Patent Application
20240291258
The present disclosure relates to a busbar arrangement, in particular for electrical multi-polar high-current connection in an electrically driven motor vehicle. Busbar arrangements, particularly in electrically driven motor vehicles, are subject to various requirements. On the one hand, they must have the requisite current-carrying capacity, which is constantly increasing in response to the expanding capacity of electric motor drive systems and the increasing charging power of the traction battery or the charging infrastructure. Moreover, on the grounds of unavoidable ohmic losses, measures are frequently required for the evacuation of heat from current-carrying components of the busbar arrangement. In order to provide as much space as possible for the traction battery, thus permitting the delivery of a high electrical capacity, it is also endeavored to achieve a high integration density. This handicaps compliance with the requisite clearances and creepage distances between busbars which are energized at different electrical potentials, which compliance becomes more structurally complex as the charging potential and the traction battery potential increases. It is known, for example from DE 10 2019 214 218 A1, for busbars to be embedded in plastic. On the grounds of the differing coefficients of thermal expansion of components employed, this solution is comparatively complex. It is further known, for example from CN 102255162 A1, for a multipolar busbar arrangement to be produced by lamination. As the laminated region of these busbars can only be configured with a planar design, complex busbar profiles are not achievable. Moreover, structures of this type generally lack sufficient mechanical stability, which is necessary in an electric motor vehicle, not only during driving but also in the event of an accident.
In this context, a need has arisen for a busbar arrangement, in particular for electrical multipolar high-current connection in an electrically driven motor vehicle, which has a high integration density, which permits comparatively complex busbar profiles whilst maintaining compliance with minimum distances for stipulated clearances and creepage distances, and which moreover assumes sufficient and long-term mechanical stability. This object is fulfilled by a busbar arrangement as presently disclosed in claim 1. An equally advantageous application is the subject matter of the sub-claim. Advantageous configurations are the respective subject matter of the dependent claims. It should be observed that individual features described in the present disclosure can be mutually combined in an arbitrary and technologically appropriate manner, thereby disclosing further configurations of the present disclosure. The present disclosure is further characterized and specified by the description, particularly in conjunction with the figures.
The present disclosure relates to a busbar arrangement, in particular for electrical multipolar high-current connection in an electrically driven vehicle, for example between the traction battery and the electric drive motor and/or between a charging infrastructure which is located externally to the motor vehicle and the traction battery. The busbar arrangement according to the present disclosure includes a plurality of essentially planar supports formed of an electrically insulating material which are stacked in a stacking direction, each of which forms one or more trough-shaped receptacles which are open on one side. According to the present disclosure, a plurality of busbars are provided, formed of a metal, such as copper, or of a metal alloy, each of which is accommodated in one of the receptacles. Preferably in at least one support, and preferably in all the supports of the busbar arrangement, a plurality of busbars are respectively accommodated in each associated receptacle. Preferably, the plurality of busbars which are provided for each support are mutually electrically insulated.
According to the present disclosure, at least one support, and preferably all the supports, include a contact surface for the respective busbar, and thus a base forming a trough base of the trough-shaped receptacle and, for each receptacle, a first flange which circumferentially encloses the respective busbar and forms a side wall of the trough-shaped receptacle, in order define an associated clearance and creepage distance to the support, which is formed of an electrically insulating material. The flange preferably encloses the narrow sides of the respectively accommodated busbar. The electrically insulating material, for example, is a plastic, such as a thermoplastic. The support is produced, for example, by a thermal forming process, such as an injection-molding process. The support can be configured with a one-piece or multi-piece design. For example, the support is configured with a one-piece design, and includes an integral unit formed of the base and the one or more first flanges which extend upwards from the base. Each of the busbars is preferably accommodated in the respective receptacle in an adhesive-free arrangement. The busbars are preferably accommodated in the trough-shaped receptacle in a form-fitted and/or interference-fitted manner. By means of the solution according to the present disclosure, a busbar arrangement is provided, in particular for electrical multipolar high-current connection in an electrically driven motor vehicle, which assumes a high integration density, which permits comparatively complex busbar profiles whilst maintaining compliance with stipulated minimum distances for clearances and creepage distances, and which moreover provides sufficient and long-term mechanical stability. The core element of the busbar arrangement according to the present disclosure is the combination and functional integration of various requirements in the most compact structural arrangement possible. For example, the busbars are stamped from a single sheet of metal, and are then electrically insulated from one another by means of the supports. A compact design is thus achieved, which thermally approximates to a cool connection and thus features short transmission paths which, in turn, result in a compact structure and a reduction in the constituent material of copper busbars. Moreover, as a result of the mutual proximity of busbars, a form of heat dissipation and transmission to inactive busbars/regions can occur, thereby exploiting the good thermal conductivity of the busbar material, for example in the formation of the widest surface connection possible to a heat sink, such as a cooling duct.
At least one support preferably includes a second flange which projects in the direction of the immediately adjoining support and which, in combination with the first flange of the immediately adjoining support, forms a labyrinth-shaped creepage distance and/or clearance between two busbars which are accommodated in the immediately adjoining support. By means of the thus elongated labyrinth-shaped clearance, tracking resistance is enhanced, spacing between busbars in the immediately adjoining support can be reduced, thus saving structural space, and heat dissipation between the thus more closely adjoining busbars can moreover be improved. For example, the second flange is configured and arranged to engage in the clear gap between two first flanges of the immediately adjoining support and between two busbars of the immediately adjoining support, without touching said immediately adjoining support.
