WO2024233560A1

WO2024233560A1 - Sealed electrical devices

Info

Publication number: WO2024233560A1
Application number: PCT/US2024/028174
Authority: WO
Inventors: Samuel Naumowicz; Derek Hodge TURNER; Keith Singer; Kenny Chui; Jackson Robert BRIGHT
Original assignee: Sensata Technologies Inc
Current assignee: Sensata Technologies Inc
Priority date: 2023-05-08
Filing date: 2024-05-07
Publication date: 2024-11-14
Anticipated expiration: 2025-11-08
Also published as: CN121175776A

Abstract

A hermetically-sealed electrical device includes a housing and a header assembly. The header assembly includes contact terminals, feedthroughs, and/or a tube extending through a cover plate. Glass-to-metal seals and/or braze joints are used to seal the contact terminals, the feedthroughs, and/or the tube to the cover plate, which may obviate the need for a ceramic header. The cover plate may be resistance welded to a lower housing or can.

Description

SEALED ELECTRICAL DEVICES

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of US Provisional Application No. 63/500,734, entitled “Electrical Device with Glass-to-Metal Sealing,” filed on May 8, 2023, the entirety of which is hereby incorporated by reference.

FIELD OF THE TECHNOLOGY

[0002] The subject disclosure relates to electrical switching devices, such as contactor devices and electrical fuse devices, and more particularly to improved sealed electrical switching devices.

BACKGROUND OF TECHNOLOGY

[0003] Many conventional devices are known to selectively power on or off electrical devices. For example, electrical contactors, e.g., high-voltage DC contactors, and fuses, e.g., electrical fuses and/or pyrotechnic fuses, are conventionally available and used in electrical systems. Contactors may be configured to interrupt or complete a circuit to control electrical power to and from a device. Fuses may be used for overcurrent protection. For example, fuses may be used to prevent short circuits, overloading, and/or permanent damage to an electrical system or a connected electrical device.

[0004] Many contactors and fuses, including those used in high-voltage, direct-current applications, make use of an electrically-insulative, hermetically-sealed assembly that allows the internal atmosphere of the device to be controlled. Some conventional contactors and fuses include hermetic seals formed using ceramic-to-metal or epoxy sealing. However, these conventional sealing technologies are expensive, resulting in expensive contactors and fuses. Moreover, epoxy sealing may have performance shortcomings, e.g., associated with cracking, poor sealing, and/or other issues that can cause inferior thermal and/or electrical performance.

[0005] Accordingly, there is a need in the art for improved hermetically-sealed contactors and fuses and methods of making such contactors and fuses.

SUMMARY OF THE TECHNOLOGY

[0006] The subject technology relates to improved electrical devices and methods of making those devices. In examples, aspects of this disclosure relate to improved hermetically- sealed contactors and fuses that incorporate a header fabricated using glass-to-metal sealing techniques. In other aspects, the present disclosure relates to improved hermetically-sealed contactors and fuses that include a header that is resistance welded to a can or housing. For example, such contactors and fuses may be less expensive and/or more reliable than some existing contactors and fuses. Additional aspects of this disclosure relate to methods of making improved hermetically-sealed contactors and fuses.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] So that those having ordinary skill in the art to which the disclosed systems and techniques pertain will more readily understand how to make and use the same, reference may be had to the following drawings.

[0008] FIG. 1 includes a perspective view of an electrical device and an exploded perspective view of a portion of the electrical device, in accordance with aspects of this disclosure. [0009] FIG. 2 is a cross-sectional view of the electrical device of FIG. 1, taken along section line 2-2 in FIG. 1, in accordance with aspects of this disclosure.

[0010] FIG. 3 is a cross-sectional view of the electrical device of FIG. 1, taken along section line 3-3 in FIG. 1, in accordance with aspects of this disclosure.

[0011] FIG. 4 is a side view of a portion of the electrical device of claim 1, in accordance with aspects of this disclosure.

[0012] FIG. 5 is a flow chart illustrating aspects of a method of manufacturing an electrical device, such as the electrical device illustrated in FIG. 1, in accordance with aspects of this disclosure.

[0013] FIG. 6 is a cross-sectional view of a portion of the electrical device of FIG. 3, generally corresponding to the section 6 — 6 shown in FIG. 3., in accordance with aspects of this disclosure.

[0014] FIG. 7 is a cross-sectional view showing aspects of a welding apparatus and an operation for assembling an electrical device, such as the electrical device illustrated in FIG. 1.

[0015] FIG. 8 is a flow chart illustrating aspects of a method of manufacturing an electrical device, such as the electrical device illustrated in FIG. 1, in accordance with aspects of this disclosure.

DETAILED DESCRIPTION

[0016] The subject technology overcomes many of the prior art problems associated with hermetically-sealed electrical devices. In brief summary, aspects of the subject technology may provide improved hermetically-sealed electrical devices. Some aspects of this disclosure include an improved header for an electrical device that is, at least in part, formed using glass-to-metal sealing technologies. Some aspects of this disclosure also describe methods of manufacturing the header. Still further aspects of this disclosure relate to improvements to an electrical device housing, which may include a header attached to a can or lower housing. Additional aspects of this disclosure relate to methods of manufacturing the improved electrical device housing.

