Power electronic devices and power electronic functional systems

Abstract

The power electronic device (1) comprises at least one power semiconductor (16) and a first circuit board (30) connected to the power semiconductor (16) in a control manner, wherein the power electronic device (1) further comprises at least one lead frame (20) forming a control connection between the power semiconductor (16) and the first circuit board (30), wherein the power semiconductor (16) is connected to at least one contact area (21) of the lead frame (20) in such a way that heat can be transferred from the power semiconductor (16) to the lead frame (20) and can be carried away from the lead frame (20) by the power semiconductor (16), wherein the power electronic device (1) further comprises a housing (40), some areas of the housing at least defining a fluid reservoir (41) in which a coolant fluid can be accommodated, the respective power semiconductor (16) and the respective lead frame (20) being arranged in the fluid reservoir (41).

Description

Technical Field

[0001] The invention relates to power electronic devices and power electronic functional systems which ensure thermally and energetically optimized cooling of power semiconductors.

[0002] Power electronic devices and power electronic functional systems can be used in the field of power electronics or in the field of assembly and connection technology. Background Art

[0003] like Figure 1 A conventional power electronic device shown by way of example in FIG. 1 generally comprises a power module 3 which is mounted on a cooling element 6 , also referred to as a cold plate, and through which flows a cooling medium 7 . Furthermore, the power module is generally connected to an intermediate circuit capacitor 5 via a busbar 4 .

[0004] The gate driver circuit and the control electronics or chip 8 are typically arranged on a control circuit board 2 comprising power electronics.

[0005] exist Figure 2 3 shows the structure of a conventional power module 3 in an enlarged view. It can be seen that the chip 8 here is connected via bonding wires 9 and solder layers 10 with an electrical DCB connection 11 made of copper-ceramic-copper layers to a substrate, also referred to as base plate 12. A thermal paste 13 promotes the transfer of heat from the base plate 12 to the cooling element 6 and thus to the cooling medium 7.

[0006] The following documents are referred to for explanation of other configurations of conventional power electronic devices and in particular of cooling aspects of conventional power electronic devices.

[0007] US 9,560,790 B2 discloses a cooling system for a motor vehicle. The cooling system includes a carburetor, a condenser arranged downstream of the carburetor, a pump arranged downstream of the condenser, and a two-phase cooling unit arranged downstream of the pump and connected in series upstream of the carburetor. The two-phase cooling unit can receive heat energy from a heat generating device to preheat a working fluid and guide the preheated working fluid to the carburetor. The heat generating device can be a power electronic device thermally coupled to the two-phase cooling unit.

[0008] US 9,363,930 B2 discloses a cooling system having a cold plate configured to be in contact with a coolant fluid and to discharge a gaseous coolant. Furthermore, the cooling system comprises a heat exchanger configured to transfer heat from the coolant vapor to the coolant fluid.

[0009] US 5,455,458 discloses a cooling device for power semiconductors arranged in a housing with a base plate on a heat extraction base. The space inside the housing is filled with a phase change material that absorbs heat at a transition temperature below the critical temperature of the power semiconductor to absorb heat during peak loads. Wires thermally couple the power semiconductor to the phase change material. Heat is extracted from both the semiconductor wafer and the phase change material via the base element.

[0010] US 2008 / 0266802 A1 discloses a technique for cooling connection points in power electronic circuits, such as connection points formed by wire bonding connections. A phase change heat sink is thermally coupled at or near the connection point, and during operation a continuous phase change occurs in the heat sink to extract heat from the connection point. The heat sink may extend over a larger area than the connection point to improve cooling and heat dissipation over a larger area. It is provided that the phase change is arranged below the chip or component to be cooled.

[0011] WO 2014 / 131589 A1 discloses a cooling device for a converter phase change memory for cooling and dissipating heat of the converter at power loss peaks. The cooling device comprises a component to be cooled with a varying power loss, wherein the component to be cooled comprises a converter module. A cooling element with cooling ribs and a phase change memory are thermally coupled to the cooling device, wherein the cooling element and the phase change memory are thermally connected to each other via at least one heat pipe.

