HALF-BRIDGE FOR AN ELECTRIC DRIVE OF AN ELECTRIC VEHICLE OR A HYBRID VEHICLE, POWER MODULE FOR AN INVERTER AND INVERTER

Description

[0001] The invention relates to a power module for an inverter of an electric drive of an electric vehicle or a hybrid vehicle and a corresponding inverter.

[0002] Purely electric vehicles and hybrid vehicles are known in the prior art, which are powered exclusively or in conjunction with one or more electric motors as drive units. To supply the electric motors of such electric vehicles or hybrid vehicles with electrical energy, the electric vehicles and hybrid vehicles comprise electrical energy storage devices, in particular rechargeable electric batteries. These batteries are designed as direct current sources, but the electric motors generally require alternating current. Therefore, a power electronics system with a so-called inverter is usually connected between a battery and an electric motor of an electric vehicle or a hybrid vehicle.

[0003] Such inverters typically comprise semiconductor switching elements, typically formed from transistors. It is known to provide the semiconductor switching elements with varying degrees of integration, namely either as discrete individual switches with a low degree of integration but high scalability, as power modules with a high degree of integration but low scalability, or as half-bridges, which, in terms of degree of integration and scalability, range between individual switches and half-bridges. Each half-bridge comprises a high-side switching position (hereinafter: "highside") with a higher electrical potential and a low-side switching position (hereinafter: "lowside") with a lower electrical potential. The high-side and the low-side can each comprise one or more individual switches connected in parallel.

[0004] From the publication DE 11 2016 000 460 T5, a power converter for a hybrid vehicle or a pure electric vehicle is known, comprising a power semiconductor module, a capacitor, and DC busbars. The DC busbars have terminals for connection to the power semiconductor module and the capacitor, and the DC busbars have an opening portion for inserting the power semiconductor module. From the document JP 2004 055 832 A, busbars are known that are formed by laminating high-voltage busbar electrodes, low-voltage busbar electrodes, and insulating layers.

[0005] DE 10 2006 050 291 A1 discloses an electronic assembly comprising a semiconductor power switch and a semiconductor diode. A lower side of the semiconductor power switch comprises an output contact mounted on a chip field of a carrier strip. Furthermore, an upper side of the semiconductor power switch comprises a control contact and an input contact. An anode contact of the semiconductor diode is arranged on the input contact of the semiconductor power switch and electrically connected thereto. A cathode contact of the diode is electrically connected to the output contact of the power semiconductor switch.

[0006] DE 10 2006 008 632 A1 discloses a power semiconductor component comprising a leadframe, at least one vertical power semiconductor component, and at least one further electronic component. The vertical power semiconductor component has a first side and a second side. At least one first contact surface and at least one control contact surface are arranged on the first side. At least one second contact surface is arranged on the second side. The at least one further electronic component is arranged on the second contact surface of the vertical power semiconductor component.

[0007] DE 10 2015 012 915 A1 discloses a semiconductor module having at least two semiconductor elements, each having at least one first electrode on a first side and at least one second electrode on a second side. The first semiconductor element is arranged above the second semiconductor element. An electrically conductive connection is arranged between the first semiconductor element and the second semiconductor element. The at least one second electrode of the first semiconductor element is mechanically and electrically connected to the electrically conductive connection. The at least one first electrode of the second semiconductor element is mechanically and electrically connected to the electrically conductive connection.

[0008] From the as yet unpublished DE 10 2019 220 010.9, a power module is known in which the signal terminals and the power terminals are all arranged on a common side of the substrate and surrounded by a potting compound. The power terminals and the signal terminals are all accessible from the common side of the substrate, such that the power terminals and the signal terminals extend through the potting compound, as viewed from the common side of the substrate, and are arranged within a base area defined by the substrate, as viewed from the direction of their passage through the potting compound.

