WO2023275133A1

WO2023275133A1 - Electronic system and mobility device comprising such an electronic system

Info

Publication number: WO2023275133A1
Application number: PCT/EP2022/067872
Authority: WO
Inventors: Gregory Hodebourg
Original assignee: Valeo Systemes De Controle Moteur
Priority date: 2021-06-30
Filing date: 2022-06-29
Publication date: 2023-01-05
Also published as: FR3124918A1

Abstract

The invention relates to an electronic system (100) comprising a heat sink (206) and an electronic module (110), the electronic module (110) being assembled onto the heat sink (206), the electronic module (110) comprising: - a first electrical connection part (3041) and a second electrical connection part (3042), preferably made of metal, each having a main plate (3061, 3062), the main plates (3061, 3062) extending along a main single plane (PP) so as to be substantially coplanar, and the main plates (3061, 3062) being separated from one another along the main plane (PP) by at least one gap (310); - at least one electronic component (1121) electrically connected to an upper face (3081) of the main plate (3061) of the first electrical connection part (3041); and - an electrically insulating overmould (402), made of, inter alia, resin, securing the first electrical connection part (3041) to the second electrical connection part (3042); the electronic system (100) being characterised in that the electrically insulating overmould (402) further comprises at least one recess (800), the recess (800) separating the first main plate (3061) from the second main plate (3062) along the main plane (PP), the recess (800) being filled with a filling material (700), the filling material (700) comprising a material having a melting temperature higher than the melting temperature of the electrically insulating overmould (402).

Description

TITLE: ELECTRONIC SYSTEM AND MOBILE DEVICE COMPRISING A

SUCH ELECTRONIC SYSTEM

The present invention relates to an electronic system, a voltage converter comprising such an electronic system and a mobility device comprising such an electronic system or such a voltage converter.

An electronic system is known comprising a heat sink and an electronic module, the electronic module being assembled on the heat sink, the electronic module comprising: a first and a second electrical connection part, preferably made of metal, each having a main plate, the main plates extending along the same main plane so as to be substantially coplanar and the main plates being separated from each other along the main plane by at least one gap; at least one electronic component electrically connected to an upper face of the main plate of the first electrical connection part; and an electrically insulating overmoulding, for example in resin, holding together the first and the second electrical connection part;

[0003] However, in the event of overheating of the electronic module, the heat diffuses into the electrically insulating overmoulding so that the latter softens and no longer provides effective maintenance of the main plates of the electrical connection parts. From then on, these main plates can move in the main plane until they come into contact with each other, which causes a short circuit that can initiate a fire outbreak.

The object of the invention is to at least partially overcome the aforementioned problem.

[0005] It is therefore proposed, according to a first aspect of the invention, an electronic system comprising a heat sink and an electronic module, the electronic module being assembled on the heat sink, the electronic module comprising: a first and a second part electrical connection, preferably made of metal, each having a main plate, the main plates extending along the same main plane so as to be substantially coplanar and the main plates being separated from each other along the main plane by at least one gap; at least one electronic component electrically connected to an upper face of the main plate of the first electrical connection part; and an electrically insulating overmoulding, for example made of resin, holding together the first and the second electrical connection part, characterized in that the electrically insulating overmolding also comprises at least one recess, this recess separating one from the other according to the main plane the first and the second main plate, this recess being filled with a filler material, this filler material comprising a material having a melting temperature higher than the melting temperature of the electrically insulating overmoulding.

Thanks to the invention, the main plates of the electrical connection parts remain insulated from each other by the filling material even when the main plates move along the main plane when the electrical insulating overmoulding softens. Therefore, these main plates cannot come into contact with each other, which prevents the appearance of a short circuit that could initiate a fire outbreak.

[0007] An electronic system according to the invention may also include one or more of the following optional characteristics, taken in isolation or in any technically possible combination.

[0008] According to a first feature, the recess in the electrically insulating overmoulding is at least partially located in the gap separating the main plates from the first and from the second electrical connection part.

[0009] According to another characteristic, the electronic module is a power module.

[0010] Within the meaning of the invention, a power module is an electronic module containing semiconductor chips (for example so-called power transistors), designed to produce energy conversion circuits, such as those for example of a switching cell, an inverter or even a bridge rectifier.