[0012] However, there are thermal limitations in the proposed cooling devices designed specifically for cooling power electronics, so that despite the surrounding coolant fluid the heat generated by the power semiconductors cannot be dissipated or cannot be dissipated in a sufficiently short time, especially under peak loads.

[0013] In order to overcome this disadvantage, a greatly increased heat transfer surface is usually implemented in conventional embodiments. However, this leads to a significantly increased installation space requirement, so that power electronic functional systems equipped with such cooling devices have a low power density.

[0014] Furthermore, such systems are not scalable in terms of their power. Furthermore, the systems known in the art often have unwanted so-called parasitic inductances which can influence the signals emitted by the power electronic functional units and / or lead to voltage overshoots during switching. Summary of the invention

[0015] Starting from this, the object of the present invention is to provide a power electronic device and a power electronic functional system which ensures cooling of power semiconductors in a thermally and energetically optimized manner.

[0016] This object is achieved by a power electronic device and a power electronic functional system according to the present invention.

[0017] Furthermore, according to the invention there is provided a motor vehicle which comprises at least one power electronic device according to the invention or a power electronic functional system according to the invention.

[0018] The features described below, including those in the description and drawings in the following description including additional embodiments of the invention, may be combined in any technically useful way.

[0019] The invention relates to a power electronic device comprising at least one power semiconductor and a first circuit board connected to the power semiconductor in a control manner.

[0020] Furthermore, the power electronic device comprises at least one lead frame forming a control connection between the power semiconductor and the first circuit board. According to the invention, it is provided that the power semiconductor is connected to at least one contact area of ​​the lead frame in such a way that heat can be transferred from the power semiconductor to the lead frame and can be carried away from the lead frame by the power semiconductor. In this case, the power electronic device further comprises a housing which at least defines the boundaries of some areas of a fluid reservoir in which a coolant fluid is / can be accommodated. For the purpose of transferring heat from the respective power semiconductor and / or from the respective lead frame to the coolant fluid, the respective power semiconductor and the respective lead frame are arranged in the fluid reservoir.

[0021] The power electronic device is a device for realizing a power electronic device.

[0022] The power semiconductor can also be referred to as a chip and has the function of a switching device. A control unit, which is also advantageously included in the power electronics device and can be formed by a microcontroller and a gate driver in one embodiment, is configured to feed a signal to the power semiconductor via a circuit board. The power semiconductor then performs a switching process on the component to be controlled, for example, on the electric motor or the corresponding phase of the electric motor, by transmitting an electrical signal.

[0023] In particular, the power semiconductor can be connected to the lead frame by means of sintering or welding. In this case, the power semiconductor can be connected to the lead frame via the so-called chip underside. Similarly, the connection between the lead frame and the circuit board can be achieved by sintering or welding.

[0024] The power supply can in particular be realized via a battery connected to the printed circuit board, which battery supplies current to the printed circuit board, the lead frame and the power semiconductors via an intermediate circuit capacitor.

[0025] Current provided by the battery may be routed through the circuit board and high current contacts to operate the components.

[0026] The control unit itself can be arranged outside the space bounded by the housing, in particular on a circuit board and control-connected to the circuit board.

[0027] The intermediate circuit capacitor can also be arranged on the printed circuit board.

[0028] A so-called lead frame is a solderable metal conductor support in the form of a frame or comb, which is specially designed for semiconductor chips. In addition to a contact area for contacting a power semiconductor, such a lead frame comprises a plurality of wire elements extending from the contact area, which in turn are configured for electrical contact with other electronic components, in particular with a circuit board.

[0029] In the present invention, the lead frame thus fulfills the function of being considered a "heat sink", i.e. a heat distributor. In addition, heat is also absorbed by the power semiconductor via the circuit board and transferred from the circuit board to the coolant. In addition, the lead frame serves to make electrical contact with the circuit board, in particular via its so-called "drain" connection.