[0009] From the as yet unpublished DE 10 2020 205 420.7, a power module is known in which the power connections and signal connections are all formed in a flat lead frame. The ends of the power connections and signal connections extend laterally from the encapsulating compound and each have a right-angled bend perpendicular to a surface along which the flat lead frame extends.

[0010] Busbars are used to connect the power connections from the outside. A positive busbar is used to contact the DC positive power connection and is connected to it. A negative busbar is used to contact the DC negative power connection and is connected to it. An AC busbar is used to contact the AC power connection and is connected to it. Due to the high voltage differences between the potentials applied to the respective power connections in high-voltage applications, which can amount to several hundred volts, the power connections and their associated busbars must be electrically insulated from one another. To achieve this, the creepage distances and clearances between the individual power connections and between the individual busbars must maintain a minimum distance.

[0011] To meet this requirement, the distance between the power terminals or between the busbars in previously known half-bridges and inverters is chosen to be relatively large. If the distance is large enough, the required clearance and creepage distances are maintained and the requirements are met. A small distance between the busbars results in a low-inductance busbar design, in which the half-bridges or inverter require more space, which runs counter to the current automotive industry's goal of making the electronic components installed in vehicles increasingly compact.

[0012] It is an object of the invention to provide a half-bridge for an electric drive of an electric or hybrid vehicle in which the above-mentioned disadvantages are at least partially overcome.

[0013] This object is achieved according to the invention by the half-bridge, the power module, and the inverter according to the independent patent claims. Advantageous embodiments and further developments of the invention are set forth in the dependent patent claims.

[0014] The invention relates to a half-bridge for an electric drive of an electric vehicle or a hybrid vehicle.

[0015] The substrate can be designed, for example, as a DBC (Direct Bonded Copper) substrate, a DPC (Direct Plated Copper) substrate, an AMB (Active Metal Brazing) substrate, or an IM (Insulated Metal) substrate. The semiconductor switching elements, in particular transistors and diodes, are arranged on the substrate, as well as the associated power connections and signal connections. The substrate is preferably rectangular, in particular as a flat, disc-like rectangle with two opposite side edges. If necessary, the substrate can also be square.

[0016] The semiconductor switching elements in the half-bridge form a high-side and a low-side. The high-side comprises one or more semiconductor switching elements connected in parallel, enabling current flow between the AC power terminal and the DC positive power terminal. The low-side comprises one or more semiconductor switching elements connected in parallel, enabling current flow between the AC power terminal and the DC negative power terminal. The high-side and low-side are connected in series.

[0017] The power terminals, in turn, are electrically connected to power contacts integrated into the semiconductor switching elements, e.g., source and drain electrodes, or to a ground, so that electrical power can be transferred from one power terminal through a semiconductor switching element to another power terminal. The power terminals ensure the electrical supply to the electric motor that drives the electric or hybrid vehicle.

[0018] The signal terminals serve to electrically switch the semiconductor switching elements and are electrically connected to the signal contacts integrated into the semiconductor switching elements. Depending on the design of the semiconductor switching elements, the semiconductor switching element can be switched to conduct or block current by applying current or voltage to the signal contact. Preferably, the semiconductor switching elements are switched in this way according to pulse width modulation (PWM) to enable a sinusoidal temporal progression of the phase currents.

[0019] The semiconductor switching elements, the power terminals, and the signal terminals of the half-bridge according to the invention are preferably arranged on a first surface of the substrate. The power terminals and the signal terminals can be easily contacted there by external components, in particular busbars. The first surface is preferably one of the two opposing, comparatively largest surfaces of the layered substrate. The first surface defines a main plane of the substrate.

[0020] The substrate is preferably encapsulated with a potting compound using an injection molding process. The power terminals and / or the signal terminals preferably have external sections that extend outward from the potting compound from a second surface orthogonal to the first surface. The second surface is a "side surface" of the encapsulated, layered substrate, which is generally significantly smaller than the first surface. Preferably, the external sections each have an end that extends perpendicular to the first surface. This enables easy electrical contacting of the power terminals or the signal terminals from outside the half-bridge.

