CN218784016U - Electrical assembly and voltage converter - Google Patents

Abstract

The utility model relates to an electrical component, include: a heat sink (704), the circuit (110), comprising: -a first "main" electrical conductor (106B), -a first electrical component (112) mounted on a first surface of the first main electrical conductor (106B), -an electrical insulator (302) sealing the first main electrical conductor (106B) and the electrical component (112), the electrical insulator (302) having an upper face (304) opposite the first main electrical conductor (106B), the electrical circuit (110) being bonded to the heat sink (704) via an electrically insulating connection element (900); and a flame-retardant element (404) extending at least against 85% of a portion (604) of the upper face (304) of the electrical insulator (302), or extending a predetermined distance from at least 85% of a portion (604) of the upper face (304) of the electrical insulator (302), the portion (604) comprising one or more points of the upper face (304) of the electrical insulator (302) closest to the first electrical component (112).

Description

Electrical components and voltage converters

technical field

The utility model relates to an electrical component and a voltage converter including the electrical component.

Background technique

Known electrical assemblies include an electrical circuit placed against a heat sink, the electrical circuit including a first "main" electrical conductor, a first electrical component mounted on a first surface of the first main electrical conductor, and a seal enclosing the first main electrical conductor and an electrical insulator of an electrical component, the electrical insulator having an upper face opposite the first main electrical conductor.

However, in the event of overheating of the first electrical component, for example in the event of a short circuit in the case of a controllable switch, the heat diffuses into the electrical insulator so that its upper face risks fire, endangering surrounding elements.

The purpose of the present invention is to at least partly overcome the above-mentioned problems.

Utility model content

To this end, according to the first aspect of the present invention, there is provided an electrical assembly comprising a heat sink, a circuit and a fire protection element, the circuit comprising:

– the first "primary" electrical conductor,

- a first electrical component mounted on a first surface of a first main electrical conductor,

- an electrical insulator sealing the first main electrical conductor and the electrical component, the electrical insulator having an upper face opposite the first main electrical conductor,

The electrical circuit is joined to said heat sink by an electrically insulating connection element, and the flameproof element extends against at least 85% of a portion of the upper face of the electrical insulator, or extends a predetermined distance from at least 85% of a portion of the upper face of the electrical insulator, the The portion comprises one or more points of the upper face of the electrical insulator closest to the first electrical component.

Thus, the spread of fire is prevented or at least limited due to the fire protection element.

The electrical assembly according to the first aspect of the present invention may also have one or more features of the following specific embodiments considered individually or in any technically possible combination.

In a particular embodiment of the invention, the circuit is a power module.

In a particular embodiment of the invention, the first main electrical conductor is a bus bar.

In a particular embodiment of the invention, the first main electrical conductor is a busbar intended to be connected to a high potential of the electrical power source.

In a particular embodiment of the invention, the second main electrical conductor is a busbar intended to be connected to a phase of the rotating electric machine.

In a particular embodiment of the invention, the second main electrical conductor comprises first and second "partial" electrical conductors, said first and second partial electrical conductors being busbars.

In a particular embodiment of the invention, the third main electrical conductor is a bus bar.

In a particular embodiment of the invention, the third main electrical conductor is a busbar intended to be connected to a low potential of the electrical power source.

In a particular embodiment of the invention, the first main electrical conductor and/or the third main electrical conductor takes the shape of a horizontal planar plate, for example with a thickness of 1 mm to 2 mm.

In a particular embodiment of the invention, the first main electrical conductor and the third main electrical conductor take the shape of two coplanar plates extending side by side.

In a particular embodiment of the invention, the first main electrical conductor and/or the second partial electrical conductor and/or the third main electrical conductor takes the shape of a horizontal planar plate, for example with a thickness of 1 mm to 2 mm.

In a particular embodiment of the invention, the first main electrical conductor, the second partial electrical conductor and the third main electrical conductor take the shape of coplanar plates extending side by side.

In a particular embodiment of the invention, the second surface of the first electrical conductor opposite to the first surface on which the first electrical component is mounted has a portion uncovered by the electrical insulator, the portion uncovered by the electrical insulator via An electrically insulating connection element is attached to the heat sink.