[0030] The circuit board is in particular a so-called high-current PCB.

[0031] The housing and therefore also the coolant fluid contained in the reservoir surrounds the respective power semiconductor and the respective lead frame.

[0032] Thus, a fluid reservoir is designated here as a fluidly closed space for holding a coolant fluid.

[0033] Regardless of possible variations with regard to the number of power semiconductors and lead frames, these are arranged in a fluid reservoir according to the invention.

[0034] In particular, it is provided that the coolant fluid is an inert and / or electrically insulating fluid with respect to the components it wets.

[0035] A unit consisting of a printed circuit board, a lead frame and at least one power semiconductor may also be referred to as a half-bridge module.

[0036] Therefore, the power semiconductor can be optimally cooled with the power electronics according to the invention, so that it can be operated with correspondingly high electrical powers.

[0037] The structure of the power electronic device according to the present invention has low parasitic inductance. In addition, only low resistance needs to be overcome. In addition, it can be seen that there is no need to use expensive and / or heavy materials such as ceramics to construct the power electronic device according to the present invention.

[0038] In the development of a power electronic device, what is provided is: the power electronic device includes at least one additional power semiconductor and at least one additional lead frame, which forms a control connection between the additional power semiconductor and a first circuit board, wherein the additional power semiconductor is connected to at least one contact area of ​​the additional lead frame in the following manner: heat can be transferred from the additional power semiconductor to the additional lead frame and can be carried away from the additional lead frame by the additional power semiconductor, and wherein the additional power semiconductor and the additional lead frame are arranged on a side of the first circuit board opposite to the power semiconductor and the lead frame.

[0039] The invention is not limited to the fact that only one power semiconductor and lead frame are arranged on the circuit board, but according to the invention several power semiconductors and lead frames can be arranged on both sides of the circuit board.

[0040] It can also be provided here that the further power semiconductor is connected to the contact region of the further lead frame on the side facing away from the first printed circuit board.

[0041] In an embodiment with only one power semiconductor and one lead frame, the housing is sealed off from the first circuit board. Accordingly, the first circuit board is used here to define the fluid reservoir. For sealing purposes, additional seals can be arranged between the housing and the respective circuit board or circuit board side.

[0042] Vertical electrical connections, called through-holes, can be used to connect the high-current contacts to the circuit board, which vertical electrical connections themselves have a sealing effect for the high-current contacts and the circuit board, so that no additional sealing against the coolant fluid is required here.

[0043] By using the circuit board as part of the seal of the fluid reservoir, electrical contacting of the power semiconductor to the outside can be achieved via the through-holes in the circuit board and via the high-current contacts. The high-current contacts can be soldered to the circuit board at the through-hole points. Therefore, there is no need to seal the high-current contacts.

[0044] For the purpose of efficient heat dissipation, the wire elements of the corresponding lead frame can form a total heat transfer surface Ag for transferring heat to the coolant fluid, the relationship between which total heat transfer surface Ag and the connection surface Ac of the corresponding lead frame on which the corresponding lead frame is in contact with the corresponding power semiconductor produces the following ratio: Ag / Ac>1.

[0045] This means that the total heat transfer area realized by the wire elements of the respective lead frame is at least as large as the contact area. In an advantageous embodiment of the power electronics device, the total heat transfer surface is significantly larger, ie at least twice as large as the contact surface.

[0046] This area ratio ensures an optimal distribution of the heat generated by the respective power semiconductor and thus an optimal heat dissipation and cooling of the respective power semiconductor.

[0047] A so-called optimal heat spreading effect is thus achieved.

[0048] In an advantageous embodiment, it is provided that the area on the first printed circuit board which is defined by the end region of the wire element of the respective lead frame is at least twice as large as the area of ​​the respective power semiconductor facing the first printed circuit board.

[0049] In particular, the level at which the corresponding lead frame and the corresponding power semiconductor are attached may be spaced apart from the first circuit board.