[0021] A busbar is provided for external contacting of the DC plus power connection and the DC minus power connection, each of which is connected to the respective power connection. The busbar of the DC plus power connection and the DC minus power connection extends in a direction parallel to the main plane of the substrate between a printed circuit board and the substrate. The busbar has a top side facing the printed circuit board and a bottom side facing the substrate.

[0022] According to the invention, the busbar of the DC plus power connection and / or the DC minus power connection is at least partially covered with a current-insulating coating. The current-insulating coating can comprise a prefabricated component, for example made of plastic, which has a recess for accommodating the busbar(s). Alternatively, the current-insulating coating can be an injection-molded part that is injection-molded onto the DC plus power connection and / or the DC minus power connection.

[0023] By at least partially covering the busbar of at least one of the two DC power terminals with the current-insulating coating, the creepage distance between the busbars of the two DC power terminals is extended. This ensures reliable galvanic isolation between the busbars of the two DC power terminals. At the same time, the distance between the two busbars of the DC power terminals can be reduced, resulting in a low-inductance inverter.

[0024] The invention further relates to a power module with at least three half-bridges according to the invention, wherein each of the half-bridges is preferably assigned to one of at least three current phases of an alternating current generated by the power module based on a fed-in direct current. Furthermore, the invention relates to an inverter for an electric drive of an electric vehicle or a hybrid vehicle with such a power module. This results in the advantages already described in connection with the half-bridge according to the invention also being applicable to the power module and the inverter according to the invention.

[0025] According to one embodiment, the busbar is covered on the top and / or bottom with the current-insulating coating. The top side of the busbar faces the circuit board. The bottom side of the busbar faces the substrate or the potting compound. Covering only one side of the busbar with the current-insulating coating has the advantage of saving material. Covering the busbar with the current-insulating coating on both sides has the advantage of further extending the creepage distance between the busbars of the two DC power connections.

[0026] According to a further embodiment, the busbar covered with the current-insulating coating has two surface sections that enclose an angle with one another along the direction parallel to the main plane of the substrate. Along the direction parallel to the main plane of the substrate, the covered busbar has a first surface section. At the end of the first surface section, the first surface section transitions into a second surface section that encloses the angle with the first surface section. The angle is preferably greater than 90 degrees and less than 180 degrees. The second surface section can be implemented by a rib formed in the current-insulating coating. This measure additionally extends the creepage distance between the busbars of the two DC power connections.

[0027] According to a further embodiment, only one of the two busbars is covered with the current-insulating coating, while the other of the two busbars is coated with an insulating thin-film foil on a side facing away from the substrate. The insulating thin-film foil can, for example, be led out of a DC link capacitor. The insulating thin-film foil is a flexible foil that can be particularly easily adapted to the shape of the busbar that is not covered, in particular overmolded, with the current-insulating coating. This ensures improved galvanic isolation between the two busbars.

[0028] According to a further embodiment, the circuit board is fixed to the top side of the current-insulating coating of the DC Plus busbar and / or the current-insulating coating of the DC Plus busbar is fixed to the bottom side of the inverter housing. This ensures particularly stable fixing of the circuit board. A secure connection between the busbar and the associated DC power connection is therefore guaranteed. A screw connection and a hot-stitched plastic dome are provided for fixing. A hot-stitched plastic dome is a plastic dome that extends from the current-insulating coating through an opening in the circuit board. It is melted by hot-stitching and hardens after subsequent cooling, thus providing a secure fixation.

[0029] The invention is explained below by way of example with reference to embodiments shown in the figures.

[0030] They show: Fig. 1 is a schematic side sectional view of an inverter comprising a half-bridge according to the invention according to a conventional embodiment; Fig. 2 is a schematic perspective sectional view of the inverter from Fig. 1 ; Fig. 3 is a schematic side sectional view of an inverter comprising a half-bridge according to the invention according to an embodiment; and Fig. 4 is a schematic perspective sectional view of the inverter from Fig. 3 .

