inner surface 16 of the enclosure 12. In one or more embodiments, the cover 342 can be disposed at least partially within the portion 44 having reduced thickness, e.g., the cover can be a filler material that at least substantially fills the portion 344.

[0059] The cover 342 can be disposed over the portion 344 using any suitable technique. For example, the cover 342 can be disposed over the portion 344 using at least one of adhering, mechanically fastening, bonding, laser assisted diffusion bonding, brazing, glassing, or welding.

[0060] In one or more embodiments, a pressure vent can include one or more passageways and a cover disposed over the passageways. For example, FIGS. 5-6 are various schematic views ofMedtronic Ref. No. A0012900 WOO 1 another embodiment of a pressure vent 422 that can be utilized with the power source package 10 of FIG. 1 and is described in reference to the enclosure 12 of the package of FIG. 1. All design considerations and possibilities described herein regarding pressure vent 22 of FIG. 1 and pressure vent 322 of FIG. 4 apply equally to pressure vent 422 of FIGS. 5-6 unless stated otherwise.

[0061] The vent 422 includes one or more passageways 446, where each passageway extends between a first opening 448 defined by the outer surface 14 of the enclosure 12 and a second opening 454 defined by the inner surface 16 of the enclosure. The vent 422 can include any suitable number of passageways 446, e.g., one, two, three, four, or more passageways. In one or more embodiments, the vent 422 includes a plurality of passageways 446. Further, the passageways 446 can be arranged in any suitable pattern as shown in FIG. 6, which is a schematic perspective view of the vent 422 as formed in the enclosure 12. In one or more embodiments, the passageways 446 are randomly or pseudo-randomly disposed through the enclosure 12.

[0062] Each passageway 446 can take any suitable shape and have any suitable dimensions. For example, at least one passageway 446 can have an elliptical, rectangular, or triangular cross- sectional shape in a plane substantially parallel to the outer surface 14 of the enclosure 12. In such cross-sectional plane, each passageway 446 can have any suitable cross-sectional area.

[0063] Each passageway 446 extends along a passageway axis 402 between the first opening 448 and the second opening 454. The passageway 446 can have a constant cross-sectional area along the passageway axis 402. In one or more embodiments, the cross-sectional area of the passageway 446 can vary along the passageway axis 402. For example, at least one passageway 446 can have a chamfered portion proximate at least one of the first opening 448 or second opening 454 of the passageway. The passageways 446 can have the same cross-sectional area. In one or more embodiments, one or more passageways 446 can have a cross-sectional area that is different from one or more additional passageways.

[0064] The passageways 446 can be disposed through the enclosure 12 using any suitable technique. For example, each passageway 446 can be disposed through the enclosure 12 by at least one of drilling, laser drilling, ablating, etching, 3D printing, metal injection molding, powder metallurgy and sintering, direct laser sintering, etc. In one or more embodiments, the passageways 446 can be molded or formed when forming the enclosure 12.

[0065] The vent 422 can also include a cover 442 disposed over either the first opening 448 or the second opening 454 of each passageway 446. In one or more embodiments, the cover 442 can be disposed on the outer surface 14 of the enclosure 12 and over the first opening 448 of eachMedtronic Ref. No. A0012900 WOO 1 passageway 446. In one or more embodiments, the cover 442 can be disposed on the inner surface 16 of the enclosure 12 and over the second opening 454 of each passageway 446.

[0066] The cover 442 can be any suitable cover, e.g., cover 342 of pressure vent 322 of FIG. 4. The cover 442 can take any suitable shape and have any suitable dimensions. As shown in FIG. 6, the cover 442 can take an elliptical shape.

[0067] In one or more embodiments, the vent 422 can include a second cover (not shown) disposed over the second opening 454 of each passageway 446 and the cover 442 (which in this embodiment can be considered a first cover) is disposed over the first opening 448 of each passageway.

[0068] The cover 442 can be disposed over the passageways 446 using any suitable technique. Further, the cover 442 can be connected to the enclosure 12 using any suitable technique, e.g., adhering, mechanically fastening, bonding, laser assisted diffusion bonding, brazing, glassing, or welding. In one or more embodiments, the cover 442 can be disposed so that at least a portion of the material of the cover is disposed at least partially within one or more passageways 446 using any suitable technique, e.g., melt bonding, deposition, etc.

[0069] In one or more embodiments, one or more of the passageways 446 can be at least partially filled with any suitable material to prevent ingress of fluid or debris when the passageways are exposed to the exterior of the IMD. For example, a parylene coating can be disposed over one or more of the passageways 446 and one or more portions of the outer surface of the IMD. Such coating can have any suitable thickness, e.g., at least 5 micrometers and no greater than 10 micrometers. Further, for example, a silicone or parylene material can be disposed in one or more of the passageways 446.

