Laser weld technique

Abstract

A method includes delivering a laser beam along a weld path surrounding an opening defined by a surface of a substrate. The method further includes sealing the opening by collapse of material surrounding the opening, in response to the laser beam, into the opening.

Description

LASER WELD TECHNIQUE

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 612,889, filed December 20, 2023, the entire content of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The disclosure relates to methods of welding of substrates, for example, for medical device components.BACKGROUND

[0003] Laser welding may be used to produce welds for items such as medical devices and related components. Laser welding may provide hermetic seals for medical device enclosures and associated components for the medical devices.SUMMARY

[0004] This disclosure is directed to systems and techniques for sealing an opening in a substrate, particularly an injection hole in the battery of a medical device, with a laser weld around the opening. The laser welding may be controlled to prevent transfer of heat to a liquid electrolyte solution within the battery.

[0005] In some examples, a method includes delivering a laser beam along a weld path surrounding an opening defined by a surface of a substrate. The method may further include sealing the opening by collapse of material surrounding the opening, in response to the laser beam, into the opening.

[0006] In some examples, a medical device includes a battery including a liquid electrolyte within the battery and a sealed injection hole. The liquid electrolyte may be sealed within the battery by delivery of a laser beam along a weld path surrounding an unsealed injection hole to form the sealed injection hole. The sealed injection hole may be sealed by collapse of material surrounding the unsealed injection hole.

[0007] In some examples, a system includes a laser apparatus and a controller. The controller may include processing circuitry configured to control the laser apparatus to deliver a laser beam along a weld path. The weld path may surround an opening defined by a surface of a substrate. The processing circuitry may be further configured to seal theopening by collapse of material surrounding the opening, in response to the laser beam, into the opening.

[0008] This summary is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the apparatus and methods described in detail within the accompanying drawings and description below. Further details of one or more examples are set forth in the accompanying drawings and the description below.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The details of one or more examples of this disclosure are set forth in the accompanying drawings and the descriptions below. Other features, objects, and advantages of this disclosure will be apparent from the description and drawings, and from the claims.

[0010] FIG. 1 is a conceptual diagram illustrating an example medical device system including a medical device implanted within a patient, in accordance with techniques of this disclosure.

[0011] FIG. 2 is a conceptual diagram illustrating an example battery for a computing device, in accordance with techniques of this disclosure.

[0012] FIG. 3 is a conceptual diagram illustrating a substrate that includes an opening, in accordance with techniques of this disclosure.

[0013] FIG. 4A is a conceptual diagram illustrating side section view of a substrate with an opening, in accordance with techniques of this disclosure.

[0014] FIG. 4B is a conceptual diagram illustrating a top view of the substrate of FIG. 4A, in accordance with techniques of this disclosure.

[0015] FIG. 5A is a conceptual diagram illustrating side section view of a substrate with an opening of varying width along its length, in accordance with techniques of this disclosure.

[0016] FIG. 5B is a conceptual diagram illustrating a top view of the substrate of FIG. 5A, in accordance with techniques of this disclosure.

[0017] FIG. 6A is a conceptual diagram illustrating side section view of a substrate that includes an offset opening, in accordance with techniques of this disclosure.

[0018] FIG. 6B is a conceptual diagram illustrating a top view of substrate of FIG. 5A, in accordance with techniques of this disclosure.

[0019] FIG. 7 is a conceptual diagram illustrating side section view of a portion of an external casing of an example battery that includes a sealed injection hole, in accordance with techniques of this disclosure.

[0020] FIG. 8A depicts an example sealed hole in a substrate, in accordance with techniques of this disclosure.

[0021] FIG. 8B depicts another example sealed hole in a substrate, in accordance with techniques of this disclosure.

[0022] FIG. 9 is a flowchart illustrating an example method of sealing an opening in a substrate, in accordance with techniques of this disclosure.

[0023] FIG. 10 is a block diagram illustrating a system including a controller and laser apparatus for sealing an opening in a substrate, in accordance with techniques of this disclosure.DETAILED DESCRIPTION

[0024] This disclosure is directed to systems and techniques for sealing an opening in a substrate with a laser weld around the opening. In some examples, the substrate may be a battery of a medical device and the opening may be an injection hole in the battery. The laser welding may be controlled to prevent transfer of heat to a liquid electrolyte solution within the battery. The described systems and techniques may provide a fast and efficient welding process that reduces heat exposure to anything other than the intended substrate to be welded. In some examples, the described systems and techniques may, during a welding process, reduce heat transfer to a liquid electrolyte solution within a battery, increase the speed of a welding process, and provide a weld seal with fewer defects.

[0025] Laser welding may be used to seal holes or openings in a material. When sealing holes and openings in a material, previous laser weld sealing processes direct a laser beam at least partially through the openings, which may expose contents within the openings to the laser beam. Exposing solids and fluids within the openings to the laser beam may negatively impact the quality of the weld seal. For example, such exposure may cause outgassing of the solids or fluids within the opening, creating voids and other defects within the material in the seal. Furthermore, a pulsed laser may create overlappingweld zones in the area of the seal, which increases the likelihood of thermal effects in the materials surrounding each discrete weld zone, thereby increasing the likelihood of differing material properties throughout the weld.

[0026] The systems and techniques of this disclosure may deliver a laser beam along a weld path surrounding an opening defined by a surface of a substrate. A laser apparatus may deliver the laser beam once around the edge of an opening to be sealed at a high rate of speed (e.g., in a period of one second or less). A continuous path in a single circuit around the opening may reduce the interaction time of the laser beam with the weld components to prevent or reduce potential adverse interactions (e.g., outgassing and thermal effects). By doing so, the technique reduces variation in weld quality to provide a more robust seal and more consistent results. By following a laser beam path that avoids the interior of the opening, the techniques of this disclosure may also prevent evaporation and loss of liquid electrolyte within a battery. Evaporation of liquid electrolyte during the welding process of a battery can cause further defects in the weld. Delivering a fast, continuous laser beam along a weld path surrounding the opening may reduce or prevent laser leakage into the opening, while heating the surrounding material sufficiently to collapse the opening and form a seal. This may result in a continuous weld without discrete weld zones.

[0027] Both straight and angled holes may be welded. In angled holes, an exit opening is offset from an entry opening. The path used for angled holes may encompass both the entry and the exit openings to collapse and seal the entire hole.

[0028] FIG. 1 is a conceptual diagram illustrating an example medical device system 2 including an implantable medical device 10 implanted within a patient 4. IMD 10 may include one or more power sources to allow for operation of IMD 10, e.g., to allow wireless communication with external device 12. The one or more power sources for IMD 10 may include one or more batteries configured to hold a chemical solution to provide power for IMD 10. The example techniques may be used with a battery of IMD 10, which may be in wireless communication with other devices not pictured in FIG. 1.

[0029] In some examples, IMD 10 is implanted outside of a thoracic cavity of patient 4 (e.g., subcutaneously in the pectoral location illustrated in FIG. 1). IMD 10 may be positioned near the sternum near or just below the level of the heart of patient 4 (e.g., at least partially within the cardiac silhouette). IMD 10 may be positioned on other locations,such as patient 4’s cranium region. IMD 10 may include one or more sensors (not shown in FIG. 1) and may be configured to sense data via the one or more sensors. In some examples, IMD 10 takes the form of the Reveal LINQ™ or LINQ II™ ICM. In some examples, the one or more sensors are configured to sense cardiac signals and / or patient motion / activity, e.g., electrodes configured to detect a cardiac electrogram (EGM), one or more accelerometers configured to detect cardiac contractions and / or patient body motion / activity, or one or more optical sensors configured to detect pulsatile blood flow associated with cardiac contractions.

