Electrical connector assembly

An electrical connector assembly includes a first electrically conductive contact member and a second electrically conductive contact member. Both contact members have non-planar interface surfaces. The second interface surface is complimentary to the first interface surface. Magnetic field concentrators are spaced apart to concentrate a magnetic field in a zone. The magnetic field is associated with electric current carried by the electrical connector assembly. A flexible circuit carrier has openings to receive the magnetic field concentrators. The flexible circuit carrier comprises a flexible dielectric layer and a conductive traces. A magnetic field sensor is mounted on the flexible circuit carrier in the zone.

TECHNICAL FIELD

The present disclosure relates to an electrical connector assembly for electrical conductors.

BACKGROUND

Power electronic modules or power inverters can be designed for normal load conditions or overload conditions on vehicles. At peak load conditions, appropriate thermal management is critical. For example, as inverters deal with the peak load current, the interface between two mating conductors or contacts becomes more critical because this interface can be a bottleneck for electrical current and thermal heat flow. There is an inherent resistance at the interface which generates heat. This also hinders thermal flow used for cooling, which makes heat management difficult. To reduce electrical resistance at the contact interface, the outside envelope size of the contacts can be increased. However, this results in an inefficient use of space within the inverter. It is desired to reduce electrical resistance at the contact interface without increasing the outside envelope size of the contacts.

SUMMARY

In one embodiment, an electrical connector assembly includes a first electrically conductive contact member having a non-planar first interface surface, and a second electrically conductive contact member having a non-planar first interface surface. The second contact member has a non-planar second interface surface which is complementary to a first interface surface of the first contact member. Magnetic field concentrators are spaced apart to concentrate a magnetic field in a zone. The magnetic field is associated with electric current carried by the electrical connector assembly. A flexible circuit carrier has openings to receive the magnetic field concentrators. The flexible circuit carrier comprises a flexible dielectric layer and a conductive traces. A magnetic field sensor is mounted on the flexible circuit carrier in the zone to detect the magnetic field; hence, measure the current carried by the electrical connector assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

InFIG. 1andFIG. 2, an electrical connector assembly10includes an electrically conductive first contact12and an electrically conductive second contact14. The first contact12includes an outer portion11and an inner portion13which is offset from the outer portion11.

The inner portion13of the first contact12terminates in a socket316that comprises an optional terminating end47, which may extend in a generally perpendicular direction with respect to the inner portion13. In one embodiment, the socket316is a generally hollow member for receiving conductor16. For example, the socket316has an interior recess, such as a substantially cylindrical recess, for receiving a conductor16(e.g., stripped of dielectric insulation) that is soldered, welded (e.g., welded sonically), brazed, bonded, crimped or otherwise connected. The conductor16may comprise a cable, a wire, a twisted wire or cable, a solid wire, or another suitable conductor for transmitting electrical energy.

In an alternate embodiment, the socket316the optional terminating end47may be removed or bored out such that the conductor16may extend through the socket316to be welded, soldered or otherwise mechanically and electrically connected to the (upper) surface or inner portion13of the first contact. Further, the outer portion11can be larger, such as longer and wider, to accommodate the thermal dissipation.

As illustrated, the outer portion11of the first contact12has a generally triangular shape, a tear-drop shape, or arrow-head shape with a rounded tip or rounded point, although other embodiments may have different shapes. The inner portion13is connected to the outer portion11by a step or transition portion15. For example, the transition portion15provides a greater surface area for dissipating heat from one or more heat generating components of a circuit board or substrate, where the inner portion13and the outer portion11are offset in generally parallel planes with respect to each other.

The first contact12may be attached to an end of an electrical conductor16, whereas the second contact14may be connected or coupled to one or more heat generating components of a power inverter (not shown) or power electronics module. The conductor16may be soldered, welded, brazed, crimped or otherwise connected to the first contact12(e.g., at the socket316). In one embodiment, the first contact12may have a socket316with a substantially cylindrical surface, or bore. Further, an exterior of the socket316may engage or mate with a collar or sleeve21to receive or secure the conductor16and to facilitate the electrical and mechanical connection between the wire and the first contact12.