In a particular embodiment of the invention, the electrically insulating connecting element comprises solid material particles.

In a particular embodiment of the invention, the solid material particles each have a diameter greater than a predetermined value.

In a particular embodiment of the invention, the electrically insulating connecting element comprises an electrically insulating sheet or plate interposed between the portion not covered by the electrical insulating body and the heat sink.

In a particular embodiment of the invention, the electrically insulating sheet or plate interposed between the part not covered by the electrical insulator and the heat sink is made of graphite or ceramic.

In a particular embodiment of the invention, the surface of the heat sink to which the portion not covered by the electrical insulator is attached is formed by a film of electrically insulating material.

In a particular embodiment of the invention, the surface of the heat sink to which the electric circuit is attached is formed by a film of electrically insulating material.

In a particular embodiment of the invention, the film of electrically insulating material is obtained, for example, by anodizing the surface of the heat sink to which the electric circuit is attached.

In a particular embodiment of the invention, the surface of the part not covered by the electrical insulator is formed by a film of electrically insulating material.

In a specific embodiment of the invention, the heat sink is made of aluminum or an aluminum alloy, and the electrically insulating film is formed of an oxide film.

In a particular embodiment of the invention, the electrical insulator has a lower face and/or the surface of the heat sink to which the circuit is attached comprises protrusions controlling the thickness of the electrical connection element.

In a particular embodiment of the invention, said predetermined distance is less than 1 mm, preferably less than 0.5 mm, even more preferably greater than 0.2 mm.

The distance between the fire protection element and the upper face of the electrical insulator is preferably as small as possible in order to be as close as possible to the electrical component to prevent the spread of fire. However, it is possible to insert a layer of adhesive or resin between the fire protection element and the upper face of the electrical insulator, in particular to promote a good distribution of the bearing forces between the fire protection element and the electrical insulator. The distance between the fire protection element and the upper face of the electrical insulator is less than 1 mm, preferably less than 0.5 mm, even more preferably greater than 0.2 mm, allowing the fire protection element to retain a good degree of ability to arrest or limit the spread of fire.

In a particular embodiment of the invention, the fire protection element is made of metal, such as steel.

In a particular embodiment of the invention, the fire protection element is in the form of a plate.

In a particular embodiment of the invention, the electrical insulator is epoxy. Therefore, the electrical insulator is hard enough to form a protective shell.

In a particular embodiment of the invention, the circuit further comprises a second "main" electrical conductor and at least one electrical connection for connecting the first electrical component to the second main electrical conductor, each electrical connection having a The conductive cross-section of the main electrical conductor is at least one tenth smaller than the conductive cross-section.

In a particular embodiment of the present invention, the electrical assembly further includes a magnetic ring, and the circuit further includes a second electrical component mounted on a first surface of a second main electrical conductor, the second main electrical conductor comprising First and second "sections" of electrical conductors, with a magnetic ring wound around the second section of electrical conductors.

In a particular embodiment of the invention, the electrical insulator seals the first main electrical conductor, the first electrical component and the second main electrical conductor.

In a particular embodiment of the invention, the electrical insulator seals the first main electrical conductor, the second main electrical conductor, the third main electrical conductor, the first electrical component and the second electrical component.

In a particular embodiment of the invention, the circuit also comprises at least one second electrical connection intended to connect a second electrical component to a third "main" electrical conductor, each second electrical connection having A conductive cross-section that is at least one-tenth smaller than the conductive cross-section of the second main electrical conductor.

In a particular embodiment of the invention, the second part of electrical conductors is electrically connected to the first part of electrical conductors by welding, brazing or screwing.

In a particular embodiment of the invention, the electrical assembly further comprises a plastics material overmolding surrounding the magnetic ring and the second part of the electrical conductor, and wherein the fire protection element is attached to the plastics material overmolding.

In a particular embodiment of the invention, the fire protection element has at least one tongue, each tongue being overmoulded in the plastics material overmoulding for attaching the fire protection element to the plastics material overmoulding.

