Contact device for a power electronics module

Abstract

A contact device (210) for a power electronics module (140) for contacting two electrical conductors (215, 220) with different potentials, comprising a carrier (235) made of an electrically non-conductive material in which a first contact line (300) and a second contact line (305) are integrated, wherein a first contact spring (240) of the first contact line (300) and a second contact spring (245) of the second contact line (305) are arranged projecting on the carrier (235), wherein the contact springs (240, 245) are arranged and configured such that, in the assembled state of the contact device (210), they hold the conductors (215, 220) between them and are biased against each other, wherein each contact spring (240, 245) contacts one of the conductors (215, 220).Furthermore, the invention relates to a power electronics module (140) for an electric drive axle (100) and an electric drive axle (100) for a vehicle (105) that is at least partially electrically driven.

Description

[0001] The present invention relates to a contact device for a power electronics module for contacting two electrical conductors with different potentials, a power electronics module with a contact device, and an electric drive axle for a vehicle that is at least partially electrically driven, with at least one such power electronics module or such a contact device.

[0002] Various contact methods are known for connecting electrical conductors in a power electronics module, such as soldered contacts, welded contacts (especially laser-welded contacts), screw connections, press-fit connections, contact springs, or contact clamps. Contact springs or contact clamps are generally designed for contacting an electrical conductor from both sides. Single-sided contact springs are also known, but have significant disadvantages regarding the required counter-pressure for reliable contact. The component into which the contact spring is integrated could shift into an undesired position during assembly due to the one-sided force of the contact spring, with the component's final position only being reached once the preload of the contact spring has been completely released.However, this means that the necessary contact during operation is no longer guaranteed.

[0003] The known contacting methods, in particular contacts using a contact spring or clamp, are currently only of very limited use when there is little available installation space, especially when only one side of the respective electrical conductor to be contacted is accessible for contacting, but both a positive potential and a negative potential still need to be contacted.

[0004] One object of the invention is to provide a contact device for connecting two electrical conductors with different potentials for a power electronics module, which does not require complex connection techniques such as soldering, welding, or the like and is more resistant to tolerances. The invention achieves this object by means of the subject matter of the independent claims. Dependent claims describe preferred embodiments.

[0005] According to a first aspect of the invention, a contact device for contacting two electrical conductors with different potentials for a power electronics module comprises a carrier made of an electrically non-conductive material in which a first contact line and a second contact line are integrated, wherein a first contact spring of the first contact line and a second contact spring of the second contact line are arranged projecting from the carrier, the contact springs being spaced apart from each other and configured such that, in the assembled state of the contact device, they hold the conductors between them and are biased against each other, with each contact spring contacting one of the conductors. In other words, the contact device proposed here implements a combination of two single-sided contact springs for different contact lines in a common carrier.Supporting component.

[0006] In the disassembled state of the contact device, the electrical conductors are not connected to the contact device and therefore not to the capacitors. In contrast, the assembled state of the contact device is to be understood as the operating state of the power electronics module, in which an electrically conductive contact is established between two electrical conductors with different potentials on the one hand and associated capacitors on the other. In this sense, the respective contact lead is preferably configured to contact a capacitor of the power electronics module at the end opposite the respective contact spring. The contact device can be connected to a housing after or during assembly, for example by screwing, clipping, or otherwise securely fixed, i.e., in particular by a positive-locking connection.

[0007] Preferably, a first contact tab for the first contact line and a second contact tab for the second contact line are extended from a side of the carrier facing the capacitors. In other words, each contact line consists of a connecting section embedded in the carrier, a contact spring on one side, and a contact tab on the other. The respective contact tab is designed according to the shape of the capacitors and aligned with the carrier. The respective contact tab can be designed for screwing to the capacitor or for attaching to a pin or bolt.

[0008] Such a contact device is easy to assemble and disassemble. Furthermore, the contact device can be assembled automatically. It can also be designed to prevent incorrect assembly and ensure reliable contact between the contact springs and the corresponding conductors. Additionally, the contact device is reusable, as the contact springs can be detached or removed from the conductors without damage. Therefore, the contact device can be assembled and disassembled more frequently.

[0009] The contact leads are preferably overmolded with the electrically insulating material of the carrier, while the two contact springs are not. Similarly, the contact tabs can also be left unmolded. The term "integrated" into the carrier means that the contact leads are arranged on the carrier in such a way that they are insulated or protected from external influences or unwanted electrical interaction with each other. The carrier is preferably made of plastic. It is manufactured, for example, by injection molding. This allows the carrier to be very flexible in its spatial design and adapted to almost any installation space.