In one embodiment, the second contact14may be mounted to an electrically insulating substrate18, such as a circuit board. The first contact12has a first contact surface20, and second contact14has a second contact surface22. In one embodiment, the first contact surface20mates with the second contact surface22directly or indirectly via an intervening layer of solder, braze, electrically conductive fluid (e.g., electrically conductive grease) or electrically conductive adhesive (e.g., polymer or plastic matrix with metallic filler).

In certain embodiments, materials used for manufacturing could be base metal, an alloy or metals, and or composite of metals. However, it needs to be ensured that manufacturing processes and choice of materials used in manufacturing are accurate enough to achieving interlocking engagement between the first contact surface20and the second contact surface22, except where knurled surfaces are adopted for some alternate embodiments.

In one embodiment, the first and second contacts12and14are preferably formed out of copper, a metal, an alloy, or an electrical grade alloy. For example, the first contact12and second contact14can be coated with a coating such as zinc, nickel, a zinc alloy, a nickel alloy, tin over nickel or other known possible metallic coatings or layers. The first and second contacts12and14may be machined or cast as long as the cast is accurate enough to achieving interlocking engagement between the first contact surface20and the second contact surface22.

In one embodiment, the first and second contacts12and14, or the non-planar mating surfaces thereof, may be manufactured using additive or subtractive manufacturing processes such as three-dimensional printing. For example, patterns in the first contact surface20and the second contact surface22could be created by additive and subtractive manufacturing, or metal vapor deposition using raw materials such as metals, and alloys, or plastic and polymer composites with metal filler or metal particles embedded therein for suitable electrical conductivity. In one embodiment, the three dimensional printing process could use polymers or plastics with metals or conductive materials embedded therein. In other embodiments, the three dimensional printing process could use conductive graphene layers that are flexible and capable of electrical connection by a conductive adhesive. Three-dimensionalprinting allows creation metallic and insulating objects using one pass manufacturing methods resulting in reduction of manufacturing costs.

The connector assembly10can transfer high current electrical energy between a conductor16(e.g., cross-sectional conductor size of suitable dimension or dimensions) and a conductive trace (e.g.,115) or conductor (e.g., strip, pad or otherwise) of a circuit board18or heat-generating component (e.g., semiconductor switch) in a power inverter or other power electronics. The electrical connector assembly10may use one or more of the following features: (1) nontraditional shapes of each conductor or contact member (12,14) at the circuit board transition, or where the second contact member14is mounted, or (2) increased transition surface area through non-planar interface contours, such as ridges, valleys, grooves or waves in mating surfaces of the contact members (12,14). Reducing the electrical and thermal resistances at the mating surfaces reduces the heat generation and increases the effectiveness of cooling methods.

In one embodiment, the circuit board18comprises a dielectric layer17with one or more electrically conductive traces, such as metallic trace115(inFIG. 1) that overlies the dielectric layer17. The dielectric layer17may be composed of a polymer, a plastic, a polymer composite, a plastic composite, or a ceramic material. The conductive traces may be located on one or both sides of the circuit board18along with one or more heat generating elements, such as power semiconductor switches. For example, metallic trace115may be coupled to an emitter terminal or a collector of a transistor (e.g., insulated gate bi-polar junction transistor) of a power electronics module (e.g., an inverter) or a source terminal or drain terminal of a field effect transistor of a power electronics module. The metallic trace115may carry an alternating current signal of one phase of an inverter or a pulse-width modulated signal, for instance.