[0011] According to another characteristic, the electronic component is a transistor. [0012] According to another feature, the electronic component is a transistor of the FET (Field-Effect Transistor) or IGBT (Insulated-Gate Bipolar Transistor) type.

[0013] According to another feature, the FET type transistor is a silicon MOSFET (Si-MOSFET) or silicon carbide (SiC-MOSFET) or is a gallium nitride FET transistor (GaN-FET).

[0014] According to another feature, the electronic component is a FIEMT (high-electron-mobility transistor) transistor, for example made of gallium nitride.

According to another characteristic, the electronic component is a transistor having the shape of a plate, for example substantially rectangular, having an upper face and a lower face.

According to another characteristic, the electronic component is a transistor having a lower face pressed against the upper face of the main plate of the first electrical connection part to which the electronic component is connected.

According to another characteristic, the electronic component is a transistor having an upper face electrically connected, for example by at least one ribbon or a wire, to an upper face of the second main plate.

[0018]According to another feature, the electrically insulating overmolding covers at least part of the electronic component.

[0019] According to another characteristic, the electrically insulating overmolding completely covers the electronic component.

According to another characteristic, at least one of the first and the second electrical connection part comprises at least one electrical connector projecting from its main plate.

[0021] According to another characteristic, in the gap, a lower face of the electrically insulating overmoulding is flush with a lower face of the main plate of the first electrical connection part.

[0022] According to another characteristic, in the gap, a lower face of the electrically insulating overmoulding is flush with a lower face of the main plate of the second electrical connection part. [0023]According to another characteristic, the electrically insulating overmoulding covers at least part of the upper face of the main plate of the first electrical connection part and/or at least part of the upper face of the main plate of the second electrical connection part.

[0024] According to another characteristic, the filler material comprises particles of solid material whose average size is greater than a predetermined minimum distance.

[0025] According to another feature, the particles of solid matter are glass or ceramic microbeads.

According to another characteristic, the predetermined minimum distance is between 50 pm and 250 pm, preferably between 120 pm and 180 pm.

According to another characteristic, the heat sink is fixed to said electronic module by means of an electrically insulating connecting element, said electrically insulating connecting element also forming said filling material.

According to another characteristic, the main plates are separated from each other along the main plane by a minimum distance greater than 1000 μm, preferably greater than 1200 μm.

According to another characteristic, the predetermined minimum distance is less than the minimum distance separating the main plates along the main plane.

[0030]According to another characteristic, the electrically insulating overmolding leaves exposed at least a part of a lower face of the main plate of at least one of the first and the second electrical connection part, this part left exposed being in contact heat with said heat sink.

It is also proposed, according to a second aspect of the invention, a voltage converter comprising an electronic system according to the first aspect of the invention.

It is also proposed, according to a third aspect of the invention, a mobility device comprising an electronic system according to the first aspect of the invention or a voltage converter according to the second aspect of the invention.

[0033] A mobility device is for example a land motor vehicle, an aircraft or a drone. A land motor vehicle is for example a motor vehicle, a motorcycle or a motorized bicycle.

The invention will be better understood using the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[0036] [Fig. 1] FIG. 1 schematically represents an electronic system comprising a voltage converter implementing the invention,

[0037] [Fig. 2] Figure 2 is an exploded view in three dimensions of the voltage converter of Figure 1,

[0038] [Fig.3] Figure 3 is a three-dimensional top view of a power module of the voltage converter of Figure 2, without overmolding,

[0039] [Fig.4] Figure 4 is a view similar to that of Figure 3, with overmolding,

[0040] [Fig.5] Figure 5 is a three-dimensional bottom view of a power module of the voltage converter of Figure 2, without overmolding,

[0041] [Fig.6] Figure 6 is a three-dimensional top view of a power module of the voltage converter of Figure 2 with overmolding, and

[0042] [Fig.7] Figure 7 is a schematic section along the axis AA of Figure 6 of a power module assembled with a heat sink.

[0043] With reference to FIG. 1, an electronic system 100 implementing the invention in one embodiment of the invention will now be described.

The electronic system 100 is for example intended to be installed in a motor vehicle.