[0070] As mentioned herein, the various embodiments of vents can be connected to an enclosure of the power source package (e.g., enclosure 12 of the power source package 10 of FIG. 1) using any suitable technique. For example, FIG. 7 is a schematic cross-section view of another embodiment of a vent 522 that is disposed in the via 62 connected to the enclosure 12 of the power source package 10 of FIG. 1. All design considerations and possibilities described herein regarding the vent 22 of FIG. 1 apply equally to the vent 522 of FIG. 7. The vent 522 includes a substrate 550 and one or more passageways 546 disposed through the substrate, where each passageway includes a first opening 548 defined by an outer surface 552 of the substrate and a second opening 554 defined by an inner surface 556 of the substrate. The vent 522 further includes a cover 542 disposed over the second opening 554 of each passageway 546. The cover 542 can have any suitable dimensions. In one or more embodiments, the cover 542 can have a thickness of at least 1 micron and no greater than 500 microns.Medtronic Ref. No. A0012900 WOO 1

[0071] The substrate 550 can include any suitable material, e.g., the same material utilized to form an enclosure (e.g., enclosure 12 of FIG. 1). In one or more embodiments, the substrate 550 can include a helium impermeable material. As shown in FIG. 7, the vent 522 is connected to the enclosure 12 by connecting the substrate 550 of the vent to the enclosure using any suitable technique, e.g., adhering, mechanically attaching, bonding, laser diffusion assisted bonding, welding, melt bonding, etc.

[0072] FIG. 8 is a schematic cross-section view of another embodiment where the vent 522 is attached to the enclosure 12. A ferrule 560 can be disposed at least partially within the via 62 of the enclosure 12 and connected to the inner surface 16 of the enclosure using any suitable technique. In one or more embodiments, at least a portion of the ferrule 560 can also be connected to an inner wall 64 defined by the via 62 of the enclosure 12. The ferrule 560 can take any suitable shape and have any suitable dimensions. As shown, the ferrule 560 includes a flange 566 that extends toward a center of the via 62 of the enclosure 12 and is configured to be connected to the substrate 550 of the vent 522 using any suitable technique. The ferrule 560 can take any suitable shape and have any suitable dimensions. For example, the ferrule 560 can take a shape that is similar to the shape taken by the cover 542 of the vent 522. For the vent 422 illustrated in FIGS. 5-6, the flange 566 would take an elliptical shape in a plane parallel to the inner surface 556 of the substrate 550. Although not shown, a filler material can be disposed between the vent 522 and the ferrule 560 to bond the vent to the ferrule. For example, glass can be disposed in molten form between the vent 522 and the ferrule 560 to attach the vent to the ferrule.

[0073] FIG. 9 is a schematic cross-section view of another embodiment where the vent 522 is attached to the enclosure 12. As shown, the vent 522 is disposed in the via 62 of the enclosure 12. One or more bonds 568 can be formed between a metal layer 569 (e.g., titanium) that is disposed on the outer surface 14 of the enclosure 12 and the substrate 550 of the vent 522 using any suitable technique to connect the vent 522 to the enclosure. The metal layer 569 can be disposed using any suitable technique, e.g., metallization of the outer surface 14 of the enclosure 12. Such metallization can be connected to the enclosure 12 and the substrate 550 of the vent 522 using any suitable technique, e.g., laser assisted diffusion bonding. In one or more embodiments, the bond 568 and the metal layer 569 can encircle a boundary between the vent 522 and the enclosure 12 on at least one of the outer surface 14 or the inner surface 16 to provide a seal between the vent and the enclosure.

[0074] As mentioned herein, the power source package 10 can be utilized in any suitable device or system. For example, FIGS. 10-12 are various views of one embodiment of an implantableMedtronic Ref. No. A0012900 WOO 1 medical device (IMD) 600. The IMD 600 includes a hermetic housing 602 that extends along a housing axis 601 between a first end 604 and a second end 606 of the housing. The IMD 600 further includes an electronics module 674 disposed within a first portion 638 of the housing 602 adjacent the first end 604 of the housing, and a power source package 610 disposed within a second portion 640 of the housing that is adjacent the second end 606 of the housing. The power source package 610 is electrically connected to the electronics module 674.

[0075] The IMD 600 can include any suitable implantable medical device, e.g., electrocardiogram (ECG) monitors, sensors (such as glucose, pressure), implantable pulse generators (IPGs) (e.g., pacemakers), implantable cardioverter defibrillators (ICDs), etc. Further, for example, one or more of the described power source packages and be utilized with electronic devices that are external to the human body, e.g., EKG sensors, ECG sensors, oxygen sensors, glucose sensors, hearing aids, etc. Further, for example, the IMD 600 can include one or more embodiments of implantable medical devices described in at least one of U.S. Patent No.11,633,611 to Ries et al. and entitled FEEDTHROUGH ASSEMBLY AND DEVICE INCLUDING SAME; or U.S. Patent No. 11,865,639 to Ruben et al. and entitled HERMETIC ASSEMBLY AND DEVICE INCLUDING SAME.