As best seen inFIG. 3andFIG. 4, a bore24extends through a dielectric layer17of the circuit board18, and the second contact14comprises an annular pad26with optional bore28. The optional bore28is coaxially aligned with the bore24. In one embodiment, the annular pad26comprises a hollow conductive stub or metallically plated through-hole. As illustrated, the optional bore28or plated through-hole can support an electrical connection to one or more conductive traces on the bottom side of the circuit board18.

In an alternate embodiment, the optional bore28allows excess solder or excess conductive adhesive to be relieved or exhausted during the soldering or connecting of the first contact surface20with or toward the second contact surface22.

In place of soldering process, advanced manufacturing processes including vapor phase deposition of conductive materials could be used to form the first and second conductive surfaces (20,22). With use of vapor phase deposition, manufacturing defects, such as air void in metallic bonds between mating surfaces can be eliminated. For example, voids or similar defects in the first contact surface20and the second contact surface22can be eliminated; particularly, if the first contact member12and the second contact member14are electrically and mechanically joined with a fastener (e.g.,602) and/or retainer (e.g.,603) in an alternate embodiment (e.g., as illustrated inFIG. 6).

InFIG. 3andFIG. 4, both the first contact surface20and the second contact surface22are non-planar surfaces or non-planar mating surface. Non-planar means ridges30, valleys32, grooves, elevations, depressions, or waves are present in the first contact surface20or the second contact surface22. Mating surfaces refers to the first contact surface20and the second contact surface22, collectively. The mating surfaces have suitable size, shape and registration for interlocking engagement of the mating surfaces, with or without an intervening solder layer, braze layer, conductive adhesive layer, or thermal grease layer. In one embodiment, as illustrated inFIG. 3andFIG. 4, the cross section of the first contact surface20comprises a substantially triangular cross-section or a saw-tooth cross section. Similarly, the second contact surface22comprises a substantially triangular cross-section or saw-tooth cross section.

As shown, inFIG. 1throughFIG. 4, inclusive, the ridges (30,34) comprise substantially linear elevations with sloped sides, whereas valleys (32,36) between each pair of ridges (30,34) comprise substantially linear depressions with sloped sides. In one configuration, a peak height is measured from a top of each ridge (30,34) to the bottom of a corresponding valley (32,36). The first contact surface20includes a plurality of elongated first ridges30and first valleys32, where a first valley32is positioned between each adjacent pair of first ridges30. Similarly, the second contact surface22includes a plurality of elongated second ridges34and second valleys36, where a second valley36is positioned between each adjacent pair of second ridges34. As best seen inFIG. 3, the first and second surfaces20,22are adjoined, connected or soldered together, directly, in a meshing position or, indirectly, by an intermediary layer40of conductive solder, braze conductive adhesive, thermal grease, or otherwise. Thus, first ridges30of first contact surface20are received by the second valleys36of the second contact surface22, and second ridges34of the second contact surface22are received by the first valleys32of the first contact surface20.

FIG. 5illustrates in an alternate embodiment of a connector assembly. InFIG. 5, the first contact12ahas a non-planar first contact surface20aand the second contact14ahas a non-planar second contact surface22a.The first contact surface20aincludes a plurality of elongated rounded crests30aand rounded depressions32a,where a depression32ais positioned between each adjacent pair of crests30a. Similarly, the second contact surface22aincludes a plurality of elongated rounded crests34aand rounded depressions36a,where a depression36ais positioned between each adjacent pair of crests34a.The first and second surfaces20aand22acan also be soldered or connected together in a meshing position by a layer of conductive solder, braze, conductive adhesive, thermal grease, or otherwise. Thus, crests30aof first contact surface20aare received by the depressions36aof the second contact surface22a,and crests34aof the second contact surface22aare received by the depressions32aof the first contact surface20a.