[0030] IMD 10 may include a battery with a liquid electrolyte within the battery, and a sealed injection hole. In some examples, the battery may include an external casing that contains the liquid electrolyte, wherein the sealed injection hole is in the external casing. The liquid electrolyte may be sealed within the battery by delivery of a laser beam to the battery material along a weld path surrounding an unsealed injection hole to form the sealed injection hole that seals the liquid electrolyte within the battery. Delivery of the laser beam may collapse the material surrounding the opening of the unsealed injection hole and thereby seal the injection hole. In some examples, the laser beam may be a continuous laser beam.

[0031] Although the techniques of this disclosure are described with respect to a medical device like IMD 10, it may be understood that the techniques are applicable to many other devices that may benefit from laser weld sealing of openings (for example, holes). For example, the techniques of this disclosure may be used to seal an injection hole for a battery acting as a power source of external device 12. In some examples, the techniques of this disclosure are used to repair pin hole leaks in containers configured to hold fluids, for example, petrochemical fluids. The techniques of this disclosure may be used to seal holes in a container configured to hold fluid, to reduce or avoid heat transfer to a fluid inside the container. In some examples, the techniques of this disclosure are used to seal holes in a substrate while reducing exposure of the substrate to heat. In some examples, the techniques of this disclosure are used to seal openings in any component. In some examples, the techniques of this disclosure are used to repair castings, or repair cooling holes in gas turbine components. In some examples, the material with a hole to be sealed includes one or more of a metal, an alloy, or a polymer.

[0032] FIG. 2 is a conceptual diagram illustrating an example battery 100 for a computing device, in accordance with techniques of this disclosure. In some examples, the computing device may be a medical device, e.g., IMD 10 of FIG. 1. Battery 100 and external casing 112 may be at least partially filled with a chemical solution (e.g., a liquid electrolyte solution) as the source of chemical energy for powering battery 100.

[0033] Battery 100 may include external casing 112, and injection hole 102. Injection hole 102 may configured to allow injection of the chemical solution into battery 100. Injection hole 102 may include an opening extending fully through a thickness of external casing 112. The chemical solution may be injected through injection hole 102 and into the interior of external casing 112. The chemical solution may include one or more electrolytes configured to transport positively charged ions between the cathode and anode terminals of the power source. In some examples, the chemical solution may include sulfuric acid, potassium hydroxide, sodium hydroxide, hydrochloric acid, nitric acid, zinc chloride, lithium iodide, lithium hexafluorophosphate, copper sulfate, or any other electrolyte suitable for allowing electrical charge to pass between the terminals of a battery. Although described herein in some examples with reference to sealing an opening in a casing of a battery with a chemical solution inside the casing, in other examples, the techniques described herein may be used to seal an opening in any container configured to hold any fluid, gas, and / or powder. The technique may be beneficial in cases where a substance inside the container are volatile when exposed to heat, for example highly reactive gasses and / or explosive powders. In some examples, the technique may be used to hermetically seal a container that contains inert substances.

[0034] After injection of the chemical solution, battery 100 may need to be sealed to prevent leakage of the chemical solution. Leakage may expose an environment near the battery to the chemical solution, and hinder proper operation of battery 100. According to techniques of this disclosure, injection hole 102 may be sealed through delivery of a laser beam along a weld path surrounding the opening of injection hole 102 in battery 100. For example, the weld path may follow an edge of injection hole 102. The weld path may circumnavigate injection hole 102. In some examples, the laser beam may be delivered along a length of the weld path for a single circuit of the path around the opening. For example, the laser beam may complete only one pass along the weld path around injectionhole 102. The laser beam may be applied in multiple passes along the weld path around injection hole 102.

[0035] The energy from the laser beam may cause material around the edge of injection hole 102 to collapse into injection hole 102 and refreeze, sealing injection hole 102. In some examples, material surrounding injection hole 102 along a portion of the length of injection hole 102 through external casing 112 may collapse inward toward injection hole 102 to seal injection hole 102. In some examples, the laser beam may be configured not to pierce fully through the thickness of external casing 112, and material along a portion of the length of injection hole 102 close to an outer surface of external casing 112 may collapse to seal injection hole 102. The power required of the laser beam may depend on one or more parameters, for example, one or more of the beam diameter, spatial beam profile (e.g., gaussian, top hat, etc.), weld speed, or material geometry (e.g., thickness, opening shape, etc.). The power of the laser beam may be adjusted to between 1 and 100,000 Watts. In some examples, the power of the laser beam is adjusted to between 1 and 10 Watts. In some examples, the power of the laser beam is adjusted to between 10 and 100 Watts. In some examples, the power of the laser beam is adjusted to between 100 and 200 Watts. In some examples, the power of the laser beam is adjusted to between 0 and 200 Watts. In some examples, the power of the laser beam is adjusted to between 200 and 1,000 Watts. In some examples, the power of the laser beam is adjusted to between 1,000 and 10,000 Watts. In some examples, the power of the laser beam is adjusted to between 10,000 and 100,000 Watts.

[0036] FIG. 3 is a conceptual diagram illustrating a substrate 300 that includes opening 302, in accordance with techniques of this disclosure. Opening 302 may be substantially similar to injection hole 102 of FIG. 2. For example, in some examples opening 302 is an injection hole in a portion of an external casing of a battery that includes opening 302. In some examples, substrate 300 may be the portion of the external casing of the battery that includes opening 302. Substrate 300 includes outer surface 304. In some examples, outer surface 304 may be an outer surface of the external casing of the battery that includes opening 302.

[0037] Opening 302 may include an interior 306. Interior 306 may include all the empty space that constitutes opening 302 in substrate 300. When sealing opening 302, if a laser beam is directed at least partially within interior 306 of opening 302, it mayjeopardize the quality of the weld. In examples where opening 302 is an injection hole in a battery, if the laser beam is directed within interior 306, the laser beam may pass through opening 302 and strike chemical solution within the battery. This may cause unwanted outgassing of chemicals, as well as introduce the chemical solution into the weld, compromising the strength of the seal created by the weld. Therefore, in accordance with the techniques of this disclosure, a laser beam may be delivered to the material of substrate 300 along weld path 310 surrounding opening 302such that the laser beam does not enter interior 306 of opening 302. For example, the laser beam may be delivered to substrate 300 along weld path 310 following an edge of opening 302. In examples where opening 302 is an injection hole in a portion of an external casing of a battery that contains a chemical solution, the laser beam may be delivered to the material of substrate 300 along weld path 310 surrounding opening 302 such that the laser beam does not contact the chemical solution within the external casing.

[0038] In order to ensure that the laser beam does not enter interior 306 (or contact the chemical solution in certain examples), an entirety of weld path 310 may be spaced a distance, d, away from the perimeter of opening 302. The distance (d) may be constant between weld path 310 and the perimeter of opening 302 along the length of weld path 310 around opening 302. In some examples, the distance between weld path 310 and the perimeter of opening 302 along the length of weld path 310 around opening 302 varies, and distance (d) may represent an average distance of weld path 310 from the perimeter of opening 302. The laser beam may define a beam width (e.g., a diameter) such that, as a center of the laser beam follows weld path 310, an edge of the laser beam does not enter interior 306 of opening 302. In some examples, the beam width is between 0.1 and 1 thousandths of an inch. In some examples, the beam width may be approximately equal to 0.5 thousandths of an inch. For example, the laser beam may define a beam width of 0.5 thousandths of an inch, and weld path 310 may be spaced a distance (d) of 0.5 thousandths of an inch away from the perimeter of opening 302. In some examples, the distance (d) may be equal to or larger than the radius of beam width.