[0076] In one or more embodiments, the IMD 600 is adapted to be implanted within a chamber of the heart of the patient, e.g., to monitor electrical activity of the heart and / or provide electrical therapy to the heart. In the example shown in FIG. 10, the IMD 600 includes the housing 602, fixation 676 (which may be a helix, tines, other fixation mechanism or combination of fixation mechanisms), and electrodes 678 and 680.

[0077] The housing 602 of the IMD 600 can include any suitable dimensions and take any suitable shape or shapes. The housing 602 extends between the first end 604 and the second end 606 along the housing axis 601. In one or more embodiments, the housing 602 can have a cylindrical (e.g., pill-shaped) form factor. In one or more embodiments, the housing 602 includes an elongated tubular housing. Further, the housing 602 can include any suitable material.

[0078] Housing 602, also referred to as an elongated housing, houses the electronics module 674 that can include any suitable electronic components or circuitry, e.g., sensing circuitry for sensing electrical activity via electrodes 678 and 680 and therapy generation circuitry for delivering electrical stimulation therapy via the electrodes. Electronic components can include any discrete and / or integrated electronic circuit components that implement analog and / or digital circuits capable of producing the functions attributed to the IMD 600 described herein. In one or more embodiments, housing 602 can also house components for sensing other physiological parameters, such as acceleration, pressure, sound, and / or impedance. Although shown with twoMedtronic Ref. No. A0012900 WOO 1 electrodes 678 and 680, the device 600 can include any suitable number of electrodes disposed in any suitable portion or portions of the housing.

[0079] Additionally, the housing 602 can also house a memory that includes instructions that, when executed by processing circuitry housed within housing, cause the IMD 600 to perform various functions attributed to the device herein. In one or more embodiments, the housing 602 can house communication circuitry that enables the IMD 600 to communicate with other electronic devices, such as a medical device programmer. In one or more embodiments, the housing 602 can house an antenna for wireless communication. The housing 602 can also house the power source package 610. The housing 602 can be hermetically or near-hermetically sealed using any suitable technique to help prevent fluid ingress into the housing. For example, in one or more embodiments, one or more portions of the housing 602 can be hermetically sealed together utilizing one or more laser diffusion bonding techniques described in co-owned U.S. Patent No. 10,124,559 B2, entitled KINETICALLY LIMITED NANO-SCALE DIFFUSION BOND STRUCTURES AND METHODS.

[0080] The housing 602 includes the first portion 638 and the second portion 640. The second portion 640 can, in one or more embodiments, define at least part of an enclosure 612 that houses a power source 630 of the power source package 610 of the IMD 600. In one or more embodiments, the enclosure 612 of the power source package 610 defines the second portion 640 of the housing 602 of the IMD 600.

[0081] The first portion 638 of the housing 602 can be connected to the second portion 640 of the housing using any suitable technique. In one or more embodiments, the first portion 638 of the housing 602 can be connected to the second portion 640 of the housing using laser bonding. For example, electromagnetic radiation (e.g., light) can be directed through an outer surface of the first portion 638 and focused at an interface between the first portion and the second portion 640 to form a laser bond.

[0082] FIG. 11 is a schematic block diagram of one embodiment of the IMD 600 including power source package 610, the electronics module 674, and an electrical contact assembly 682. Although the IMD of FIG. 11 is described as IMD 600, the structures shown in FIG. 11 can also be used in other implantable or external medical devices, such as cardioverter-defibrillators, physiological monitors, or neurostimulators, or any other electronic devices.

[0083] The housing 602 includes the first and second portions 638, 640 and a side wall 684 disposed within the housing between the power source package 610 and the electrical contact assembly 682. The side wall 684 can be disposed within the first and second housing portions 638, 640 of the housing 602 or at the boundary of first and second housing portions. In one orMedtronic Ref. No. A0012900 WOO 1 more embodiments, the side wall 684 can be defined by a portion of the enclosure 612 of the power source package 610 as shown in FIG. 12.

[0084] The side wall 684 extends across housing 602 between the power source package 610 on one side and the electrical contact assembly 682 on the other side. The side wall 684 can include at least one feedthrough (not shown) to allow for electrical connection between the power source package 610 and the electronics module 674. The IMD 600 further includes a feedthrough header assembly 686 that can also include at least one feedthrough to allow for an electrical connection between electrode 678 and electronic layers 688 of electronics module 674. Electronics module 674 is disposed between the electrode 678 and the electrical contact assembly 682. The electronic contact assembly 682 provides an electrical connection between the power source package 610 and the electronics module 674. For example, the electronics module 674 can include one or more electrical contacts that are adapted to electrically connect the module to the electronic contact assembly 682.

[0085] The electronics module 674 can include any suitable elements or components. For example, as shown in FIG. 11, the electronics module 674 includes one or more electronic layers 688 and the feedthrough header assembly 686 electrically connected to the one or more electronic layers. The electronics module 674 can also include one or more coils 690 electrically connected to the electronic layers 688.