Referring again toFIG. 1, the first contact12has a substantially triangular shape (e.g., or a tear-drop shape) with curved corners and the second contact14has a substantially circular, substantially elliptical or rounded surface area for thermal transfer of thermal energy from a heat-generating device (e.g., semiconductor switch) mounted on the circuit board18to one or more of the following: (1) conductor16, (2) inner portion13or step portion15, and (3) ambient air around the conductor16, the inner portion13, or the step portion15(e.g., rise portion). In alternate embodiments, the shape of the contacts (12,14) can vary from those illustrated inFIG. 1throughFIG. 6, inclusive. The contacts can be funnel-shaped or circular to provide a smooth transition. The contacts could also be diamond or oval-shaped. The interface surfaces20and22can be a variety of three-dimensional (3D) or non-planar surfaces as long as they increase the surface area of the interface, such as V shaped, diamond, waffle, wave, knurled or tetrahedral. For a knurled surface (not shown), alignment may not be important as with the ridges.

The contacts can be bonded together by a variety of means, such as solder, braze, conductive adhesive, cold-press, and bolting (e.g., with conductive grease). Such interfaces could be applied to a circuit-board-style connection (as illustrated inFIG. 1) or to a bus-bar connection (e.g., with a bus-bar of metal or alloy with a substantially rectangular cross-section or substantially polyhedral cross-section).

Thus, this connector assembly10transfers heat away from heat-generating electrical or electronic components on the circuit board or substrate18. A thermal flow path is supported from the heat-generating component on the circuit board18via one or more conductive traces115to the second contact14on the circuit board18and then to the first contact12that is connected to the conductor16. The interface surfaces (20and22or20aand22a) facilitate efficient heat transfer from the second contact (14or14a) to the first contact (12or12a) and to the cable or conductor16connected to it, which can dissipate the heat to the ambient air. The step15in the first contact12helps to direct the heat away from the circuit board18or substrate. Because of the overall teardrop, curved or rounded triangular shape of the contact members12and14, the heat tends to be directed/channeled toward the first contact member12which is attached to the conductor16.

FIG. 6is an exploded perspective view an alternate embodiment of an electrical connector assembly110in accordance with the disclosure. The electrical connector assembly110ofFIG. 6is similar to the electrical connector assembly10ofFIG. 1, except the electrical connector assembly110ofFIG. 6further comprises a hole or opening601in the first contact member112that is aligned with the bore28(in the second contact member14) for receipt of a fastener, such as fastener602(e.g., threaded bolt or screw) and retainer603(e.g., nut). Like reference numbers inFIG. 1andFIG. 2indicate like elements or features.

In certain prior art electronic power modules, such as power inverters, an increase of electrical resistance at an electrical contact interface results in heat generation, which compounds thermal issues. With the connector assembly disclosed in this document, the peak overloading of the electronic power module can be managed while keeping the electronic power module compact (e.g., for installation on a vehicle). The connector assembly has decreased interface thermal resistance while keeping package size compact and smaller than conventional connector assemblies. The shape of the transition area or step promotes an easy flow path for the thermal and electrical energy that passes through it. The contact surface area of the connector assembly is increase at the transition for heat dissipation to ambient air, whereas overall envelop of the connector assembly remains compact by using three-dimensional, non-planar mating surfaces. This conductor assembly can be cooled from two sides or opposite sides of the circuit board18.

The conductor assembly is well-suited for thermal transfer because of the shape of the conductive contact members, or their respective (interlocking) mating surfaces, at the transition between the first contact surface and the second contact surface, and the non-planar form of the interface/mating surfaces. The shape of the contacts and mating surfaces promotes a smooth flow of electrical current and thermal heat from one contact member (e.g.,12,14) to the other so that the transition area does not create appreciable electrical or thermal resistance. The transition or interface between the mating surfaces will always be a point where there is a natural thermal resistance. To compensate, there is an increase in surface area at the transition or step from one conductor contact surface to other conductor contact surface, and with this design, the transition surface or step area is increased without increasing the envelope size of the contact assembly.

FIG. 7is a perspective view of one embodiment of an electrical connector assembly210with a first configuration of a current sensor705. Like reference numbers inFIG. 1andFIG. 7throughFIG. 9, indicate like elements or features.