[0039] Weld path 310 is depicted in FIG. 3 as an example weld path for a laser beam to follow while delivering energy to the material of substrate 300 in order for the laser beam to seal opening 302. In some examples, weld path 310 may be physically etched or otherwise mapped on substrate 300 in order to aid tracking of the weld path by atechnician guiding the laser beam, or automatic tracking by a computing system in control of the laser beam. For example, a controller may control a laser apparatus to deliver a laser beam along weld path 310. In some examples, weld path 310 is a representation of the weld path that a laser beam may follow when sealing opening 302, and not a representation of a physical object.

[0040] As shown in FIG. 3, opening 302 may define a substantially circular shape, and weld path 310 may circumnavigate opening 302. A laser beam may be delivered to the material of substrate 300 along the weld path in a single circuit around the opening. The delivery of the laser beam to the material of substrate 300 may cause material surrounding opening 302 to collapse into opening 302 and seal opening 302. The material of substrate 300 may collapse from around an edge of opening 302. The amount of material that may collapse from around opening 302 depends on the beam power of the laser beam. For example, a higher wattage laser beam delivered to the material may penetrate more deeply and collapse material from not only the edge of opening 302 at outer surface 304, but also at least partially from the edge of opening 302 within interior 306 of opening 302. The power of the laser beam may be adjusted to prevent the laser beam from piercing fully through a thickness of substrate 300 from outer surface 304 to an inner surface. Although depicted in FIG. 3 as circular, in some examples, opening 302 may define a substantially elliptical shape. In some examples opening 302 may define any shape, e.g., a square, triangle, or any other polygonal shape, curved shape, or combination thereof.

[0041] FIG. 4A is a conceptual diagram illustrating side section view of substrate 400 with opening 402, in accordance with techniques of this disclosure. FIG. 4B is a conceptual diagram illustrating a top view of the substrate of FIG. 4A, in accordance with techniques of this disclosure. Substrate 400 may be substantially similar to substrate 300 of FIG. 3. Opening 402 may be substantially similar to opening 302 of FIG. 3. In some examples opening 402 is an injection hole in a portion of an external casing of a battery that includes opening 402. In some examples, substrate 400 may be the portion of the external casing of the battery that includes opening 402. Substrate 400 includes outer surface 404 and inner surface 408. In some examples, outer surface 404 may be an external surface of the external casing of the battery that includes opening 402 and inner surface 408 may be an internal surface of the external casing of the battery that includes opening 402.

[0042] In the example of FIGS. 4A and 4B, opening 402 extends fully through a thickness, t, of substrate 400, from outer surface 404 to inner surface 408. Opening 402 may extend between outer end 414, defined by outer surface 404, and inner end 418, defined by inner surface 408. A laser beam may be delivered to material of substrate 400 on outer surface 404 along a weld path surrounding outer end 414 of opening 402. For example, opening 402 may be an injection hole in a portion of an external casing of a battery that includes opening 402, and the laser beam may be delivered to the external surface of the external casing around opening 402 defined at the outer surface 404. In some examples, opening 402 may not extend all the way through thickness, t, of substrate 400. In some examples, thickness, t, may range from 0.01 millimeters to 1.3 millimeters. In some examples, thickness, t, of substrate 400 ranges from 0.01 millimeters to 0.05 millimeters. In some examples, thickness, t, of substrate 400 ranges from 0.05 millimeters to 0.5 millimeters. In some examples, thickness, t, of substrate 400 ranges from 0.5 millimeters to 1.3 millimeters. A higher wattage laser beam delivered to the material may penetrate more deeply. The power of the laser beam may be adjusted to prevent the laser beam from piercing fully through thickness, t, of substrate 400 from outer surface 404 to an inner surface. In examples where opening 402 is an injection hole in a portion of an external casing of a battery, such power adjustment may prevent excess heat from being transferred to a chemical solution inside the casing of the battery during the weld operation.

[0043] Opening 402 may extend through substrate 400 such that a longitudinal axis of opening 402 is substantially normal to the surface plane of outer surface 404. In the example of FIGS. 4A and 4B, the opening width, w, of opening 402 may not change in size along the length of opening 402 from outer surface 404 to inner surface 408. Therefore, as weld path 410 surrounds outer end 414, weld path 410 may also surround a projection of inner end 418 on outer surface 404. For example, weld path 410 may trace an edge of outer end 414 and an edge of inner end 418 projected onto outer surface 404, at a distance away from the edge of outer end 414 and the edge of inner end 418 projected onto outer surface 404. In some examples, opening width, w, is larger than the beam width of the laser beam. For example, opening width, w, may range between one and six thousandths of an inch. In some examples, a ratio of the beam width to opening width, w, may be in a range of five to fifteen percent. For example, a beam width of the laser beammay be 0.5 thousandths of an inch, and opening width, w, may be six thousandths of an inch.

[0044] FIG. 5A is a conceptual diagram illustrating side section view of substrate 500 with opening 502 of varying width along its length, in accordance with techniques of this disclosure. FIG. 5B is a conceptual diagram illustrating a top view of the substrate of FIG. 5A, in accordance with techniques of this disclosure. Substrate 500 may be substantially similar to substrate 300 of FIG. 3. Opening 502 may be substantially similar to opening 302 of FIG. 3. In some examples opening 502 is an injection hole in a portion of an external casing of a battery that includes opening 502. In some examples, substrate 500 may be the portion of the external casing of the battery that includes opening 502. Substrate 500 includes outer surface 504 and inner surface 508. In some examples, outer surface 504 may be an external surface of the external casing of the battery that includes opening 502 and inner surface 508 may be an internal surface of the external casing of the battery that includes opening 502.

[0045] Opening 502 may extend fully through a thickness, to, of substrate 500, from outer surface 504 to inner surface 508. Opening 502 may extend between outer end 514, defined by outer surface 504, and inner end 518 defined by inner surface 508. A laser beam may be delivered to material of substrate 500 on outer surface 504 along a weld path surrounding outer end 514 and / or inner end 518. In the example of FIGS. 5 A and 5B, the opening width, wo, of opening 502 may change in size along the length of opening 502 from outer surface 504 to inner surface 508, such that width, wo, is greater at inner end 518 than at outer end 514. Weld path 510 may surround a projection of inner end 518 on outer surface 504. For example, weld path 510 may trace a perimeter of inner end 518 a distance away from an edge of inner end 518. In some examples, a width of the shape defined by weld path 510 around opening 502 may be greater than opening width, wo, at inner end 518. In this way, the risk of laser beam piercing through from outer surface 504 to the interior of opening 502 is minimized. In some examples, weld path 510 may define a substantially elliptical shape, circular shape, or any other shape appropriate to surround outer end 514 and / or inner end 518.

[0046] In some examples, the width of a shape defined by weld path 510 may not be greater than opening width, wo, at inner end 518. In these examples, the power of the laser beam may be adjusted to prevent the laser beam from piercing fully through thickness, t,of substrate 500 from outer surface 504 to an interior of opening 502. In examples where opening 502 is an injection hole in a portion of an external casing of a battery, such power adjustment may prevent excess heat from being transferred to a chemical solution inside the casing of the battery during the weld operation.