[0050] This enables an optimum heat transfer from the respective lead frame to its surroundings or to the coolant fluid due to the fact that large-area wire elements of the respective lead frame can be completely contacted by the coolant fluid.

[0051] This can also be achieved in particular when the power semiconductor is fastened to the lead frame at the side facing away from the first printed circuit board.

[0052] In particular, it can be provided that a direct electrical connection is formed between the power semiconductor and the circuit board on the side of the power semiconductor opposite to the lead frame. This means that the power semiconductor is electrically coupled directly to the circuit board and indirectly to the circuit board via the lead frame.

[0053] This is achieved in particular by means of electrically conductive layers on both contact sides of the power semiconductor.

[0054] A further advantageous embodiment provides that the first circuit board is electrically coupled to the second circuit board, wherein the first circuit board with the power semiconductor and the lead frame arranged thereon is positioned in such a way that there is a spacing between the further lead frame and the second circuit board.

[0055] For the purpose of efficient heat dissipation, this serves in particular to ensure that the second leadframe is not covered but can be contacted by the coolant to the greatest possible extent.

[0056] In an embodiment with at least two power semiconductors and two lead frames, the housing is sealed from a second circuit board electrically connected to the first circuit board. The second circuit board is therefore used here to define the fluid reservoir. The electrical coupling of the second circuit board to the first circuit board is carried out in particular via an additional high-current contact.

[0057] In addition to the function of defining the fluid reservoir, the second printed circuit board also has the function of making contact with the outside, in particular with the intermediate circuit capacitor.

[0058] In addition, the power electronic device may further include a condensation unit configured to cool and thereby condense the vaporized coolant fluid and further provide the coolant fluid to cool the corresponding power semiconductor and / or the corresponding lead frame.

[0059] This ensures that the heat from the vaporization can also be dissipated.The coolant fluid is thus conducted in a thermal circuit.

[0060] For this purpose, the condensing unit may have a receiving space for receiving a cooling medium, in particular for the cooling medium to flow through, wherein the condensing unit is configured to absorb heat from the vaporized coolant fluid and transfer the heat to the cooling medium in the receiving space. This creates a closed system for high-performance two-phase cooling. Therefore, in this embodiment, the power electronic device is designed to have a heat exchanger function.

[0061] Furthermore, the condensing unit can have protrusions, in particular ribs, formed in the direction of the fluid reservoir, wherein the accommodation space for accommodating the cooling medium extends into these protrusions at least in some areas. The heat transfer surface of the condensing unit is thus significantly increased by these protrusions, which are particularly designed in the form of ribs. Due to the fact that the accommodation space extends into the protrusions, there is an optimal heat transfer from the protrusions to the cooling medium in the protrusions, so that the condensing unit can be efficiently cooled by the cooling medium, and the vaporized coolant fluid can be cooled with corresponding efficiency and thus condensation of the coolant fluid can be achieved.

[0062] Another aspect of the invention is a power electronic functional system comprising a plurality of power electronic devices according to the invention, wherein the power electronic devices are connected to lines for different voltage phases. In particular, the power electronic functional system can be designed in such a way that several power electronic devices according to the invention are mounted on a high current carrying conductive element, such as a multi-layer copper sheet, and are interconnected to form a multi-phase power electronic system.

[0063] Very low inductance, low impedance, high current connections can be made between individual power electronic devices.

[0064] In particular, the power electronic devices according to the invention can each be coupled to a phase of an AC voltage.Due to the possible configuration of the power electronic devices as modules, the power electronic functional system can be easily scaled accordingly with respect to output current and output power.

[0065] Heat can still be efficiently dissipated to the surrounding environment over large areas of high current-carrying conductive components or multi-layer copper sheets.

[0066] Furthermore, shielding can be implemented to achieve adequate electromagnetic compatibility.

[0067] The invention is supplemented by a motor vehicle, in particular a motor vehicle that can be driven at least partially by an electric motor, which comprises: at least one power electronic device according to the invention and / or at least one power electronic functional system according to the invention; and a cooling medium circuit fluidically coupled to a condensing unit of the corresponding power electronic device.