[0010] The contact leads are made of an electrically conductive material. They can be in sheet metal form. Therefore, the contact leads can be manufactured easily and cost-effectively by stamping and forming.

[0011] Each contact spring is to be understood as the free, uninsulated end of the respective contact lead. Similarly, each contact tab is to be understood as the free, uninsulated end of the respective contact lead. The first contact lead can be a positively polarized high-voltage lead, while the second contact lead can be a negatively polarized high-voltage lead, or vice versa. Each contact lead is intended for connection to one of the electrical conductors and for contact with an associated capacitor.

[0012] In the unassembled state of the contact device, a gap is formed between the two spatially spaced contact springs. This gap serves as a passageway for the two conductors into a clamping space formed between the contact springs. During assembly of the contact device, the conductors are inserted together into the gap between the two contact springs, causing the springs to be bent apart, at least locally, and the two conductors to be secured, in particular clamped, between them. Each contact spring and its corresponding conductor thus make electrical contact. In the initial state of the contact device, the gap is narrower than the combined thickness of the two conductors. The division into two contact leads, or two contact springs, allows the two contact springs to operate independently and exert force on their respective conductors independently.The conductors can be designed as essentially rigid busbars, conductor plates, or the like. The conductors can be arranged, at least section by section, on a separate or common support and be handled accordingly.

[0013] Each of the two contact springs is a one-sided contact spring. "One-sided" means that the contact spring is asymmetrically designed and its spring force acts in only one direction. In this context, this means that the contact spring can only press or be pre-tensioned in one direction. Therefore, the contact spring establishes an electrical contact in only one direction by pressing against the conductor due to its geometry and direction of action, after the conductor has elastically deformed the contact spring locally during assembly. The pre-tension or spring force in the direction of the conductors or the respective opposing contact spring is generated by deforming the contact spring at least locally while the conductors are inserted together into the clamping space. The contact springs are preferably arranged in a common plane and are deformable in this plane.

[0014] Because the contact springs are not surrounded by the carrier material, especially not overmolded, the required elasticity of the contact device can be ensured. Tolerance independence is guaranteed by the elasticity of the contact springs. The mechanical forces arising from tolerance deviations and deflection of the contact springs are absorbed by the overmolding of the contact lines.

[0015] By jointly securing the conductors in the clamping space between the contact springs, each contact spring generates the necessary counterforce to prevent unintentional displacement of the carrier during assembly of the contact device. The function is similar to a conventional contact clamp with two clamping arms. However, the difference in the solution according to the invention lies in the fact that the clamping function is realized while simultaneously establishing contact with two conductors at different potentials. Furthermore, contact is only required and sufficient on one side of the conductor, resulting in space savings for the power electronics module. This combination enables and ensures vibration-resistant contact even when the conductors are only accessible from one side.Contacting the conductors with such a contact device makes it possible to withstand the usual stresses, especially vibrations, that can occur during the operation of an electric drive.

[0016] Furthermore, the contact device proposed here can be used in power electronics modules with limited available installation space, where, for example, only one side of the respective conductor is accessible for a contact device, but both a positive potential and a negative potential still need to be contacted.

[0017] Furthermore, assembly is greatly simplified. Additionally, a modular add-on can be implemented, which can be adapted and integrated as needed for future projects. This allows for the provision of an easy-to-manufacture, simple, and cost-effective contact device that can be used for development-accompanying tests or for various customer requirements. The contact device according to the invention offers a high degree of flexibility combined with easy assembly and / or non-destructive and / or contamination-free disassembly.

[0018] The single-sided contact springs can be designed in fundamentally different ways. Each contact spring can be configured as a leg of a clamping arrangement formed by the contact spring pair and can have several sections with different functions. The contact springs thus form a clamp-like spring pair. Preferably, the first and / or second contact spring has a spring section and a contact section, wherein the spring section is arranged between the support and the contact section, and wherein the contact section is configured to be pre-tensioned against the associated conductor by the spring section when the contact device is mounted.The spring section is an elastically deformable part of the contact spring. When conductors are inserted into the clamping space between the contact springs, this section deforms elastically, causing the opposing contact sections to move away from each other until the clamping space or gap is opened or enlarged, and at least the conductors are held between the contact springs. During deformation, the contact spring builds up a preload force in the direction of the other contact spring and relaxes when the contact device is disassembled or when the conductors are removed from the clamping space.

[0019] Preferably, the contact springs are designed to be mirror-symmetrical to each other, particularly with respect to the mounting direction of the contact device relative to the conductors. This ensures that, during the mounting of the contact device, the electrical conductors are positioned securely between the contact springs with a substantially uniform force distribution.

