Inverter for a vehicle and method for manufacturing an inverter

Abstract

An inverter (100) for a vehicle comprises a housing (102) with a cooling channel (104) and a busbar (106) for carrying a direct voltage. The busbar (106) is arranged adjacent to the cooling channel (104) and, together with a temperature sensor, is encapsulated in a potting compound (108). A printed circuit board with an electrical circuit for controlling a function of the inverter (100) is arranged on a side of the busbar (106) facing away from the cooling channel (104). Terminals of the temperature sensor are electrically connected to the printed circuit board.

Description

[0001] The present invention relates to an inverter for a vehicle and to a method for manufacturing an inverter.

[0002] Inverters used in vehicles contain power transistors that can be cooled using a cooling medium. Temperature sensors can be used to measure the temperature of the cooling medium. These sensors are screwed, for example, to a cooling insert and the inverter housing.

[0003] Against this background, the present invention provides an improved inverter for a vehicle and an improved method for manufacturing an inverter according to the main claims. Advantageous embodiments emerge from the subclaims and the following description.

[0004] If an inverter temperature sensor is embedded in a potting compound together with an inverter bus bar, no additional steps are required to attach the sensor to the inverter.

[0005] A vehicle inverter has the following features: a housing with a cooling channel for passing a cooling medium; a busbar for carrying a DC voltage, wherein the busbar is arranged adjacent to the cooling channel, and wherein the busbar is cast in a casting compound; a temperature sensor encapsulated in the potting compound; and a circuit board having an electrical circuit for controlling a function of the inverter, wherein terminals of the temperature sensor are electrically connected to the circuit board.

[0006] The vehicle can be an electrically powered vehicle, for example a passenger car, a truck, or a rail vehicle. The inverter can be designed to convert a direct voltage, for example from a vehicle battery, into an alternating voltage, for example into a three-phase alternating voltage for driving an electrical machine. In accordance with known inverters, the inverter can comprise electronic components, for example power transistors, which heat up during operation of the inverter. Such components can be cooled using the cooling medium. For this purpose, a thermal coupling can be provided between a wall of the cooling channel and the components. For example, corresponding components to be cooled can be arranged on the busbar. The busbar can have a plate-shaped section extending over the cooling channel.The potting compound can be applied to at least one surface of the busbar during an injection molding process. The potting compound can form a cured potting element. The potting compound can be bonded to the busbar in a material-to-material and / or form-fitting manner. Using the potting compound, fastening structures can be formed which can be used, for example, to fasten the busbar to the housing or to connect the printed circuit board to the potting compound. The temperature sensor can be configured to detect a temperature and provide a temperature signal representing the temperature. The temperature sensor can be embedded in the potting compound together with the busbar during the injection molding process. The temperature sensor can be arranged adjacent to the cooling channel in order to be able to detect a temperature of the cooling medium.The circuit board can be arranged on a side of the busbar facing away from the cooling channel. The circuit board can include the electrical circuit for controlling the function of the inverter, depending on the known inverter direction. For example, the electrical circuit can be used to switch power transistors of the inverter. The electrical circuit can be configured to incorporate a temperature signal provided by the temperature signal during operation of the inverter, for example, to prevent overheating.

[0007] By embedding the temperature sensor in the potting compound, the temperature sensor is secured within the inverter. This eliminates the need for additional clips to hold a sensor cable, for example. Furthermore, it's not necessary to mount a sensor connector on the circuit board when installing the inverter.

[0008] The potting compound can span a side of the busbar facing away from the cooling channel. The potting compound can have an extension projecting beyond the busbar. The temperature sensor can be arranged in the extension. In this way, the temperature sensor can be arranged next to the busbar, so that, for example, a temperature sensor of the temperature sensor faces the cooling channel and a connection side of the temperature sensor can face the circuit board. If the inverter has a plurality of temperature sensors, the potting compound can have a corresponding number of extensions projecting beyond the busbar. The temperature sensors can thus be arranged in different extensions, for example on opposite sides of the busbar.

