WO2025259906A1

WO2025259906A1 - Electrical assembly including contactor and bus bar

Info

Publication number: WO2025259906A1
Application number: PCT/US2025/033398
Authority: WO
Inventors: Elizabeth Marilyn PATERNOSTER
Original assignee: Sensata Technologies Inc
Current assignee: Sensata Technologies Inc
Priority date: 2024-06-13
Filing date: 2025-06-12
Publication date: 2025-12-18
Anticipated expiration: 2026-12-13

Abstract

An improved electrical assembly includes an electrical device and a bus bar coupled to a fixed or stationary contact of the electrical device. In examples, the fixed contact may be made of a copper material and the bus bar may be made of an aluminum material. The bus bar may be coupled to the fixed contact using a solid state welding process.

Description

ELECTRICAL ASSEMBLY INCLUDING CONTACTOR AND BUS BAR

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority of US Provisional Patent Application No. 63/959,689, filed June 13, 2024, and titled “Electrical Assembly Including Contactor and Bus Bar,” 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 contactor devices for use with bus bars and methods of securing bus bars to such contactor 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.

[0004] In many conventional systems, a contactor has two contacts, which may be fixed contacts embodied as posts or the like. One of the contacts facilitate connection of the contactor to an electrical source, such as a high voltage source, and the other of the contacts facilitates connection of the contactor to a load, such as a load to be powered by the electrical source. In some examples, a conduit, such as a wire or the like, facilitates these connections. In other examples, however, it may be desirable to secure a bus bar or other conductive stock to one or both of the contacts. However, conventional systems and techniques that integrate a contactor and a bus bar suffer from a number of drawbacks.

[0005] Accordingly, there is a need in the art for improved switching devices, contactor devices, interrupter devices, and methods of making such devices.

SUMMARY OF THE TECHNOLOGY

[0006] The subject technology relates to improved electrical devices and methods of making and using those devices. In examples, aspects of this disclosure relate to improved electrical assemblies including a contactor or other switching device and one or more bus bars or electrical connectors couped to the contactor. Aspects of this disclosure also relate to techniques for manufacturing such electrical assemblies.

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 is a front view of an electrical device, such as a contactor, in accordance with aspects of this disclosure.

[0009] FIG. 2 is a perspective view of a bus bar for use in an electrical assembly, in accordance with aspects of this disclosure.

[0010] FIG. 3 is a perspective view of an electrical assembly including an electrical device and bus bars, in accordance with aspects of this disclosure. [0011] FIG. 4 is a perspective view demonstrating a technique for forming the electrical assembly of FIG. 3, in accordance with aspects of this disclosure.

[0012] FIG. 5 is a flowchart illustrating a process of forming an electrical assembly, in accordance with aspects of this disclosure.

DETAILED DESCRIPTION

[0013] The subject technology overcomes many of the prior art problems associated with electrical devices. In brief summary, the subject technology provides improved electrical assemblies that include a contactor or other switching device, and a bus bar coupled to the contactor/switching device.

[0014] In some applications, it is desirable to couple, e.g., by direct connection, a bus or other rigid conductive connector to a contactor or other fuse device. Conventional applications generally use copper bus bars that are fixed to stationary terminals of the contactor via laser welding. In these examples, the stationary terminals are often conventionally copper, and when the bus bar is copper, the laser welding is copper to copper.

[0015] In aspects of this disclosure, aluminum bus bars may be preferable over the copper bus bars used in some conventional applications. For instance, aluminum may be cheaper, lighter, and/or have other preferred properties. In some examples, aluminum may still provide reliable performance in applications such as electric vehicles or the like. However, conventional laser welding does not allow for a stationary contact made of copper to be reliably joined to an aluminum bus bar, e.g., because of the differences in composition and physical, mechanical, and/or metallurgical properties. [0016] In aspects of this disclosure, an aluminum bus bar is directly connected to a copper contact. For example, aspects of this disclosure include using a solid state welding process to join an aluminum bus bar to a copper contact. In some examples, the solid state welding process may be a friction stir welding process. Aspects of this disclosure maintain the value proposition of directly connecting bus bars to contactors for improved contact resistance and thermal performance, but allow for the use of aluminum instead of copper.

[0017] Without limitation, the devices and techniques described herein may provide improved electrical devices and electrical assemblies, which may be less complex, may be cheaper to manufacture and/or use, and/or that may have improved safety and/or result in improved system protection, when compared to similar conventional systems. Moreover, while aspects of this disclosure may be particularly useful in certain application, like high voltage automotive systems, the systems and techniques described herein may be useful with many electrical systems.

