Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W40/00—Arrangements for thermal protection or thermal control
  • H10W40/20—Arrangements for cooling
  • H10W40/25—Arrangements for cooling characterised by their materials
  • H10W40/255—Arrangements for cooling characterised by their materials having a laminate or multilayered structure, e.g. direct bond copper [DBC] ceramic substrates
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W40/00—Arrangements for thermal protection or thermal control
  • H10W40/10—Arrangements for heating
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W70/00—Package substrates; Interposers; Redistribution layers [RDL]
  • H10W70/40—Leadframes
  • H10W70/481—Leadframes for devices being provided for in groups H10D8/00 - H10D48/00
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W90/00—Package configurations
  • H10W90/811—Multiple chips on leadframes

Definitions

• the present invention relates to a connecting element intended to bring a part to be cooled into thermal contact, for example an electrical connection part of a power module, and a heat sink as well as an electronic system comprising a module power and a heat sink in thermal contact by such a connecting element.
• the present invention also relates to a voltage converter comprising such a system and a vehicle comprising such a voltage converter.
• a power module is an electronic module, most often containing semiconductor chips (for example so-called power transistors), designed to produce energy conversion circuits, such as those of a cell for example. switching, a voltage converter, an inverter or even a rectifier bridge.
• semiconductor chips for example so-called power transistors
• Another defect of the connecting elements in the form of glue is their significant thickness which makes it possible to guarantee the dielectric requirements between the power module and the heat sink but which increases the thermal resistance of the connecting element.
• a connecting element intended to bring into thermal contact an electrical connection part of a power module and a heat sink and comprising at least two dielectric layers and a metal layer, the metal layer being disposed between said two dielectric layers, said metal layer comprising an aluminum sheet or plate.
• the two dielectric layers make it possible to ensure the electrical insulation of the power module while ensuring efficient heat transfer, while the metal layer prevents perforation of the dielectric layers.
• the existence of an aluminum metal layer allows the production of an electrical conductive plane which makes it possible to reduce the capacitive coupling which naturally exists between the metal substrate of the power module and the heat sink .
• the connecting element according to the invention may also comprise one or more of the following optional characteristics, taken individually or in any technically possible combination.
• the metal layer has a thickness of between 10 pm and 200 pm.
• the connecting element is intended to fix the power module and the heat sink.
• the connecting element is a separate part from the power module.
• the connecting element is intended to be positioned between the heat sink and the power module.
• the metal layer is an aluminum sheet or plate.
• At least one of the faces of said aluminum sheet or plate is anodized.
• the anodized face carries a deposit of aluminum oxide or aluminum nitride.
• the metal sheet or plate is made of aluminum, at least one of the faces of which bears a deposit of aluminum oxide or aluminum nitride obtained for example by anodization.
• the deposit has a thickness of between 5 pm and 50 pm.
• the metal sheet or plate is made of aluminum, the two faces of the aluminum sheet each carry a deposit of aluminum oxide or aluminum nitride obtained for example by anodization.
• At least one of the two dielectric layers (601, 603) has a thickness of between 10 pm and 200 pm and/or a dielectric rigidity of between 40 kV/mm and 100 kV /mm and/or a thermal conductivity between 1 and 20 W/m.K.
• a power module comprising o a metal electrical connection part and having a main plate extending along a main plane; o a switch mounted on an upper face of the main plate of the electrical connection part;
• the system according to the second aspect of the invention may also include one or more of the following optional characteristics, taken individually or in any technically possible combination.
• the switch has one of its terminals electrically connected to the upper face of the main plate of the electrical connection part.
• said system comprises the connecting element.
• the power module and the connecting element are two separate parts. In other words, the connecting element is not part of the power module.
• the connecting element fixes the power module to the heat sink.
• the power module is mechanically fixed to the heat sink via the connecting element.
• the connecting element is an element that does not belong to the power module and allows it to be fixed to the heat sink.
• the power module further comprises an electrical insulating overmolding, for example made of resin, covering said switch and at least part of the upper face of the main plate of the electrical connection part.
