Half-bridge modules in power electronics traction inverters for electric or hybrid vehicles

Abstract

To provide a new half-bridge module for a power electronics traction inverter in an electric or hybrid vehicle.SOLUTION: A half-bridge module 1 includes: a substrate 3; a semiconductor switch element arranged on a first side of the substrate 3; a power terminal (plus terminal 9a, minus terminal 9b, phase terminal 9c) to which a power line that transmits traction energy can be connected; a signal terminal 10 to which a signal line can be connected to switch the semiconductor switch element; and a molding compound 12 surrounding the substrate 3 and the semiconductor switch element on the first side of the substrate 3. The power terminal and the signal terminal are all accessible from the first side of the substrate. Therefore, the power terminal and the signal terminal extend through the molding compound when viewed from the first side of the substrate, and are arranged in a base surface on which the substrate is laid when viewed in a direction in which th power terminal and the signal terminal pass through the molding compound.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a half-bridge module of a power electronic traction inverter for electric or hybrid vehicles. [Background technology]

[0002] Electric and hybrid vehicles use electric machines as drive units. To supply traction energy to the electric machines of such electric and hybrid vehicles, they further comprise an electric energy accumulator called a traction battery. The traction battery is designed as a direct current voltage battery. However, the electric machine requires an alternating current voltage. Therefore, power electronics with a traction inverter are connected between the traction battery and the electric machine of the electric or hybrid vehicle. The inverter is also known as a DC-AC converter.

[0003] Power electronic traction inverters of electric or hybrid vehicles comprise semiconductor switch elements, which are typically composed of transistors. It is known to provide the semiconductor switch elements in different integration levels: as discrete individual switches with low integration level but high scalability, as bridge modules with high integration level but low scalability, and as half-bridge modules, which rank between the individual switches and the bridge modules in terms of integration level and scalability. All previously known designs have in common that they have a relatively high inductance in the range of several tens of nH (nanohenries) due to the leakage inductance of the commutation cells. This results in high overvoltages or higher switching losses when switching the power semiconductors. Furthermore, long signal connections with high inductance lead to poor switching performance or gate control of the power semiconductors.

[0004] There is a need for a novel half-bridge module for a power electronic traction inverter of an electric or hybrid vehicle, which on the one hand is easily scalable, on the other hand requires little installation effort due to its integration, and further has low inductance in the commutation cells and signal terminals in order to keep electrical losses during switching as low as possible.

[0005] US 2018 / 0114740 A1 discloses an inverter for power electronics in electric or hybrid vehicles with low integration in the form of individual switches. Bipolar transistors, at least partially surrounded by a molding compound, are arranged on a substrate. The substrate is attached to a housing via a sintered layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 2018 / 0114740A1 Summary of the Invention [Problem to be solved by the invention]

[0007] Based on this, it is an object of the invention to provide a novel half-bridge module for a power electronic traction inverter of an electric or hybrid vehicle. [Means for solving the problem]

[0008] This problem is solved by a half-bridge module according to claim 1.

[0009] A half-bridge module according to the present invention comprises a substrate. The half-bridge module according to the present invention further comprises a semiconductor switch element disposed on a first side of the substrate. The half-bridge module according to the present invention further comprises a molding compound. The molding compound surrounds the substrate and the semiconductor switch element on the first side of the substrate.

[0010] The half-bridge module according to the present invention further comprises a power terminal to which a power line for transmitting electric traction energy can be connected, and a signal terminal to which a signal line for switching the semiconductor switch element can be connected.

[0011] All of the power and signal terminals of the half-bridge module according to the invention are accessible from the first side of the substrate, such that the power and signal terminals extend through the molding compound when viewed from the first side of the substrate and are disposed in the base plane of the substrate on which they span when viewed in the direction in which they pass through the molding compound.

[0012] The substrate can be a Direct Bonded Copper (DBC) substrate, an Active Metal Brazing (AMB) substrate, or an Insulated Metal (IM) substrate.