[0047] FIG. 6A is a conceptual diagram illustrating side section view of substrate 600 that includes an offset hole, in accordance with techniques of this disclosure. FIG. 6B is a conceptual diagram illustrating a top view of substrate 600 of FIG. 5A, in accordance with techniques of this disclosure. Substrate 600 may be substantially similar to substrate 300 of FIG. 3. Opening 602 may be substantially similar to opening 302 of FIG. 3.

[0048] In some examples opening 602 is an injection hole in a portion of an external casing of a battery that includes opening 602. In some examples, substrate 600 may be the portion of the external casing of the battery that includes opening 602. Substrate 600 includes outer surface 604 and inner surface 608. In some examples, outer surface 604 may be an external surface of the external casing of the battery that includes opening 602 and inner surface 608 may be an internal surface of the external casing of the battery that includes opening 602. In some examples, opening 602 may be offset, that is, travel at an angle through a thickness of substrate 600, in order to minimize the risk of light or other radiation extending through opening 602 and striking a chemical solution inside the battery.

[0049] Opening 602 may extend fully through a thickness of substrate 600, from outer surface 604 to inner surface 608. Opening 602 may extend between outer end 614 defined by outer surface 604 and inner end 618 defined by inner surface 608. A laser beam may be delivered to material of substrate 600 on outer surface 604 along a weld path surrounding both outer end 614 and inner end 618. In the example of FIGS. 6 A and 6B, the angle that opening 602 forms with a surface plane of substrate 600 causes outer end 614 to be offset on outer surface 604 from a projection of inner end 618 on outer surface 604. Thus, outer end 614 on outer surface 604 is not coterminous with a projection of inner end 618 to outer surface 604. Weld path 610 may at least partially follow one or both of outer end 614 and the projection of inner end 618. For example, weld path 610 may follow at least a portion of the edge of outer end 614 and at least a portion of the edge of inner end 618 projected onto outer surface 604. In some examples, as in the example of FIG. 6B, weld path 610 may circumnavigate both outer end 614 and the projection of inner end 618 onouter surface 604 such that weld path 610 does not cross the perimeter of either outer end 614 or the perimeter of inner end 618 projected on outer surface 604. In this way, the risk of the laser beam piercing through from outer surface 604 to the interior of opening 602 is minimized.

[0050] In some examples, weld path 610 may cross the perimeter of inner end 618 projected on outer surface 604. In these examples, the power of the laser beam may be adjusted to prevent the laser beam from piercing fully through a thickness of substrate 600 from outer surface 604 to an interior of opening 602. In examples where opening 602 is an injection hole in a portion of an external casing of a battery, such power adjustment may prevent excess heat from being transferred to a chemical solution inside the casing of the battery during the weld operation.

[0051] Although FIGS. 3-6B depict openings that define substantially circular shapes, in some examples, the openings may define other shapes (e.g., square, oval, etc.). In some examples, the opening at the outer surface defines one shape (e.g., a circle), while the opening at the inner surface defines another shape (e.g., an oval).

[0052] FIG. 7 is a conceptual diagram illustrating side section view of a portion 700 of an external casing of an example battery that includes sealed injection hole 702, in accordance with techniques of this disclosure. Portion 700 may be substantially similar to substrate 300 of FIG. 3. Sealed injection hole 702 may be formed through delivery of a laser beam to outer surface 704 of portion 700 in a single circuit of around an edge of an unsealed hole to form sealed injection hole 702. As described above, the power of the laser beam may be adjusted to prevent the laser beam from piercing fully through a non- welded thickness, ti, of portion 700 from outer surface 704 to inner surface 708. At least partially for this reason, material from portion 700 around an edge of the injection hole may not fully fill the injection hole. That is, a thickness, t2, of sealed injection hole 702 may be smaller than thickness, ti, of portion 700 in a non-welded region.

[0053] FIG. 8A depicts an example sealed hole 802 in a substrate 804, in accordance with techniques of this disclosure. Sealed hole 802 may be formed through delivery of a continuous laser beam to the substrate 804 in a single circuit of weld path 810 around an edge of an unsealed hole to form sealed hole 802. A pulsed laser beam may create overlapping weld zones in the area of the seal, which may increase the likelihood of thermal effects in the materials surrounding each discrete weld zone, thereby increasingthe likelihood of differing material properties throughout the weld. Delivering a fast, continuous laser beam along a weld path surrounding an opening may result in a continuous weld without discrete weld zones.

[0054] FIG. 8B depicts another example sealed hole 803 in a substrate 805, in accordance with techniques of this disclosure. Sealed hole 803 may be formed through delivery of a continuous laser beam to substrate 805 in a single circuit of weld path 811 around an edge of an unsealed hole to form sealed hole 803.

[0055] FIG. 9 is a flowchart illustrating an example method 900 of sealing an opening in a substrate, in accordance with techniques of this disclosure. The following method may be described with reference to reference numbers of FIGS. 1-7. In some examples, the substrate may be a portion of an external casing 112 of a battery 100 configured to contain a chemical solution (e.g., a liquid electrolyte solution), and the opening may be an injection hole 102 in the external casing, as shown in FIG. 2. In some examples, the method may include filling battery 100 and external casing 112 at least partially with a liquid electrolyte via injection hole 203. In some examples, it may be assumed that battery 100 and external casing 112 are already at least partially filled with a chemical solution (e.g., the liquid electrolyte).

[0056] In some examples, battery 100 may be part of a medical device, for example IMD 10 of medical device system 2, as shown in FIG. 1. IMD 10 may include one or more power sources to allow for operation of IMD 10, e.g., to allow wireless communication with external devices, including one or more batteries configured to contain the chemical solution to provide power for IMD 10. Method 900 may be used, for example, with a battery of IMD 10, which may be in wireless communication with other devices not pictured in FIG. 1.

[0057] Method 900 may include delivering a laser beam along a weld path surrounding an opening defined by a surface of a substrate (902). In some examples, the laser beam is a continuous laser beam. In some examples, step 902 may include defining the weld path to circumnavigate injection hole 102. Method 900 may further include delivering a laser beam to the substrate along the weld path in a single circuit around the opening. Method 900 may also include sealing the opening by collapse of material surrounding the opening, in response to the laser beam, into the opening (904). For example, delivering the laser beam to the material of battery 102 along the weld path maycause the material around the edge of injection hole 102 to collapse into injection hole 102 and seal injection hole 102. In some examples, delivering the laser beam (902) and the sealing the opening (904) are substantially simultaneous. In other examples, delivering the laser beam (902) may be performed for at least a sufficient period of time to cause soften, melting, or reflowing of material, resulting in sealing the opening (904).

[0058] Method 900 may be applied to many types of components with openings that may be sealed through the described laser beam weld. For example, step 902 may be used to seal an injection hole for a battery acting as a power source of a computing device. In some examples, step 902 may be used to fill holes in any component including a metal or an alloy.

[0059] In some examples, method 900 may be used to fill an opening in a substrate or component of any device or system. For example, method 900 may be used to fill example opening 302 in substrate 300 as shown in FIG. 3. Opening 302 may include an interior 306. When sealing opening 302, if a laser beam is directed at least partially within interior 306 of opening 302, it may jeopardize the quality of the weld. Therefore, step 902 may include defining weld path 310 following the edge of opening 302 such that the laser beam does not enter interior 306 of opening 302 during step 904 when delivering the laser beam along weld path 310. In examples where opening 302 is an injection hole in a portion of an external casing of a battery that contains a chemical solution, step 902 may include defining weld path 310 following the edge of opening 302 such that the laser beam does not contact the chemical solution within the external casing when delivering the laser beam along weld path 310.