[0009] A temperature sensor of the temperature sensor can be thermally coupled to the cooling channel to measure the temperature of the cooling medium. If multiple temperature sensors are used, they can be thermally coupled to the cooling channel at different positions, for example, to measure the inlet and outlet temperatures of the cooling medium.

[0010] The temperature sensor can be cylindrical in shape. A longitudinal extension of the temperature sensor can be aligned orthogonally to a main extension plane of the busbar. This allows for easy contact with the temperature sensor's connecting cables.

[0011] The inverter can have a first conductor with a first terminal and a second terminal, and a second conductor with a first terminal and a second terminal. The conductors can be encapsulated in the potting compound. The terminals can protrude from the potting compound. Connecting leads of the temperature sensor can be electrically connected to the first terminals. The second terminals can be electrically connected to the circuit board. In this way, the temperature sensor can be electrically connected to the circuit board using the conductors encapsulated in the potting compound.

[0012] The temperature sensor's connecting leads can be welded to the first terminals of the conductors. The second terminals of the conductors can be soldered to the circuit board. This ensures secure electrical and mechanical contact.

[0013] The inverter can include at least one additional temperature sensor. The at least one additional temperature sensor can also be encapsulated in the potting compound. The temperature sensor and the additional temperature sensor can be arranged on opposite sides of the busbar. Thus, two, three, four, or more temperature sensors can be installed.

[0014] The inverter may comprise a plurality of power transistors. The inverters may be connected to the busbar. For example, at least one terminal of each of the power transistors may be electrically connected to the busbar, for example, welded or soldered. The power transistors may be arranged on a side of the busbar facing the cooling channel. This makes it easy to dissipate heat from the power transistors to the cooling channel.

[0015] A method for manufacturing an inverter for a vehicle comprises the following steps: Providing a housing with a cooling channel for passing a cooling medium;

[0016] Providing a composite component comprising a busbar for carrying a DC voltage and a temperature sensor, wherein the busbar and the temperature sensor are encapsulated in a potting compound;

[0017] Providing a printed circuit board with an electrical circuit for controlling a function of the inverter; and

[0018] Arranging the composite component and the circuit board on the housing, wherein the busbar is arranged adjacent to the cooling channel, and wherein the circuit board is arranged on a side of the busbar facing away from the cooling channel, and terminals of the temperature sensor are electrically connected to the electrical circuit.

[0019] In this way, the temperature sensor in particular can be installed without any additional assembly steps.

[0020] The method may include a step of overmolding the busbar and the temperature sensor with the potting compound.

[0021] In addition, a drive system for a vehicle is presented, featuring an electric motor and a variant of the previously presented inverter. This combination offers the advantage of optimally implementing all of the aforementioned benefits.

[0022] The drive device is suitable, for example, for an electric axle drive. Such an electric axle drive for a vehicle comprises at least one drive device and a transmission device. Using the transmission device, a torque provided by the drive device can be converted into a drive torque for driving at least one wheel of the motor vehicle. The transmission device can have a transmission for reducing the speed of the electric motor and, optionally, a differential.

[0023] Accordingly, a vehicle may comprise a said drive device and additionally or alternatively a said electric axle drive.

[0024] The invention is explained in more detail by way of example with reference to the accompanying drawings. They show: Fig. 1 shows an embodiment of an inverter; Fig. 2 shows an illustration of an embodiment of a sensor device; Fig. 3 shows an illustration of an embodiment of the sensor device; Fig. 4 shows an illustration of an embodiment of a further sensor device; Fig. 5 shows an illustration of an embodiment of the further sensor device; Fig. 6 shows an illustration of an embodiment of the further sensor device; Fig. 7 shows an illustration of an embodiment of a sensor; Fig. 8 is a flowchart of an embodiment of a method for manufacturing an inverter; and Fig. 9 a schematic representation of an embodiment of a vehicle.