[0013] The half-bridge module according to the invention has, on the one hand, a certain degree of integration and, on the other hand, good scalability. It thus combines the advantages of a discrete structure based on individual switches with the advantages of a highly integrated power module. All power and signal terminals run through the molding compound and are arranged in the base plane on which the substrate rests, seen in the direction of their passage through the molding compound. This allows the power terminals to be aligned with one another in such a way that the half-bridge module ultimately has a low leakage inductance of the commutation cells, of the order of a few nanohenries, and a low leakage inductance of the signal terminals. Both of these serve the goal of switching with as few losses as possible.

[0014] A further advantage of this configuration of the power and signal terminals is that they no longer extend to the sides and are therefore no longer arranged outside the base plane on which the board rests, which results in advantages in terms of installation space.

[0015] A further advantage is that by being located on the top side, the electrical insulation distance (creepage distance) of the terminals can be increased without significantly increasing the leakage inductance of the commutation cell.

[0016] According to an advantageous development of the invention, the power terminals include a positive terminal, a negative terminal and a phase terminal. The phase terminals are arranged adjacent to a first edge of the substrate, viewed in the passing direction. The negative terminals are arranged adjacent to a second edge of the substrate, facing the first edge, viewed in the passing direction. The positive terminals are arranged between the phase terminals and the negative terminals, viewed in the passing direction, at a distance therefrom. The positive terminals are in contact with the first flat busbar. The negative terminals are in contact with the second flat busbar. The first and second busbars run one above the other. Preferably, an insulator is arranged between the first and second busbars. This development allows a further reduction of the leakage inductance of the half-bridge module. Likewise, a commutation cell with an extremely low inductance is provided. Electrical losses can be minimized.

[0017] According to an advantageous development of the invention, the first signal terminal for the first semiconductor switching element is arranged, viewed in the through direction, between the phase terminal and the positive terminal and at a distance therefrom, and the second signal terminal for the second semiconductor switching element is arranged, viewed in the through direction, between the positive terminal and the negative terminal and at a distance therefrom, whereby further installation space advantages can be realized.

[0018] All the power and signal terminals can be located at suitable positions in close proximity to the semiconductor switch elements, thus avoiding long connection paths between the power or signal terminals and the semiconductor switch elements.

[0019] According to an advantageous development of the invention, the cooling device is connected to the half-bridge module by means of a material-bonding connection, such as a sintered connection, a soldered connection or a thermally conductive adhesive connection, so that the thermal conductivity from the half-bridge module to the cooling device is as optimized as possible.

[0020] The invention further relates to a traction inverter for the power electronics of an electric or hybrid vehicle, which comprises at least two half-bridge modules according to the invention.

[0021] Advantageous developments are evident from the dependent claims and the following description.

[0022] Embodiments of the invention will now be described in detail with reference to the drawings, without being limited thereto. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 shows an exploded view of a half-bridge module according to the present invention without busbars and with an external cooling device. [Diagram 2] FIG. 2 is a top view of a half-bridge module according to the present invention without molding compound. [Diagram 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] FIG. 2 is a side view of a half bridge according to the present invention together with an external cooling device and an external circuit board. [Diagram 5] FIG. 2 is an exemplary schematic diagram of a possible embodiment of a traction inverter according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Figures 1 to 4 show different views of a half-bridge module 1 according to the invention for a power electronic traction inverter of an electric or hybrid vehicle. In Figures 1 and 4 the half-bridge module 1 is shown together with a cooling device 2. The half-bridge module 1 according to the invention can be connected to this cooling device 2.

[0025] The half-bridge module 1 comprises a substrate 3 and a semiconductor switch element 4 arranged on a first side 3a of the substrate 3. The semiconductor switch element 4 is made up of a semiconductor assembly 5 provided as a transistor.

[0026] The substrate 3 is for example a Direct Bonded Copper (DBC) substrate, which for example comprises a ceramic carrier plate 6 coated with copper layers 7, 8 on both sides.

[0027] In the region of the first side 3a of the substrate 3, the copper layer 8 is structured into a plurality of mutually separated portions 8a. The semiconductor switch elements 4 are in particular arranged on these portions 8a.