[0017] Without limitation, the devices and techniques described herein may provide hermetically-sealed devices that are cheaper to manufacture than similar conventional devices. Moreover, the devices and techniques described herein may provide superior thermal and electrical performance relative to similar conventional devices. The devices and techniques described herein may also provide hermetically-sealed contactors and fuses that use lower-cost manufacturing methods, including but not limited to stamping, cold-forging, and wire-drawing. In some instances, these methods can be employed on less expensive raw materials In contrast, conventional techniques may employ more expensive subtractive machining in the manufacture of the raw components used in their ceramic and epoxy seals.

[0018] The devices and techniques may also or alternatively facilitate the use of different and/or more preferred materials to perform functions required of the electrical device. For example, and without limitation, the devices and techniques described herein may allow for the use of certain magnets, such as neodymium magnets, to increase arc suppression. Moreover, the devices and techniques described herein may accommodate the use of hydrogen to form the internal atmosphere of the electrical device, which may be preferred in some applications.

[0019] However, this disclosure is not limited to these improvements, and not all implementations of the systems and techniques described herein may result in these improvements.

Moreover, while aspects of this disclosure may be particularly useful in electrical devices, such as contactors and fuses, the systems and techniques described herein may be useful with many hermetically-sealed applications.

[0020] Aspects of the disclosure will now be explained in more detail with reference to the Figures.

[0021] FIG. 1 is a perspective view of an electrical device 100, which may be a contactor device, a fuse device, a pyrotechnic fuse, a pyrotechnic contactor, or the like. The electrical device 100 generally includes a body or housing 102, and a header assembly 104 disposed to cover an opening of the housing 102. In the illustrated example, the header assembly 104 is a hermetic glass-to-metal header assembly that is secured to the housing 102 to cover a top opening of the housing 102. Visible in FIG. 1, the assembly 104 includes a plate or cover 106 and two fixed contact structures 108 extending through the cover 106. In examples, the housing 102 may be formed as a base body, a “can,” or a “cup,” e g., defining a substantially circular opening. The assembly 104 may be a header sealed to the housing 102, e.g., at the circular opening to seal the interior of the housing 102. Better illustrated in FIGS. 2 and 3, the housing 102 is configured to contain a number of internal components. The contact structures 108 are configured to electrically connect internal components of the electrical device 100 to external circuitry, for example, to an electrical system or device. For example, the contact structures 108 may be terminals configured to facilitate connection of electrical leads (not shown). In one non-limiting example, a power source may be coupled to one of the contact structures 108 and a load to be powered by the power source may be coupled to the other of the contact structures 108.

[0022] The housing 102 can generally include any suitable material that can support the structure and function of the electrical device 100. However, and as detailed further below, in some examples of this disclosure the housing 102 may be selected and/or configured to facilitate improved coupling to a header assembly, such as the header assembly 104. For example, the housing 102 may be configured for resistance welding to the header assembly 104. In these examples, the housing 102 may be made of a metal such as stainless steel. Also in examples, the housing 102 may be plated, e.g., by an electroless nickel plating.

[0023] The housing 102 can be configured such that an internal space of the housing 102, e g., which houses the various internal components of the electrical device 100, is hermetically sealed. An electronegative gas may be disposed in the housing 102. This hermetically sealed configuration can help mitigate or prevent electrical arcing between adjacent conductive elements, and in some embodiments, helps provide electrical isolation between spatially separated contacts. In some examples, the housing 102 can be under vacuum conditions and/or can be hermetically sealed using known means of generating hermetically sealed electrical devices. As also detailed herein, in some examples, the devices and techniques detailed herein may facilitate the use of hydrogen in the housing.

[0024] As illustrated in FIG. 1, the header assembly 104 generally includes the cover 106 and a number of additional components. The cover 106 includes a number of holes or apertures formed therein, including a pair of contact apertures 110. Each of the contact apertures 110 is sized and positioned to receive one of the contact structures 108. As shown in FIG. 1, a glass seal 112 and a braze ring 114 also are disposed in each of the contact apertures 110.

[0025] More specifically, and as shown best in the exploded view of FIG. 1, each of the terminals 108 has an elongate body 116 configured to extend into a volume defined by the housing

102, e.g., through the cover 106. The braze ring 114 is disposed to circumscribe the elongate body 116, and the glass seal 112 is disposed to circumscribe the braze ring 114. The glass seal 112 has an outer circumference configured to be received in one of the contact apertures 110. Specifically, the contact apertures 110 have a diameter sized to receive the glass seal 112. In examples, the braze ring 114 may be slid or otherwise placed on the elongate body 116 of the contact structure 108, the glass seal 112, which also has a ring-shape, may be slid, or otherwise placed on the braze ring 114, and the combination of the contact structure 108, the braze ring 114, and the glass seal 112 may be disposed in one of the contact apertures 110.