In each case, the support preferably includes one or more trough-shaped receptacles on the side of only one of its two main surfaces, i.e. in a one-sided arrangement. For example, the second flange projects upwards from the side of the base which is averted from the receptacle or receptacles, which is the receptacle-free base surface of the support base.
The openings of all the trough-shaped receptacles are preferably commonly aligned in the stacking direction. For example, all the receptacles of the busbar arrangement open in a direction which is averted from a heatsink, wherein the heatsink is arranged contiguously to the receptacle-free base surface of the base of an outer support.
According to a preferred configuration of the busbar arrangement according to the present disclosure, at least one outer support of the busbar arrangement includes a base which is designed for thermally conductive coupling with a heatsink. For example, particles of a thermally conductive material are embedded in the material of the support, in particular exclusively in the base region of the support which forms the receptacle-free base surface.
The outer support preferably includes a framework which forms the first flange or first flanges, and an insulating foil which at least partially forms the base of the outer support. Efficient evacuation of heat from the busbar(s) which is (are) accommodated in the outer support is achieved accordingly. For example, the insulating foil includes a thermoplastic foil substrate. The term “insulating foil” refers exclusively to the electrical insulating property of foil, and not necessarily, or at least only negligibly to any thermal insulating property. The material and thickness of the insulating foil of the outer support are preferably selected such that the thermal conductivity thereof in the stacking direction is superior to that of the base of all the other supports.
An outer support is preferably the support having the largest external dimensions.
A framework is understood as a support which incorporates penetrations. For example, a penetration is provided for each receptacle, the outer edge of which is oriented with a parallel offset to the first flange, and thus forms a bearing edge by way of a contact surface of the base for the busbar, whereas the insulating foil closes the penetration and at least partially forms the base of the support, and thus of the associated receptacle or receptacles.
A silicone-based, polyurethane-based or acrylate-based, preferably elastomer liner incorporating a ceramic filler, such as aluminum oxide, zinc oxide and/or boron nitride, is preferably arranged between the insulating foil and the relevant busbar. Liners of this type are commercially available under the trade name “GAP PAD®”. The liner is preferably arranged to fill the gap formed by the bearing edge between the busbar and the insulating foil, thus executing the bridging thereof in a thermally conductive manner, in comparison with an air gap.
For example, at least two busbars of the plurality of busbars which are arranged in immediately adjoining supports are connected by interference fitting in an electrically conductive manner, for example by a riveted connection or screw connection. Preferably, all the busbars in the busbar arrangement are arranged in a mutually electrically insulated manner.
At least one support preferably includes a penetration for an electric contact pin for the electrical contact-connection of the busbar arrangement and for the outfeed or infeed of an electric current. The term “contact pin” is to be interpreted broadly.
Each of the busbars is preferably configured as a stamping or as a stamped and embossed part, for example of sheet metal.
Preferably at least one busbar, within the profile thereof which is arranged in the relevant trough-shaped receptacle, incorporates a socket section for the fitting of an electrical contact element. The socket section, for example, is designed for the establishment of an interference-fitted electrical connection, such as a screw connection or a riveted connection to a connecting part, such as a contact pin. The socket section is introduced into the busbar, for example by embossing.
According to a preferred configuration of the busbar arrangement, the latter further includes a heatsink, such as a heat-exchanger or a cooling element for convection cooling, wherein the heatsink is arranged contiguously to an outer support of the plurality of supports.
The present disclosure further relates to the application of the busbar arrangement, in one of the above-mentioned embodiments, in an electric motor-driven vehicle.
The various disclosed embodiments are described in greater detail with reference to the following figures. The figures are to be understood as exemplary only and, in each case, represent only one preferred variant of embodiment. In the figures:
All the supports 2a, 2b form a contact surface for the respective busbar 4a, 4b, and thus a base 14a, 14b (c.f.
In each case, a silicone-based, polyurethane-based or acrylate-based, preferably elastomer liner 8 incorporating a ceramic filler, such as aluminum oxide, zinc oxide and/or boron nitride, is preferably arranged between the insulating foil 9 and the relevant busbar 4a. Liners 8 of this type are commercially available under the trade name “GAP PAD®”. In this case, the liner 8 is arranged to fill the gap formed by the bearing edge 11 or the penetration 10 between the busbar 4a and the insulating foil 9 in a form-fitted manner, thus executing the bridging thereof in a thermally conductive manner, for example in comparison with an air gap. As shown in
By means of the solution according to the disclosed embodiments, a busbar arrangement 1 is provided, in particular for electrical multipolar high-current connection in an electrically driven motor vehicle, which has a high integration density, which permits comparatively complex busbar 4a, 4b profiles whilst maintaining compliance with minimum distances for stipulated clearances and creepage distances, and which moreover assumes sufficient and long-term mechanical stability.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 123 913.3 | Sep 2021 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/074316 | 9/1/2022 | WO |