[0020] The mutual distance between the contact sections is significantly smaller in the initial state or in the unassembled state of the contact device than the distance between the spring sections of the contact springs extending to the contact sections.

[0021] Each contact spring section can form a turning point where the direction of curvature reverses. The first and / or second contact spring may have an insertion section to ensure secure insertion of the conductors during assembly. In other words, the contact springs taper outwards from the insertion section to their free ends in a funnel shape. If both contact springs have an insertion section, a funnel-shaped insertion space is formed. In other words, the contact springs are spread apart at their free ends. The respective insertion section is therefore located between the corresponding spring section and the corresponding insertion section.

[0022] Alternatively, the contact spring can have multiple legs. In this case, the first and / or second contact spring has two or more contact legs, each comprising a spring section and a contact section. The contact legs are essentially identical and are connected to each other as a single unit via a base body. Thus, while the contact spring is a single piece, it can be divided into any number of contact legs. This allows for a more robust contact connection, even against component deviations, unevenness, and tolerances of the electrical conductors.

[0023] According to a second aspect of the invention, a power electronics module according to the invention for an electric drive axle of a vehicle that is at least partially electrically driven comprises a contact device according to the first aspect of the invention. The power electronics module can be part of a high-voltage system of an electric drive axle. The power electronics module can be supplied with electrical energy from an energy storage device, wherein the power electronics module converts the electrical energy from the energy storage device into a form that is required for driving the vehicle. The power electronics module can include an inverter and optionally a rectifier. The inverter converts the direct current from the energy storage device into the alternating current that is required for an electric machine to drive the vehicle, in particular in an electric drive axle.In contrast, a rectifier converts the alternating current (AC) during recuperation back into direct current (DC) to power the energy storage device. Inverters and rectifiers are considered power electronic drive converters.

[0024] The electrical conductors, one of which carries a positive high voltage and the other a negative high voltage, are preferably arranged essentially parallel to each other, at least in the area of ​​the contact springs, with an insulator positioned spatially between the conductors. The insulator prevents a short circuit between the two conductors, which are arranged relatively close to each other. The conductors and the insulator are therefore arranged in a layered configuration in the area of ​​the contact springs when assembled. The clamping space between the contact springs, or the gap between the system sections, is designed according to the thickness of the layered conductor-insulator arrangement. The contact device is advantageously suited for retrofitting into an existing power electronics module. The contact device can be easily integrated into an already assembled power electronics module without complicated assembly processes.

[0025] The insulator may have a stop surface or a stop component against which the support comes into contact during assembly, in order to ensure the desired position or contact point of the contact spring sections on the associated conductor. The insulator may also have a socket for the positive locking of at least one of the conductors.

[0026] The power electronics module is preferably advantageously used in an electric drive axle for an electrically driven vehicle, also called an e-axle, particularly in or on an inverter of the electric drive axle. In this sense, an electric drive axle for a vehicle that is at least partially electrically driven, according to a third aspect of the invention, comprises an electric machine and a power electronics module proposed therein according to the second aspect of the invention, or a contact device according to the first aspect of the invention.

[0027] The electric motor of the electric drive axle converts electrical energy into mechanical energy, which drives at least one wheel of the electric drive axle. In generator mode, the electric motor converts mechanical energy into electrical energy. The electric motor is preferably a three-phase electric motor. In addition to the electric motor, the electric drive axle can optionally include a transmission to provide torque and speed for driving a drive wheel of the vehicle. The electric motor is supplied with electrical energy from the energy storage device, in particular via the power electronics module.

[0028] A vehicle that is at least partially electrically powered can be a motor vehicle, in particular a motorcycle, a passenger car, a truck, or a bus. The vehicle comprises at least two axles. Preferably, two axles are provided, wherein at least one of the axles is an electric drive axle according to the third aspect of the invention and can be driven by at least one electric motor. The electric drive axle according to the third aspect of the invention can include a power electronics module according to the second aspect of the invention.

[0029] The above definitions, as well as the explanations regarding technical effects, advantages, and advantageous embodiments of the contact device according to the invention, also apply mutatis mutandis to the power electronics module according to the second aspect of the invention and to the electric drive axle according to the third aspect of the invention, and vice versa. It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention.

[0030] The invention will now be described in more detail with reference to the attached figures, in which: Fig. 1 a highly schematic view of an electrically driven vehicle according to the invention with an electric drive axle and a power electronics module according to the invention; Fig. 2 a perspective view of the power electronics module according to the invention - which is only partially shown here Fig. 1 to illustrate an assembled state of a contact device according to the invention; Fig. 3 a schematic sectional view of the - only partially shown - contact device according to Fig. 2; and Fig. 4 a schematic perspective view of an exemplary contact spring of the contact device according to the invention in an alternative embodiment; represents.