[0025] In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, whereby a repeated description of these elements is omitted.

[0026] Fig. 1 shows an illustration of an embodiment of an inverter 100 for a vehicle. For example, the vehicle includes a battery and an electric motor for powering the vehicle. The inverter 100 is used, for example, to convert a DC voltage provided by the battery into an AC voltage for operating the electric motor.

[0027] The inverter 100 has a housing 102 with a cooling channel 104 for the passage of a cooling medium. A liquid coolant, for example, is used as the cooling medium. Waste heat generated during operation of the inverter 100 can be dissipated via the cooling medium.

[0028] According to one embodiment, a busbar 106 spans a cover of the cooling channel 104. The busbar 106 is used to carry a DC voltage. The busbar 106 is formed, for example, as a metal plate and has angled edge sections on two opposite sides.

[0029] According to one embodiment, the inverter 100 has a plurality of power transistors that are connected to the busbar 106 and are arranged on a side of the busbar 106 facing the cooling channel 104.

[0030] At least one surface of the busbar 106 facing away from the cooling channel 104 is encapsulated in a potting compound 108. The potting compound 108 forms a layer extending over the busbar 106 and optionally has a plurality of through-openings. Optionally, a plurality of electrical contacts are passed through the potting compound 108. For example, a total of nine pairs of electrical contacts are arranged in a row along a length of the busbar 106. Optionally, the potting compound 108 has a plurality of retaining domes, for example, for attaching a circuit board of the inverter 100. The retaining domes extend orthogonally away from a surface of the potting compound 108 facing away from the busbar 106.

[0031] According to one embodiment, a surface of the busbar 106 facing the cooling channel 104 is also cast into the potting compound 108.

[0032] Optionally, the potting compound 108 has a projection 110 on opposite sides over the busbar 106, for example with a through opening for fixing the potting compound 108 to the housing 102.

[0033] At least one temperature sensor is cast into the potting compound 108. According to the illustrated embodiment, two temperature sensors are cast, with the temperature sensors being arranged on opposite sides of the busbar 106. For example, a first temperature sensor is part of a first sensor device 112, and a second temperature sensor is part of a second sensor device 114. The first temperature sensor is used, for example, as an inlet temperature sensor, and the second temperature sensor as an outlet temperature sensor.

[0034] According to one embodiment, the inverter 100 is designed to convert a direct current, for example from a battery, into alternating current, which is fed, for example, to a three-phase AC motor.

[0035] According to one embodiment, a cooling insert is arranged between the busbar 106 and the cooling channel 104. According to one embodiment, power transistors, for example, SIC MOSFETs (silicon carbide MOSFETs), are arranged between the cooling insert and the busbar 106. These transistors are cooled by a coolant flowing in the cooling channel 104 beneath the cooling insert.

[0036] The circuit board, which according to one embodiment is arranged parallel to the busbar 106 on a side facing the potting compound 108, has according to one embodiment all the power electronic components required for the operation of the inverter 100 and is used as a combined control and driver board.

[0037] According to one embodiment, the busbar 106 is formed as a copper bar, which, for example, conducts the direct current from a capacitor. The busbar 106 is overmolded and, according to one embodiment, connected to the power transistors, for example, the MOSFETs, by welding.

[0038] According to one embodiment, the potting compound 106 is directly overmolded with the busbar 106, for example a copper busbar, as a so-called overmold.

[0039] This enables the integration of temperature sensors in a so-called DC overmold. This eliminates the need for the sensor to be screwed to a cooling insert and the housing 102, or for a sensor cable to be held with additional clips and a connector to be mounted on the circuit board.