In a particular embodiment of the invention, the electrical assembly further comprises a plastics material overmolding surrounding the magnetic ring and the second part of the electrical conductor, and wherein a fire protection element is inserted between the lower face of the plastics material overmolding and the electrical insulator between the upper faces.

In a particular embodiment of the invention, the plastics material overmolding surrounding the magnetic ring comprises at least one post protruding from the lower face of the overmolding, the fire protection element comprises at least one hole, the upper face of the electrical insulator comprises at least a cavity, said post for being inserted into said hole and said cavity when the second part of the electrical conductor is electrically connected to the first part of the electrical conductor, in order to retain the fire protection element on the lower face of the plastics material overmolding and between the upper faces of the electrical insulator.

In a particular embodiment of the invention, the first electrical component and/or the second electrical component is a controllable switch, such as an insulated gate field effect transistor.

In a particular embodiment of the invention, the heat sink comprises at least one cavity, the electrical circuit being located at the bottom of the cavity.

In a particular embodiment of the invention, the cavity of the heat sink is at least partially filled with an electrical insulator, gel or epoxy, so as to at least partially cover the electrical circuit.

In a particular embodiment of the invention, the cavity of the heat sink is at least partially filled with an electrical insulator, gel or epoxy, so as to completely cover the circuit.

In a particular embodiment of the invention, the insulation or gel is non-flammable or non-flammable, or comprises a flame retardant.

According to the second aspect of the present invention, there is also provided a voltage converter comprising the electrical assembly according to the first aspect of the present invention.

In a particular embodiment of the invention, the voltage converter also comprises a part, and the fire protection element has at least one flexible blade intended to be deformed by said part in order to press said circuit against on the radiator.

In a particular embodiment of the invention, the voltage converter also comprises a part, and the fire protection element has at least one flexible blade intended to be deformed by the part in order to press the circuit against the radiator bottom of the cavity.

The invention will be better understood from the following description, given by way of non-limiting example only, with reference to the accompanying drawings.

Description of drawings

Fig. 1 is the circuit diagram of realizing the electric system of the utility model.

FIG. 2 is a three-dimensional view of a power module of a voltage converter of the electrical system of FIG. 1 without overmold or fire protection elements.

Fig. 3 is a three-dimensional view of the first sub-module of the power module.

Fig. 4 is a three-dimensional view of the second sub-module of the power module.

Figure 5 is a view similar to Figure 4, without the overmold.

Figure 6 is a cross-sectional view of a portion of a power module showing the arrangement of fire protection elements.

7 is a cross-sectional view of the voltage converter showing the positioning of the power module.

FIG. 8 is a block diagram illustrating steps of a method for manufacturing a power module.

Detailed ways

An electrical system 100 implementing the present invention will now be described with reference to FIG. 1 .

For example, electrical system 100 is intended to be installed in a motor vehicle.

The electrical system 100 firstly has an electrical power source 102 designed to deliver a DC voltage U, for example between 20V and 100V, for example 48V. The electrical power source 102 has, for example, a battery.

The electrical system 100 also includes an electric machine 130 comprising a plurality of phases (not shown) intended to have respective phase voltages.

The electrical system 100 also comprises a voltage converter 104 connected between the electrical power source 102 and the electric machine 130 in order to perform a conversion between the DC voltage U and the phase voltages.

The voltage converter 104 firstly comprises a positive bus 106 and a negative bus 108 for connection to an electric power source 102 in order to receive a DC voltage U, wherein the positive bus 106 receives a high potential and the negative bus 108 receives a low potential.

The voltage converter 104 also comprises at least one power module 110 comprising one or more phase busbars 122 intended to be respectively connected to one or more phases of the electric machine 130 in order to provide their respective phase voltages.

In the depicted example, voltage converter 104 includes three power modules 110 each including a two-phase bus 122 connected to two phases of electric machine 130 .