[0068] Accordingly, a cooling medium, such as a water-glycol mixture, which is used for other purposes in a motor vehicle can be supplied to the power electronics according to the invention and the power electronics can thus be integrated into the entire cooling circuit of the motor vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The invention described above will be described in detail below based on the relevant technical background with reference to the associated drawings showing preferred embodiments. The invention is not limited in any way to the purely schematic drawings, wherein it should be noted that the exemplary embodiments shown in the drawings are not limited to the dimensions shown. In the drawings:

[0070] Figure 1 : shows a power electronic device having a conventional structure,

[0071] Figure 2 : Shows the Figure 1 An enlarged view of an area of ​​electrical connection of a chip of an embodiment,

[0072] Figure 3 : A cross-sectional view shows a power electronic device according to the present invention,

[0073] Figure 4 :shows the Figure 3 The high-current contact connection region of the high-current contact of the embodiment shown,

[0074] Figure 5 : showing another embodiment of the power electronic device according to the present invention in a cross-sectional view; and

[0075] Figure 6 : shows a power electronic functional system according to the present invention having several power electronic devices according to the present invention. DETAILED DESCRIPTION

[0076] To illustrate the prior art, it has been discussed Figure 1 and Figure 2 .

[0077] Figure 3 A first embodiment of a power electronics device 1 according to the present invention is shown.

[0078] The power electronic device comprises a power semiconductor 16, which can also be referred to as a chip. The chip or power semiconductor 16 is conductively connected to a lead frame 20 via its lower side 17, which is oriented upward in the embodiment shown here. It can be seen that the contact area 21 between the power semiconductor 16 and the lead frame 20 is significantly smaller than the total area formed by the lead frame 20, so that the heat introduced into the lead frame 20 by the power semiconductor 16 can be distributed on the large surface of the lead frame through the lead frame 20. The lead frame 20 is then electrically connected to the first circuit board 30. Accordingly, heat is also transferred from the lead frame 20 to the first circuit board 30. The power semiconductor 16 and the lead frame 20 are arranged in a fluid reservoir 41 defined by a housing 40. There is a coolant fluid 42 in the fluid reservoir 41, and the coolant fluid completely surrounds the power semiconductor 16 and the lead frame 20. Accordingly, heat can be transferred from the power semiconductor 16 to the coolant fluid 42 through the large area of ​​the lead frame 20, and accordingly, the power semiconductor 16 is effectively cooled.

[0079] The first printed circuit board 30 is therefore designed to be multifunctional, since it serves for contacting the power semiconductors 16 and for electrical contact with the outside and also serves at the same time to delimit the fluid reservoir 41 in certain areas.

[0080] The power electronic device further includes a condensing unit 100, which forms a receiving space 101 in which a cooling medium 103 is arranged. For the purpose of expanding the surface of the condensing unit 100, a protrusion 102 is provided in the direction of the first circuit board 30, which is a part of the receiving space 101 and is filled with the cooling medium 103 accordingly.

[0081] If the coolant fluid 42 vaporizes due to the temperature, it reaches the condensing unit 100 in vapor form. Due to the fact that the condensing unit is kept at a low temperature by the cooling medium 103, the coolant fluid vapor 42 condenses, so that the liquefied coolant fluid 42 then drips from the protrusions 102 and is fed to the fluid reservoir 41 for the purpose of cooling the power semiconductor 16 or the lead frame 20 again. The cooling medium 103 of the condensing unit 100 can be fluidically connected to another circuit, such as a cooling system of a motor vehicle, so that the other circuit can also be cooled via a heat exchanger - not shown here - and can be fed back for the aforementioned condensation purpose.

[0082] In the embodiment shown here, the power electronics 1 further comprises a so-called DC link capacitor 104 for connecting the power electronics 1 to a DC network.

[0083] In an alternative specific embodiment, the DC link capacitor 104 may also be mounted on the housing 40 via crimping when the power electronic device 1 is installed.