[0040] Fig. 2 shows a representation of an embodiment of a first sensor device 112, as is also shown, for example, in Fig. 1. The first sensor device 112 is arranged at an edge of the potting compound 108. The first sensor device 112 has an extension 220 that extends beyond the busbar 106. The extension 220 is formed by the potting compound 108 and comprises a receptacle for a first temperature sensor. According to one exemplary embodiment, the receptacle is cylindrical and has a longitudinal extension direction that is oriented orthogonal to a main extension direction of the busbar 106. According to one exemplary embodiment, the temperature sensor is received by the receptacle such that a temperature sensor of the temperature sensor is thermally coupled to the cooling channel in order to detect a temperature of the cooling medium.

[0041] The first temperature sensor has connecting leads 222, 224 that protrude from the encapsulating compound 108. The temperature sensor can be electrically contacted via the connecting leads 222, 224, for example, directly or via additional conductors to the circuit board.

[0042] According to one embodiment, the first sensor device 112 comprises a first conductor with a first terminal 230 and a second terminal 232, as well as a second conductor with a first terminal 234 and a second terminal 236. Except for the terminals 230, 232, 234, 236, the conductors are encapsulated in the potting compound 108. The connecting leads 222, 224 of the temperature sensor are electrically contacted with the first terminals 230, 234. For example, the first terminals 230, 234 are shaped as clamps, with the end of one of the connecting leads 222, 224 being clamped into each clamp. The second terminals 232, 236 are shaped, for example, as contact pins, here vertical pins, and can be inserted into through-openings in the circuit board to establish electrical contact between the temperature sensor and an electrical circuit on the circuit board.For example, the terminals 230, 232, 234, 236 are aligned orthogonally to a main extension plane of the busbar 106.

[0043] The conductors, like the busbar 106, are thus overmolded with the potting compound 106. According to one embodiment, the connecting leads 222, 224 of the temperature sensor are welded to the first terminals 230, 234 of the conductors. The second terminals 232, 236 of the conductors can be soldered to the circuit board.

[0044] In such a construction, the sensor is welded to the wires, referred to here as conductors, in the sheath, and the wires are soldered to the circuit board.

[0045] This allows for easy installation. Only a few assembly steps are required, as the sensor is integrated into the DC overmolding, and no additional fixtures are required. Furthermore, accurate results can be obtained from the sensor. The small number of required parts also ensures cost savings.

[0046] According to one embodiment, the temperature sensor, as described for example in Fig. 7, is received in the extension 220 so that it is in point contact with a cooling channel or a cooling insert, for example the one shown in Fig. 1 shown inverter.

[0047] According to one embodiment, a holding dome 238 is formed adjacent to the first sensor device 112, for example, which can be used for holding the circuit board.

[0048] Fig. 3 shows an illustration of an embodiment of the first sensor device 112. This is, for example, a side view of the Fig. 2 described sensor device.

[0049] The extension 220 containing the temperature sensor extends beyond a thickness of the potting compound 108 encasing the busbar 106. This allows the temperature sensor to come into thermal contact with the cooling channel.

[0050] A printed circuit board 340 is arranged spaced apart and parallel to the busbar 106 and is placed, for example, on the holding dome 238.

[0051] Free ends of the second terminals 232, 236 of the conductors are passed through the circuit board 340 and soldered, for example, in through holes of the circuit board 340.

[0052] Fig. 4 shows an illustration of an embodiment of a second sensor device 114, as is also shown, for example, in Fig. 1. The second sensor device 114 is shaped in a manner similar to the first sensor device described above and is arranged at a further edge of the potting compound 108. The second sensor device 114 has an extension 220 projecting beyond the busbar 106. The extension 220 is formed by the potting compound 108 and includes a receptacle for a second temperature sensor.

[0053] The second temperature sensor, like the first temperature sensor, has connecting leads 222, 224 that protrude from the potting compound 108. The second temperature sensor can be electrically contacted via the connecting leads 222, 224, for example, directly or via additional conductors, to the circuit board 340.