More precisely, in the depicted example, electric machine 130 includes two three-phase systems, each including three phases. The electrical phases of these two three-phase systems are offset from each other by 120°. Preferably, the first phase buses 122 of the power modules 110 are respectively connected to three phases of the first three-phase system, and the second phase buses 122 of the power modules 110 are respectively connected to three phases of the second three-phase system.

Each power module 110 includes, for each phase bus 122 , a high-side switch 112 connected between positive bus 106 and phase bus 122 , and a low-side switch 114 connected between phase bus 122 and negative bus 108 . Thus, the switches 112, 114 are arranged to form switching arms, with the phase bus 122 forming a center tap.

Each switch 112, 114 includes first and second main terminals 116, 118 and a control terminal 120 for selectively opening and closing its two main terminals 116, 118 in accordance with a control signal applied thereto. 118 between switches 112, 114. The switches 112, 114 are preferably transistors, such as Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), the gates of which form the control terminal 120 and the drains and sources form the main terminals 116, 118, respectively.

In the depicted example, the switches 112, 114 each have the form of a plate, eg, a substantially rectangular plate, with upper and lower faces. The first main terminal 116 extends on the lower face and the second main terminal 118 extends on the upper face.

It should be appreciated that positive bus bar 106, negative bus bar 108, and phase bus bar 122 are rigid electrical conductors designed to withstand at least 1A of current. They preferably have a thickness of at least 1 mm and/or a conductive cross-section of at least 1 mm ² .

Furthermore, in the depicted example, the positive busbars 106 firstly include a positive common busbar 106A connecting the power modules 110 and a positive local busbar 106B in each power module 110 connected to the positive common busbar 106A. Similarly, the negative bus 108 includes a negative common bus 108A connecting the power modules 110 and a negative local bus 108B for each of the low side switches 114 in each power module 110 , the negative local bus 108B being connected to the negative common bus 108A. These connections are shown as diamonds in Figure 1.

Furthermore, in the depicted example, both positive common bus bar 106A and negative common bus bar 108A are formed from a single conductive member.

Furthermore, in the example described, the electric machine 130 has both an alternator function and an electric motor function. More specifically, the motor vehicle also includes a combustion engine (not shown) having an output shaft to which the electric machine 130 is connected by a belt (not shown). A combustion engine is intended to drive the wheels of a motor vehicle through its output shaft. Thus, during operation as an alternator, the electric machine delivers electrical energy to the electrical power source 102 based on the rotation of the output shaft. The voltage converter 104 then operates as a rectifier. During operation as an electric motor, the electric machine drives an output shaft (in addition to or instead of the combustion engine). The voltage converter 104 then operates as an inverter.

The electric machine 130 is located, for example, in the gearbox of the motor vehicle or indeed in the clutch or actually replaces the alternator.

In the remainder of the description, the structure and layout of the elements of the voltage converter 104 will be described in more detail with reference to the vertical direction H-B, where "H" denotes top and "B" denotes bottom.

Referring to Figures 2 to 7, one of the power modules 110 will now be described in more detail, noting that the other power modules 110 are similar.

Referring to FIG. 2 , the power module 110 includes first and second sub-modules.

The first sub-module includes a positive local bus 106B and a negative local bus 108B. For each phase bus 122 it also includes a partial bus 202 forming part of that phase bus 122 . It also includes switches 112,114.

The bus bars 106B, 202, 108B take the form of horizontal planar plates having a thickness of between 1 mm and 2 mm, eg 1.5 mm, and having a horizontal planar upper face. Furthermore, the bus bars 106B, 202 , 108B are coplanar and extend adjacent to each other, which makes it possible to limit the vertical volume of the power module 110 .

The lower face of each high-side switch 112 is pressed against the upper face of the positive local bus bar 106B and is soldered to the latter in order to mechanically attach the high-side switch 112 . Furthermore, this attachment makes it possible to electrically connect its first main terminal to the positive local bus bar 106B. Furthermore, for each high-side switch 112, the first sub-module comprises one or preferably a plurality of conductive straps 210, for example made of aluminum, extending from the upper face of the high-side switch 112 in question to a corresponding one of the partial busbars 202 , in order to connect them electrically. The conductive strip 210 preferably has a conductive cross-section that is at least one-tenth smaller than the conductive cross-section of the bus bars 106B, 202, 108B.