[0031] Identical objects, functional units, and comparable components are designated by the same reference symbols throughout the figures. These objects, functional units, and comparable components are identical in terms of their technical features, unless explicitly or implicitly stated otherwise in the description.

[0032] Fig. 1 and 2show a schematic diagram of an inverter 100 according to a conventional embodiment.

[0033] Fig. 1 shows schematically a side sectional view of the inverter 100. The inverter 100 comprises several half bridges 110A, 110B, 110C, which are arranged in Fig. 2are shown schematically in a perspective sectional view. Each half-bridge 110A, 110B, 110C has a plurality of semiconductor switching elements, which are not shown here. The semiconductor switching elements form a high side and a low side, each of which comprises one or more semiconductor switching elements connected in parallel. Each of the half-bridges 110A, 110B, 110C is assigned to a current phase. Each half-bridge 110A, 110B, 110C comprises a substrate (not shown) on which the semiconductor switching elements are applied. The substrate is preferably a direct-bonded copper (DBC) substrate with a first and a second metal layer and an insulating layer arranged therebetween. The semiconductor switching elements of the respective half-bridge 110A, 110B, 110C are arranged on the first metal layer. A heat sink 132 is connected to the second metal layer.

[0034] To protect the semiconductor switching elements and the substrate from external environmental influences, they are encapsulated with a potting compound (e.g. plastic). The substrate defines a main plane parallel to the metal and insulating layers, which are perpendicular to the plane of the drawing in Fig. 1A DC plus power terminal 114 and a DC minus power terminal 116, as well as several signal terminals 120, protrude laterally from the potting compound 111 and can be contacted from above. The DC power terminals 114, 116 are used to feed in an input current, which is a direct current and can be converted into a multi-phase alternating current by controlling the semiconductor switching elements. The signal terminals 120 are used to control the semiconductor switching elements in conjunction with a control circuit board 122, which has conductor tracks and electronic components for generating control signals and sending them to the gate electrodes of the semiconductor switching elements via the signal terminals.

[0035] The DC plus power terminal 114 is contacted to the outside by means of a DC plus busbar 124. At the same time, the DC minus power terminal 116 is contacted to the outside by means of a DC minus busbar 126. Both the DC plus busbar 124 and the DC minus busbar 126 are plate-shaped and extend parallel to the main plane of the substrate between the circuit board 122 and the potting compound 111. As shown in Fig. 1 and Fig. 2 As shown, the DC-plus busbar 124 is covered on its top side 125 and bottom side 123 with a current-insulating coating 112, which is preferably provided here as an overmolding using an injection molding process. Preferably, the DC-plus busbar 124 is first overmolded with the current-insulating coating and only connected to the DC-plus power terminal 114 after overmolding.

[0036] The coating or overmolding 112 has, here for example at one end, a rib 117 comprising a first surface section 113 and a second surface section 115, wherein both surface sections 113, 115 enclose an angle. The rib 117 serves to extend the clearance and creepage distances. In this embodiment, the DC negative busbar 126 is not covered with a current-insulating coating, but is mounted beneath the overmolded DC positive busbar 124. Material recesses are provided in the DC negative busbar 126, for example, as screw points for the overmolded DC positive busbar 124.

[0037] Covering with a current-insulating coating or overmolding 112 increases the creepage distance between the two DC busbars 124, 126 and increases the reliability of the inverter 100 with regard to galvanic isolation between the positive DC potential and the negative DC potential, which is important in high-voltage applications. In this way, a minimum clearance and creepage distance can be maintained.