[0026] In examples of this disclosure, the braze ring 114 is provided to facilitate glass-to- metal sealing of the contact structure 108 to the cover 106. For instance, the contact structure 108 may be made from a high-current capacity material, such as copper. However, such material, e.g., copper, has thermal expansion properties that may make the material incompatible with glass, e.g., in conventional glass-to-metal sealing. That is, sealing glass to copper may be ineffective. The braze ring 114, fixed, e.g., by brazing, to the (copper) contact structure 108, is selected to be compatible for glass-to-metal sealing. As illustrated, the contact structure 108 may be hollowed out, e.g., to reduce a wall thickness of the contact structure 108 proximate the location of the braze ring 114. The reduced wall thickness will allow the contact structure 108 to be relatively thin and flexible, e.g., so the braze ring can be fixed to the wall. Accordingly, the braze ring 114, retained on the outer surface of the contact structure 108, restrains the contact structure, but allows for glass sealing at the braze ring 114. Without limitation, the braze ring 114 may be formed of any conventional metal used for glass-to-metal sealing, such as a controlled-expansion metal. Without limitation, the braze ring 114 may be formed of an alloy, such as an alloy of iron and nickel, including but not limited to alloy 52. In examples, the braze ring 114 may prevent a thermal expansion mismatch between the (copper) contact structure 108 and the glass seal 112, which could cause seal failure. Thus, aspects of this disclosure can facilitate creation of a glass-to-metal sealed hermetic housing that can still carry high currents, e.g., because the contact structure 108 is copper or another high-current capacity material.

[0027] As also illustrated in FIG. 1, the cover 106 can include a number of additional apertures, e.g., through which other or additional components can extend into the sealed space defined by the housing 102 and the header assembly 104. For example, FIG. 1 shows a number of feedthroughs 118 (four in FIG. 1) extending through corresponding feedthrough apertures 120 in the cover 106. In examples, the feedthroughs 118 may be electrical leads or the like. As also illustrated, second glass seals 122 are disposed in the feedthrough apertures 120, with the feedthroughs 118 passing through the glass seals 122. As detailed further herein, the second glass seals 122 facilitate sealing of the feedthroughs 118 to the cover 106, via glass-to-metal sealing, at the feedthrough apertures 120. Although four feedthroughs 118 are illustrated in FIG. 1, more or fewer may be provided.

[0028] The header assembly 104 also is illustrated as including a tube 124 that passes through the cover 106. More specifically, the cover 106 includes a tubing aperture 126 sized to receive the tube 124. For example, the tube 124 may be used to evacuate air in the housing 102, e.g., during the sealing process, to vent excess air in the housing, e.g., during a fault event, to supply a gas, such as an electronegative gas like hydrogen, to the housing 102, and/or the like. Although only one tube 124 is shown, the assembly 104 could include additional (or no) tubes.

[0029] In the example illustrated in FIG. 1 , the header assembly 104 includes multiple seal types and sealing technologies. For example, braze joints 128 are formed between the braze rings

114 and the contact structures 108. Braze joints 128 may also be formed between the tube 124 and the cover 106, e.g., at the tubing aperture 126. The contact structures 108, the braze rings 114, the tubing 124, and/or the cover 106 are formed of materials that facilitate formation of the braze joints 128. For example, any of these components can include silver, copper, and/or alloys thereof. In one specific example, the cover 106 may be made of steel, such as cold rolled steel, low carbon steel, and/or the like. Also in examples, the cover 106 may be treated, such as by plating or the like, to further facilitate formation of the braze joints 128 and/or glass-to-metal seals 130 described herein. In one non-limiting example, the cover 106 may be plated with sulfamate electrolytic nickel.

[0030] As noted above, in addition to seals created at the braze joints 128, the header assembly 104 also includes the glass-to-metal seals 130. For example, the glass seals 112 and the second glass seals 122 may be glass preforms that bond or otherwise seal to the surrounding (e.g., metal) cover 106 at the interface of the metal and glass. In at least some examples, the glass seals 112, 122 may be formed of a low-lead glass, such as a barium-alkali low-lead glass. The cover 106 may be made of any metallic material that cooperates with the glass seals 112, 122 to form the desired hermetic seal(s). In some examples of this disclosure, as detailed further herein, the cover 106 may be formed of a steel, such as low carbon steel or cold rolled steel. In examples, the cover 106 may be surface treated, e.g., by plating or the like. In at least one example, the cover 106 may have a sulfamate electrolytic nickel plating. In other examples, the cover 106 can include aluminum or an aluminum alloy.

[0031] In some aspects of this disclosure, the braze joints 128 and/or the glass-to-metal seals 130 may be leak free to 2.0 x 10'⁹ cc/sec of helium at 1 atmosphere. The braze joints 128 and/or the glass-to-metal seals 130 may also be configured to withstand an axial loading, e.g., a loading that would push the contact structures 108 into the contact apertures 110. In a non-limiting examples, the braze joints 128 and/or the glass-to-metal seals 130 may withstand axial loads up to or exceeding 35 Ibf (155N) without leaking. The braze joints 128 and/or the glass-to-metal seals

130 may also be configured to withstand side loading, e.g., normal to the axial direction just described. In a non-limiting examples, the braze joints 128 and/or the glass-to-metal seals 130 may withstand side loads up to or exceeding 35 Ibf (155N) without leaking.