Similarly, the lower face of each low-side switch 114 is pressed against the upper face of the partial bus bar 202 and soldered to the latter in order to mechanically attach the low-side switch 114 . Furthermore, this attachment makes it possible to electrically connect its first main terminal to the phase busbar 122 .

Furthermore, for each low-side switch 114, the first sub-module comprises one or preferably a plurality of conductive strips 212, for example made of aluminum, extending from the upper face of the low-side switch 114 to a respective one of the negative local bus bars 108B, so that Connect them electrically. The conductive strip 212 preferably has a conductive cross-section that is at least one-tenth smaller than the conductive cross-section of the bus bars 106B, 202, 108B.

The second sub-module comprises another part of the bus bar 204 attached to the part of the bus bar 202, for example by brazing, soldering or screwing, so that the two are mechanically attached and electrically connected to each other. Thus, each phase bus 122 includes two partial buses 202 , 204 .

Apart from their ends, parts of the busbars 204 also take the form of horizontal planar plates with a thickness between 1 mm and 2 mm, for example 1.5 mm. One of the ends of the partial bus bars 204 may take the form of a bend to facilitate their attachment to the partial bus bars 202 .

Part of the bus bar 204 also includes connection terminals 206 intended to be connected to the phases of the electric machine 130 . Typically, the form of the connection terminals 206 correlates with the form of the phase terminals of the electric machine 130 .

The second sub-module includes a magnetic ring 208 surrounding each partial bus bar 204, the magnetic ring 208 being provided with an air gap in which a Hall effect sensor (not shown) is intended to be placed in order to measure the 206 phase current.

Referring to FIG. 3 , the first submodule, indicated by reference numeral 200 , also includes an epoxy overmold 302 surrounding the positive local bus bar 106B, the negative local bus bar 108B, the partial bus bar 202 , the switches 112 , 114 and the conductive strip 210 , 212 extended to protect them. Thus, the epoxy overmold 302 forms an electrical insulator covering, inter alia, the bus bars 106B, 202 , 108B and the switches 112 , 114 . The epoxy overmold 302 has an upper face 304 opposite the bus bars 106B, 202, 108B. The upper face 304 is flat and horizontal. The material used for the overmolding 302 has a bending limit of eg greater than 80 N/mm ² , preferably greater than 100 N/mm ² . For example, the material used for the overmold 302 may be an epoxy resin with the designation G720E typeH, which has a bend limit of 140 N/mm ² , or an epoxy resin with the designation XE8495, which has a bend limit of 105 N/mm ² .

Referring to FIG. 6 , the lower face of the positive partial bus bar 106B is opposite the upper face of the positive partial bus bar 106B on which the switch 112 is mounted, having a portion S1 not covered by the epoxy overmold 302 . Similarly, the lower face of the partial busbar 202 opposite the upper face of the partial busbar 202 on which the switch 114 is mounted has a portion S2 not covered by the epoxy overmold 302 .

Referring to FIG. 4 , the second sub-module indicated by reference number 201 further comprises a plastics material overmolding 402 extending around the magnetic ring 208 and part of the busbar 204 in order to keep the magnetic ring 208 mechanically attached to the part of the busbar 204 . The second submodule 201 also comprises a fire protection element 404 formed in the example described by a horizontal metal plate attached to the lower face of the overmolding 402 and protruding therefrom. The metal plate is, for example, a steel plate. The fire protection element 404 has at least one flexible blade 406 (three in the example described), preferably in one of the regions protruding from the lower face of the overmolding 402 . In the example depicted, each flexible blade 406 is rectangular, with one end connected to the remainder of the fire protection element 404 by folding upwards. Each flexible blade 406 is obtained, for example, by stamping a sheet metal forming the fire protection element 404 . The fire protection element 404 has a thickness of, for example, between 0.5 and 1 mm.

Thus, the complete power module 110 comprises a first submodule 200 as shown in FIG. 3 and a second submodule 201 as shown in FIG. 4 , which are attached to each other.