[0060] In order to ensure that the laser beam does not enter interior 306 (or contact the chemical solution in certain examples), step 902 may include spacing weld path 310 a distance (d) away from the perimeter of opening 302. In some examples, step 902 may include spacing distance (d) as a constant distance between weld path 310 and the perimeter of opening 302 along the length of weld path 310 around opening 302. In some examples, step 902 may include spacing weld path 310 such that the distance between weld path 310 and the perimeter of opening 302 along the length of weld path 310 around opening 302 varies.

[0061] The laser beam may define a beam width (e.g., a diameter) such that, as a center of the laser beam follows weld path 310, an edge of the laser beam does not enterinterior 306 of opening 302. For example, the laser beam may define a beam width of 0.5 thousandths of an inch, and weld path 310 may be spaced a distance (d) of 0.5 thousandths of an inch away from the perimeter of opening 302. As the center of the laser beam is delivered to the material of the battery along weld path 310, the edge of the laser beam may only extend 0.25 thousandths of an inch towards the perimeter of opening 302.

[0062] Step 904 may include adjusting a power of the laser beam to prevent the laser beam from piercing fully through a thickness of the battery from an outer surface to an inner surface. The delivery of the laser beam to the material of substrate 300 may cause material surrounding opening 302 to collapse into opening 302 and seal opening 302. The material of substrate 300 may collapse from around an edge of opening 302. The amount of material that may collapse from the edge of opening 302 depends on the beam power of the laser beam. For example, a higher wattage laser beam delivered to the material may penetrate more deeply and collapse material from not only the edge of opening 302 at outer surface 304, but also at least partially from the edge of opening 302 within interior 306 of opening 302. The laser beam may be controlled to avoid piercing all the way through the thickness of substrate 300, to avoid exposing components or materials on the other side of substrate 300 to heat from the laser beam. When the opening is an injection hole in a battery, exposing the chemical solution inside the battery to the laser (or heat therefrom) may adversely affect the quality of the weld seal, and potentially release chemicals from the battery.

[0063] Although depicted in FIG. 3 as circular, in some examples, opening 302 may define a substantially elliptical shape. In some examples opening 302 may define any shape, e.g., a polygonal shape, a curved shape, or combinations thereof. Step 902 may include defining weld path 310 to surround the shape defined by opening 302. In some examples, step 902 include defining weld path 310 to follow the edge of the shape defined by opening 302 a distance away from the edge of the shape defined by opening 302.

[0064] In the example of FIGS. 4A and 4B, opening 402 may extend through substrate 400 such that a longitudinal axis of opening 402 is substantially normal to the surface plane of outer surface 404. In the example of FIGS. 4 A and 4B, the opening width, w, of opening 402 may not change in size along the length of opening 402 from outer surface 404 to inner surface 408. Therefore, as weld path 410 surrounds outer end 414, weld path 410 may also surround a projection of inner end 418 on outer surface 404, at a distanceaway from the edge of outer end 414 and the edge of inner end 418 projected onto outer surface 404. Step 902 may include defining weld path 410 to surround both outer end 414 and inner end 418 projected onto outer surface 404. In some examples, step 902 may include defining weld path 410 to follow the edges of one or more of outer end 414 or a projection of inner end 418 on outer surface 404 a distance away from said edges.

[0065] In the example of FIGS. 5 A and 5B, opening 502 may extend fully through a thickness, to, of substrate 500, from outer surface 504 to inner surface 508. Opening 502 may extend between outer end 514, defined by outer surface 504, and inner end 518 defined by inner surface 508. Method 902 may include delivering a laser beam to material of substrate 500 on outer surface 504 along a weld path surrounding outer end 514 and / or inner end 518. The opening width, wo, of opening 502 may change in size along the length of opening 502 from outer surface 504 to inner surface 508, such that width, wo, is greater at inner end 518 than at outer end 514. Step 902 may include defining weld path 510 to surround a projection of inner end 518 on outer surface 504. For example, weld path 510 may trace a perimeter of inner end 518 a distance away from an edge of inner end 518. In some examples, a width of the shape defined by weld path 510 around opening 502 may be greater than opening width, wo, at inner end 518. In this way, the risk of laser beam piercing through from outer surface 504 to the interior of opening 502 is minimized. In some examples, weld path 510 may define a substantially elliptical shape, circular shape, or any other shape appropriate to surround outer end 514 and / or inner end 518.

[0066] In some examples, the width of a shape defined by weld path 510 may not be greater than opening width, wo, at inner end 518. In these examples, step 904 may include adjusting the power of the laser beam to prevent the laser beam from piercing fully through thickness, t, of substrate 500 from outer surface 504 to an interior of opening 502.

[0067] In the example of FIGS. 6A and 6B, opening 602 may be offset, that is, travel at an angle through a thickness of substrate 600, in order to reduce or avoid passage of light or other radiation extending through opening 602 and striking an unintended part / surface (e.g., a chemical solution inside a battery). Opening 602 may extend fully through a thickness of substrate 600, from outer surface 604 to inner surface 608. Opening 602 may extend between outer end 614 defined by outer surface 604 and inner end 618 defined by inner surface 608 at an angle. The angle that opening 602 forms with a surface plane of substrate 600 may cause outer end 614 to be offset on outer surface 604 from aprojection of inner end 618 on outer surface 604. Thus, an edge of outer end 614 on outer surface 604 is not coterminous with a projection of inner end 618 on outer surface 604. Step 902 may include defining weld path 610 to follow a combination of the edge of outer end 614 and the edge of inner end 618 projected onto outer surface 604. Step 902 may include defining weld path 610 to follow at least a portion of the edge of outer end 614 and at least a portion of the edge of inner end 618 projected onto outer surface 604. In some examples, as in the example of FIG. 6B, weld path 610 may circumnavigate both outer end 614 and the projection of inner end 618 on outer surface 604 such that weld path 610 does not cross the perimeter of either outer end 614 or the perimeter of inner end 618 projected on outer surface 604. That is, step 902 may include defining weld path 610 such that weld path 610 circumnavigates both outer end 614 and the projection of inner end 618 on outer surface 604, wherein weld path 610 does not cross the perimeter of either outer end 614 or the perimeter of inner end 618 projected on outer surface 604. In this way, the risk of the laser beam piercing through from outer surface 604 to the interior of opening 602 is minimized.

[0068] In some examples, step 902 may include defining weld path 610 to cross the perimeter of inner end 618 projected on outer surface 604 at least one intersection point. In these examples, step 904 may include adjusting the power of the laser beam to prevent the laser beam from piercing fully through a thickness of substrate 600 from outer surface 604 to an interior of opening 602.

[0069] The steps of method 900 may be implemented in circuitry of a controller configured to control a laser apparatus to deliver a laser beam along a weld path surrounding an opening defined by a surface of substrate. The circuitry of controller may also be configured to seal the opening by collapse of material surrounding the opening, in response to the laser beam, into opening.

[0070] FIG. 10 is a block diagram illustrating system 1000 including controller 1020 and laser apparatus 1030 for sealing opening 1002 in substrate 1012, in accordance with techniques of this disclosure. Controller 1020 may include processing circuitry 1022 configured to control laser apparatus 1030 to deliver a laser beam along a weld path surrounding opening 1002 defined by a surface of substrate 1012. Processing circuitry 1022 may also be configured to seal opening 1002 by collapse of material surrounding opening 1002, in response to the laser beam, into opening 1002.