[0038] To fix the coating or overmolding 112 on the top side of the circuit board 122, a first screw connection is provided, in which a screw 1121 is guided through a hole 1222 in the circuit board 122 into an opening 1122 formed in the coating or overmolding 112. Alternatively, a hot-stamped plastic dome can be used, as in Fig. 3This enables a high mechanical stability of the overall structure comprising the coating or overmolding 112, the potting compound 111 and the printed circuit board 122, and ensures the connection between the power connections 114, 116 and the busbars 124, 126. In addition, the signal connections 120 pass through the coating or overmolding 112 and further above also through the printed circuit board 122, as shown in Fig. 2 shown in more detail. To fix the coating or overmolding 112 to the underside of an inverter housing 134, a second screw connection is provided, in which a screw 1123 is guided through a recess 1124 formed in the coating or overmolding 112 into an opening arranged in the inverter housing 134.

[0039] The overmolded busbar, consisting of the DC plus busbar 124 and the overmold 112, is screwed into the inverter housing 134 via the molded dome or screwing point 1124 using the screw 1123. The printed circuit board 122 is screwed through the hole (or bore) 1222 using the screw 1121 into the formed screw dome 1122 of the plastic overmold 112. By screwing 1123 of the overmolded busbar into the rigid inverter housing 134 and screwing the printed circuit board 122 into the overmolded busbar using the screw 1121, a structure with high mechanical stability / rigidity is created.

[0040] The screwing points, including screws 1121 and 1123, are preferably arranged adjacent to each other. This allows the circuit board 122 to be optimally connected to the rigid inverter housing 134 via the overmolded busbar. At the same time, vibration loads on the circuit board 122 can be reduced.

[0041] By screwing the overmolded busbar into the inverter housing 134 using screw 1123, the overmolded busbar is further mechanically stabilized and mechanical stress, such as vibration, on the connection between the positive power terminals 114 on the one hand and the DC plus busbar 124 on the other hand is reduced. The signal terminals 120 are pushed through the overmold 112 and contacted with the printed circuit board 122.

[0042] Fig. 3 and 4 show a schematic representation of an inverter 200 according to an embodiment of the invention.

[0043] Fig. 3shows a schematic side sectional view of the inverter 200. Fig. 4shows the inverter 200 in a perspective sectional view. The inverter 200 comprises a plurality of half-bridges 210, although only one half-bridge 210 is shown here. Each half-bridge 210 has a plurality of semiconductor switching elements that are not shown here. The semiconductor switching elements form a high-side and a low-side, each of which comprises one or more semiconductor switching elements connected in parallel. Each of the half-bridges 210 is assigned to a current phase. Each half-bridge 210 comprises a substrate (not shown) on which the semiconductor switching elements are applied. The substrate is preferably a direct-bonded copper (DBC) substrate with a first and a second metal layer and an insulating layer arranged therebetween. The semiconductor switching elements of the respective half-bridge 210 are arranged on the first metal layer. A heat sink 232 is connected to the second metal layer. Analogous to the inverter 100 from Fig. 1-2Here, too, the semiconductor switching elements and the substrate are encapsulated with a potting compound 211 (e.g. plastic) to protect them from external environmental influences. The substrate defines a main plane parallel to the metal and insulating layers, which are perpendicular to the plane of the drawing in Fig. 3A DC plus power terminal 214 and a DC minus power terminal 216, as well as several signal terminals 220, protrude laterally from the potting compound 211 and can be contacted from above. The DC power terminals 214, 216 are used to feed in an input current, which is a direct current and can be converted into a multi-phase alternating current by controlling the semiconductor switching elements. The signal terminals 220 are used to control the semiconductor switching elements in conjunction with a control circuit board 222, which has conductor tracks and electronic components for generating control signals and sending them to the gate electrodes of the semiconductor switching elements via the signal terminals.

[0044] The DC plus power terminal 214 is contacted to the outside by means of a DC plus busbar 224. At the same time, the DC minus power terminal 216 is contacted to the outside by means of a DC minus busbar 226. Both the DC plus busbar 224 and the DC minus busbar 226 are plate-shaped and extend parallel to the main plane of the substrate between the circuit board 222 and the potting compound 211. As shown in Fig. 3 and Fig. 4 As shown, the DC plus busbar 224 is covered on its upper side 225 with a current-insulating coating 212, which is preferably provided here as an overmolding using an injection molding process. However, the DC plus busbar 224 is not coated on its underside 223. Preferably, the DC plus busbar 224 is first overmolded with the current-insulating coating and only connected to the DC plus power terminal 214 after overmolding.