• the overmolding leaves visible at least part of the lower face of the main plate of the electrical connection part, this part left visible being fixed to the heat sink via the element of connection.
• At least part of the lower face of the main plate of the electrical connection part is exposed to the outside of the power module, this exposed part being fixed to the heat sink via of the connecting element.
• the switch is made in the form of one or more transistors connected in parallel.
• the transistor(s) are of the FET type (from the English “Field-Effect Transistor”) or of the IGBT type (from the English “Insulated-Gate Bipolar Transistor”).
• the FET type transistor(s) are MOSFETs with silicon substrate (Si-MOSFET) or silicon carbide (SiC-MOSFET) or are gallium nitride FET transistors (GaN-FET ).
• the transistor(s) are HEMT transistors (from the English “high-electron-mobility transistor”), for example made of gallium nitride.
• one of the dielectric layers is fixed by heat-pressing with the underside of the electrical connection part.
• one of the dielectric layers is fixed by thermo-pressing with the heat sink.
• one of the electrical layers is in electrical connection with the power module, for example via a capacitor.
• a voltage converter comprising a system according to the second aspect of the invention.
• a mobility device comprising a voltage converter according to the third aspect of the invention or an electrical system according to the second aspect of the invention.
• a mobility device is for example a motorized land vehicle, an aircraft or a drone.
• a motorized land vehicle is for example a motor vehicle, a motorcycle, a motorized bicycle or a motorized wheelchair.
• Figure 1 schematically represents an electrical system comprising a voltage converter implementing the invention in one embodiment of the invention
• Figure 2 is a section along the axis AA shown in Figure 3 of a power module of the voltage converter of Figure 1 assembled on a heat sink by means of a connecting element according to a first mode of carrying out the invention
• Figure 3 is a top view of a power module of the voltage converter of Figure 1, without overmolding,
• the electrical system 100 is for example intended to be installed in a mobility device such as a motor vehicle.
• the electrical system 100 firstly comprises an electrical power source 102 designed to deliver a direct voltage U, for example between 800 V and 1000 V, for example 850 V.
• the electrical power source 102 is therefore a direct voltage source.
• This electrical power source includes, for example, a battery.
• the electrical system 100 further comprises an electrical machine 130 comprising several phases (not shown) intended to present respective phase voltages.
• the electrical 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 direct 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 direct 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 a phase bus bar intended to be respectively connected to a phase of the electrical machine 130, to provide their respective phase voltages.
• the voltage converter 104 comprises three power modules 110 each comprising a phase bus bar 122 connected to a phase of the electrical machine 130.
• the electrical machine 130 comprises a three-phase system comprising three phases.
• the phase bus bars 122 of the three power modules 110 are connected to the three phases of the three-phase system.
• Each power module 110 comprises, for each phase bus bar 122, a first electrical component (here a high side switch 112) connected between the positive bus bar 106 and the phase bus bar 122 and a second electrical component (here a low side switch 114), connected between the phase bus bar 122 and the negative bus bar 108.
• the switches 112, 114 are arranged to form a switching arm, in which the phase bus bar 122 forms a midpoint.
• Each switch 112, 114 comprises first and second main terminals 116, 118 and a control terminal 120 intended to selectively open and close the switch 112, 114 between its two main terminals 116, 118 as a function of a signal command applied to it.
• the switches 112, 114 are preferably made by means of one or more transistors connected in parallel.
• the transistors are for example field effect transistors with a metal-oxide-semiconductor structure (from the English “Metal Oxide Semiconductor Field Effect Transistor” or MOSFET) with a silicon or silicon carbide substrate having a gate forming the terminal control 120, and a drain and a source respectively forming the main terminals 116, 118.
• the switches 112, 114 could be insulated gate bipolar transistors (from the English "Insulated Gate Bipolar Transistor” or IGBT) or Gallium nitride field effect transistors (Field Effect Transistors).
• the switches 112, 114 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 112, 114 are intended to be crossed, between their main terminals 116, 118, by a current greater than 1 A.
• the positive bus bar 106, the negative bus bar 108 and the phase bus bars 122 are rigid electrical conductors. They preferably have a thickness of between 0.3 mm and 1.5 mm, preferably less than 1.2 mm.