Referring to Figure 5, the fire protection element 404 also has three tongues 502 for embedding in the overmold 402 for attaching the fire protection element 404 thereto.

Referring to FIG. 6, for each switch 112, 114, the fire protection element 404 extends to at least 85% (100% in the example described) of the portion 604 of the upper face 304 of the electrical insulator 302 closest to said switch 112, 114. ) within 1 mm, preferably within 0.2 mm. More precisely, this portion 604 (indicated by a bold dashed line in FIG. 6 ) brings together at least the points of the upper face 304 of the electrical insulator 302 that are closest to said switches 112 , 114 . These points closest to the switches 112 , 114 are indicated by reference numeral 606 in FIG. 6 . In the depicted example, the points closest to the switches 112 , 114 are those points positioned in vertical alignment with the switches 112 , 114 . Thus, in the example described, the fire protection element 404 extends at least over the switch 112, 114 so as to cover it.

In general, portion 604 brings together points of upper face 304 of electrical insulator 302 that are located at a distance less than or equal to predetermined distance D from switch 112 , 114 in question. The predetermined distance D is greater than the thickness E of the overmold 302 between the switches 112, 114 and the upper surface 304 of the overmold 302, which corresponds to the thickness E of the switches 112, 114 and the overmold 302. Minimum distance between upper faces 304 . The predetermined distance D is, for example, smaller than 4 mm. In the example described, it is about 2mm.

In the event of a short circuit in the power module 110, the conductive straps 210, 212 get hotter and hotter until they break. However, since they are embedded in the hard epoxy, the pieces of conductive ribbon 210, 212 remain in contact and allow current to flow. The flowing current then heats the switches 110, 112 and the heat spreads into the overmold 302 until its upper face 304 catches fire. The points closest to each switch 110, 112 are those points where the temperature rises first due to the proximity of the switches 110, 112 and are therefore the points to be protected preferentially. Thus, the presence of the fire protection element 404 makes it possible to prevent the spread of fire, or at least to delay it.

Referring to FIG. 7 , the voltage converter 104 includes a housing 702 that defines a housing for housing a circuit board (not shown), such as a printed circuit board, for controlling the switches 112 , 114 . The voltage converter 104 also includes a heat sink 704 for dissipating heat, particularly from the switches 112 , 114 . Heat sink 704 includes, inter alia, cooling fins 706 . It also includes shafts for receiving screws (not shown) for connecting the housing 702 to the heat sink 704 . Heat sink 704 also includes three cavities 708 .

Each power module 110 is intended to be joined to the bottom of one of the cavities 708 by means of an electrically insulating connection element 900 so as to be located between the casing 702 and the heat sink 704 .

In the example described here, the electrically insulating connection element 900 is, for example, a thermal adhesive. In an alternative embodiment, the electrically insulating connecting element is thermally conductive paste. In yet another alternative embodiment, the electrically insulating connecting element is thermal grease.

In the example described here, the electrically insulating connection element 900 also comprises particles of solid material (not shown in FIG. 7 ), such as plastic. Thus, the thickness of the electrically insulating connection element 900 is determined by the diameter of the solid material particles. Thus, it can be ensured that the electrically insulating connection element 900 is thick enough to limit the risk of arcing between the exposed surfaces S1 and S2 outside the epoxy overmolding of the power semiconductor module 110 and heat sink 704, thereby limiting the chances of a fire occurring. risk, especially if the power module 110 heats up and the electrically insulating connecting element 900 becomes soft as a result.

In an alternative embodiment of the invention, the electrically insulating connection element 900 comprises an electrically insulating sheet or plate, for example made of ceramic or graphite, which is interposed between the power module 110 and the surfaces S1 and S2 of the heat sink 704 .

In another alternative embodiment of the invention, the bottom of the cavity 708 of the heat sink 704 is formed by a film of electrically insulating material, for example obtained by anodizing the surface of the bottom of the cavity 708 . Therefore, when the heat sink 704 is made of aluminum or an aluminum alloy, the electrical insulating film is formed of an oxide film.