[0031] Fig. Figure 1 shows an electric drive axle 100 in an electrically powered vehicle 105. The vehicle 105 may additionally include an internal combustion engine 110, which is connected via a transmission 115 to a drive wheel 120 of the vehicle 105. In this case, the vehicle 105 would be a hybrid vehicle.

[0032] The electric drive axle 100 comprises an electric machine 125, which can also act on the drive wheel 120, preferably by means of the gearbox 115. Furthermore, an inverter 130 is provided, which can be supplied with electrical energy from an electrical energy storage device 135. The inverter 130 and the energy storage device 135 are, in this case, part of a power electronics module 140. The electrical energy storage device 135 is preferably of electrochemical design; however, a fuel cell or another power source can also be used, for example. The inverter 130 is preferably configured to provide phase-shifted alternating currents to the electric machine 125. The electric machine 125 is implemented as a permanent magnet synchronous machine by way of example; however, other embodiments are also possible.The supplied voltages and frequencies of the alternating currents can be determined such that the electric machine 125 converts a predetermined torque or rotates at a predetermined speed. Field-oriented control can be implemented to control the direction of rotation and speed. The nominal voltage of the electrical energy storage device 135 is typically several hundred to over 1000 V. The current through the electric machine 125 can be several hundred A.

[0033] In Fig. Figure 2 shows only a part of the power electronics module 140. The power electronics module 140 comprises two capacitors 200, 205, which are connected to electrical conductors 215, 220 of the power electronics module 140 via a contact device 210 according to the invention. The electrical conductors 215, 220 have different potentials. The first electrical conductor 215 is designed to carry positive high voltage (HV+) and the second electrical conductor 220 is designed to carry negative high voltage (HV-). Thus, the conductors 215, 220 are high-voltage conductors, or HV conductors for short. The two conductors 215, 220 are essentially parallel at their free ends and are electrically insulated from each other by an insulator 225. The insulator 225 is spatially arranged between the end sections of the conductors 215, 220. The insulator 225 can, for example, be part of a cover 230 of the electric machine 125.The insulator 225 can be made of plastic.

[0034] The contact device 210 comprises a carrier 235 made of plastic, in which, as in Fig. As can be seen in Figure 3, a first contact line 300 and a second contact line 305 are integrated. In the assembled state, the first contact line 300 is contacted with the first conductor 215 and is thus intended for carrying positive high voltage. In the assembled state, the second contact line 305 is contacted with the second conductor 220 and is thus intended for carrying negative high voltage. Each contact line 300, 305 has a contact spring 240, 245 at one free end for contacting one of the conductors 215, 220, and a contact tab 250, 255 at the opposite free end for contacting one of the capacitors 200, 205. The contact tabs 250, 255 are not surrounded by the material of the electrically insulating carrier 235 and are therefore brought out of the carrier 235.The respective contact line 300, 305 is designed to contact a corresponding capacitor 200, 205 at one end opposite the respective contact spring 240, 245.

[0035] The contact springs 240, 245 of the contact leads 300, 305 are shown to extend from the carrier 235 on an underside and are not surrounded by the material of the electrically insulating carrier 235. The contact springs 240, 245 are mirror-symmetrical with respect to one mounting direction and are spaced apart from each other and designed such that, in the assembled state of the contact device 210, which is in Fig. Figure 3 shows that the conductors 215, 220 and the insulator 225 are held between them in a clamping space 310 and are pre-tensioned against each other. A contact spring 240, 245 contacts each of the conductors 215, 220.

[0036] After Fig. 3 Both contact springs 240, 245 each have a spring section 315, 320, an insertion section 325, 330, and a contact section 335, 340 arranged between the spring section 315, 320 and the insertion section 325, 330. The respective spring section 315, 320 is thus arranged between the carrier 235 and the contact section 335, 340. The contact springs 240, 245 are spread apart at their free ends.

[0037] During the assembly of the contact device 210, the conductors 215, 220 are aligned in the assembly direction, i.e., when they are aligned according to Fig. As the spring section 3 is moved downwards towards the conductors 215 and 220, it is inserted via an insertion chamber 345 spatially between the two insertion sections 325 and 330 into a gap between the system sections 335 and 340 up to the clamping chamber 310, whereby the system sections 335 and 340 are pushed away from each other, i.e., to the left and right respectively. During this process, the spring sections 315 and 320 deform elastically and build up a spring preload force, while the system sections 335 and 340 laterally contact the corresponding conductors 215 and 220. Thus, the conductors 215 and 220 are clamped spatially between the system sections 335 and 340. The system sections 335, 340 are thus designed to come into contact with the associated conductor 215, 220 when the contact device 210 is mounted, by means of the associated spring section 315, 320. In the first embodiment, the contact springs 240, 245 of the contacting lines 300, 305 are single-legged and single-sided.