The electronic system 100 firstly comprises an electrical power source 102 designed to deliver a DC voltage U, for example between 10 V and 100 V, for example 48 V or else 12 V.

The electrical power source 102 is therefore a DC voltage source. This electrical power source comprises for example a battery.

The electronic system 100 further comprises an electric machine 130 comprising several phases (not shown) intended to present respective phase voltages. The electronic system 100 further comprises a voltage converter 104 connected between the electrical power source 102 and the electrical machine 130 to perform a conversion between the DC voltage U and the phase voltages.

The voltage converter 104 firstly comprises a positive bus bar 106 and a negative bus bar 108 intended to be connected to the electrical power source 102 to receive the DC voltage U, the positive bus bar 106 receiving a high electrical potential and the negative bus bar 108 receiving a low electrical potential.

The voltage converter 104 further comprises at least one electrical module 110. This electrical module 110 is a power module. The power module 110 comprises one or more phase busbars intended to be respectively connected to one or more phases of the electric machine 130, to supply their respective phase voltages.

In the example described, the voltage converter 104 comprises three power modules 110 each comprising two phase bus bars 122i, 122 ₂ connected to two phases of the electric machine 130.

More specifically, in the example described, the electric machine 130 comprises two three-phase systems each comprising three phases, and intended to be electrically out of phase by 120° with respect to each other. Preferably, the first phase busbars 122i of the power modules 110 are respectively connected to the three phases of the first three-phase system, while the second phase busbars 122 ₂ of the power modules 110 are respectively connected to the three phases of the second system three-phase.

Each power module 110 comprises, for each phase busbar 122i, a first electrical component (here a high side switch 112i) connected between the positive busbar 106 and the phase busbar 122i and a second component (here a low side switch 114i), connected between the phase busbar 122i and the negative busbar 108. Thus, the switches 112i, 114i are arranged to form a switching arm, in which the phase 122i forms a midpoint.

Each power module 110 also includes, for each phase bus bar 122 ₂ , a third electrical component (here a switch of high side 112 ₂ ) connected between the positive bus bar 106 and the phase bus bar 122 ₂ and a fourth electrical component (here a low side switch 114 ₂ ) connected between the phase bus bar 122 ₂ and the negative bus bar 108 Thus, the switches 112 ₂ , 114 ₂ are arranged so as to form a switching arm, in which the phase bus bar 122 ₂ forms a midpoint.

Each switch 112i, 114i, 112 ₂ , 114 ₂ comprises first and second main terminals 116, 118 and a control terminal 120 intended to selectively open and close the switch 112i, 114i, 112 ₂ , 114 ₂ between its two main terminals 116, 118 depending on a control signal applied thereto. The switches 112i, 114i, 112 ₂ , 114 ₂ are preferably transistors, for example field effect transistors with a metal-oxide-semiconductor structure (from the English "Metal Oxide Semiconductor Field Effect Transistor" or MOSFET) having a gate forming the control terminal 120, and a drain and a source respectively forming the main terminals 116, 118. Alternatively, the switches 112i, 114i, 112 ₂ , 114 ₂ could be insulated-gate bipolar transistors Insulated Gate Bipolar Transistor” or IGBT). In yet another alternative, the switches 112i , 114i , 112 ₂ , 114 ₂ could be gallium nitride FET transistors (GaN-FET).

In the example described, the switches 112i, 114i, 112 ₂ , 114 ₂ each have the shape of a plate, for example substantially rectangular, having an upper face and a lower face. The first main terminal 116 extends on the lower face, while the second main terminal 118 extends on the upper face. The switches 112i, 114i, 112 ₂ , 114 ₂ are intended to be crossed, between their main terminals 116, 118, by a current greater than 1 A.

It will be appreciated that positive busbar 106, negative busbar 108 and phase busbars _122i , 1222 are rigid electrical conductors designed to carry electrical currents of at least 1 A intended to pass through the switches 112i , 114i , 112 ₂ , 114 ₂ . They preferably have a thickness of at least 1 mm.

Furthermore, in the example described, the positive busbar 106 comprises first of all a positive common busbar 106A connecting the power modules 110 and, in each power module 110, a positive local busbar 106B connected to the positive common bus bar 106A. Similarly, negative bus bar 108 has a common bus bar 108A connecting the power modules 110 and, in each power module 110, a negative local busbar 108B1, 108B2 for each low side switch _114i , 1142, the negative local busbars 108B1, 108B2 being connected to the busbar negative common 108A. The connections are represented in FIG. 1 by diamonds.