As illustrated inFIG. 7andFIG. 8, the current sensor705is integrated into the electrical connector assembly210. In certain embodiments, the current sensor705may support high bandwidth for sensing the electrical current of alternating current signal carried by the electrical connector assembly210. Magnetic field concentrators702are spaced apart to concentrate a magnetic field in a zone. The magnetic field is associated with electric current carried by the electrical connector assembly210. A flexible circuit carrier704has openings708to receive the magnetic field concentrators702. The flexible circuit carrier704comprises a flexible dielectric layer and a conductive traces. In one embodiment, the conductive traces may be internal to the flexible circuit carrier with the exception of metallic pads or metal plated through-holes for mounting a magnetic field sensor. A magnetic field sensor706is mounted on the flexible circuit carrier704in the zone to detect the magnetic field; hence, measure the current carried by the electrical connector assembly210.

The flexible circuit carrier704comprises a flexible dielectric layer and a conductive traces that supply electrical energy to the magnetic field sensor706, and that carry output signals indicative of the electrical current in the electrical connector assembly210. In one embodiment, the conductive traces terminate in a connector707(inFIG. 8) with a dielectric body721and multiple conductive pins or pin receptacles, wherein the connector707is selected from the group consisting of a card-edge connector, a circuit board transition header and a ribbon cable connector. The dielectric layer of the flexible circuit carrier704is composed of polyimide, a flexible or resilient polymer, or a flexible or resilient plastic material. In one embodiment, the conductive traces may comprise copper traces or embedded metallic wires.

In one configuration, the electrical connector assembly210is associated with or mounted on a substrate, such as a circuit board18. For example, the circuit board18comprises a dielectric layer17, metallic traces115and a conductive via or metallized through-hole that is integral with, or mechanically and electrically connected to, the second electrically conductive contact member14. In the embodiment ofFIG. 7andFIG. 8, the conductive via or metallized through-hole28(inFIG. 1) extends from or below the second electrically conductive contact member14. In one configuration, the second electrically conductive contact member14comprises a conductive pad (e.g.,22) on a first side722of the circuit board and extends through a conductive via or a metallized through-hole28to a second side724of the circuit board opposite the first side722to support double-sided cooling of the connector assembly210on the circuit board.

The circuit board18can operate at temperatures in a range between approximately 100 degrees Celsius and approximately 120 degrees Celsius by dissipating thermal energy to ambient air via the double-sided cooling and the electrical connector assembly210. Accordingly, the electrical connector assembly210is well-suited for operating with inlet coolant temperatures set at or below 105 degrees Celsius, which is representative of the coolant temperature of engine coolant of a vehicle.

As illustrated inFIG. 7, the current sensor is mounted on an outer surface or upper surface of the electrical connector assembly210; the current sensor comprises a set of magnetic field concentrators702, where a magnetic field sensor706can be mounted above or between the magnetic field concentrators702in proximity or alignment of any concentration of magnetic flux produced by the magnetic field concentrators704.

FIG. 8is a perspective view of one embodiment of an electrical connector assembly210with another configuration of a current sensor705. The configuration ofFIG. 8is similar to the configuration ofFIG. 7, exceptFIG. 8further shows the magnetic field sensor706and the flexible circuit carrier704that terminates in a connector707(e.g., ribbon connector or card edge connector). Like reference numbers inFIG. 8andFIG. 7indicate like elements.

For example as shown inFIG. 8, a flexible circuit carrier704comprises a flexible dielectric body or ribbon with conductive traces and openings708to receive the magnetic field concentrators. As shown, the magnetic field concentrators702extend above the flexible circuit carrier704and there is clearance gap between an outer perimeter of each magnetic field concentrator702and the contour of the openings708. A magnetic field sensor706is mounted to the flexible circuit carrier704and the terminals of the magnetic field sensor706are electrically connected to the circuit traces of the flexible circuit carrier704by solder or a conductive adhesive.