In yet another alternative embodiment of the present invention, the lower face of the epoxy overmold 302 and/or the surface of the bottom of the cavity 708 of the heat sink 704 to which the power module 110 is attached includes a control electrical connection element 900. thick protrusions.

Thus, the use of sheets, electrically insulating plates, films of electrically insulating material or protrusions also limits the risk of arcing between the exposed surfaces S1 and S2 outside the epoxy overmolding of the power semiconductor module 110 and heat sink 704, and the resulting fires.

In the example described here, once the power module 110 has been bonded to the heat sink 704, the cavity 708 of the heat sink 704 is at least partially filled with a gel 950, such as a nonflammable or nonflammable gel or a gel containing a flame retardant. glue so as to completely cover the power module 110.

As a variant, the cavity 708 is at least partially filled with an electrical insulator or epoxy, so as to completely cover the power module 110 .

Thus, in the event of a fire in one of the power modules 110, the gel, electrical insulator or epoxy prevents the spread of the fire, or at least delays it.

When the housing 702 is attached to the heat sink 704 , the housing 702 is intended to bear on the one or more flexible blades 406 in order to deform them so as to press the power module 110 against the heat sink 704 . Preferably, the one or more flexible blades 406 are designed such that they transmit a vertical force of at least 70N to the power module 110 once deformed by the housing 702 . This pressing thus makes it possible to prevent the movement of the bus bars away from the heat sink 704 over time and wear of the electrical connection element 900 . This pressing also makes it possible to avoid the use of screws to attach the power module 110 to the heat sink 704 .

Preferably, the circuit board is housed in the housing 702 and is attached to the housing 702 before the housing 702 is attached to the heat sink 704 and bears on the one or more flexible blades 406 .

Referring to FIG. 8 , a method 800 for manufacturing a power module 110 will now be described.

In step 802 the first and second sub-module 200 , 201 without the overmolding 302 , 402 is obtained.

In step 804 , epoxy resin is injected under low pressure, which is then cross-linked to form epoxy overmold 302 . The low pressure injection makes it possible to avoid damaging the fragile conductive strips 210,212.

In step 806 the plastic material is injected under high pressure to form the plastic material overmold 402 .

In step 808, the two submodules 200, 201 are attached to each other. To this end, the fire protection element 404 is glued against the upper face 304 of the epoxy overmold 302 and the partial busbar 204 is attached to the partial busbar 202 .

The utility model is not limited to the above-mentioned embodiments. In fact, it will be apparent to those skilled in the art that modifications may be made therein.

For example, overmold 302 may be a material other than epoxy.

Conversely, when attaching the partial busbar 204 to the partial busbar 202 in step 808, the fire protection element 404 may not be attached to the lower face of the overmold 402 and not be glued to the overmolding of the epoxy 302. Instead, it is only inserted between the lower face of the overmold 402 and the upper face 304 of the overmold of epoxy 302 . In this particular embodiment, the lower face of the overmold 402 includes overmolded posts, for example two in number and in the shape of a pillar, which protrude from the lower face of the overmold 402 and which when in step The attachment of the partial bus bars 204 to the partial bus bars 202 at 808 is intended to be inserted into corresponding holes in the fire protection element and cavities in the upper face 304 of the overmolding of epoxy 302 .

Furthermore, the terms used should not be understood as being limited to the elements of the above-described embodiments, but as covering all equivalent elements that a person skilled in the art can deduce from their general knowledge.