[0032] The braze joints 128 and/or the glass-to-metal seals 130 may also facilitate improved operation of the electrical device 100. For example, during operation, the electrical device 100 may facilitate the application of voltages up to or exceeding 4000 volts at 60 seconds at sea level between the contact structures 108 with a leakage current being below 1 milliampere. Moreover, the electrical device 100 will have no evidence of flashover, arcing, breakdown, or other damage at this electrical loading. The electrical device 100 may also facilitate the application of voltages up to or exceeding 4000 volts at 60 seconds at sea level between the contact structures 108 and each of the feedthroughs 118 with a leakage current being below 1 milliampere. Moreover, the electrical device 100 will have no evidence of flashover, arcing, breakdown, or other damage at this electrical loading. The electrical device 100 may also facilitate insulation resistance between the contact structures 108 and/or between the contact structures 108 and each of the feedthroughs 118 of up to or greater than 100 megohms at 1000 volts DC.

[0033] FIG. 2 is a cross-sectional view of the electrical device 100 taken along the section line 2-2 in FIG. 1. FIG. 2 shows the contact structures 108 extending through cover 106 and into an interior 202 of the housing 102. As detailed herein, aspects of this disclosure allow for the interior 202 of the housing 102 to be hermetically sealed. For example, at least a portion of the interior 202 may be an arc chamber. The arc chamber may be filled with a gas, such as hydrogen, that facilitates arc suppression. [0034] A number of internal components also are shown in the interior 202. For example,

FIG. 2 shows a movable contact 204 disposed on a distal end of a movable shaft 206. As is conventional in the art, the shaft 206 may be selectively movable to configure the movable contact 204 in a first position contacting the contact structures 108, e.g., to allow for current flow between the contact structures 108, and a second position (illustrated) in which the movable contact 204 is spaced from the contact structures 108. In the illustrated example, an end of the shaft 206 opposite the movable contact 204 includes a plunger 208. The plunger 208 extends into an opening defined by a coil 210, e.g., an electromagnetic coil. The electromagnetic coil 210 may be selectively energized to cause the plunger 208 (and thus the shaft 206 and the movable contact 204) to move relative to the contact structures 108.

[0035] FIG. 2 also shows an interrupt mechanism 212, e.g., proximate an inner surface of the cover 106 and between the contact structures 108. In examples, the interrupt mechanism can include a triggering device 214, which may be a pyrotechnic trigger, for example, and a projectile 216. In operation, the triggering device 214 may detonate in response to an overcurrent, a power surge, arcing, or some other event. The detonation applies a force that causes the projectile 216 to strike the shaft 206, driving the shaft 206 (and thus the movable contact 204) away from the contact structures 108, thereby inhibiting current flow through the electrical device 100.

[0036] FIG. 2 also shows that the electrical device 100 can include one or more additional components exterior to the housing 102. Specifically, FIG. 2 shows two magnets 218 coupled to the electrical device 100. In the illustrated example, the magnets 218 are disposed proximate the housing 102 generally at positions radially spaced from the contact structures 108. The magnets 218 may be provided to assist with current interruption. For example, certain types of magnets, such as neodymium magnets may be desirable to provide a high current interruption capability. Example implementations of devices described herein may facilitate the use of neodymium magnets, in particular when a stainless steel is used for the housing 102, according to examples described herein. Of course, this disclosure is not limited to neodymium magnets, and in some examples, magnets may not be provided, e.g., as in FIG. 1.

[0037] In the illustrated example, the magnets 218 are coupled to the electrical device via a magnet mounts 220. The magnet mounts 220 are generally illustrated as L-shaped members, having a first leg 222 on top of the cover 106 and a second leg 224 extending generally along, but spaced from, an outer surface of the housing 102. In this example, the magnets 218 may be secured to the second leg 224, e.g.., between the second leg 224 and the housing 102. The magnet mounts 220 are for example only. Any structure, configuration and/or the like that retains the magnets 218 in a desired position may be used. In still further examples, the magnet mounts 220 may not be included. For instance, the magnets 218 may be secured directly to the housing 102.

[0038] Although FIG. 2 shows the electrical device 100 as including various internal and external components, FIG. 2 is for example only. Aspects of this disclosure can be used with any number or types of electrical devices that include a header assembly and a housing, like the header assemblyl04 and the housing 102.

[0039] FIG. 3 is a cross-sectional view of the electrical device 100 taken along the section line 3-3 in FIG. 1. FIG. 3 shows electrical components 302 disposed in the interior 202 of the housing. The electrical components 302 may be connected to one of the feedthroughs 118. Without limitation, the electrical components 302 may be coupled to the coil 210, to the interrupt mechanism 212, and/or to any other of the components associated with the electrical device. In other examples, the electrical components 302 can be coupled to one or more electronic components outside the electrical device 100, e.g., to send and/or receive signals to/from outside the housing 102.