[0028] The copper layer 7 formed on the second, opposing side 3b of the substrate 3 is structured and therefore does not apply over the entire surface of the ceramic carrier 6.

[0029] In addition to the substrate 3 and the semiconductor switch element 4, the half-bridge module 1 according to the present invention includes a power terminal 9 and a signal terminal 10.

[0030] The power terminals 9 serve to connect power lines formed as bus bars 11. The power lines serve to transmit electrical traction energy. The signal terminals 10 serve to connect signal lines in order to activate the semiconductor switch elements 4 and control their switching state and switch accordingly.

[0031] In Fig. 4, a power line formed as a bus bar 11 is shown. This power line is connected to the power terminal 9. Fig. 4 further shows a circuit board 19 carrying a signal line connected to the signal terminal 10 of the half-bridge module 1. Note that in Figs. 1, 2 and 3, the power line 11 and the circuit board 19 are not shown.

[0032] The half-bridge module 1 according to the invention further comprises a molding compound 12, in particular made of plastic, which surrounds the substrate 3 and the semiconductor switch element 4 on the first side 3a of the substrate 3.

[0033] All of the power terminals 9 and signal terminals 10 are accessible at this first side 3a of the substrate 3. The power terminals 9 and signal terminals 10 extend through the molding compound 12 as viewed from the first side 3a of the substrate 3, and are located in a base plane of the substrate 3 on which the substrate 3 spans as viewed in the direction in which they pass through the molding compound 12. This base plane of the substrate 3 is particularly visible in FIG. 2 and is bounded by an edge 13 of the substrate 3.

[0034] Thus, when viewed in cross-section in FIG. 3, all of the power terminals 9 and signal terminals 10 extend upwardly without protruding laterally beyond the base surface of the substrate 3 , which is bounded by edges 13 .

[0035] As can be seen best in Figures 2 and 3, the power terminals 9 include a positive terminal 9a, a negative terminal 9b and a phase terminal 9c. In Figures 2 and 3, the positive terminal 9a of the power terminals 9 is marked with a plus sign, the negative terminal 9b is marked with a minus sign and the phase terminal 9c is marked with a P. When the power terminals 9 are viewed in a direction passing through the molding compound 12, the phase terminal 9c is arranged adjacent to a first edge 13 of the substrate 3 and the negative terminal 9b is arranged adjacent to a second edge 13 of the substrate 3 opposite the first edge 13. These two edges 13 form the short side of the substrate 3. The edge 13 extending between these edges 13 forms the long side of the substrate 3. The power terminal 9 formed as a positive terminal 9a of the half-bridge module 1 according to the invention is arranged between and at a distance from the phase terminal 9c and the negative terminal 9b when viewed in a direction passing through the molding compound 12. As can be seen in Figures 2 and 3, the distance of the positive terminal 9a to the phase terminal 9c is smaller than the distance of the positive terminal 9a to the negative terminal 9b.

[0036] As already mentioned above, the power terminals 9 are connected with power lines formed as busbars 11. According to Fig. 4, the two positive terminals 9a are in contact with a first common flat busbar 11a, the negative terminal 9b is in contact with a second common flat busbar 11b and the phase terminal 9c is in contact with a common third flat busbar 11c.

[0037] A first flat busbar 11a for the two positive terminals 9a and a second flat busbar 11b for the two negative terminals 9b extend outwardly beyond a second edge 13 of the substrate 3. The two busbars 11a, 11b for the positive terminals 9a and the negative terminals 9b run partly one above the other with an insulator 14 between them. The first flat busbar 11a and / or the second flat busbar 11b include a plastic overmolded portion.

[0038] The third flat busbar 11 c is in contact with the two phase terminals 9 c and extends outwardly beyond the first edge 13 of the substrate 3 .