[0086] The power source package 610 of the IMD 600 can include any suitable package, e.g., power source package 10 of FIG. 1. All design considerations and possibilities described herein regarding power source package 10 of FIG. 1 apply equally to power source package 610 of FIGS. 10-12 unless stated otherwise. As shown in FIG. 12, power source package 610 includes the enclosure 612 including an outer surface 614 and an inner surface 616, where the enclosure defines the second portion 640 of the housing 602 of the IMD 600. The power source package 610 also includes a betavoltaic power source 630 disposed within an interior volume 620 of the enclosure 612, and a pressure vent 622 disposed on or at least partially in the enclosure and in fluid communication with the interior volume of the enclosure. The pressure vent 622 is configured to vent at least a portion of helium or other gas disposed or generated within the enclosure 612 through the pressure vent to an external environment 624 of the enclosure.

[0087] As mentioned herein, the pressure vent 622 can be disposed in any suitable portion or portions of the enclosure 612 of the package 610. As shown in FIG. 12 the vent 622 is disposed in the second end 606 of the housing 602 of the IMD 600. The pressure vent 622 can include any suitable pressure vent described herein, e.g., pressure vent 22 of FIG. 1. In one or moreMedtronic Ref. No. A0012900 WOO 1 embodiments, the pressure vent 622 can include one more passageways disposed through the enclosure 612 as described, e.g., in reference to pressure vent 422 of FIG. 5.

[0088] As shown in FIGS. 13-14, which are schematic views of a portion of the enclosure 612 of the power source package 610, the pressure vent 622 includes a plurality of passageways 646 each extending between a first opening 648 defined by the outer surface 614 of the enclosure 612 and a second opening 654 defined by the inner surface 616 of the enclosure. The pressure vent 622 also includes a cover 642 disposed on the inner surface 616 of the enclosure 612 and over the second opening 654 of each passageway 646 of the plurality of passageways and hermetically sealed to the enclosure 612 using any suitable technique. The cover 642 is shown as being transparent in FIG. 13. In one or more embodiments, the cover 642 can be opaque, partially transmissive, translucent, etc. Although shown as being disposed on the inner surface 616 of the enclosure 612, the cover 642 can be disposed on the outer surface 614 of the enclosure 612 and over the first opening 648 of each passageway 646. In one or more embodiments, the pressure vent 622 can include a second cover disposed on the outer surface 614 of the enclosure 612 and over the first opening 648 of each passageway 646, and the cover 642 (i.e., in this embodiment the first cover) can be disposed on the inner surface 616 of the enclosure 612 and over the second opening 654 of each passageway.

[0089] The cover 642 can be sealed to the enclosure 612 using any suitable technique. In one or more embodiments, the cover 642 can be melt-bonded to the outer or inner surface 614, 616 of the enclosure 612. In one or more embodiments, the cover 642 can be mechanically fastened to the enclosure 612 by a ledge 692 (FIG. 12) that is connected to the inner surface 616 of the enclosure 612. In one or more embodiments, the ledge 692 can be integral with the inner surface 616 of the enclosure. The ledge 692 can be configured to restrain the cover 642 against the inner surface 616 of the enclosure 612.

[0090] The passageways 646 can take any suitable shape and have any suitable dimensions. As shown in FIGS. 13-14, at least one of the passageways 746 takes an elliptical shape in a plane orthogonal to the housing axis 601 (FIG. 1). FIGS. 15-16 illustrate another embodiment of a pressure vent 722 disposed on or at least partially in the enclosure 612 of the power source package 610 of IMD 600. Each passageway 746 can take arc shape in the plane orthogonal to the housing axis 601 of FIG. 10.

[0091] Returning to FIGS. 10-14, the pressure vent 622 can also include a bolt passageway 694 extending between a first opening 695 defined by an outer surface 696 of a bolt 697 connected to the second end 606 of the housing 602 of the IMD 600 and a second opening 698 defined by the inner surface 616 of the enclosure 612 of the power source package 610. The cover 642 of theMedtronic Ref. No. A0012900 WOO 1 pressure vent 622 is further disposed over the first opening 695 or the second opening 698 of the bolt passageway 694 and hermetically sealed to the enclosure 612. In the embodiment illustrated in FIGS. 10-14, the cover 642 is disposed over the second opening 698 of the bolt passageway 694. The bolt passageway 694 can take any suitable shape and have any suitable dimensions. Although depicted as including a single bolt passageway 694, the pressure vent 622 can include any suitable number of bolt passageways.

[0092] As mentioned herein, the pressure vent 622 can be disposed in any suitable portion or portions of the enclosure. Although not shown, in one or more embodiments, the pressure vent 622 can be disposed in a first end 606 of the enclosure 612, where the pressure vent is configured to vent the at least a portion of helium disposed within the interior volume 620 of the enclosure through the pressure vent into the first portion 638 of the housing 602 of the IMD 600. In one or more embodiments, the pressure vent 622 can be disposed between the first portion 638 and the second portion 640 of the housing 602 of the IMD 600 as shown, e.g., in FIG. 3.