[0040] FIG. 3 also shows the tubing 124 in cross-section. As noted above, the tubing 124 may be provided to exchange air in the interior 202 of the housing 102 and/or to evacuate the interior 202 of the housing 102. In some examples of this disclosure, using the tubing 124, the interior 202 may be filled with hydrogen or another inert gas. For example, particular implementations of this disclosure can incorporate a stainless steel housing as the housing 102, which may facilitate use of the magnets 218 and/or a hydrogen or other inert atmosphere in the interior 202.

[0041] FIG. 4 is a partial cross-section of the header assembly 104 particularly showing aspects of the braze joints 128 at one of the contact structures 108 and at the tubing 124 and showing aspects of the glass-to-metal seal 130 associated with one of the contact structures 108. As noted above, the braze joints 128 and/or the glass-to-metal seals 130 may also facilitate improved operation of the electrical device 100. For example, during operation, the electrical device 100 may facilitate the application of voltages up to or exceeding 4000 volts at 60 seconds at sea level between the contact structures 108 with a leakage current being below 1 milliampere. Moreover, the electrical device 100 will have no evidence of flashover, arcing, breakdown, or other damage at this electrical loading. The electrical device 100 may also facilitate the application of voltages up to or exceeding 4000 volts at 60 seconds at sea level between the contact structures 108 and each of the feedthroughs 118 with a leakage current being below 1 milliampere. Moreover, the electrical device 100 will have no evidence of flashover, arcing, breakdown, or other damage at this electrical loading. The electrical device 100 may also facilitate insulation resistance between the contact structures 108 and/or between the contact structures 108 and each of the feedthroughs 118 of up to or greater than 100 megohms at 1000 volts DC.

[0042] FIG. 5 is a flowchart showings aspects of a process 500, which may be a manufacturing process to form a hermetically-sealed electrical device, like the electrical device 100.

[0043] At an operation 502, the process 500 includes providing a head plate. For example, the head plate may be the cover 106 discussed above. For example, the cover 106 has a plurality of apertures, including the contact apertures 110, the feedthrough apertures 120, and/or the tube aperture 126. In examples, the cover 106 may be made of a metal, such as aluminum or an aluminum alloy.

[0044] At an operation 504, the process 500 includes providing a glass seal in an opening in the head plate. For example, when the head plate is the cover 106, the cover 106 can include the contact aperture 110, and the glass seal 112 may be placed in the contact aperture 110. The glass seal 112 can be a glass preform, e g., of a predetermined size and configuration.

[0045] At an operation 506, the process 500 includes providing a terminal proximate the glass seal. For example, and as described above, the contact structure 108 may be a terminal disposed in the contact aperture 110. For example, the glass seal 112 may be a ring that circumscribes an outer surface of the contact structure 108.

[0046] At an operation 508, the process 500 includes providing a braze ring proximate the terminal. For example, the braze ring 114 illustrated in FIG. 1 is a sleeve disposed on an outer surface of the contact structure 108. Thus, the braze ring 114 may contact both the contact structure 108 and the glass seal.

[0047] At an operation 510, the process 500 includes creating an assembly including a braze joint at the braze ring and a glass-to-metal seal at the glass seal. In implementations of this disclosure, the operation 510 can include performing a brazing operation, such as vacuum brazing or the like, to form the braze j oint 128 at an interface of the braze ring 114 and the contact structure 108. The glass-to-metal seal 130 can be formed at the glass seal 112, e.g., between the glass seal 112 and the cover 106 and/or between the glass seal 112 and the braze ring 114. In examples, the operation 510 can include performing a glass-to-metal sealing process to form the desired seal(s) at the glass seal 112. The result of the operation 510 may be the assembly 104 discussed above.

[0048] Although the operation 510 is illustrated and described as a single process, as will be appreciated, the operation 510 may be performed in multiple steps. For example, and without limitation, the braze joint 128 may be formed prior to forming the glass-to-metal seals 130. For instance, the braze ring 114 may be brazed to the contact structure 108 prior to insertion into to the cover 106. Thus, the operations 506 and 508 may include a single operation of providing the contact structure 108 with the braze ring 114 joined thereto. In still further examples, the assembly may be pre-assembled as in the operations 502-508, but the glass-to-metal sealing may be performed prior to the brazing process. In still further examples, because brazing and glass-to- metal sealing may both include the application of heat, aspects of the brazing and glass-to-metal sealing may be done contemporaneously, e.g., via the same application of heat, such as in a furnace or the like. [0049] At an operation 512, the process 500 includes securing the assembly to a housing.

For example, the assembly 104 may be secured to the housing using known methods, including epoxy sealing or the like.

[0050] At an operation 514, the process 500 can include evacuating the housing. For example, ambient air in the housing after sealing may be removed and/or replaced with an electronegative gas, such as hydrogen, to provide a hermetically-sealed electrical device, like the electrical device 100.