• the positive bus bar 106 firstly comprises a common positive bus bar 106A connecting the power modules 110 and, in each power module 110, a local positive bus bar 106B connected to the positive common bus bar 106A.
• negative bus bar 108 has a common bus bar negative 108A connecting the power modules 110 and, in each power module 110, a negative local bus bar 108B connected to the negative common bus bar 108A.
• the connections are represented in Figure 1 by diamonds.
• the positive common bus bar 106A and the negative common bus bar 108A are each formed from a single conductive part.
• the electric machine 130 is a rotating electric machine having the function of an electric motor intended to drive the wheels of the motor vehicle via its output axis.
• the electrical machine 130 supplies electrical energy towards the electrical power source 102 from the rotation of the output axis.
• the voltage converter 104 then functions as a rectifier.
• the electric machine drives the output shaft.
• the voltage converter 104 then functions as an inverter.
• the voltage converter 104 comprises a system 900 according to the invention.
• This system comprises a heat sink 206, also called a heat sink, having heat exchange surfaces 204 on which a power module 110 is respectively mounted.
• the heat exchange between the heat exchange surface 204 of the heat sink 206 and the power module 110 is produced using thermal contact via a connecting element 600 positioned between the heat exchange surface 204 of the heat sink 206 and the power module 110.
• the power module 110 comprises several electrical connection parts 304, 304i, 304 2 , 304 3 preferably made of metal.
• Each electrical connection part 304, 304i, 304 2 , 304 3 has a main plate 306, 306i, 306 2 , 306 3 extending along a main horizontal PP plane, 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.
• 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.
• the main plates 306, 306i, 3062, 306s are separated from each other along the main plane PP by at least one gap 310.
• At least one of the electrical connection parts 304, 304i, 304 2 , 304 3 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 straight tab 312 2 .
• the right tab 312 2 forms with the main plate 306 2 the phase bus bar 122, the main plate 306i with the pin 312i which is associated with it forms the positive local bus bar 106B and the main plate 306 3 forms with one of the folded tabs 312i associated with it (the lower one in Figure 3) the negative local bus bar 108B.
• Each pin 312i has a fixed end 314 fixed to the main plate 306, 306i 306 3 , a main portion 316 extending vertically in the example described and ending in a free end 318 and an elbow 320 connecting the fixed end 314 to the main portion 316.
• the electrical connector 312 2 projects into the main plane PP. Furthermore, the electrical connector 312 2 has a fixed end 314 attached to the main plate 306 2 .
• the electrical connection parts 304 are obtained in the example described by cutting a metal plate.
• the metal plate is made of copper.
• the metal plate could be aluminum or even gold.
• the power module 110 comprises switches 112, 114 each electrically connected between two upper faces 308i, 308 2 , 308 3 of respectively two of the main plates 306i, 306 2 , 306 3 for example to pass and interrupt on command a power current between these two main plates 306i, 306 2 , 306 3 .
• each switch 112, 114 is made by a single MOSFET transistor with a silicon carbide substrate.
• the first main terminal 116 and the second main terminal 118 correspond respectively to the drain and the source of the MOSFETs producing the switch.
• each switch 112, 114 is made by a plurality of MOSFET transistors with a carbide substrate of silicon connected in parallel, that is to say that their sources are electrically connected together as well as their drains.
• the switch 1 12 is mounted on and electrically connected to the upper face 308i of the main plate 306i of the electrical connection part 304i and a first electrical connection element electrically connects the switch 1 12 on the upper face 3082 of the main plate 3062 of the electrical connection part 304 2 .
• the first electrical connection element comprises two metal strips
• each metal strip 326i is connected directly to the upper face 3082 of the main plate 3062 of the electrical connection part 304 2 by a welding process or by a sintering process.
• the second end of each metal strip 326i is connected directly to the switch 112 by a welding process or by a sintering process.
• the welding processes used are, for example, ultrasonic or friction welding processes.
• each metal ribbon forms a bridge, one end of which rests flat on the upper face of the switch 112 and the other end of which rests flat on the upper face 3082 of the main plate 3062 of the electrical connection part 304 2 .
• the switch 114 is mounted on and electrically connected to the upper face 3082 of the main plate 3062 of the electrical connection part 304 2 and a second electrical connection element electrically connects the switch 114 to the upper face 3083 of the main plate 306s of the electrical connection part 304 3 .
• the second electrical connection element comprises two metal strips