In one embodiment, the magnetic field sensor706comprises any device for sensing a magnetic field, such as a Hall-effect sensor. In some embodiments, the current sensor705is also significantly miniaturized as compared to conventional toroidal core sensors and Hall-effect sensors. Therefore, current sensor705that is integrated with the power connector supports cost, weight, and volume reduction of electronic assemblies (e.g., power inverters for vehicles).

As shown in the illustrative embodiment ofFIG. 8, the magnetic field sensor706comprises a magnetic field sensor integrated circuit (IC) chip or current sensor705that uses magnetic field concentrators702on sides radially outward from a central axis740of a conductor16connected to the electrical connector assembly210to reduce or eliminate effects of stray magnetic fields and to strengthen magnetic field observed or observable by the magnetic field sensor706. For instance, the concentrators702are adhesively bonded or adhered to the connector itself, where the magnetic field sensor706is surface mounted on a flexible circuit carrier704by soldering or conductive adhesive to conductive pads on the flexible circuit board. The circuit assembly742of the flexible circuit board704and the magnetic field sensor706has openings that align with the concentrators. To keep the circuit assembly742in place, the circuit assembly742could be adhered to the electrical connector assembly210, retained to the electrical connector assembly210via dielectric retainer or clips710, or by using a dielectric protrusion (e.g., extending inward into the housing toward the flexible circuit) or other retention features within the inverter housing.

Collectively, the circuit assembly742and concentrators702form a miniaturized current sensor705that takes a minimal space on the electrical connector assembly210and leaves adequate area for double sided cooling with heat sinks or other similar methods.

FIG. 9is a perspective view of one embodiment of a plurality of electrical connector assemblies with respective current sensors705. The configuration ofFIG. 9is similar to the configuration ofFIG. 7andFIG. 8, except inFIG. 9one flexible circuit carrier716supports multiple current sensors705added to monitor current through multiple connectors (210,310). Like reference numbers inFIG. 7throughFIG. 9, inclusive, indicate like elements.

InFIG. 9, an electrical connector assembly comprises a first connector210and a second connector310. The first connector210comprises a first electrically conductive contact member and a second electrically conductive contact member. The first contact member has a non-planar first interface surface. The second contact member has a non-planar second interface surface which is complementary to the first interface surface and which engages the first interface surface. A second connector310comprises a first electrically conductive contact member and a second electrically conductive contact member. The first contact member has a non-planar first interface surface. The second contact member has a non-planar second interface surface which is complementary to the first interface surface and which engages the first interface surface.

A first magnetic field is associated with electric current carried by the first connector210. A first pair720of magnetic field concentrators702is spaced apart to concentrate the first magnetic field724in a first zone. A first magnetic field sensor724is mounted on the flexible circuit carrier704in the first zone. The first magnetic field sensor724detects the first magnetic field; hence, the first current in the first connector. In one configuration, the first magnetic field sensor724is the same as or analogous to the magnetic field sensor706ofFIG. 7, for example.

A second magnetic field is associated with electric current carried by the second connector310. The second pair718of magnetic field concentrators702is spaced apart to concentrate in a second magnetic field in a second zone. The second magnetic field sensor722detects the second magnetic field; hence, the second current in the second connector310. In one configuration, the second magnetic field sensor722is the same as or analogous to the magnetic field sensor706ofFIG. 7, for example.

As shown inFIG. 9, the flexible circuit carrier716has openings to receive the first pair720of magnetic field concentrators702and the second pair718of magnetic field concentrators702. The flexible circuit carrier704comprises a flexible dielectric layer and a conductive traces that supply electrical energy to the first magnetic field sensor724and the second field sensor722, and that carry output signals indicative of the first current and the second current. While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. It will be noted that alternative embodiments of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the present invention as defined by the appended claims.