[0071] Controller 1020 and laser apparatus 1030 may communicate via near-field communication technologies (e.g., inductive coupling, near field communication (NFC), or other communication technologies operable at ranges less than 10-20 cm) and far-field communication technologies (e.g., the 802.11 or Bluetooth® specification sets, cellular network communications such as according to the 3G, 4G, or 5G protocols, or other communication technologies operable at ranges greater than near-field communication technologies). In some examples, controller 1020 may communication with laser apparatus 1030 through a server including one or more other computing devices. In some examples, controller 1020 may be a part of laser apparatus 1030 and communicate directly through electrical connections.

[0072] Processing circuitry 1022 may include fixed function circuitry and / or programmable processing circuitry. Processing circuitry 1022 may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or analog logic circuitry. In some examples, processing circuitry 1022 may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to processing circuitry 1022 herein may be embodied as software, firmware, hardware or any combination thereof. References to controller 1020 performing operations of the disclosure may be understood as processing circuitry 1022 of controller 1020 performing said operations.

[0073] Controller 1020 may also include a memory. The memory may include computer-readable instructions that, when executed by processing circuitry 1022, cause controller 1020 and processing circuitry 1022 to perform various functions attributed to controller 1020 and processing circuitry 1022 herein. The memory may include any volatile, non-volatile, magnetic, optical, or electrical media, such as a random-access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically - erasable programmable ROM (EEPROM), ferroelectric RAM (FRAM), dynamic randomaccess memory (DRAM), flash memory, or any other digital media. The memory may store, as examples, programmed values for one or more operational parameters of laserapparatus 1030. The memory may also store data or instructions for transmission to another device using communication circuitry of controller 1020.

[0074] In some examples opening 1002 is an injection hole in a portion of an external casing of a medical device battery that includes opening 1002. In some examples, substrate 1012 may be the portion of the external casing of the battery that includes opening 1002.

[0075] Opening 1002 may include an interior. The interior may include all the empty space that constitutes opening 1002 in substrate 1012. When sealing opening 1002, if a laser beam is directed at least partially within the interior of opening 1002, it may jeopardize the quality of the weld. In examples where opening 1002 is an injection hole in a battery, if the laser beam is directed within the interior, the laser beam may pass through opening 1002 and strike chemical solution within the battery. This may cause unwanted outgassing of chemicals, as well as introduce the chemical solution into the weld, compromising the strength of the seal created by the weld. Furthermore, direct beam exposure may affect the integrity of other components such as insulators, cathodes, anodes, current collectors, and other components that may be inside a container with an opening to be sealed. Therefore, processing circuitry 1022 may control laser apparatus 1030 to deliver a laser beam to the material of substrate 1012 along weld path around opening 1002 such that the laser beam does not enter the interior of opening 1002. For example, laser apparatus 1030 may deliver the laser beam to substrate 1012 along the weld path following an edge of opening 1002. In examples where opening 1002 is an injection hole in a portion of an external casing of a battery that contains a chemical solution, the laser beam may be delivered to the material of substrate 1012 along the weld path around opening 1002 such that the laser beam does not contact the chemical solution within the external casing.

[0076] In order to ensure that the laser beam does not enter the interior of opening 1002, processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam in a weld path, wherein the entirety of the weld path is spaced a distance, d, away from the perimeter of opening 1002. In some examples, distance, d, may be constant between the weld path and the perimeter of opening 1002 along the length of the weld path. In some examples, the distance between the weld path and the perimeter of opening 1002 may vary, and the distance, d, may represent an average distance of the weld path from theperimeter of opening 1002. Processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam with a beam width (e.g., a diameter) such that, as a center of the laser beam follows the weld path, an edge of the laser beam does not enter the interior of opening 1002. In some examples, the beam width may be between 0.1 and 1 thousandths of an inch. In some examples, the beam width may be approximately equal to 0.5 thousandths of an inch. For example, the laser beam may define a beam width of 0.5 thousandths of an inch, and the weld path may be spaced a distance, d, of 0.5 thousandths of an inch away from the perimeter of opening 1002.

[0077] In some examples, opening 1002 may define a substantially circular shape. In some examples opening 1002 may not define a substantially circular shape. The weld path may circumnavigate opening 1002. In some examples, processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along in a single circuit around the weld path. For example, laser apparatus 1030 may deliver the laser beam in a single pass around opening 1002. The delivery of the laser beam to the material of substrate 1012 may cause material surrounding opening 1002 to collapse into opening 1002 and seal opening 1002. The material of substrate 1012 may collapse from around an edge of opening 1002. The amount of material that may collapse from around opening 1002 depends on the beam power of the laser beam. For example, a higher wattage laser beam delivered to the material may penetrate more deeply and collapse material from not only the edge of opening 1002 at an outer surface of substrate 1012, but also at least partially from the edge of opening 1002 within the interior of opening 1002. Processing circuitry 1022 may control laser apparatus 1030 to adjust the power of the laser beam to prevent the laser beam from piercing fully through a thickness of substrate 1012 from the outer surface of substrate 1012 to an inner surface of substrate 1012. In some examples, the weld path may define a substantially elliptical shape surrounding opening 1002. In some examples, the weld path may define any shape, e.g., a polygonal shape, a curved shape, or combinations thereof.

[0078] In some examples, opening 1002 may not extend fully through a thickness of substrate 1012. In some examples, opening 1002 may extend fully through a thickness of substrate 1012, from an outer surface to inner surface of substrate 1012. In some examples, the thickness of the substrate may range from 0.01 millimeters to 1.3 millimeters. In some examples, the thickness of the substrate ranges from 0.01 millimetersto 0.05 millimeters. In some examples, the thickness of the substrate ranges from 0.05 millimeters to 0.5 millimeters. In some examples, the thickness of the substrate ranges from 0.5 millimeters to 1.3 millimeters. Opening 1002 may extend between an outer end, defined by the outer surface of substrate 1012, and inner end, defined by the inner surface of substrate 1012. Processing circuitry 1022 may control laser apparatus 1030 to deliver a laser beam to material of substrate 1012 on the outer surface of substrate 1012 along a weld path surrounding the outer end of opening 1002. For example, opening 1002 may be an injection hole in a portion of an external casing of a battery that includes opening 1002, and the laser beam may be delivered to the external surface of the external casing around opening 1002 defined at the outer surface of the external casing. A higher wattage laser beam delivered to the material may penetrate more deeply. Processing circuitry 1022 may control laser apparatus 1030 to adjust the power of the laser beam be adjusted to prevent the laser beam from piercing fully through a thickness of the substrate 1012 from the outer surface to the inner surface of substrate 1012.

[0079] Opening 1002 may define an opening width. That is, the shape defined by opening 1002 may define a width. In examples where opening 1002 does not define a circular shape, the opening width may be the average width of the shape defined by opening 1002. In some examples, the opening width is larger than the beam width of the laser beam. For example, the opening width may range between one and six thousandths of an inch. In some examples, a ratio of the beam width to opening width, w, may be in a range of five to fifteen percent. For example, a beam width of the laser beam may be 0.5 thousandths of an inch, and the opening width may be six thousandths of an inch. Processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam at a particular beam width.

[0080] Opening 1002 may extend through substrate 1012 such that a longitudinal axis of opening 1002 is substantially normal to the outer surface of substrate 1012. The width of opening 1002 may or may not change in size along the length of opening 1002 from an outer surface to an inner surface of substrate 1012. In examples where the longitudinal axis of opening 1002 is substantially normal to the outer surface of substrate 1012, and where width of opening 1002 does not change in size along the length of opening 1002, an outer end of opening 1002 on the outer surface of substrate 1012 may be coterminous with a projection of the inner end of opening 1002 on the outer surface of substrate 1012.Processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path that surrounds both the outer end of opening 1002 and the projection of the inner end of opening 1002 on the outer surface of substrate 1012.