[0093] As mentioned herein, the power source package 610 can include any suitable electronic components or circuitry, e.g., electronic components 32 of power source package 10 of FIG. 1. The power source package 610 includes an accumulator 699 disposed within the enclosure 612 of the package. The accumulator 699 can be electrically connected to the betavoltaic power source 630 and can be configured to store charge generated by the power source. In one or more embodiments, the accumulator 699 can be disposed external to the enclosure 612 of the power source package 610 and electrically connected to the power source 630 of the package using any suitable technique, e.g., by a via 626.

[0094] As mentioned herein, the various embodiments of power source packages can be utilized with any suitable implantable medical device. For example, FIGS. 17-18 are various views of another embodiment of an implantable medical device (IMD) 800. All design considerations and possibilities described herein regarding IMD 600 of FIGS. 10-14 apply equally to IMD 800 of FIGS. 17-18. The IMD 800 includes a hermetic housing 802 and an electronics module 874 disposed within the housing. The IMD 800 also includes a power source package 810 disposed within the housing 802 that is electrically connected to the electronics module 874. The power source package 810 can include any suitable power source package, e.g., power source package 10 of FIG. 10. The IMD 800 can include any suitable implantable medical device, e.g., one or more embodiments of implantable medical devices described, e.g., in at least one of U.S. Patent No. 11,633,611 to Ries et al. and entitled FEEDTHROUGH ASSEMBLY AND DEVICE INCLUDING SAME; or U.S. Patent No. 11,865,639 to Ruben et al. and entitled HERMETIC ASSEMBLY AND DEVICE INCLUDING SAME.Medtronic Ref. No. A0012900 WOO 1

[0095] The housing 802 includes a dielectric substrate 804. In one or more embodiments, a patterned conductive layer 801 can be disposed on the substrate 804 and can include an external electrode 809 disposed on the substrate. The external electrode 809 can be electrically connected to the electronics module 874 using any suitable technique. In one or more embodiments, the external electrode 809 can be adapted to direct energy (e.g., a signal) to tissue of a patient. In one or more embodiments, the external electrode 809 can be adapted to receive energy from tissue of the patient, thereby functioning as a sensor. In one or more embodiments, the external electrode 809 can be adapted to direct and receive energy to and from tissue of a patient.

[0096] The IMD 800 can take any suitable shape. In one or more embodiments, at least one of the housing 802 or the dielectric substrate 804 can take a rectangular shape in a plane that is substantially parallel to a major surface 805 of the dielectric substrate. Further, the IMD 800 can have any suitable dimensions.

[0097] The power source package 810 can include a pressure vent 822 disposed in any suitable portion or portions of an enclosure 812 of the package. As shown in FIG. 18, the pressure vent 822 can be disposed through the dielectric substrate 804 and fluidly connected to an interior volume 820 of the package 810 using any suitable technique.

[0098] Returning to FIG. 1, the power source package 10 can be manufactured using any suitable technique. For example, FIG. 19 is a flowchart of one embodiment of a technique 900 of forming the power source package 10. Although described regarding power source package 10 of FIG. 1, the technique 900 can be utilized to manufacture any suitable power source package.

[0099] At 902, the betavoltaic power source 30 can be disposed within the interior volume 20 of the enclosure 12 using any suitable technique. The pressure vent 22 can be disposed on or at least partially in the enclosure 12 at 904 so that the vent is in fluid communication with the interior volume 20 of the enclosure using any suitable technique. For example, as shown in FIG. 5 and in reference to vent 422, one or more passageways 446 can be disposed into the enclosure 12 so that each passageway extends between the first opening 448 defined by the outer surface 14 of the enclosure and the second opening 454 defined by the inner surface 16 of the enclosure. The cover 442 of the vent 422 can be disposed over the first opening 448 or the second opening 454 of each passageway 446 using any suitable technique. Further, the cover 442 of the vent 422 can be hermetically sealed to the enclosure 12 using any suitable technique. In the embodiment of vent 522 that includes the substrate 550, the vent can be disposed on or at least partially in the enclosure 12 by using any suitable technique as described, e.g., in reference to FIGS. 7-9.Medtronic Ref. No. A0012900 WOO 1

[0100] For the vent 322 described in reference to FIG. 4, such vent can be disposed on or at least partially in the enclosure 12 by reducing a thickness of the portion 344 of the enclosure 12 to define the vent.

[0101] At 906, a gas (e.g., helium) disposed or generated within the enclosure 12 can be vented through the pressure vent 22 to the external environment 24 using any suitable technique. Any suitable amount of gas can be vented to the external environment over any suitable time period. In one or more embodiments, the gas can be vented so that the pressure of the interior volume 20 of the enclosure 12 remains at or below a pressure threshold, e.g., at or below 40 atm.