Furthermore, in the example described, the positive common busbar 106A and the negative common busbar 108A are each formed from a single conductive part.

In addition, in the example described, the electric machine 130 is a rotating electric machine having both the function of an alternator and of an electric motor. More specifically, the motor vehicle further comprises a heat engine (not shown) having an output shaft to which the electric machine 130 is connected for example by a belt (not shown). The heat engine is intended to drive the wheels of the motor vehicle via its output shaft. Thus, in operation as an alternator, the electrical machine 130 provides electrical energy in the direction of the electrical power source 102 from the rotation of the output shaft. The voltage converter 104 then functions as a rectifier. In operation as an electric motor, the electric machine drives the output shaft (in addition to or instead of the combustion engine). The voltage converter 104 then functions as an inverter.

[0061] The electric machine 130 is for example located in a gearbox or else in a clutch of the motor vehicle or else instead of the alternator.

In the following description, the structure and arrangement of the elements of the voltage converter 104 will be described in more detail, with reference to a vertical direction H-B, "H" representing the top and "B" representing the bottom. . This vertical direction H-B being denoted in the figures by the reference V.

[0063] Referring to Figure 2, the voltage converter 104 comprises a heat sink 206, also called heat sink, having heat exchange surfaces 204 on which are respectively mounted the power modules 110 (a single module of power 110 is shown in Figure 2). The heat exchange between the heat exchange surface 204 of the heat sink 206 and the power module 110 is achieved for example by means of a contact, direct or by means of a conductive paste thermally, between the heat exchange surface 204 of the heat sink 206 and the power module 110.

[0064] The voltage converter 104 also includes a support box 208 on which is fixed a secondary electronic module such as a control module 210. In the example of Figure 1, the control module 210 is a control card. Additionally and optionally, the support box 208 is mounted on the heat sink 206.

Referring to Figure 3, the power module 110 comprises several electrical connection parts 304, 304i, 304 ₂ , 304 ₃ preferably metal.

In particular, the power module 110 comprises a first electrical connection part 304i having a main plate 306i having an upper face 308i, a second electrical connection part 304 ₂ having a main plate 306 ₂ having an upper face 308 ₂ and a third electrical connection part 304 ₃ having a main plate 306 ₃ presenting an upper face 308 ₃ .

Each electrical connection part 304, 304i, 304 ₂ , 304 ₃ has a main plate 306, 306i, 306 ₂ , 306 ₃ extending along a horizontal main plane PP, the same for all the main plates 306, 306i , 306 ₂ , 306 ₃ so that the main plates 306, 306i, 306 ₂ , 306 ₃ are substantially coplanar. In particular, in the example described, the main plates 306, 306i, 306 ₂ , 306 ₃ have respective horizontal upper faces 308, 308i, 308 ₂ , 308 ₃ extending at the same level. For the sake of clarity, the upper faces 308, 308i, 308 ₂ , 308 ₃ are indicated in FIG. 3 only for the main plates 306, 306i, 306 ₂ , 306 ₃ which are the largest.

Furthermore, the main plates 306, 306i, 306 ₂ , 306 ₃ are separated from each other along the main plane PP by at least one gap 310. In the example described, each gap 310 has a width less than or equal to equal to five millimeters. This means that the two main plates delimiting the gap 310 are separated by at most five millimeters along this gap 310.

On the other hand, in the example described, each interstice 310 has a width greater than or equal to 1000 μm, preferably greater than or equal to 1200 μm. This means that the two main plates delimiting the gap 310 are separated by at least 1000 μm, preferably at least 1200 μm, along this gap 310 In general, at least one of the electrical connection parts 304 (all in the example described) also has at least one electrical connector projecting from its main plate 306, 306i, 306 ₂ , 306 ₃ . Each electrical connector is for example either in the form of a pin 312i, or in the form of a bent tongue 312 ₂ , 312 ₃ , or even in the form of a straight tongue 312 ₄ .