[0051] Although not shown in FIG. 5, the process 500 can also include providing the brazedjoints 128 at the tube 124 and/or providing the glass-to-metal seals 130 at the feedthroughs 118. In examples, all of the brazedjoints 128 may be formed in a single process, e.g., the entire assembly 104 may be exposed to a brazing process, such as a vacuum brazing process, a furnace brazing process, or the like to create the brazing j oints at the braze rings 114 and at the tube 124. In other examples, the brazing joints can be formed individually. The glass-to-metal seals 130 associated with the contact structures 108 and associated with the feedthroughs 118 may similarly all be formed via a single process, e.g., a process applied to the entire header assembly 104.

[0052] As just described, aspects of this disclosure relate to providing electrical devices incorporating a header assembly that incorporates glass-to-metal sealing techniques. The header assembly using the glass-to-metal sealing can provide a number of benefits over conventional header assemblies.

[0053] In some aspects of this disclosure, a hermetically-sealed and electrically-insulative assembly for use in high-voltage DC contactors, fuses, and pyrotechnic fuses may make use of glass-to-metal sealing technology along with a unique combination of materials and geometry to reduce cost and improve performance in comparison to conventional sealed assemblies.

[0054] Hermetic glass-to-metal assemblies according to this disclosure may be assembled using manufacturing methods that are less expensive than existing ceramic-to-metal or epoxy sealing, including in electrical devices like contactors and fuses.

[0055] The hermetic glass-to-metal assemblies described herein also may utilize lower cost manufacturing methods in its raw materials, further reducing cost in comparison to existing ceramic-to-metal and epoxy sealing applications.

[0056] Thus, hermetic glass-to-metal assemblies described herein may utilize unique combinations of materials and geometries to provide thermal and electrical performance that may be superior to existing glass-to-metal seals used in unrelated products (e.g., motor protectors), thus allowing the use of this technology in electrical devices including but not limited to, contactors and fuses.

[0057] Additional aspects of this disclosure relate to additional devices and methods incorporating the glass-to-metal header assemblies like those just described. For example, FIG. 6 is a partial, cross-sectional view 600 of the electrical device 100, taken along the sectioning line 6-6 in FIG. 3. More specifically, FIG. 6 shows an interface of the header assembly 104, e.g., the cover 106, with the housing 102.

[0058] As noted above, the housing 102 can be embodied as a can or cup. FIG. 6 shows the housing 102 as including a generally cylindrical sidewall 602 and an outtumed rim 604. In examples, the rim 604 may be bent relative to the sidewall 602 by an angle of between about 30- degrees and about 55-degrees, although other angles may be used. In some examples, the rim 604 may be in-turned, e.g., to define an opening narrower than an opening defined by the sidewall 602. In still further examples, the housing 102 may be substantially cylindrical, e.g., the rim 604 may not be provided and/or the rim 604 may refer to the area proximate the termination of the sidewall 602 where the housing 102 meets the cover 106.

[0059] The sidewall 602 terminates at an edge 606. In the illustrated example, the edge 606 is provided at the termination of the rim 604. In examples, the edge 606 is a pinch trim edge, e.g., formed via pinch trimming. Pinch trimming generally describes a process in which metal is cut by pinching the metal between two die sections. As a result of pinch trimming, the edge 606 is sharp, forming a generally circular edge. As illustrated, the edge 606 is formed at a junction between an inner surface 608 of the housing 102 and an end surface 610 of the housing 102. In the example of FIG. 6, the housing may be fabricated by first pinch trimming the sidewall 602 of the housing 102, and then bending the sidewall 602 to form the rim 604. Although pinch trimming is described herein for making the edge 606, the edge 606 is not limited to being formed using this process. Any process that forms the edge 606 as a sharp edge can be used.

[0060] As illustrated in FIG. 6, a bottom surface 612 of the cover 106 contacts the edge 606 of the sidewall 602. In examples, the bottom surface 612 is substantially planar, such that the cover 106 contacts the housing 102 about the entirety of the edge 606.

[0061] In examples of this disclosure, the cover 106 is secured to the housing 102 at the junction of the bottom surface 612 and the edge 606. In some examples, the bottom surface 612 and the edge 606 are welded together. For example, the bottom surface 612 and the edge 606 may be resistance welded. [0062] As will be appreciated with the benefit of this disclosure, the cover 106 and the housing 102 may be selected and/or fabricated to facilitate welding or other joining processes. For instance, and without limitation, in some examples the cover 106 may be a low carbon steel, such as a cold-rolled steel. In non-limiting examples, the cover 106 may comprise an AISI 1006-1024 steel, which may be cold rolled, cold drawn, or otherwise manufactured. In examples, the material of the cover 106 may be selected for its use in glass-to-metal sealing, as discussed above. The material may also be selected for its ability to be welded, e.g., using a resistance weld.

[0063] The cover 106 may also or alternatively be treated, e.g., to facilitate glass-to-metal sealing and/or welding, as described herein. For example, the cover 106 may be plated. In one non-limiting example, the cover 106 may have a nickel plating. In at least one example, the plating can be a sulfamate electrolytic nickel plating. In examples, the plating may be on the order of from about .0001 to about .0005 inches thick. However, other types of plating and/or other thicknesses of plating may also be used. As noted, any surface treatment that is compatible with glass-to-metal sealing and/or techniques for joining the cover 106 to the housing 102 may be used.