[0102] For the embodiment illustrated in FIG. 12, the enclosure 612 of power source package 610 can optionally be connected to the first portion 638 of the housing 602 of the implantable medical device 600 at 908, where the enclosure of the power source package defines the second portion 640 of the housing of the implantable medical device. One or more electronic components such as electronics module 674 can optionally be disposed within the first portion 638 of the housing 602 at 910, and the electronic components of the electronics module 674 can optionally be electrically connected at 912 to the power source package 610 using any suitable technique. Further, the pressure vent 622 can be disposed at 904 by disposing the plurality of passageways 646 in the enclosure 612 at the second end 606 of the housing 602. The cover 642 can be disposed over the first opening 648 or the second opening 654 of each passageway 646 of the plurality of passageways, and the cover can be hermetically sealed to the enclosure 612 using any suitable technique, e.g., melting bonding. In one or more embodiments, the pressure vent 622 can further be disposed at 904 by disposing the bolt passageway 694 in the housing 602, where disposing the cover 642 of the pressure vent further includes disposing the cover over the first opening 695 or second opening 698 of the bolt passageway. Further, in one or more embodiments, the pressure vent 622 at 904 can be disposed by disposing the pressure vent on or at least partially in the second end 606 of the enclosure 612 of the power source package 610.The enclosure 612 can be vented by venting the at least a portion of the helium or gas disposed or generated within the enclosure through the pressure vent 622 into the first portion 638 of the housing 602 of the implantable medical device 600. In this embodiment, the pressure vent 622 can be disposed at 904 by disposing the vent between the first portion 638 and the second portion 640 of the housing 602 of the device 600 using any suitable technique.

[0103] It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in aMedtronic Ref. No. A0012900 WOO 1 different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

[0104] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to a tangible medium such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer).

[0105] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor” as used herein may refer to any of the foregoing structure or any other physical structure suitable for implementation of the described techniques. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0106] This disclosure includes without limitation the following clauses:

[0107] Clause 1 : A power source package including an enclosure having an outer surface and an inner surface, where the enclosure includes a helium impermeable material; a betavoltaic power source disposed within an interior volume of the enclosure; and a pressure vent disposed on or at least partially in the enclosure and in fluid communication with the interior volume of the enclosure. The pressure vent is configured to vent at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

[0108] Clause 2: The package of Clause 1, where the enclosure includes titanium.

[0109] Clause 3: The package of any one of Clauses 1-2, where the betavoltaic power source comprises tritium.

[0110] Clause 4: The package of any one of Clauses 1-3, where the power source package further includes an accumulator disposed within the enclosure and electrically connected to the betavoltaic power source..[OHl] Clause 5: The package of any one of Clauses 1-4, where the pressure vent includes a portion of a wall of the enclosure.Medtronic Ref. No. A0012900 WOO 1

[0112] Clause 6: The package of Clause 5, where the pressure vent further includes a cover disposed on the outer surface or the inner surface of the enclosure.

[0113] Clause 7: The package of Clause 6, where the cover includes glass.

[0114] Clause 8: The package of any one of Clauses 6-7, where the cover is disposed on the outer surface of the enclosure.

[0115] Clause 9: The package of any one of Clauses 6-7, where the cover is disposed on the inner surface of the enclosure.

[0116] Clause 10: The package of any one of Clauses 1-9, where a gas pressure within the interior volume of the enclosure is no greater than about 10 atm over ambient atmosphere.

[0117] Clause 11 : The package of any one of Clauses 1-10, where the enclosure further includes a first portion and a second portion, where the pressure vent is disposed between the first portion and the second portion and forms the enclosure with the first portion and the second portion.

[0118] Clause 12: The package of any one of Clauses 1-10, where the enclosure extends along an enclosure axis between a first end and a second end.

[0119] Clause 13: The package of Clause 12, where the enclosure includes a cylindrical shape in a plane substantially parallel to the enclosure axis.

[0120] Clause 14: The package of any one of Clauses 12-13, where the pressure vent is disposed in the first end or the second end of the enclosure.

[0121] Clause 15: The package of any one of Clauses 1-10, where the pressure vent includes a passageway extending between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of enclosure, and a cover disposed over the first opening or the second opening of the passageway and hermetically sealed to the enclosure.

[0122] Clause 16: The package of Clause 15, where the cover is disposed on the outer surface of the enclosure and over the first opening of the passageway.

[0123] Clause 17: The package of Clause 15, where the cover is disposed on the inner surface of the enclosure and over the second opening of the passageway.

[0124] Clause 18: The package of any one of Clauses 15-17, where the passageway includes a plurality of passageways.

[0125] Clause 19: An implantable medical device including a housing extending along a housing axis between a first end of the housing and a second end of the housing; an electronics module disposed within a first portion of the housing that is adjacent the first end of the enclosure; and a power source package disposed within a second portion of the housing that is adjacent the second end of the housing, where the power source package is electrically connected to the electronics module. The power source package includes an enclosure including an outer surface and an innerMedtronic Ref. No. A0012900 WOO 1 surface, where the enclosure defines the second portion of the housing, a betavoltaic power source disposed within an interior volume of the enclosure, and a pressure vent disposed on or at least partially in the enclosure and in fluid communication with the interior volume of the enclosure. The pressure vent is configured to vent at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

[0126] Clause 20: The device of Clause 19, where the pressure vent is disposed in the second end of the housing.