[0038] Fig. Figure 3 also shows that the conductors 215 and 220 are each enclosed by the insulator 225 and thus attached to the cover 230.

[0039] In a Fig. In the alternative embodiment shown in Figure 4, the first and / or second contact spring 240, 245 has at least two, and in this case exactly three, contact legs 400, 405, 410, each comprising a spring section 415, a contact section 420, and an insertion section 425 extending from the carrier 235. The contact legs 400, 405, 410 are essentially parallel and identical to one another. The spring sections 415 of all contact legs 400, 405, 410 are integrally connected to one another via a base body 430, which is connected to the remaining contact line 300, 305. Fig.3 is integrally formed. The base body 430 can be an extension of the respective contact line 300, 305, which is led out of the carrier 235 of the contact device 140. Alternatively, the base body 430 can be an integral part of the spring sections 415. The base body 430 can be at least partially surrounded by the material of the carrier 235. Reference sign 100 electric drive axle 105 vehicles 110 internal combustion engine 115 gearbox 120 drive wheel 125 electric machine 130 inverters 135 energy storage 140 Power electronics module 200 first capacitor 205 second capacitor 210 Contact device 215 first electrical conductor 220 second electrical conductor 225 Insulator 230 lids 235 carriers 240 first contact spring 245 second contact spring 250 first contact tab 255 second contact tab 300 first contact line 305 second contact line 310 Terminal space 315 first spring section of the first contact spring 320 second spring section of the second contact spring 325 First insertion section of the first contact spring 330 second insertion section of the second contact spring 335 first assembly section of the first contact spring 340 second assembly section of the second contact spring 345 Introduction chamber 400 first contact leg 405 second contact leg 410 third contact leg 415 Spring section 420 Plant section 425 Introductory section 430 basic bodies

Claims

[1] Contact device (210) for a power electronics module (140) for contacting two electrical conductors (215, 220) with different potentials, comprising a carrier (235) made of an electrically non-conductive material in which a first contacting line (300) and a second contacting line (305) are integrated, wherein a first contact spring (240) of the first contacting line (300) and a second contact spring (245) of the second contacting line (305) are arranged projecting on the carrier (235), wherein the contact springs (240, 245) are arranged and configured such that, in the assembled state of the contact device (210), they hold the conductors (215, 220) between them and are biased against each other, wherein each contact spring (240, 245) contacts one of the conductors (215, 220). [2] Contact device (210) according to claim 1, wherein the first and / or second contact spring (240, 245) has a spring section (315, 320, 415) and a contact section (335, 340, 420), wherein the spring section (315, 320, 415) is arranged between the support (235) and the contact section (335, 340, 420), and wherein the contact section (335, 340, 420) is configured to come into contact with the associated conductor (215, 220) when the contact device (210) is mounted, by means of the spring section (315, 320, 415). [3] Contact device (210) according to claim 2, wherein the first and / or second contact spring (240, 245) has two or more contact legs (400, 405, 410), each comprising a spring section (415) and a contact section (420). [4] Contact device (210) according to one of the preceding claims, wherein the respective contact line (300, 305) is configured to contact a capacitor (200, 205) of the power electronics module (140) at one end opposite the respective contact spring (240, 245). [5] Contact device (210) according to claim 4, wherein a first contact tab (250) of the first contact line (300) and a second contact tab (255) of the second contact line (305) are brought out on a side of the carrier (235) facing the capacitors (200, 205). [6] Contact device (210) according to one of the preceding claims, wherein the carrier (235) is made of plastic. [7] Contact device (210) according to one of the preceding claims, wherein the contact springs (240, 245) are designed to be mirror-symmetrical to each other. [8] Power electronics module (140) for an electric drive axle (100) of a vehicle (105) that is at least partially electrically driven, comprising a contact device (210) according to one of the preceding claims. [9] Power electronics module (140) according to claim 8, wherein the conductors (215, 220) in the area of ​​the contact springs (240, 245) are arranged substantially parallel to each other, and wherein an insulator (225) is arranged spatially between the conductors (215, 220). [10] Electric drive axle (100) for a vehicle (105) that is at least partially electrically driven, comprising a power electronics module (140) according to claim 8 or claim 9 or a contact device (210) according to any one of claims 1 to 7.

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