In the example described here, the straight tabs 312 ₄ form with their main plates 306 ₂ , 306 ₃ the phase busbars 122i, 122 ₂ , the bent tab 312 ₃ forms with its main plate 306i the local busbar positive 106B and the bent tongues 312 ₂ form with their main plates 306 the negative local busbars 108B1, 108B2.

Each electrical connector 312i, 312 ₂ , 312 ₃ has a fixed end 314 fixed to the main plate 306, 306i, a main portion 316 extending vertically in the example described and ending in a free end 318 and a elbow 320 connecting the fixed end 314 to the main portion 316. For the sake of clarity, these various elements of the electrical connectors 312i, 312 ₂ , 312 ₃ are only indicated in FIG. 3 for two electrical connectors 312i , 312 ₂ , l one in the shape of a pin, the other in the shape of a tongue.

[0073] In the case of a straight tab, the electrical connector 312 ₄ projects into the main plane PP over a great length to allow its connection, for example at least one centimeter. In addition, the electrical connector 312 ₄ has a fixed end 314 fixed to the main plate 306 ₂ , 306 ₃ , this fixed end 314 having a large width to allow the passage of current, for example of at least one centimeter.

The electrical connection parts 304 are obtained in the example described by cutting out a metal plate.

In the example described here, the metal plate is copper. Alternatively, the metal plate could be aluminum or even gold.

Furthermore, as explained previously, the power module 110 comprises the transistors 112i, 112 ₂ , 114i , 114 ₂ each electrically connected between two upper faces 308, 308i, 308 ₂ , 308 ₃ of respectively two of the main plates 306 , 306i, 306 ₂ , 306 ₃ for example to pass and interrupt on command a power current, which can for example be greater than a ampere between these two main plates 306, 306i, 306 ₂ , 306 ₃ . Each transistor

112 ₁ , 112 ₂ , 114i , 114 ₂ firstly has a lower face pressed against one of the two upper faces 308i, 308 ₂ , 308 ₃ to which this transistor is electrically connected. For example, the lower face of the transistor 112i is fixed by soldering to the upper face 308i of the main plate 306i of the first electrical connection part 304i. Each transistor 112i, 112 ₂ , 114i, 114 ₂ also has an upper face, part of which is electrically connected to the other of the two upper faces. In the example described, the upper face of transistor 112i,

112 ₂ , 114i , 114 ₂ further comprises a control part of the transistor 112i , 112 ₂ , 114i, 114 ₂ , electrically connected to an upper face of a third main plate 306, for example by a wire 328 in the example describe.

A first electrical connection element electrically connects transistor 112i to upper face 308 ₂ of main plate 306 ₂ of second electrical connection part 304 ₂ . The first electrical connection element comprises two strips 326i, one end of each metal strip 326i is welded to the upper face 308 ₂ of the main plate 306 ₂ of the second electrical connection part 304 ₂ by a welding process. The second end of each metal strip 326i is soldered directly to transistor 112i by a soldering process. The welding methods used are, for example, ultrasonic or friction welding methods.

Similarly, the lower face of the transistor 114i is fixed by soldering to the upper face 308 ₂ of the main plate 306 ₂ of the second electrical connection part 304 ₂ .

A second electrical connection element electrically connects the transistor 114i to the upper face 308 of the main plate 306 of another electrical connection part 304 (different from the electrical connection parts 304i, 304 ₂ , 304 ₃ ). The second electrical connection element comprises two ribbons 326 ₂ , one end of each metal ribbon 326 ₂ is welded to the upper face 308 of the main plate 306 of an electrical connection part 304 (different from parts 304i, 304 ₂ , 304 ₃ ) by a welding process. The second end of each metal strip 326 ₂ is soldered directly to transistor 114i by a soldering process. The welding methods used are, for example, ultrasonic or friction welding methods. Similarly, the lower face of the transistors 112 ₂ and 114 ₂ are fixed by soldering and electrically connected to the upper face 308i, 308 ₃ of an electrical connection part 304i, 304 ₃ and have their upper face electrically connected to an upper face of another main plate 306 ₃ , 306 by means of two ribbons 326.

In the example described, the ribbons 326, 326i, 326 ₂ are made of aluminum and have for example a section of 2mmx0.3mm. In a variant embodiment, the ribbons 326, 326i, 326 ₂ are made of gold.