[0018] Aspects of the disclosure will now be explained in more detail with reference to the Figures.

[0019] FIG. 1 is an elevation view of an electrical device 100. In the example, the electrical device is a contactor device, although in other examples the electrical device 100 may be a fuse device, a pyrotechnic fuse, or the like.

[0020] As shown in FIG. 1, the electrical device 100 generally includes a body or housing 102. The housing 102 generally includes an upper housing 104 and a lower housing 106. As also shown, two fixed contacts 108 are illustrated as extending, e.g., above, the upper housing 104. The fixed contacts 108 are configured to electrically connect internal components disposed in the upper housing 104 (not shown in FIG. 1) of the electrical device 100 to external circuitry, for example, to an electrical system or device. For example, the fixed contacts 108 may be terminals configured to facilitate connection of first electrical leads (not shown) from a voltage source to second electrical leads (also not shown) of a load to be powered by the voltage source.

[0021] As also illustrated in FIG. 1, and as detailed further herein, the fixed contacts 108 may be coupled to bus bars 110 that facilitate coupling of the electrical device 100 to the electrical source and/or the load. As is conventionally known, components within the upper housing 104 can include a movable contact that is movable between a first position spaced from one or both of the fixed contacts 108 (to prevent current flow between the fixed contacts 108) and a second position contacting both of the fixed contacts 108 (to facilitate current flow between the fixed contacts 108). In examples of this disclosure, the fixed contacts 108 may be made of copper or a copper alloy, and/or the bus bars 110 may be made of aluminum or an aluminum alloy. However, in other examples other conductive materials may be used.

[0022] In at least some examples, and as detailed further herein, the bus bars 110 include cutouts configured to cooperate with the fixed contacts 108. For example, the cutouts may form a clearance fit or an interference fit with at least a portion of an outer surface of the fixed contacts 108. Moreover, and as described further below, the bus bars 110 may welded to the fixed contacts 108. In at least some examples, a solid state weld may be formed at an interface of the bus bars 110 and the fixed contacts 108 (e.g., at an interface of the cutout of one of the bus bars 110 and the corresponding one of the fixed contacts 108).

[0023] FIG. 2 is a perspective view of an example of a bus bar 200, which may be one of the bus bars 110. In the illustrated example, the bus bar 200 includes a body 202. The body 202 is generally elongated and generally rectangular in shape, although the body 202 is not limited to the illustrated shape or configuration. Depending upon the implementation, the body 202 of the bus bar 200 may be longer, shorter, thinner, thicker, wider, narrower, and/or otherwise shaped or formed. In the illustrated example, comers of the bus bar 200 are rounded or radiused, although such is not required. The bus bar 200 is made of a conductive material, such as aluminum, an aluminum alloy, and/or any other conductive material, including but not limited to copper, copper alloys, and/or the like. Generally, the bus bar 200 may take any shape or configuration and/or be made of any material that facilitates the flow of electricity.

[0024] In the example of FIG. 2, the body 202 has a first surface 204, which may a top surface or a bottom surface, for example, and an opposite second surface 206 (obscured in the view of FIG. 2). A spacing between the first surface 204 and the second surface 206 generally corresponds to a thickness, t, of the bus bar 200. Although in the illustrated example, the first surface 204 and the second surface 206 are generally parallel, thus resulting in a relatively constant thickness over the entirety of the bus bar 200, in other examples the first surface 204 and the second surface 206 may be formed to alter the thickness, e.g., by being angled, stepped, arcuate, and/or the like, relative to each other. The surfaces 204, 206 are also illustrated as extending generally longitudinally between opposing ends 208 and generally laterally between opposing sides 210 of the bus bar 200.

[0025] As shown in FIG. 2, the bus bar 200 also includes a cutout 212. The cutout 212 is illustrated as a bore formed in the first surface 204, e.g., not extending through the entire thickness, t, of the bus bar 200. In other examples, the cutout 212 may extend all the way through the body

202 (e.g., the cutout may be a hole). In examples, the cutout 212 is sized to cooperate with one of the fixed contacts 108. Accordingly, a diameter of the cutout 212 may closely approximate an outer diameter of the fixed contact 108. For example, the cutout 212 may have a diameter that provides a clearance fit with the fixed contact 108. Tn other examples, the cutout 212 may be sized to provide an interference fit with the fixed contact 108. Although in the illustrated example the fixed contact 108 and the cutout 212 have circular profiles, in other examples the profiles may be other than circular. Moreover, the fixed contacts 108 and/or the cutout 212 may have angled or sloped surface. Without limitation, the diameter of the cutout 212 illustrated in FIG. 2 may vary along the thickness, t, of the body 202.