[0064] The material for the housing 102 may also be selected for its compatibility with the cover 106 to facilitate joining, e.g., by resistance welding, as described herein. In some examples of this disclosure, the housing 102 may be a stainless steel can. Without limitation, the housing 102 can have a thickness on the order of from about 0.015 to about 0.045 inches. The housing 102 can also include a surface treatment, such as a plating or the like. In one non-limiting example, the housing 102 can include an electroless nickel plating. For example, the plating can be on the order of from about .0001 to about .0005 inches thick. The plating may also be a high phosphorous plating, e.g., containing phosphorous in an amount of between about 8% and about 20%. Also in examples, an activator, such as woods nickel strike may be applied to the housing 102 prior to plating. However, the housing 102 is not limited to the materials and/or finishes given herein as examples. Any materials that facilitate joining of the housing 102 to the cover 106 may be used.

[0065] In examples, the combination of the stainless steel housing 102 and the gas-to-metal sealed header assembly 104 including a steel cover 106 may provide certain benefits. For example, and without limitation, this combination can allow for use of neodymium magnets, e.g., as the magnets 218. Moreover, this combination may facilitate the use of a hydrogen atmosphere in the arc chamber volume 202. In some applications, a hydrogen gas backfill is optimal to extinguish heavy arcing events. However, hydrogen will permeate through epoxy-filled contactors. Conventionally, then, such atmosphere has required the use of a ceramic header and a metallic housing. These conventional metallic housings are low-carbon steel, and neodymium magnets, which are conventionally used inside hermetic contactors, are susceptible to hydrogen embrittlement if kept in a hydrogen environment. However, the present disclosure may be less expensive than conventional devices, while still providing higher current interruption performance by providing both neodymium magnets and a hydrogen-enriched arcing chamber.

[0066] As noted above, in some aspects of this disclosure a header assembly, which may be the header assembly 104, may be secured to the housing 102 to create a hermetically sealed inner volume. Specifically, in the example of FIG. 6, the bottom surface 612 of the cover 106 may be sealed to the edge 606 of the housing 102. FIG. 7 shows an example schematic of aspects of a welding operation for welding the cover 106 to the housing 102.

[0067] More specifically, FIG. 7 is a cross-sectional representation of a welding apparatus 700 used to resistance weld the header assembly 104 to the housing 102. Although the illustrated example shows the header assembly 104, which may be the glass-to-metal sealed header assembly discussed above, aspects of this disclosure may be used with other types of header assemblies. Moreover, although the housing 102 is shown, this is merely for ease of reference. Aspects of this disclosure may be used with other types of housings.

[0068] In the example of FIG. 7, the welding apparatus 700 includes a lower electrode holder 702. The lower electrode holder 702 defines a bore 704 configured to receive the housing 102. The lower electrode holder 702 also is configured to retain a lower electrode 706, e.g., proximate a top or open end of the bore 704. The lower electrode 706 may be a ring-shaped electrode that is arranged such that when the housing 102 is disposed in the bore 704, the lower electrode 706 contacts the rim 604 of the housing 102, e.g., proximate the edge 606. As noted above, the edge 606 may be a sharp edge, which may be formed using a pinch trimming operation. However, other configurations for the edge 606 also may be used.

[0069] As also shown in FIG. 7, the header assembly 104 is placed on the housing 102. The welding apparatus 700 can optionally include a positioning device 708 to maintain a position of the header assembly 104 relative to the housing 102 retained in the bore 704. For example, when used, the positioning device 708 may axially align the cover 106 and the housing 102. In the illustrated example, the positioning device 708 is embodied as a ring having a central opening that has a diameter that is slightly larger than an outer diameter of the cover 106. The illustrated positioning device is for example only; other structures or arrangements also may be contemplated by those having ordinary skill in the art with the benefit of this disclosure.

[0070] The welding apparatus 700 also includes an upper electrode holder 710, which is configured to carry or retain an upper electrode 712. As illustrated in FIG. 7, the upper electrode

712 is positioned on a top surface of the cover, generally opposite the position at which the edge 606 contacts the bottom surface 612 of the cover 106. Thus, and as shown in FIG. 7, the welding apparatus 700 positions the cover 106 on the housing 102 and places a first electrode (the lower electrode 706) proximate the edge 606 of the housing 102 and the bottom surface 612 of the cover 106. The welding apparatus 700 also positions a second electrode (the upper electrode 712) on the top surface of the cover 106.

[0071] The lower electrode holder 702 and the upper electrode holder 710 may be movable relative to each other, e g. in an axial direction. For example, the holders 702, 710 may be movable away from each other to facilitate insertion of the header assembly 104 and/or the housing 102. The holders 702, 710 also may be movable toward each other, e.g., to apply a pressure to the housing 102 and/or to the cover 106 using the electrodes 706, 712. When this pressure is applied, a current may be passed through one or both of the electrodes 706, 712 to create a resistance weld at the edge 606/bottom surface 612 interface.