[0084] For the purpose of damping voltage peaks, so-called buffer capacitors 95 are arranged in an electrically conductive manner on the first printed circuit board 30 .

[0085] There is a spacing 80 between the lead frame 20 and the first circuit board 30. In the embodiment shown here, the spacing 80 is arranged in such a way that the power semiconductor 16 is placed with its side facing away from the lead frame 20 and thus with its top side on the first circuit board 30 and in electrically conductive contact with the first circuit board. In this way, heat can be transferred directly from the power semiconductor 16 to the first circuit board 30.

[0086] A seal 70 is arranged between the housing 70 and the circuit board 30. An electrical signal is transmitted or power supply is implemented through a high current contact portion 92 coupled to the first circuit board 30.

[0087] This connection can be Figure 4 See the enlarged view in .

[0088] It can also be seen here that the respective high-current contact 92 is electrically conductively connected to the first circuit board 30 by means of so-called respective through-holes 94. The through-holes 94 also ensure a fluid seal for the coolant fluid 42 while it passes through the circuit board 30.

[0089] Figure 5 A further embodiment of a power electronics device 1 according to the invention is shown.

[0090] This implementation method and Figure 3 The essential difference of the embodiment shown is that the further power semiconductor 50 and the further lead frame 60 are arranged on the side of the first circuit board 30 opposite the power semiconductor 16 and the lead frame 20. Like the power semiconductor 16 and the lead frame 20, and therefore likewise the further power semiconductor 50 and the further lead frame 60 are completely surrounded by the coolant fluid 42. This is ensured by the spacing 91 between the first circuit board 30 and the second circuit board 90, which together with the housing 40 delimits the fluid reservoir 41.

[0091] The connection between the first circuit board 30 and the second circuit board 90 is realized here via an additional high-current contact 93. Figure 3 In the first embodiment shown, the power electronics 1 are electrically connected via high-current contacts 92 , whereas in the embodiment shown here, these high-current contacts are connected to the second circuit board 90 .

[0092] therefore, Figure 5 The embodiment shown has the advantage that both power semiconductors 16 , 50 can be cooled simultaneously in a very space-saving manner by condensation of the coolant fluid 42 on a common condensation unit 100 .

[0093] Figure 6 A power electronic functional system according to the invention is shown, which comprises several power electronic devices 1 according to the invention. The power electronic devices 1 are connected via high current contacts 92 to current-carrying wires 200, which in particular can be copper sheets via which heat can also be dissipated. For example, one phase of a three-phase motor is connected to the output of the power electronic functional unit, here with an AC connection. The power electronic functional unit is thus connected to a three-phase motor of a common type in electric drive systems.

[0094] The power electronic device and the power electronic functional system enable the power semiconductor to be cooled in a thermally and energetically optimized manner, so that the power semiconductor can be designed for high performance.

[0095] Description of Reference Numerals

[0096] 1 Power Electronics

[0097] 2 Control circuit board

[0098] 3 Power Module

[0099] 4 Busbars

[0100] 5 Intermediate circuit capacitor

[0101] 6 Cooling element

[0102] 7 Cooling medium

[0103] 8 Chips

[0104] 9 Bonding wire

[0105] 10 Solder layer

[0106] 11 DCB

[0107] 12 Base plate

[0108] 13 Thermal paste

[0109] 16 Power Semiconductors

[0110] 17 Chip bottom

[0111] 20 Lead frame

[0112] 21 Contact area

[0113] 30 First Circuit Board

[0114] 40 Shell

[0115] 41 Fluid reservoir

[0116] 42 Coolant

[0117] 50 Other power semiconductors

[0118] 60 Additional lead frame

[0119] 70 Seals

[0120] 80 Interval

[0121] 90 Second circuit board

[0122] 91 The interval between the first circuit board and the second circuit board

[0123] 92 High current contact

[0124] 93 Additional high current contacts

[0125] 94 Through Holes

[0126] 95 Snubber capacitor

[0127] 100 Condensing unit

[0128] 101 Accommodation Space

[0129] 102 Protrusion

[0130] 103 Cooling medium

[0131] 104 DC link capacitor

[0132] 200 current-carrying wires / layer

[0133] 201 AC phase output.