[0026] FIG. 3 shows an example of an electrical assembly 300 according to examples of this disclosure. The electrical assembly 300 may be the electrical device 100, for example. As illustrated in FIG. 3, the electrical assembly 300 includes two instances of the bus bars 200. Specifically, each instance of the bus bar 200 is coupled to one of the fixed contacts 108. In examples, the electrical assembly 300 may be a battery disconnect unit, e.g., for use in connecting/dis connecting a high voltage battery and a load.

[0027] In FIG. 3, the interface of the cutout 212 of the bus bars 200 is shown relative to the fixed contacts 108. Specifically, the distal ends of the fixed contacts 108 are disposed in the cutouts 212. FIG. 3 also shows welds 302 formed proximate the interface of the bus bars 200 and the fixed contacts 108. In examples of this disclosure, the welds 302 are formed via a solid-state joining process. In specific examples, the welds 302 are formed via friction welding, e.g., friction stir welding. As noted above, in some examples the fixed contacts 108 can comprise copper and/or the bus bars 200 can comprise aluminum, and the welds 302 formed via the solid-state joining process may couple the disparate materials. Of course, other conductive materials can be used. In at least some alternative examples, the fixed contacts 108 may include aluminum and/or an aluminum alloy and the bus bars 200 may include copper and/or a copper alloy. [0028] FIG. 4 shows an example of a system 400 for forming an electrical assembly like the electrical assembly 300. The system 400 includes a jig 402 configured to position the electrical device 100 and the bus bar(s) 200 relative to each other. FIG. 4 also shows a weld head 404.

[0029] The jig 402 generally includes a lower portion 406 that defines a volume 408 configured to receive and position the electrical device 100. As illustrated, the lower portion 406 includes a panel 410 that can be selectively removed to insert/retract the electrical device 100. The volume 408 is configured to retain the body of the electrical device 100 in a predetermined position. The position may be a fixed position, e.g., that substantially eliminates movement of the electrical device 100 relative to the jig 402.

[0030] As also illustrated, the jig 402 includes an upper portion 412 comprising a base plate 414 and an upper clamp 416. The upper portion 412 is positioned above the volume 408 such that the fixed contacts 108 (obscured in FIG. 4) extend through the base plate 414. As illustrated, the base plate 414 can include two slots 418 that receive the fixed contacts 108 when the electrical device 100 is loaded into the volume 408. Removable inserts 420 may be selectively placed in the slots 418, e.g., to inhibit lateral movement of the electrical device 100 once disposed in the volume 408/slots 418. For instance, the inserts 420 may be secured in the slots by fasteners, such as bolts, screws, or the like.

[0031] The bus bars 200 are disposed on the base plate 414 such that the fixed contacts 118 are received in the cutouts 212 (not visible in FIG. 4, but described above). With the bus bars 200 positioned in this manner, the upper clamp 416 may be secured on the base plate 414, e.g., via fasteners. The upper clamp 416 can define a cavity configured to receive the bus bars 200, for example. The cavity may be configured to receive the bus bars 200 in a predetermined orientation and/or to restrict movement of the bus bars 200 relative to the jig 402. The upper clamp 416 can also include holes 422 generally aligned with the position of the fixed contacts 118.

[0032] In operation, with the electrical device 100 and the bus bars 200 secured by the jig 402, the weld head 404 is lowered into the holes 422 to contact the bus bars 200 and/or the fixed contacts 118 and form the welds 302 (discussed above, but not visible in FIG. 4). As noted above, the weld head 404 may be configured to perform a solid state welding, including but not limited to by performing a friction stir welding process. For instance, the weld head 404 may comprise a probe that rotates and contacts the bus bars 200 and/or the fixed contacts 108 (e.g., if the cutouts 212 of the bus bars 200 are through holes) to generate heat that softens the bus bars 200 and/or the fixed contacts 108 to facilitate joining through mechanical pressure. Once welded, a completed electrical assembly, like the electrical assembly 300, is removed from the jig 402. For example, the panel 410, the upper clamp 416, and the inserts 420 may be removed, and the completed electrical assembly 300 may be removed from the jig 402.

[0033] The system 400 and the jig 402 are for example only. Any arrangement that facilitates positioning of the electrical device 100 relative to the bus bars 200 such that the welds 302 can be formed may be used.