[0039] The above configuration of the power terminals 9 and the signal terminals 10, in particular their arrangement in combination with the configuration and arrangement of the busbars 11, minimizes the leakage inductance. As a result, a low inductance half-bridge module can be provided, in which the inductance of the commutation cells is of the order of a few nanohenries. This reduces electrical losses to a minimum. Furthermore, advantages also arise in terms of installation space, since all the power terminals 9 and the signal terminals 10 are arranged within the base plane of the substrate 3.

[0040] As best seen in Figures 2 and 3, portions 8a of copper layer 8 formed on first side 3a of substrate 3 are electrically interconnected via contact elements formed, for example, as bond terminals 15.

[0041] 2, a so-called gate driver 16 is arranged on a circuit board 19. The gate driver 16 performs the function of operating, i.e., gate control, the semiconductor switch element 4. The gate driver 16 can operate the semiconductor switch element 4 via a signal line 10.

[0042] 2, the first signal terminal 10 for the first semiconductor switch element 4 is disposed between and at a distance from the phase terminal 9c and the positive terminal 9a when viewed in a direction through the molding compound 12. The second signal terminal 10 for the second semiconductor switch element 4 is disposed between and at a distance from the positive terminal 9a and the negative terminal 9b when viewed in a direction through the molding compound 12.

[0043] As already mentioned above, the molding compound 12 is disposed on the first side 3a of the substrate 3 and surrounds the substrate 3 along with the semiconductor switch elements 4 on the first side 3a. The power terminals 9 and the signal terminals 10 extend outwardly through the molding compound 12.

[0044] On the opposite side 3b, the molding compound 12 exposes the copper layer 7 of the substrate 3. On this second side 3b, the half-bridge module 1 is then connected via a material-bonding connection, for example a sintered layer 17, to a separate cooling device 2 shown in Figures 1 and 4. The cooling device 2 is preferably a water cooler. Figure 4 shows very diagrammatically channels 18 through which water flows in the cooling device 2.

[0045] The half-bridge module 1 includes, for example, two semiconductor switch elements 4, two positive terminals 9a, two negative terminals 9c, and two phase terminals 9c. The half-bridge module 1 includes six power terminals 9 in total. All the power terminals 9 and signal terminals 10 are arranged in the base surface of the substrate 3 when viewed in a direction passing through the molding compound 12. Therefore, it is not necessary to provide clearances between adjacent bridge modules 1 for arranging the power terminals and the signal terminals, and multiple half-bridge modules 1 can be arranged relative to each other in a space-saving manner.

[0046] The half-bridge module 1 according to the invention is characterized by a compact design and a very low inductance. It combines the advantages of discrete individual switches with those of a highly integrated bridge module. The half-bridge module 1 according to the invention is scalable, which allows low effort in implementing the half-bridge module 1 in power electronics.

[0047] FIG. 5 exemplarily and diagrammatically shows a possible embodiment of a traction inverter 20 according to the invention for the power electronics of electric or hybrid vehicles. The traction inverter 20 comprises, for example, six half-bridge modules 1 according to the invention. The phase terminal 9c is contacted to each of the two half-bridge modules 1 via a common third busbar 11c. Meanwhile, the positive terminal 9a and the negative terminal 9b are each contacted to all six half-bridge modules 1 via a common first busbar 11a or a common second busbar 11b. As can be seen, all terminals 9a, 9b, 9c are present on the first side 3a of the substrate 3. The half-bridge modules 1 are arranged on a cooling device 2 formed as a water cooler by means of a sintered layer not shown in FIG. 5. [Explanation of symbols]

[0048] 1 Half-bridge module 2 Cooling device 3. Substrate 3a 1st side 3b 2nd side 4. Semiconductor Switching Elements 5. Semiconductor Assembly 6 Carrier Plate 7 Copper Layer 8 Copper Layer 8a part 9 Power terminal 9a positive terminal 9b Negative terminal 9c phase terminal 10 Signal terminal 11 Busbar 11a 1st bus bar 11b 2nd bus bar 11c 3rd busbar 12 Molding Compound 13 Edge 14 Insulators 15 Bond connection 16 Gate Drivers 17 Sintered layer 18 Channels 19 Circuit Board 20 Traction inverter