[0127] Clause 21 : The device of Clause 20, where the pressure vent includes a plurality of passageways each extending between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of the enclosure, and a cover disposed over the first opening or the second opening of each passageway of the plurality of passageways and hermetically sealed to the enclosure.

[0128] Clause 22: The device of Clause 21, where the pressure vent further includes a bolt passageway extending between a first opening defined by an outer surface of a bolt connected to the second end of the housing and a second opening defined by the inner surface of the enclosure. The cover of the pressure vent is further disposed over the first opening or the second opening of the bolt passageway and hermetically sealed to the enclosure.

[0129] Clause 23: The device of any one of Clauses 21-22, where the cover is disposed on the inner surface the enclosure at the second end of the housing.

[0130] Clause 24: The device of Clause 23, where the enclosure further includes a ledge disposed on the inner surface of the enclosure at the second end of the housing and configured to restrain the cover against the inner surface of the enclosure.

[0131] Clause 25: The device of any one of Clauses 23-24, where the cover is melt-bonded to the inner surface of the housing.

[0132] Clause 26: The device of any one of Clauses 21-22, where the cover is disposed on the outer surface of the enclosure at the second end of the housing.

[0133] Clause 27: The device of any one of Clauses 21-26, where at least one passageway of the plurality of passageways includes an elliptical shape in a cross-sectional plane substantially orthogonal to the housing axis.

[0134] Clause 28: The device of any one of Clauses 21-26, where at least one passageway of the plurality of passageways includes an arc shape in a cross-sectional plane substantially orthogonal to the housing axis.Medtronic Ref. No. A0012900 WOO 1

[0135] Clause 29: The device of Clause 19, where the enclosure of the power source package extends along an enclosure axis between a first end and a second end, where the second end of the enclosure defines the second end of the housing of the device.

[0136] Clause 30: The device of Clause 29, where the pressure vent is disposed on or at least partially in the first end of the enclosure of the power source package and is configured to vent the at least a portion of helium disposed within the interior volume of the enclosure through the pressure vent into the first portion of the housing of the device.

[0137] Clause 31 : The device of Clause 19, where the pressure vent is disposed between the first portion and the second portion of the housing of the device.

[0138] Clause 32: The device of any one of Clauses 19-31, where the power source package further includes an accumulator disposed within the enclosure and electrically connected to the betavoltaic power source.

[0139] Clause 33: The device of Clause 19, where the pressure vent of the power source package includes a passageway extending between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of enclosure, and a cover disposed over the first opening or the second opening of the passageway and hermetically sealed to the enclosure.

[0140] Clause 34: The device of Clause 33, where the passageway is disposed in a side surface of the enclosure that extends between a first end and a second end of the enclosure, where the second end of the enclosure defines the second end of the housing of the device.

[0141] Clause 35: A method including forming a power source package. Forming the power source package disposing a betavoltaic power source within an interior volume of an enclosure that includes an outer surface and an inner surface, disposing a pressure vent on or at least partially in the enclosure so that the vent is in fluid communication with the interior volume of the enclosure, and venting at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

[0142] Clause 36: The method of Clause 35, where disposing the pressure vent includes disposing a passageway into the enclosure that extends between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of the enclosure, disposing a cover over the first opening or the second opening of the passageway, and hermetically sealing the cover to the enclosure.

[0143] Clause 37: The method of Clause 36, where disposing the passageway includes disposing a plurality of passageways into the enclosure each extending between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of theMedtronic Ref. No. A0012900 WOO 1 enclosure, where the cover is disposed on the first opening or the second opening of each passageway of the plurality of passageways.

[0144] Clause 38: The method of Clause 35, where disposing the pressure vent includes reducing a thickness of a portion of the enclosure to define the pressure vent.

[0145] Clause 39: The method of Clause 35, further including connecting the enclosure of the power source package to a first portion of a housing of an implantable medical device, where the enclosure of the power source package defines a second portion of the housing of the implantable medical device, and further where the housing of the implantable medical device extends along a housing axis between a first end and a second end. The first portion of the housing is adjacent the first end and the second portion of the housing is adjacent the second end.

[0146] Clause 40: The method of Clause 39, further including disposing an electronic component within the first portion of the housing, and electrically connecting the electronic component to the power source package.

[0147] Clause 41 : The method of any one of Clauses 39-40, where disposing the pressure vent of the power source package includes disposing a plurality of passageways in the enclosure at the second end of the housing, where each passageway extends between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of the enclosure; disposing a cover over the first opening or second opening of each passageway of the plurality of passageways; and hermetically sealing the cover to the enclosure.

[0148] Clause 42: The method of Clause 41, where disposing the pressure vent of the power source package further includes disposing a bolt passageway in the housing and extending between a first opening defined by an outer surface of a bolt connected to the second end of the housing and a second opening defined by the inner surface of the enclosure, where disposing the cover of the pressure vent further includes disposing the cover over the first opening or second opening of the bolt passageway.