In the example described, the wire 328 is made of aluminum and has a diameter of 0.2 mm. In an alternative embodiment, the wire 328 is made of gold.

In the example described, the pin-shaped electrical connectors 312i are used to connect the power module 110 to the control module 210, in order to make measurements of electrical quantities and to control the transistors 112i, 112 ₂ , 114 _I , 114 ₂ .

In addition, still in the example described, the electrical connectors 312 ₂ are connected to the negative common bus bar 108A and the electrical connector 312 ₃ is connected to the positive common bus bar 106A.

In addition, still in the example described, the two electrical connectors 312 ₄ in the form of a straight tab respectively form the two phase bus bars 122i, 122 ₂ of the power module 110.

[0086] Referring to Figure 4, the molding of the power module 110 is shown and bears the reference 402. The molding 402 is an electrical insulator and completely covers each transistor 112i, 112 ₂ , 114i, 114 ₂ , each ribbon 326 , 326i, 326 ₂ and each wire 328 and at least part of the upper faces 308, 308 _I , 308 ₂ , 308 ₃ of the main plates 306, 306i, 306 ₂ , 306 ₃ .

The molding 402 is for example in resin, for example still in epoxy. Preferably, the overmold 402 is integral in one piece.

[0088] Referring to Figure 5, at least one of the main plates 306, 306i, 306 ₂ , 306 ₃ has, on a lower face 502, 502i, 502 ₂ , 502 ₃ at least one cavity 504 for retaining the overmolding 402 Each retaining cavity 504 is open on the edge of the main plate 306, 306i, 306 ₂ , 306 ₃ presenting this cavity.

In other words, the retaining cavity 504 is located at the periphery of the lower face 502, 502i, 502 ₂ , 502 ₃ of the main plate 306, 306i, 306 ₂ , 306 ₃ . In Furthermore, each retaining cavity 504 defines a horizontal step offset vertically above the lower face 502, 502i, 502 ₂ , 502 ₃ of the main plate 306, 306i, 306 ₂ , 306 ₃ . Each retaining cavity 504 is produced for example by stamping.

As can be seen in FIG. 6, the molding 402 leaves the underside 502i of the main plate 306i of the first electrical connection part 304i visible. This part left visible is designed to be pressed against the heat sink 206. Thus, the heat sink 206 is in thermal contact with the lower face 502i left visible by the overmolding 402. This thermal contact is achieved, in the example described here, via an insulating and thermally conductive electrical connection element 700.

[0090] Similarly overmolding 402 leaves visible the lower faces 502, 502 ₂ , 502 ₃ of the main plate 306, 306 ₂ , 306 ₃ of each of the other electrical connection parts 304, 304 ₂ , 304 ₃ . These parts left visible are designed to be pressed against the heat sink 206. Thus, the heat sink 206 is in thermal contact with the lower faces 502, 502 ₂ , 502 ₃ left visible by the overmolding 402. This thermal contact is here achieved via the insulating and thermally conductive electrical connection element 700.

In addition, each retaining cavity 504 is filled with the overmolding 402, and the overmolding 402 has, in this retaining cavity 504, a lower face flush with the lower face 502 of the main plate 206.

[0092] Furthermore, it will be appreciated that the fixed end 314 of each electrical connector 312i, 312 ₂ , 312 ₃ , 312 ₄ has an entirely uncovered underside of molding 402. In addition, the molding 402 fills each gap 310 and has, in each interstice 310, a lower face flush with the lower faces 502, 502i, 502 ₂ , 502 ₃ of the main plates 206, 206i, 206 ₂ , 206 ₃ .

The overmolding 402 has at least one resin pad 506 projecting downwards and designed to come into direct contact with the heat sink 206 in order to define a predefined spacing between the lower faces 502, 502i, 502 ₂ , 502 ₃ of the main plates 306, 306i, 306 ₂ , 306 ₃ and the heat sink 206, and thus the thickness of the thermal conductive element filling this gap. In the example described, each resin stud 506 projects from the underside of the overmolding present in one of the interstices 310 between the main plates 306, 306i, 306 ₂ , 306 ₃ . Furthermore, the main plates 306, 306i, 306 ₂ , 306 ₃ are separated from each other along the main plane PP by at least one recess 800 made in the overmolding 402. Thus, each recess in the electrically insulating overmolding is at least partially located in the gap separating the main plates 306, 306i, 306 ₂ , 306 ₃ from the electrical connection parts 304, 304i, 304 ₂ , 304 ₃ .