[0054] According to one embodiment, the second sensor device 114 comprises a first conductor with a first terminal 230 and a second terminal 232, as well as a second conductor with a first terminal 234 and a second terminal 236. Except for the terminals 230, 232, 234, 236, the conductors are encapsulated in the potting compound 108. The connecting lines 222, 224 of the second temperature sensor are electrically contacted with the first terminals 230, 234. For example, the first terminals 230, 234 are shaped as clamps, with the end of one of the connecting lines 222, 224 being clamped into each clamp. The second terminals 232, 236 are shaped, for example, as contact pins, here vertical pins, and can be inserted into through-openings in the circuit board 340 in order to establish electrical contact between the second temperature sensor and an electrical circuit on the circuit board 340.For example, the terminals 230, 232, 234, 236 are aligned orthogonally to a main extension plane of the busbar 106.

[0055] The conductors, like the busbar 106, are thus overmolded with the potting compound 106. According to one embodiment, the connecting leads 222, 224 of the second temperature sensor are welded to the first terminals 230, 234 of the conductors. The second terminals 232, 236 of the conductors can be soldered to the circuit board 340.

[0056] Fig. 5 shows an illustration of an embodiment of the second sensor device 114, as already described with reference to Fig. 4. The second sensor device 114 is arranged adjacent to a through-opening 540 of the potting compound 108.

[0057] Fig. 6 shows a side view of an embodiment of the second sensor device 114, as already described with reference to Fig. 4. The terminal 230 is shaped as a flag and has a groove extending from a free end of the terminal 230, into which a free end of the connecting line 222 is clamped.

[0058] Fig. Figure 7 shows an illustration of an embodiment of a temperature sensor 750, as described with reference to the preceding figures. The temperature sensor 750 can be used, for example, for the sensor devices described with reference to the preceding figures.

[0059] The temperature sensor 750 has a cylindrical body. Connecting leads 222, 224 extend from one end of the body. A temperature sensor is arranged at an end opposite the connecting leads 222, 224.

[0060] During the manufacture of the inverter, the body of the temperature sensor 750 is overmolded with the potting compound.

[0061] Fig. 8 shows a flowchart of an embodiment of a method for manufacturing an inverter as described with reference to the preceding figures.

[0062] The method comprises a step 801 of providing a housing with a cooling channel for conducting a cooling medium, and a step 803 of providing a composite component comprising a busbar for carrying a DC voltage and at least one temperature sensor, wherein the busbar and the temperature sensor are encapsulated in a potting compound. Optionally, the composite component is manufactured in a step 805 by overmolding or encapsulating the busbar and the at least one temperature sensor with the potting compound. In a step 807, a printed circuit board with an electrical circuit for controlling a function of the inverter is provided. In a step 809, the composite component and the printed circuit board are arranged on the housing. The busbar is arranged adjacent to the cooling channel. The printed circuit board is arranged on a side of the busbar facing away from the cooling channel.Terminals of the temperature sensor are electrically connected to the electrical circuit.

[0063] Fig.9 shows a schematic representation of a vehicle 900 according to an exemplary embodiment. The vehicle 900 has an electric axle drive with an electric machine 902. Electrical energy for operating the electric machine 902 is provided by a power supply device 904, for example, a battery. For example, the power supply device 904 provides a direct current, which is converted into an alternating current, for example, a three-phase alternating current, using an inverter 100, as described by way of example with reference to the preceding figures, and is supplied to the electric machine 902. A shaft driven by the electric machine 902 is coupled directly or using a transmission device 906 to at least one wheel 908 of the vehicle 900. Thus, the vehicle 900 can be moved using the electric machine 902.According to one embodiment, the electric axle drive comprises a housing in which the inverter 100, the electric machine 902 and the transmission device 906 are arranged in an integrated manner.