Claims

1. A power electronic device (1), comprising at least one power semiconductor (16) and a first circuit board (30) connected to the power semiconductor (16) in a control manner, the power electronic device (1) further comprising at least one lead frame (20) forming a control connection between the power semiconductor (16) and the first circuit board (30), It is characterized in that The power semiconductor (16) is connected to at least one contact area (21) of the lead frame (20) in such a way that heat can be transferred from the power semiconductor (16) to the lead frame (20) and can be conducted away from the lead frame (20) from the power semiconductor (16), wherein the power electronic device (1) further comprises a housing (40), which at least in some areas delimits a fluid reservoir (41), in which a coolant fluid (42) can be accommodated, wherein the respective power semiconductor (16) and the respective lead frame (20) are arranged in the fluid reservoir (41) for the purpose of transferring heat from the respective power semiconductor (16) and / or from the respective lead frame (20) to the coolant fluid (42).

2. The power electronic device according to claim 1, It is characterized in that The power electronic device (1) comprises a further power semiconductor (50) and at least one further lead frame (60), the at least one further lead frame forming a control connection between the further power semiconductor (50) and the first circuit board (30), wherein the further power semiconductor (50) is connected to at least one contact area of ​​the further lead frame (60) in such a way that heat can be transferred from the further power semiconductor (50) to the further lead frame (60) and can be conducted away from the further lead frame (60) to the further power semiconductor (50), and wherein the further power semiconductor (50) and the further lead frame (60) are arranged on a side of the first circuit board (30) opposite to the power semiconductor (16) and the lead frame (20).

3. A power electronic device according to claim 1 or 2, It is characterized in that The wire elements of the respective lead frame (20, 60) form a total heat transfer surface Ag for transferring heat to the coolant fluid (42), the relationship between the total heat transfer surface Ag and the connection surface Ac of the respective lead frame (20, 60) on which the respective lead frame (20, 60) is in contact with the respective power semiconductor (16, 50) resulting in the following ratio: Ag / Ac>1.

4. The power electronic device according to claim 1 or 2, It is characterized in that A plane where the corresponding lead frame (20, 60) and the corresponding power semiconductor (16, 50) are attached has a spacing (80) from the first circuit board (30).

5. The power electronic device according to claim 2, It is characterized in that The first circuit board (30) is electrically coupled to a second circuit board (90), wherein the first circuit board (30) on which the power semiconductor (16, 50) and the lead frame (20, 60) are arranged is positioned in such a way that the further lead frame (60) is spaced apart from the second circuit board (90).

6. A power electronic device according to claim 1 or 2, It is characterized in that The power electronic device (1) further comprises a condensation unit (100) configured to cool and thereby condense the vaporized coolant fluid (42) and to provide the coolant fluid for cooling the respective power semiconductor (16, 50) and / or the respective lead frame (20, 60).

7. The power electronic device according to claim 6, It is characterized in that The condensing unit (100) has a receiving space (101) for receiving a cooling medium (103), wherein the condensing unit (100) is configured to absorb heat from vaporized coolant fluid (42) and transfer the heat to the cooling medium (103) in the receiving space (101).

8. The power electronic device according to claim 7, It is characterized in that The condensing unit (100) has protrusions (102) formed in the direction of the fluid reservoir (41), wherein the accommodation space (101) for accommodating the cooling medium (103) extends into these protrusions (102) at least in some areas.

9. A power electronic functional system comprising a plurality of power electronic devices (1) according to any one of claims 1 to 8, in, The power electronic device (1) is connected to lines for different voltage phases.

10. A motor vehicle, the vehicle being capable of being driven at least in part by an electric motor, the motor vehicle include: A power electronic device (1) according to any one of claims 1 to 8 or a power electronic functional system according to claim 9.

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