Claims (15)

1. An electrical assembly, characterized in that, the electrical assembly comprises: radiator (704), An electrical circuit (110) comprising a first "main" electrical conductor (106B), a first electrical component (112) mounted on a first surface of said first main electrical conductor (106B), and sealing said first main electrical conductor body (106B) and an electrical insulator (302) of said electrical component (112), said electrical insulator (302) having an upper face (304) opposite said first main electrical conductor (106B), said circuit ( 110) bonded to said heat sink (704) via an electrically insulating connection element (900), and a fire protection element (404) extending against at least 85% of a portion (604) of an upper face (304) of said electrical insulator (302) or extending from a portion ( 604) extending a predetermined distance, said portion (604) comprising one or more points of said upper face (304) of said electrical insulator (302) closest to first electrical component (112). 2. The electrical assembly according to claim 1, characterized in that, the second surface of the first electrical conductor (106B) opposite to the first surface on which the first electrical component (112) is installed has an uncoated The portion (S1) covered by said electrical insulator (302), said portion (S1) not covered by said electrical insulator is attached to said heat sink (704) via said electrically insulating connection element (900). 3. The electrical assembly according to any one of the preceding claims, characterized in that said electrically insulating connection element (900) comprises an insertion between said part not covered by said electrical insulator (302) and said heat sink Particles of solid material and/or electrically insulating sheets or plates between containers (704). 4. The electrical assembly according to claim 2, characterized in that the surface of the heat sink (704) to which the portion (S1) not covered by the electrical insulator (302) is attached is formed with an electrical insulating material membrane. 5. The electrical assembly according to claim 1 or 2, characterized in that the electrical insulator (302) has a lower face, the lower face and/or the heat sink (704) to which the electrical circuit is attached The surface of the includes protrusions to control the thickness of the electrical connection element (900). 6. The electrical assembly according to claim 1 or 2, characterized in that the fireproof element (404) is made of metal and has a plate shape. 7. An electrical assembly according to claim 1 or 2, characterized in that said circuit further comprises a second "main" electrical conductor (122) and means for connecting said first electrical component (112) to said At least one electrical connection (210) of the second main electrical conductor (122), each electrical connection (210) having a conductive cross section at least one tenth smaller than the conductive cross section of said first main electrical conductor (106B). 8. The electrical assembly according to claim 7, wherein the electrical assembly further comprises a magnetic ring (208), and wherein the circuit further comprises a first magnetic ring mounted on the second main electrical conductor (122). A second electrical component (114) on one surface, said second main electrical conductor (122) comprising a first "part" electrical conductor and a second "part" electrical conductor (202; 204), said magnetic ring (208 ) is wrapped around said second portion of electrical conductor (204). 9. The electrical assembly according to claim 8, characterized in that the electrical assembly further comprises a plastics material overmolding (402) surrounding the magnetic ring (208) and the second part electrical conductor (204) ), and wherein said fire protection element (404) is interposed between a lower face of said plastics material overmolding (402) and an upper face of said electrical insulator (302). 10. An electrical assembly according to claim 8, characterized in that the plastics material overmolding (402) surrounding the magnetic ring (208) comprises at least one post protruding from the lower face of the overmolding, the said fire protection element (404) comprises at least one hole, said electrical insulator (304) upper face comprises at least one cavity, said post is used when said second part electrical conductor (204) is electrically connected to said first part electrical conductor The body (202) is inserted into said hole and said cavity to hold said fire protection element (404) between the lower face of the plastics material overmolding and the upper face of said electrical insulator. 11. The electrical assembly of claim 8, further comprising at least one second electrical connection (212) for connecting the second electrical component (114) to The third "main" electrical conductor (108B), each second electrical connection (212) has a conductive cross-section that is at least one-tenth smaller than the conductive cross-section of the second main electrical conductor (122). 12. The electrical assembly according to claim 8, characterized in that the second portion of electrical conductors (204) is electrically connected to the first portion of electrical conductors (202) by welding, brazing or screwing. 13. The electrical assembly according to claim 1 or 2, wherein the heat sink (704) comprises at least one cavity (708), and the electrical circuit is located at the bottom of the cavity (708). 14. The electrical assembly of claim 13, wherein the cavity (708) is at least partially filled with an electrical insulator, gel (950) or epoxy, so as to at least partially cover the electrical circuit. 15. A voltage converter, characterized in that the voltage converter comprises an electrical assembly according to any one of the preceding claims, the voltage converter further comprising a part (702), and the fire protection element ( 404) having at least one flexible blade (406) for being deformed by said portion (702) in order to press said circuit against said heat sink (704).

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