[0045] The DC plus busbar 224 has a bend. Accordingly, the coating or overmolding 212 at one end includes an angle between a first surface section 213 and a second surface section 215. In the region of the angle, the DC plus busbar 224 is only locally recessed. The DC minus busbar 226 is covered on its side facing the DC plus busbar 224 with a current-insulating thin-film foil 227 and extends through the coating or overmolding 212 of the DC plus busbar 224. The current-insulating thin-film foil 227 is locally recessed in order to arrange a screw dome (see recess 2124) for screwing using a screw 2123, as shown here by way of example.

[0046] Covering with a current-insulating coating or overmolding 212 increases the creepage distance between the two DC busbars 224, 226 and increases the reliability of the inverter 200 with regard to galvanic isolation between the DC plus potential and the DC minus potential, which is important in high-voltage applications. The use of the current-insulating thin-film foil 227 ensures potential isolation. The DC plus busbar 224 is only coated or overmolding on the top side, so there is no overmolding between the two DC busbars 224 and 226. The overmolding 212 insulates the DC plus busbar 224 from the circuit board 222. The DC plus busbar 224 preferably has a copper surface on the underside. The insulation between the DC plus busbar 224 and the DC minus busbar 226 is provided by the current-insulating thin-film foil 227. In this way, a minimum clearance and creepage distance can be maintained.

[0047] To fix the coating or overmolding 212 on the top side of the circuit board 222, a hot-stamped plastic dome 2121 is provided, as shown in Fig. 3 is shown in more detail. The plastic dome 2121 passes through a hole 2222 formed in the circuit board 222. By means of a hot caulking process, the plastic dome 2121 is melted so that the plastic material completely closes the hole 2222. A base body 2122 of the plastic dome 2121 supports the circuit board 222 from below. This enables a high mechanical stability of the overall structure consisting of the coating or overmolding 212, the potting compound 211 and the circuit board 222, and ensures the connection between the power connections 214, 216 and the busbars 224, 226. In addition, the signal connections 120 pass through the coating or overmolding 112 and further above also through the circuit board 122, as shown in Fig. 4shown in more detail. For fixing the coating or overmolding 212 on the underside of an inverter housing 234, analogous to the embodiment of Fig. 1-2 a screw connection is provided in which a screw 2123 is guided through a recess 2124 formed in the coating or overmolding 212 into an opening arranged in the inverter housing 234.

[0048] The overmolded busbar, consisting of the DC plus busbar 224 and the overmold 212, is screwed into the inverter housing 234 using the screw 2123 via the molded dome (see recess 2124), which serves as a screwing point. The circuit board 222 is fixed to the overmold 212 through the hole (or bore) 2222 using the hot-stitched dome 2121. By screwing the overmolded busbar 2123 into the rigid inverter housing 234 and fixing the circuit board 222 to the overmolded DC plus busbar 224 using the hot-stitched plastic dome 2121, a structure with high mechanical stability / rigidity is provided.

[0049] The screwing point for screw 2123 and the fixing point for the plastic dome 2121 are preferably arranged adjacent to each other. This allows the circuit board 222 to be optimally connected to the rigid inverter housing 234 via the overmolded DC plus busbar 224. At the same time, the vibration loads on the circuit board 222 can be reduced.