[0034] FIG. 5 is a flowchart demonstrating a process 500 for forming an electrical assembly, like the electrical assembly 300. The process 500 is illustrated as a number of steps, each generally represented by a single block in the flow chart. In examples, one or more of the steps of the process 500 may be performed in a different order, two or more of the steps may be combined, and/or any of the steps may be performed as a plurality of sub-steps. The flowchart is provided for example only. [0035] At an operation 502, the process 500 includes providing an electrical device. For example, the electrical device may be a contactor, a fuse device, or any other electrical device, including the electrical device 100. In examples, the electrical device provided at the operation 502 includes one or more fixed contacts, like the fixed contacts 108. The fixed contacts 108 may be copper or any other conductive material.

[0036] At an operation 504, the process 500 includes providing one or more bus bars. The bus bar(s) may be the bus bar 110 and/or the bus bar 200 discussed above. The bus bar may include a cutout, such as the cutout 212. The bus bar may be aluminum or some other conductive material.

[0037] At an operation 506, the process 500 includes coupling the bus bar(s) to the electrical device. In examples described herein, the operation 506 may include coupling the bus bar to a fixed contact using a steady state welding process, such as a friction stir welding process. In examples, the operation 506 can be carried out using the jig 402 discussed above.

[0038] As just described, aspects of this disclosure relate to an electrical assembly in which a contactor or other device includes one or more fixed or stationary copper contacts and an aluminum bus bar includes a cutout or cavity sized to receive the stationary contact. The bus bar is mated or otherwise coupled to the copper stationary contact. For example, the electrical assembly may be used in electric vehicle applications. The bus bar is then solid-state, e.g., friction, welded to the stationary terminal to fuse the two metals together via the solid-state joining process. The process has the ability to join the two materials with low contact resistance without damaging the contactor and/or while maintaining hermeticity within the contactor .

[0039] Aspects of this disclosure may allow for joining two disparate materials (e.g., aluminum and copper) to maintain improved performance with respect to contact resistance and thermal performance. Friction welding is also a relatively easily implemented process as it may only require a friction stir welding head and a CNC. Conventional laser welding techniques are not effective at bonding different metals and the laser welder is relatively more expensive. Moreover, by directly joining bus bars to innovative high-voltage components, electric assemblies according to aspects of this disclosure can provide reduced package size, mass, and/or increased performance with respect to contact resistance (CR) and current density.

[0040] 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 assembly comprising: an electrical device comprising a fixed contact; and a bus bar welded to the fixed contact.

2. The electrical assembly of claim 1, wherein the bus bar is welded to the fixed contact via solid-state welding.

3. The electrical assembly of claim 1 or claim 2, wherein the fixed contact comprises a first conductive material and the bus bar comprises a second conductive material different from the first conductive material.

4. The electrical assembly of claim 3, wherein the first conductive material comprises copper and the second conductive material comprises aluminum.

5. The electrical assembly of any one of claim 1 through claim 4, wherein the bus bar comprises a cutout sized to receive at least a portion of the fixed contact.

6. The electrical assembly of claim 5, wherein: the cutout comprises a bore formed in a first surface of the bus bar; and at least a portion of the fixed contact is disposed in the bore.

7. The electrical assembly of claim 5, wherein: the cutout comprises a hole extending through the bus bar from a first surface of the bus bar to a second surface of the bus bar; and at least a portion of the fixed contact is disposed in the hole.

8. The electrical assembly of claim 7, wherein: the at least the portion of the fixed contact is disposed in the hole such that a top surface of the fixed contact is substantially co-planar with the first surface of the bus bar.

9. The electrical assembly of claim 8, further comprising: a friction weld formed at an interface of the top surface of the fixed contact and the first surface of the bus bar.

10. The electrical assembly of claim 5, wherein the cutout and the fixed contact are sized such that the portion of the fixed contact forms an interference fit with the cutout.

11. The electrical assembly of any one of claim 1 through claim 10, wherein the electrical device comprises a housing and the fixed contact extends from the housing.

12. The electrical assembly of claim 1 1, further comprising a movable contact disposed within the housing and movable between a first position contacting the fixed contact and a second position spaced from the fixed contact.

13. A method of making the electrical assembly of any one of claim 1 through claim

12, comprising: providing the electrical device including the fixed contact; providing the bus bar, the bus bar comprising a cutout; positioning the electrical device relative to the bus bar such that the fixed contact is disposed at least partially in the cutout; and solid state welding the bus bar and the fixed contact at an interface of the bus bar and the fixed contact.

14. The method of claim 13, wherein the positioning the electrical device relative to the bus bar comprises: coupling the electrical device to a jig; and coupling the bus bar to the jig.

15. The method of claim 13, wherein the solid state welding comprises friction welding the bus bar and the fixed contact at the interface.