[0081] In some examples, the width or angle of opening 1002 through substrate 1012 may cause the projection of the inner end of opening 1002 on the outer surface of substrate 1012 to not be coterminous with the outer end of opening 1002 on the outer surface of substrate 1012. In some examples, the inner end of opening 1002 projected onto the outer surface of substrate 1012 may define a shape that is larger than, and surrounds the shape defined by the outer end of substrate 1012 on the outer surface of substrate 1012.Processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path that follows an edge of the projection of the inner end of opening 1002 on the outer surface of substrate 1012. For example, processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path that surrounds the projection of the inner end of opening 1002 on the outer surface of substrate 1012. In some examples, processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam in a weld path that defines a substantially elliptical shape, circular shape, or any other shape appropriate to surround the outer end of opening 1002 on the external surface of substrate 1012 and / or the projection of the inner end of opening 1002 on the external surface of substrate 1012.

[0082] In some examples, although the width or angle of opening 1002 through substrate 1012 may cause the projection of the inner end of opening 1002 on the outer surface of substrate 1012 to not be coterminous with the outer end of opening 1002 on the outer surface of substrate 1012, processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path that surround the outer end of opening 1002 on the outer surface of substrate 1012. In these examples, processing circuitry 1022 may control laser apparatus 1030 to adjust the power of the laser beam to prevent the laser beam from piercing fully through a thickness of substrate 1012 from the outer surface of substrate 1012 to an interior of opening 1002.

[0083] In some examples, opening 1002 may be offset, that is, travel at an angle through a thickness of substrate 1012, in order to minimize the risk of light or other radiation extending through opening 1002 and striking an unintended part / surface (e.g., a chemical solution inside a battery). Opening 1002 may extend fully through a thickness ofsubstrate 1012, from an outer surface to inner surface of substrate 1012. Opening 1002 may extend between an outer end defined by the outer surface of substrate 1012 and inner end defined by the inner surface of substrate 1012 at an angle. The angle that opening 1002 forms with a surface plane of substrate 1012 may cause the outer end of opening 1002 to be offset on the outer surface of substrate 1012 from a projection of the inner end of opening 1002 on the outer surface of substrate 1012. Thus, the outer end on the outer surface may not be coterminous with a projection of the inner end on the outer surface.

[0084] Processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path that follows a combination of the edge of the outer end of opening 1002 and the edge of the inner end of opening 1002 projected onto the outer surface of substrate 1012. In some examples, Processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path that surrounds both the outer end of opening 1002 and the inner end of opening 1002 projected onto the outer surface of substrate 1012. In some examples, processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path that follows at least a portion of the edge of the outer end and at least a portion of the edge of the inner end of opening 1002 projected onto the outer surface of substrate 1012. In some examples, as in the example of FIG. 6B, weld path 610 may circumnavigate both outer end 614 and the projection of inner end 618 on outer surface 604 such that weld path 610 does not cross the perimeter of either outer end 614 or the perimeter of inner end 618 projected on outer surface 604. That is, processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path (e.g., weld path 610) such that the weld path circumnavigates both the outer end and the projection of the inner end of opening 1002 on the outer surface of substrate 1012, wherein weld path does not cross the perimeter of either the outer end or the perimeter of the inner end projected on the outer surface.

[0085] In some examples, processing circuitry 1022 may control laser apparatus 1030 to deliver the laser beam along a weld path that crosses the perimeter of the inner end of opening 1002 projected on the outer surface of substrate 1012 at at least one intersection point. In these examples, processing circuitry 1022 may control laser apparatus 1030 to adjust the power of the laser beam to prevent the laser beam from piercing fully through a thickness of substrate 1012 from the outer surface to an interior of opening 1002.

[0086] 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 non-transitory computer-readable 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).

[0087] 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” or “processing circuitry” 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.

[0088] The following examples are illustrative of the techniques described herein.

[0089] Example 1: A method including: delivering a laser beam along a weld path surrounding an opening defined by a surface of a substrate; and sealing the opening by collapse of material surrounding the opening, in response to the laser beam, into the opening.

[0090] Example 2: The method of example 1, where the weld path circumnavigates the opening.

[0091] Example 3 : The method of examples 1 or 2, where the laser beam is continuous.

[0092] Example 4: The method of any of examples 1 to 3, where the weld path consists of a single circuit around the opening.

[0093] Example 5: The method of any of examples 1 to 4, where an entirety of the weld path is spaced from the opening.

[0094] Example 6 : The method of any of examples 1 to 5, where the substrate defines an outer surface and an inner surface, where the opening extends fully through a thickness of the substrate from the outer surface to the inner surface.

[0095] Example 7: The method of example 6, where the opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface, and where the weld path surrounds the outer end.

[0096] Example 8: The method of example 6, where the opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface, and where the weld path extends along a projection of the inner end onto the outer surface.

[0097] Example 9: The method of example 6, where the opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface, where the opening is angled through the thickness of the substrate such that the outer end is not coterminous with a projection of the inner end on the outer surface, and where the weld path at least partially follows one or both of the outer end and the projection of the inner end.

[0098] Example 10: The method of any of examples 1 to 9, where the substrate includes a medical device battery.

[0099] Example 11: The method of example 10, where the battery includes an outer surface and an inner surface and a thickness therebetween, where the thickness is in a range of from 0.01 millimeters to 1.3 millimeters.

[0100] Example 12: The method of any of examples 1 to 11, where the laser beam defines a beam width, where the opening defines an opening width, and where the beam width is in a range of from five to fifteen percent of the opening width.

[0101] Example 13: The method of any of examples 1 to 12, where the opening defines an opening width of about six thousandths of an inch.

[0102] Example 14: The method of any of examples 1 to 13, where the laser beam defines a beam width of about half a thousandth of an inch.

[0103] Example 15: The method of any of examples 1 to 14, where delivering the laser beam includes delivering the laser beam along an entirety of the weld path within one second.

[0104] Example 16: The method of any of examples 1 to 15, where a distance from an edge of the opening to the weld path is equal to or greater than a radius of a beam width of the laser beam.

[0105] Example 17: The method of any of examples 1 to 16, where the substrate includes an external casing of a battery containing a liquid electrolyte, and wheredelivering the laser beam along the weld path the opening includes delivering the laser beam to the external casing along the weld path such that the laser beam does not contact the liquid electrolyte within the battery.

[0106] Example 18: The method of any of examples 1 to 17, where the opening includes an injection hole for a battery of a medical device, the method further including filling the battery with a liquid electrolyte via the injection hole.

[0107] Example 19: The method of any of examples 1 to 18, where the opening defines a substantially elliptical shape.

[0108] Example 20: The method of any of examples 1 to 19, where delivering the laser beam includes adjusting a power of the laser beam to prevent the laser beam from piercing fully through a thickness of the substrate from an outer surface to an inner surface.

[0109] Example 21: A medical device including: a battery including: a liquid electrolyte within the battery; and a sealed injection hole, where the liquid electrolyte is sealed within the battery by delivery of a laser beam along a weld path surrounding an unsealed injection hole to form the sealed injection hole, where the sealed injection hole is sealed by collapse of material surrounding the unsealed injection hole.

[0110] Example 22: The medical device of example 21, where the weld path circumnavigates the unsealed injection hole.

[0111] Example 23: The medical device of examples 21 or 22, where the laser beam is continuous.