• each metal ribbon 3262 one end of each metal ribbon 3262 is connected directly to the upper face 308s of the main plate 306s of the electrical connection part 304 3 by a welding or sintering process.
• the second end of each metal strip 3262 is connected directly to the switch 114 by a welding or sintering process.
• the welding processes used are for example ultrasonic or friction welding processes.
• each metal ribbon forms a bridge, one end of which rests flat on the upper face of the switch 114 and the other end of which rests flat on the upper face 308 3 of the main plate 306 3 of the connection part electric 304 3 .
• the ribbons 326i, 3262 are made of aluminum. In a variant embodiment, the ribbons 326i, 3262 are made of gold. Alternatively, the ribbons 326i, 3262 may be made of copper.
• wire 328 is made of aluminum. In a variant embodiment, wire 328 is made of gold. Alternatively, wire 328 may be made of copper.
• the ribbons 326i, 3262 have, seen from above, a substantially rectangular shape.
• the pin-shaped electrical connectors 312i associated with the electrical connection parts 304 serve to connect the power module 110 to a control module 210, in order to control the switches 112, 114 .
• one of the electrical connectors 312i associated with the electrical connection part 304 3 (the top one in FIG. 3) is also intended to be connected to the control module 210 to measure the electrical current flowing through it. this electrical connection part 304 3 .
• the power module 110 has an overmolding 402.
• the overmolding 402 is an electrical insulator and covers each switch 1 12, 1 14 and at least part of the upper faces 308, 308i, 3082, 308 3 of the main plates 306, 306i, 3062, 306 3 .
• the overmolding 402 also covers each wire 328 and the metal ribbons 326i, 3262.
• the overmolding 402 is for example made of resin, for example also of epoxy containing elements, preferably spherical, of silica representing for example by mass between 80 and 90% of the epoxy/silica assembly. [0091] Preferably, the overmolding 402 is integral in a single piece.
• the overmolding 402 leaves the lower face 502i of the main plate 306i of the 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 here made via a connecting element insulating and thermally conductive 600.
• the overmolding 402 leaves visible the lower faces 502, 502 2 , 502 3 of the main plates 306, 306 2 , 306 3 of each of the other electrical connection parts 304, 304 2 , 304 3 . These parts left exposed 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 produced via the insulating and thermally conductive electrical connection element 600.
• the overmolding 402 fills each gap 310 and has, in each gap 310, a lower face flush with the lower faces 502 of the main plates 206.
• the connecting element 600 is in this example a laminated film comprising two dielectric layers 601, 603 and a metal layer 602, the metal layer 602 being arranged between the two dielectric layers 601, 603.
• the so-called upper dielectric layer 601 is intended to be in contact with the power module and the so-called lower dielectric layer 603 is intended to be in contact with the heat dissipation surface of the heat sink.
• the metal layer is not in electrical contact with the power module 110.
• this metal layer is electrically connected, for example by a capacitor, to the power module 110.
• each of the two dielectric layers is produced by a sheet of resin with a thickness of between 10 pm and 200 pm.
• the resin sheet is for example made in the form of epoxy containing ceramic and/or silica beads
• Each of the dielectric layers also has a dielectric rigidity of between 40kV/mm and 100 kV/mm and a thermal conductivity of between 1 and 20 W/m.K.
• the upper layer 601 of the connecting element 600 is positioned on the lower face 502, 502i, 502 2 , 502 3 of the electrical connection parts and the lower layer 603 of the element connection 600 is positioned on the heat dissipation face 204 of the heat sink 206.
• a thermo-pressing operation of the stack thus produced is then carried out to ensure the mechanical assembly of the power module 110 with the heat sink 206 via the connecting element 600.
• the connecting element 600 is a separate part from the power module 110, this connecting element 600 being positioned between the heat sink 206 and the power module 110. so as to mechanically attach the power module 110 to the heat sink 206.
• the lower face 502i of the main plate 306i of the electrical connection part 304i is exposed to the outside of the power module 110, this exposed part being fixed to the heat sink. heat 206 via the connecting element 600.
• the two metal layers can be produced in the form of a metal plate instead of metal sheets.

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• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=84370175

Family Applications (1)

Country Status (3)

Family Cites Families (3)

• 2022
  • 2022-09-27 FR FR2209809A patent/FR3140208B1/fr active Active
• 2023
  • 2023-09-27 WO PCT/EP2023/076811 patent/WO2024068798A1/fr not_active Ceased
  • 2023-09-27 EP EP23776402.2A patent/EP4595104A1/de active Pending

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