Claims

1. A half-bridge module (1) of a power electronic traction inverter for an electric or hybrid vehicle, comprising: A substrate (3); a semiconductor switch element (4) disposed on a first side (3a) of the substrate (3); a power terminal (9) to which a power line for transmitting electrical traction energy can be connected; a signal terminal (10) to which a signal line can be connected in order to switch the semiconductor switch element (4); a molding compound (12) surrounding the substrate (3) and the semiconductor switch element (4) on the first side (3a) of the substrate (3); all of the power terminals (9) and the signal terminals (10) are accessible from the first side (3a) of the substrate (3), such that the power terminals (9) and the signal terminals (10) extend through the molding compound (12) when viewed from the first side (3a) of the substrate (3) and are disposed within a base plane on which the substrate (3) spans when viewed in a direction in which the power terminals (9) and the signal terminals (10) pass through the molding compound (12); the power terminal (9) includes a positive terminal (9a), a negative terminal (9b), and a phase terminal (9c), and a first signal terminal (10) for a first semiconductor switch element (4) is disposed between the phase terminal (9c) and the positive terminal (9a) and at a distance from the phase terminal (9c) and the positive terminal (9a) when viewed in the passing direction; a second signal terminal (10) for a second semiconductor switch element (4) is arranged, in a passing direction, between the positive terminal (9a) and the negative terminal (9b) and at a distance from the positive terminal (9a) and the negative terminal (9b).

2. 2. A half-bridge module according to claim 1, wherein the power terminals (9) include a positive terminal (9a), a negative terminal (9b) and a phase terminal (9c), the phase terminal (9c) is arranged adjacent to a first edge (13) of the substrate (3) when viewed in the passing direction, and the negative terminal (9b) is arranged adjacent to a second edge (13) of the substrate (3) opposite to the first edge when viewed in the passing direction; A half-bridge module, characterized in that the positive terminal (9a) is arranged between the phase terminal (9c) and the negative terminal (9b) and at a distance from the phase terminal (9c) and the negative terminal (9b) when viewed in the passing direction.

3. 3. The half-bridge module according to claim 2, wherein the positive terminal (9a) is in contact with a first bus bar (11a), the negative terminal (9b) is in contact with a second bus bar, and the first bus bar (11a) and the second bus bar (11b) extend one above the other.

4. 4. A half-bridge module as claimed in claim 3, characterized in that the first busbar (11a) and the second busbar (11b) are guided outwardly beyond the second edge (13) of the substrate (3).

5. 5. A half-bridge module according to claim 3 or 4, characterized in that an insulator (14) is arranged between the first busbar (11a) and the second busbar (11b).

6. 5. A half-bridge module according to claim 3 or 4, characterized in that the first busbar (11a) and / or the second busbar (11b) comprise a plastic overmoulding.

7. A half-bridge module according to any one of claims 2 to 6, The power terminals (9) include a positive terminal (9a), a negative terminal (9b), and a phase terminal (9c); The phase terminal (9c) is in contact with a third busbar (11v), the third busbar (11v) being guided outwardly beyond the first edge (13) of the substrate (3).

8. 2. The half-bridge module according to claim 1, wherein the first signal terminal (10) and the second signal terminal (10c) are in contact with a circuit board (19).

9. A half-bridge module according to any one of claims 1 to 8, a molding compound (12) surrounding the substrate (3) and the semiconductor switch element (4) on the first side (3a) of the substrate (3) at least partially exposes the substrate (3) on an opposing second side (3b) of the substrate (3), and the half-bridge module is connected to a separate cooling device (2) on the second side (3b) of the substrate (3).

10. 10. The half-bridge module of claim 9, wherein the cooling device is connected to the half-bridge module using a material bonding connection, the material bonding connection being a sintered connection, a soldered connection, or a thermally conductive adhesive connection.

11. A traction inverter (20) for the power electronics of an electric or hybrid vehicle, comprising at least three half-bridge modules according to any one of the preceding claims.

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