[0149] Clause 43: The method of any one of Clauses 41-42, where disposing the cover includes melt bonding the cover to the inner surface of the enclosure.

[0150] Clause 44: The method of any one of Clauses 39-40, where disposing the pressure vent of the power source package includes disposing the pressure vent on or at least partially in an end surface of the enclosure of the power source package, where the end surface of the enclosure is adjacent the first portion of the housing of the implantable medical device, where venting the at least a portion of helium includes venting the at least a portion of the helium generated within the enclosure through the pressure vent into the first portion of the housing of the implantable medical device.Medtronic Ref. No. A0012900 WOO 1

[0151] Clause 45: The method of any one of Clauses 39-40, where disposing the pressure vent includes disposing the pressure vent between the first portion and the second portion of the housing of the device.

[0152] All references and publications cited herein are expressly incorporated herein by reference in their entirety into this disclosure, except to the extent they may directly contradict this disclosure. Illustrative embodiments of this disclosure are discussed and reference has been made to possible variations within the scope of this disclosure. These and other variations and modifications in the disclosure will be apparent to those skilled in the art without departing from the scope of the disclosure, and it should be understood that this disclosure is not limited to the illustrative embodiments set forth herein. Accordingly, the disclosure is to be limited only by the claims provided below.

Claims

Medtronic Ref. No. A0012900 WOO 1WHAT IS CLAIMED IS:

1. A power source package comprising: an enclosure comprising an outer surface and an inner surface; a betavoltaic power source disposed within an interior volume of the enclosure; and a pressure vent disposed on or at least partially in the enclosure and in fluid communication with the interior volume of the enclosure, wherein the pressure vent is configured to vent at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

2. The package of claim 1, wherein the enclosure further comprises a first portion and a second portion, wherein the pressure vent is disposed between the first portion and the second portion and forms the enclosure with the first portion and the second portion.

3. The package of any one of claims 1 or 2, wherein the pressure vent comprises: a passageway extending between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of enclosure; and a cover disposed over the first opening or the second opening of the passageway and hermetically sealed to the enclosure.

4. The package of claim 3, wherein the cover is disposed on the outer surface of the enclosure and over the first opening of the passageway.

5. The package of claim 3, wherein the cover is disposed on the inner surface of the enclosure and over the second opening of the passageway.

6. The package of any one of claim 3-5, wherein the passageway comprises a plurality of passageways.

7. An implantable medical device comprising: a housing extending along a housing axis between a first end of the housing and a second end of the housing; an electronics module disposed within a first portion of the housing that is adjacent the first end of the housing; andMedtronic Ref. No. A0012900 WOO 1 the power source package of claim 1, the power source package being disposed within a second portion of the housing that is adjacent the second end of the housing, wherein the power source package is electrically connected to the electronics module, and further wherein the enclosure of the power source package defines the second portion of the housing.

8. The device of claim 7, wherein the pressure vent is disposed in the second end of the housing.

9. The device of claim 8, wherein the pressure vent further comprises a bolt passageway extending between a first opening defined by an outer surface of a bolt connected to the second end of the housing and a second opening defined by the inner surface of the enclosure, wherein the cover of the pressure vent is further disposed over the first opening or the second opening of the bolt passageway and hermetically sealed to the enclosure.

10. The device of claim 8, wherein the cover is disposed on the inner surface the enclosure at the second end of the housing.

11. The device of claim 10, wherein the enclosure further comprises a ledge disposed on the inner surface of the enclosure at the second end of the housing and configured to restrain the cover against the inner surface of the enclosure.

12. The device of claim 7, wherein the enclosure of the power source package extends along an enclosure axis between a first end and a second end, wherein the second end of the enclosure defines the second end of the housing of the device, and further wherein the pressure vent is disposed on or at least partially in the first end of the enclosure of the power source package and is configured to vent the at least a portion of helium disposed within the interior volume of the enclosure through the pressure vent into the first portion of the housing of the device.

13. A method comprising forming a power source package, wherein forming the power source package comprises: disposing a betavoltaic power source within an interior volume of an enclosure that comprises an outer surface and an inner surface; disposing a pressure vent on or at least partially in the enclosure so that the vent is in fluid communication with the interior volume of the enclosure; andMedtronic Ref. No. A0012900 WOO 1 venting at least a portion of helium generated within the enclosure through the pressure vent to an external environment of the enclosure.

14. The method of claim 13, wherein disposing the pressure vent comprises: disposing a passageway into the enclosure that extends between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of the enclosure; disposing a cover over the first opening or the second opening of the passageway; and hermetically sealing the cover to the enclosure.

15. The method of claim 14, wherein disposing the passageway comprises disposing a plurality of passageways into the enclosure each extending between a first opening defined by the outer surface of the enclosure and a second opening defined by the inner surface of the enclosure, wherein the cover is disposed on the first opening or the second opening of each passageway of the plurality of passageways.

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