[0064] According to one embodiment, the inverter 100 has, in accordance with known inverters, a plurality of power transistors 960 which are suitably controlled to convert the direct current into the alternating current. Reference symbol 100 inverters 102 housings 104 Cooling channel 106 Busbar 108 Potting compound 110 overhang 112 first sensor device 114 second sensor device 220 extension 222 first connecting line 224 second connection line 230 first connection of the first conductor 232 second connection of the first conductor 234 first connection of the second conductor 236 second connection of the second conductor 238 Holding dome 340 circuit board 540 passage opening 750 temperature sensor 801 Step of providing a housing 803 Step of providing a composite component 805 Step of manufacturing 807 Step of providing a printed circuit board 809 Arranging step 900 vehicles 902 electric machine 904 Energy supply facility 906 transmission device 960 majority of power transistors.

Claims

[1] Inverter (100) for a vehicle (900), the inverter (100) having the following features: a housing (102) with a cooling channel (104) for passing a cooling medium; a busbar (106) for carrying a DC voltage, wherein the busbar (106) is arranged adjacent to the cooling channel (104), and wherein the busbar (106) is cast in a casting compound (108); a temperature sensor (750) encapsulated in the potting compound (108); and a circuit board (340) having an electrical circuit for controlling a function of the inverter (100), wherein terminals of the temperature sensor (750) are electrically connected to the circuit board. [2] Inverter (100) according to claim 1, wherein the potting compound (108) spans a side of the busbar (106) facing away from the cooling channel (104) and has an extension (220) projecting beyond the busbar (106), wherein the temperature sensor (750) is arranged in the extension (220). [3] Inverter (100) according to one of the preceding claims, wherein a temperature sensor of the temperature sensor (750) is thermally coupled to the cooling channel (104) to detect a temperature of the cooling medium. [4] Inverter (100) according to one of the preceding claims, wherein the temperature sensor (750) is cylindrically shaped, wherein a longitudinal extension direction of the temperature sensor (750) is aligned orthogonally to a main extension plane of the busbar (106). [5] Inverter (100) according to one of the preceding claims, with a first conductor with a first terminal (230) and a second terminal (232), and a second conductor with a first terminal (234) and a second terminal (236), wherein the conductors are cast in the potting compound (108), wherein the terminals (230, 232, 234, 236) protrude from the potting compound (108), and wherein connecting lines (222, 224) of the temperature sensor (750) are electrically contacted with the first terminals (230, 234), and wherein the second terminals (232, 236) are electrically contacted with the printed circuit board (340). [6] Inverter (100) according to claim 5, wherein the connecting leads (222, 224) of the temperature sensor (750) are welded to the first terminals (230, 234) of the conductors, and wherein the second terminals (232, 236) of the conductors are soldered to the circuit board (340). [7] Inverter (100) according to one of the preceding claims, with a further temperature sensor which is cast in the casting compound (108), wherein the temperature sensor (750) and the further temperature sensor are arranged on opposite sides of the busbar (106). [8] Inverter (100) according to one of the preceding claims, comprising a plurality of power transistors (960) which are connected to the busbar (106) and are arranged on a side of the busbar (106) facing the cooling channel (104). [9] A method for manufacturing an inverter (100) for a vehicle (900), the method comprising the following steps: Providing (801) a housing (102) with a cooling channel (104) for passing a cooling medium; Providing (803) a composite component comprising a busbar (106) for carrying a DC voltage and a temperature sensor (750), wherein the busbar (106) and the temperature sensor (750) are encapsulated in a potting compound (108); Providing (807) a circuit board (340) with an electrical circuit for controlling a function of the inverter (100); and Arranging (809) the composite component and the circuit board (340) on the housing (102), wherein the busbar (106) is arranged adjacent to the cooling channel (104), and wherein the circuit board (340) is arranged on a side of the busbar (106) facing away from the cooling channel (104), and terminals of the temperature sensor (750) are electrically connected to the electrical circuit. [10] Method according to claim 9, comprising a step (811) of overmolding the busbar (106) and the temperature sensor (750) with the potting compound (108).

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