[0112] Example 24: The medical device of any of examples 21 to 23, where the weld path consists of a single circuit around the unsealed injection hole.

[0113] Example 25: The medical device of any of examples 21 to 24, where an entirety of the weld path is spaced from the opening.

[0114] Example 26: The medical device of any of examples 21 to 25, where the battery includes: an outer surface and an inner surface; a first thickness between the outer surface and the inner surface in a non-welded region; and a second thickness in the region of the sealed injection hole, where the second thickness is smaller than the first thickness.

[0115] Example 27: The medical device of any of examples 21 to 26, where the battery includes an outer surface and an inner surface and a thickness therebetween, where the thickness is in a range of from 0.01 millimeters to 1.3 millimeters.

[0116] Example 28: The medical device of any of examples 21 to 27, where the battery includes an external casing including the sealed injection hole, and where the liquid electrolyte is sealed within the external casing by delivery of the laser beam along the weld path surrounding the unsealed injection hole to form the sealed injection hole.

[0117] Example 29: A system including: a laser apparatus; and a controller including processing circuitry configured to: control the laser apparatus to deliver a laser beam along a weld path surrounding an opening defined by a surface of a substrate; and seal the opening by collapse of material surrounding the opening, in response to the laser beam, into the opening.

[0118] Example 30: The system of example 29, where the weld path circumnavigates the opening.

[0119] Example 31 : The system of examples 29 or 30, where the laser beam is continuous.

[0120] Example 32: The system of any of examples 29 to 31, where the weld path consists of a single circuit around the opening.

[0121] Example 33: The system of any of examples 29 to 32, where an entirety of the weld path is spaced from the opening.

[0122] Example 34: The system of any of examples 29 to 33, where the substrate defines an outer surface and an inner surface, where the opening extends fully through a thickness of the substrate from the outer surface to the inner surface.

[0123] Example 35: The system of example 34, where the opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface, and where the weld path surrounds the outer end.

[0124] Example 36: The system of example 34, where opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface, and where the weld path extends along a projection of the inner end onto the outer surface.

[0125] Example 37: The system of example 34, where the opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface, where the opening is angled through the thickness of the substrate such that the outer end is not coterminous with a projection of the inner end on the outer surface, and where the weld path at least partially follows one or both of the outer end and the projection of the inner end.

[0126] Example 38: The system of any of examples 29 to 37, where the substrate includes a medical device battery.

[0127] Example 39: The system of example 38, where the battery includes an outer surface and an inner surface and a thickness therebetween, where the thickness is in a range of from 0.01 millimeters to 1.3 millimeters.

[0128] Example 40: The system of any of examples 29 to 39, where the laser beam defines a beam width, where the opening defines an opening width, and where the beam width is in a range of from five to fifteen percent the opening width.

[0129] Example 41: The system of any of examples 29 to 40, where the opening defines an opening width of around six thousandths of an inch.

[0130] Example 42: The system of any of examples 29 to 41, where the laser beam defines a beam width of around half a thousandth of an inch.

[0131] Example 43: The system of any of examples 29 to 42, where the controller is configured to control the laser apparatus to deliver the laser beam along an entirety of the weld path within one second.

[0132] Example 44: The system of any of examples 29 to 43, where a distance from an edge of the opening to the weld path is equal to or greater than a radius of a beam width of the laser beam.

[0133] Example 45: The system of any of examples 29 to 44, where the substrate includes an external casing of a battery containing a liquid electrolyte, and where the controller is configured to control the laser apparatus to deliver the laser beam to the external casing along the weld path such that the laser beam does not contact the liquid electrolyte within the battery.

[0134] Example 46: The system of any of examples 29 to 45, where the opening defines a substantially elliptical shape.

[0135] Example 47: The system of any of examples 29 to 44, where the controller is configured adjust a power of the laser beam to prevent the laser beam from piercing fully through a thickness of the substrate from an outer surface to an inner surface.

[0136] Various aspects of the disclosure have been described. These and other aspects are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A method comprising: delivering a laser beam along a weld path surrounding an opening defined by a surface of a substrate; and sealing the opening by collapse of material surrounding the opening, in response to the laser beam, into the opening.

2. The method of claim 1, wherein the laser beam is continuous, and wherein the weld path consists of a single circuit circumnavigating the opening.

3. The method of claim 1 or 2, wherein the substrate defines an outer surface and an inner surface, wherein the opening extends fully through a thickness of the substrate from the outer surface to the inner surface, wherein the opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface, and wherein the weld path surrounds one or more of the outer end and a projection of the inner end onto the outer surface.

4. The method of any of claims 1 to 3, wherein the substrate defines an outer surface and an inner surface, wherein the opening extends fully through a thickness of the substrate from the outer surface to the inner surface, wherein the opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface, wherein the opening is angled through the thickness of the substrate such that the outer end is not coterminous with a projection of the inner end on the outer surface, and wherein the weld path at least partially follows one or both of the outer end and the projection of the inner end.

5. The method of any of claims 1 to 4, wherein the substrate comprises a medical device battery comprising an outer surface and an inner surface and a thickness therebetween, wherein the thickness is in a range of from 0.01 millimeters to 1.3 millimeters.

6. The method of any of claims 1 to 5, wherein delivering the laser beam comprises delivering the laser beam along an entirety of the weld path in a period of one second or less.

7. The method of any of claims 1 to 6, wherein a distance from an edge of the opening to the weld path is equal to or greater than a radius of a beam width of the laser beam.

8. The method of any of claims 1 to 7, wherein the substrate comprises an external casing of a battery containing a liquid electrolyte, and wherein delivering the laser beam along the weld path the opening comprises delivering the laser beam to the external casing along the weld path such that the laser beam does not contact the liquid electrolyte within the battery.

9. The method of any of claims 1 to 8, wherein the opening comprises an injection hole for a battery of a medical device, the method further comprising filling the battery with a liquid electrolyte via the injection hole.

10. The method of any of claims 1 to 9, wherein delivering the laser beam comprises adjusting a power of the laser beam to prevent the laser beam from piercing fully through a thickness of the substrate from an outer surface to an inner surface.

11. The method of any of claims 1 to 10, wherein the laser beam defines a beam width, wherein the opening defines an opening width, andwherein the beam width is in a range of from five to fifteen percent of the opening width.

12. The method of any of claims 1 to 11, wherein a distance from an edge of the opening to the weld path is equal to or greater than a radius of a beam width of the laser beam, and wherein the method comprises delivering the laser beam along an entirety of the weld path in a period of one second or less.

13. A system comprising: a laser apparatus; and a controller comprising processing circuitry configured to: control the laser apparatus to deliver a laser beam along a weld path surrounding an opening defined by a surface of a substrate; and seal the opening by collapse of material surrounding the opening, in response to the laser beam, into the opening.

14. The system of claim 13, wherein the weld path consists of a single circuit circumnavigating the unsealed injection hole, wherein a distance from an edge of the opening to the weld path is equal to or greater than a radius of a beam width of the laser beam, wherein the laser beam is continuous, and wherein the controller is configured to control the laser apparatus to deliver the continuous laser beam along an entirety of the weld path in a period of one second or less.

15. The system of claim 13 or 14, wherein the substrate defines an outer surface and an inner surface, wherein the opening extends fully through a thickness of the substrate from the outer surface to the inner surface, wherein the opening extends between an outer end defined by the outer surface and an inner end defined by the inner surface,wherein the opening is angled through the thickness of the substrate such that the outer end is not coterminous with a projection of the inner end on the outer surface, and wherein the weld path at least partially follows one or both of the outer end and the projection of the inner end.

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