[0072] In some examples, the resistance weld created by the welding apparatus 700 creates a hermetic seal between the header assembly 104 and the housing 102. The resistance weld may allow for a hydrogen gas backfill, which may result in greater contactor break performance. Moreover, when stainless steel is used for the housing 102, neodymium magnets may be placed outside of the hermetic assembly to prevent hydrogen embrittlement while still providing a magnetic field benefit that aids in contactor break performance.

[0073] FIG. 8 is a flowchart showings aspects of a process 800, which may be a manufacturing process to form a hermetically-sealed electrical device, like the electrical device

100. In some examples, the process 800 can correspond to aspects of operations 512 and 514 of the process 500 described above. [0074] At an operation 802, the process 800 includes providing a housing. For example, the housing may be the housing 102 discussed above. For example, the housing may be a can or cup. The housing may be formed, at least in part, using pinch trimming, such that the housing includes a pinch trim edge circumscribing an opening. In at least some examples, the housing may be formed of a stainless steel and/or may be plated, e.g., using electroless nickel plating.

[0075] At an operation 804, the process 800 includes providing a header. For examples, the header may be the header assembly 104 described above. For instance, the header may be a glass-to-metal sealed header assembly. In other examples, the header may be otherwise formed and/or include features and/or components different from those described herein.

[0076] At an operation 806, the process 800 includes resistance welding the header to the housing. For example, the header may be resistance welded using a resistance welding apparatus like the welding apparatus 700 discussed above.

[0077] At an operation 808, the process 500 includes, optionally, securing magnets relative to the housing. For example, and as discussed above, when the housing is made of stainless steel, magnets, such as neodymium magnets, may be positioned outside of the housing. FIG. 2 shows the magnets 218 positioned along an outer surface of the housing 102. The magnets may be aligned with ends of a movable contact and may assist in arc suppression and/or resistance.

[0078] At an operation 510, the process 500 includes evacuating/backfilling the housing. For example, ambient air in the housing after sealing may be removed and/or replaced with an electronegative gas, such as hydrogen, to provide a hermetically-sealed electrical device, like the electrical device 100. A hydrogen-rich environment may be particularly useful for suppressing arcs, but other gases and/or environmental conditions may also be of use and may be used with aspects of this disclosure.

[0079] While the subject technology has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and/or modifications can be made to the subject technology without departing from the spirit or scope of the subject technology. For example, each claim may depend from any or all claims in a multiple dependent manner even though such has not been originally claimed.

Claims

WHAT IS CLAIMED IS:

1. An electrical device comprising: a housing; and a header assembly sealed to the housing, the header assembly comprising: a cover; a contact aperture formed through the cover; a contact terminal disposed in the contact aperture; a braze ring proximate an outer surface of the contact terminal; and a glass seal between the braze ring and an inner surface of the contact aperture, wherein a braze j oint is formed at a first interface of the outer surface of the contact terminal and the braze ring, and wherein a glass-to-metal seal is formed at a second interface of the cover and the glass seal and/or at a third interface of the glass seal and the braze ring.

2. The electrical device of claim 1, wherein the header assembly further comprises: a feedthrough aperture formed through the cover; a feedthrough extending through the feedthrough aperture into the housing; and a second glass seal between the feedthrough and an inner surface of the feedthrough aperture, wherein a second glass-to-metal seal is formed at the second glass seal and the feedthrough aperture.

3. The electrical device of claim 2, wherein the feedthrough comprises an electrical lead, the electrical device comprising: one or more electronics disposed in the housing and coupled to the electrical lead.

4. The electrical device of any one of claim 1 through claim 3, wherein the header assembly further comprises: a tube aperture formed through the cover, and a tube extending through the tube aperture into the housing.

5. The electrical device of claim 4, wherein the tube is configured to at least one of evacuate an atmosphere in the housing or supply a gas to an interior of the housing.

6. The electrical device of any one of claim 1 through claim 5, wherein the contact terminal has a bore formed therein, the bore reducing a wall thickness of the contact structure proximate the braze ring.

7. The electrical device of any one of claim 1 through claim 6, wherein the header assembly is resistance welded to the housing.

8. The electrical device of claim 7, wherein the housing comprises: a sidewall terminating at an edge; and the edge is resistance welded to a surface of the cover.

9. The electrical device of claim 8, wherein the edge is a pinch trimmed edge.

10. The electrical device of any one of claim 1 through claim 9, wherein at least one of: the housing comprises stainless steel; or the cover comprises low carbon steel.

11. The electrical device of claim 10, wherein at least one of the housing or the cover is plated.

12. The electrical device of any one of claim 1 through claim 11, further comprising: at least one magnet disposed proximate an outer surface of the housing.

13. The electrical device of claim 12, wherein the at least one magnet comprises at least one neodymium magnet.

14. The electrical device of claim 13, wherein: the housing comprises stainless steel; and an interior of the housing comprises hydrogen.

15. The electrical device of claim 12, further comprising at least one magnet mount coupled to the header assembly, the at least one magnet mount positioning the at least one magnet proximate the outer surface of the housing.