In the example described, each recess 800 has a width greater than or equal to 500 μm.

The recess 800 is filled with a filling material comprising a material having a melting temperature higher than the melting temperature of the electrically insulating overmoulding 402.

In the example described here, the filler material comprises particles of solid material whose average size is greater than a predetermined minimum distance between 50 μm and 250 μm, preferably between 120 μm and 180 μm

In addition, as shown schematically in Figure 7, the filling material may be formed by the insulating and thermally conductive electrical connection element 700.

In the example described here, the particles of solid material included in the insulating and thermally conductive electrical connection element 700 are glass or ceramic microbeads.

Thus, when fixing the power module 110 on the heat exchange surface 204 of the heat sink 206, the insulating and thermally conductive electrical connection element 700 will penetrate into the recess 800 so that the microbeads will ensure a minimum clearance between the main plates to avoid any direct contact between them in the event that the overmolding 402 heats up and softens.

[0101] It will also be noted that the invention is not limited to the embodiments described above. It will indeed appear to those skilled in the art that various modifications can be made to the embodiments described above, in the light of the teaching which has just been disclosed to them.

In the detailed presentation of the invention which is made above, the terms used must not be interpreted as limiting the invention to the embodiments set out in the present description, but must be interpreted to include therein all the equivalents of which the forecast is within the reach of those skilled in the art by applying his general knowledge to the implementation of the teaching which has just been disclosed to him.

Claims

[1] Electronic system (100) comprising a heat sink (206) and an electronic module (110), said electronic module (110) being assembled on said heat sink (206), said electronic module (110) comprising: a first ( 304i) and a second electrical connection part (304 ₂ ), preferably made of metal, each having a main plate (306i, 306 ₂ ), the main plates (306i, 306 ₂ ) extending along the same main plane (PP ) so as to be substantially coplanar and the main plates (306i, 306 ₂ ) being separated from each other along the main plane (PP) by at least one gap (310); at least one electronic component (112i) electrically connected to an upper face (308i) of the main plate (306i) of the first electrical connection part (304i); and an electrically insulating overmoulding (402), for example in resin, holding together the first (304i) and the second (304 ₂ ) electrical connection part; said electronic system (100) being characterized in that the electrically insulating overmoulding (402) further comprises at least one recess (800), said recess (800) separating from one another along the main plane (PP) the first (306i) and second (306 ₂ ) main plate, said recess (800) being filled with a filler material (700), said filler material (700) comprising a material having a melting temperature higher than the temperature melting said electrically insulating overmold (402).

[2] Electronic system (100) according to the preceding claim wherein said filling material (700) comprises particles of solid material whose average size is greater than a predetermined minimum distance.

[3] Electronic system (100) according to the preceding claim wherein the particles of solid matter are glass or ceramic microbeads.

[4] Electronic system (100) according to claim 2 or 3 wherein the predetermined minimum distance is between 50 pm and 250 pm, preferably between 120 pm and 180 pm.

[5] Electronic system (100) according to one of the preceding claims wherein the heat sink (206) is fixed to said electronic module (110) by means of an electrically insulating connecting element (700), said electrically insulating connecting element insulation (700) also forming said filling material (700).

[6] Electronic system (100) according to one of the preceding claims wherein the main plates (306i, 306 ₂ ) are separated from each other along the main plane (PP) by a minimum distance greater than 1000 pm, preferably greater than 1200 pm.

[7] Electronic system (100) according to one of the preceding claims wherein the electrically insulating molding (402) leaves visible at least a portion of a lower face (502i, 502 ₂ ) of the main plate (306i, 306 ₂ ) of at least one of the first (304i) and the second (304 ₂ ) electrical connection part, this part left visible being in thermal contact with said heat sink (206).

[8] Voltage converter (104) comprising an electronic system (100) according to one of the preceding claims.

[9] Mobility device comprising a voltage converter (104) according to claim 8 or an electronic system (100) according to one of claims 1 to 7.