[0050] By screwing the overmolded busbar into the inverter housing 234 using screw 2123, the overmolded busbar is further mechanically stabilized and mechanical stress, such as vibration, on the connection between the positive power terminals 214 on the one hand and the DC plus busbar 224 on the other hand is reduced. The signal terminals 220 are pushed through the overmold 212 and contacted with the printed circuit board 222. Reference symbol

[0051] 100, 200Inverter 110A-C, 210Half bridge 111, 211Potting compound 112, 212Coating / overmolding 1121Screw 2121Plastic dome 1122Opening 2122Base body 1123, 2123Screw 1124, 2124Recess 113, 213First surface section 114, 214DC plus power connection 115, 215Second surface section 116, 216DC minus power connection 117Rib 118, 218Top side 120, 220Signal connections 122, 222Printed circuit board 1222, 2222Hole 123, 223Bottom side 124, 224DC plus busbar 125, 225Top 126, 226DC minus busbar 227Thin-film foil 132, 232Heat sink 134, 234Inverter housing

Claims

1. Half-bridge (210) for an electric drive of an electric vehicle or a hybrid vehicle, the half-bridge (110A-C) comprising a substrate, semiconductor switching elements, power connections (214, 216) and signal connections (220), the power connections (214, 216) comprising a positive DC power connection (214), a negative DC power connection (216) and an AC power connection, wherein the signal connections (220) are electrically connected to the semiconductor switching elements in such a way that the semiconductor switching elements are able to be switched by means of the signal connections (220), wherein the power connections (214, 216) are electrically connected to the semiconductor switching elements in such a way that the semiconductor switching elements permit or interrupt an electrical power transmission between the power connections (214, 216), wherein a respective busbar (224, 226) is provided for the positive DC power connection (214) and for the negative DC power connection (216) for the purpose of external contact-connection, said busbar being connected to the respective power connection (214, 216), wherein the busbar (224, 226) of the positive DC power connection (214) and of the negative DC power connection (216) extends along a direction parallel to a main plane of the substrate between a printed circuit board (222) and the substrate, wherein the busbar (224, 226) has a top side (225) and a bottom side (223), wherein the busbar (224, 226) of the positive DC power connection (214) and / or of the negative DC power connection (216) is at least partially covered with a current-insulating coating (212), wherein the current-insulating coating (212) is fixed to the top side of the printed circuit board (222) and is fixed to the bottom side of an inverter housing (234) of the electric drive, wherein a screw connection is provided to fix the busbar (224, 226) of the positive DC power connection (214) and / or of the negative DC power connection (216) to the inverter housing (234), and a hot-swaged plastic dome (2121) is provided to connect the printed circuit board (222) to the busbar (224, 226) of the positive DC power connection (214) and / or of the negative DC power connection (216), wherein the hot-swaged plastic dome is a plastic dome that is designed to extend out of the current-insulating coating through an opening (2222) in the printed circuit board (222).

2. Half-bridge (210) according to Claim 1, wherein the current-insulating coating (212) is a prefabricated component, which comprises a recess for receiving the busbar (224, 226) of the positive DC power connection (214) and / or of the negative DC power connection (216).

3. Half-bridge (210) according to Claim 1, wherein the current-insulating coating (212) is an injection-moulded part, which is injected onto the busbar (224, 226) of the positive DC power connection (214) and / or of the negative DC power connection (216) by means of an injection-moulding process.

4. Half-bridge (210) according to one of the preceding claims, wherein the top side and / or the bottom side of the busbar (124, 224, 126, 226) is covered with the current-insulating coating (112, 212).

5. Half-bridge (210) according to one of the preceding claims, wherein the busbar (124, 224, 126, 226) covered with the current-insulating coating (112, 212) has two surface sections, which enclose an angle with one another, along the direction parallel to the main plane of the substrate.

6. Half-bridge (210) according to one of the preceding claims, wherein only one of the two busbars (224, 226) is covered with the current-insulating coating (212), wherein the other of the two busbars (224, 226) is coated on a side facing away from the substrate with an insulating thin-layer film (227).

7. Power module for an inverter, comprising at least three half-bridges (210) according to one of the preceding claims.

8. Inverter for an electric drive of an electric vehicle or a hybrid vehicle, comprising a power module according to Claim 7.