DE102020120124A1 - Device for thermal and electromagnetic management for an electronic module - Google Patents

Abstract

The invention relates to a device for the thermal and electromagnetic management of an electronic module, which comprises an electronic module (1), a material with phase change (3) (MCP) and an enclosure (2) intended to use the material with phase change ( 3) and the electronic module (1), characterized in that: - the material with phase change (3) is a metal or a metal alloy into which the electronic module (1) is embedded, - the electronic module (1) an electronic device and a protective housing (11) defining an outer surface and designed to encapsulate the electronic device in order to avoid contact of the phase change material (3) with the electronic device, and - the device has a system for positioning (4) the An electronic module in the enclosure configured to deform the phase change material (3) for contact with the entire exterior surface s protective housing (11) of the electronic module. A particularly advantageous application of this is the field of thermal management of electronic devices that can be placed in a hazardous thermal environment, especially in vehicle applications, for all equipment that is installed under the hood of a vehicle and controlled by an electronic card included in the equipment.

Description

TECHNICAL AREA

The invention relates to the field of electronic devices. A particularly advantageous application of this is the field of thermal management of electronic devices that can be placed in a hazardous thermal environment, especially in vehicle applications for all equipment installed under the hood of a vehicle and controlled by an electronic device such as an electronic card, included in the equipment.

STATE OF THE ART

The electronic devices generate self-heating, and if they are placed in an environment that is subject to strong temperature increases, such as in the vehicle area, the risk that the temperature of the electronic device and / or those of the associated components will reach their maximum allowable temperature is conventional by 150 ° C, so very high. Systems are sought to thermally isolate the electronic device and to dissipate its own heating.

It is known to detect thermal power or temperature peaks through the fusion of a material with a phase change, as in the document US 7,069,979 B1 described to absorb. This device is used here for solenoid valves and electric motors. The phase change material is used to absorb the calories.

In addition, the electronic devices take advantage of the electromagnetic protection to ensure trouble-free operation without data theft. In addition, it is important to protect the immediate environment of an electronic device from electromagnetic emissions from the electronic device with the aim of complying with the normative restrictions and ensuring normal operation of the systems in its vicinity.

The principle of the Faraday cage is known to protect a component electromagnetically from external radiation, or to protect the environment from the radiation of the component. The known devices are enclosures whose shells are made of an electromagnetic material.

The principle of the Faraday cage is sometimes thermal insulation, as in the patent application FR2713327 A1 with regard to building panels for the production of walls described assigned.

However, there is no satisfactory solution in the field of microelectronics to provide thermal protection together with electromagnetic shielding of an electronic device.

One object of the present invention is therefore to offer a device for the thermal and electromagnetic management of an electronic module.

The other objects, features and advantages of the present invention will become apparent upon examination of the following specification and accompanying drawings. It goes without saying that other benefits can be included.

SUMMARY

To achieve this aim, the invention provides a device for thermal and electromagnetic management of an electronic module comprising an electronic module, a phase change material (MCP) and an enclosure intended to contain the phase change material and the electronic module. The device is characterized in that: the phase change material is a metal or metal alloy in which the electronics module is embedded.

Advantageously, the electronic module comprises an electronic device and advantageously its connectors and a protective housing which defines an outer surface of the electronic module and is intended to encapsulate the electronic device in order to avoid contact of the phase change material with the electronic device.

In a characterizing manner, the apparatus includes a system for positioning the electronics module in the enclosure configured to provide for phase change material contact with the entire exterior surface of the electronics module, and more particularly with the protective housing. In addition, this centering system makes it possible to ensure a minimum MCP thickness all around the electronic module, which ensures the function of the thermal shield. It advantageously limits any possibility of an additional electromagnetic leak due to its material and / or its shape.

Using an MCP in contact with the electronics module makes it possible to ensure that the temperature of the electronics module remains close to the temperature of the phase change of the MCP. In fact, the MCP absorbs the heat, regardless of whether it is the heat from the surroundings of the electronic module or the heat generated by the electronic module. In particular, when it changes phase, the MCP absorbs a large amount of heat. The MCP releases the absorbed heat again when the temperature of the environment is lower than the phase change temperature.

Choosing an MCP that is a metal or a metal alloy ensures good thermal conductivity (on the order of 30 W / m / K, while conventional organic MCPs are around 1W / m / K), which reduces thermal transfers, in particular when releasing the heat to the outside (advantageously when solidifying the MCP). This also enables the temperature of the electronic module to be more uniform, and thus the self-heating of the components it contains to be better combated, which corresponds to a function of a heat sink. In addition, the choice of such an MCP makes it possible to provide electromagnetic protection, which is referred to as a shielding of the electronic module. In addition, the metallic or made of a metal alloy MCP have a large variety of phase change temperatures, which makes it possible to adapt to different conditions of use, and thus ambient temperatures.

And finally, the electronic module must be completely surrounded by MCP to provide thermal protection and electromagnetic shielding. The positioning system ensures a correct position of the electronic module, in particular when the phase changes of the MCP, which according to the invention advantageously changes from the solid state to the liquid state and vice versa. In the liquid state, the electronic module would tend to rise under the action of gravity, or more generally, to move under the action of the forces, vibrations or accelerations imposed by external conditions of use. The positioning system ensures, in particular, thermal, and advantageously sufficient, minimal electromagnetic protection on the entire outer surface of the electronic module.

In an optional manner, the invention can further exhibit at least any of the following properties:

The MCP is advantageously an MCP with a transition from solid / liquid.

A further aspect of the present invention relates to a use of a device, as described above, for the thermal and electromagnetic management of an electronic module configured to control an actuator or a sensor of a road vehicle.

Figure list

• [1] Die 1 eine erfindungsgemäße Vorrichtung zum thermischen und elektromagnetischen Management darstellt
• [2A] Die 2A bis 2F die möglichen Schritte der Zusammensetzung zur Herstellung einer Vorrichtung gemäß 1 darstellen.
• [2B]
• [2C]
• [2D]
• [2E]
• [2F]
• [3] Die 3 eine erfindungsgemäße Vorrichtung gemäß 1 in Perspektive unter Angabe der Abmessungen darstellt.

The objects, objects, as well as the characteristics and advantages of the invention will become more apparent from the detailed description of a mode of implementation of the latter, which is illustrated by the following accompanying drawings, in which:

• [ 1 ] The 1 represents a device according to the invention for thermal and electromagnetic management
• [ 2A ] The 2A to 2F the possible steps of the composition for manufacturing a device according to 1 represent.
• [ 2 B ]
• [ 2C ]
• [ 2D ]
• [ 2E ]
• [ 2F ]
• [ 3 ] The 3 an inventive device according to 1 in perspective with indication of the dimensions.

The drawings are given by way of example and in no way limit the invention. They represent schematic schematic representations which are intended to facilitate the understanding of the invention and are not necessarily on the scale of practical applications.

DETAILED DESCRIPTION

Before beginning a detailed overview of the modes of implementation of the invention, optional properties are set out below that may be used in conjunction therewith or as alternatives.

The positioning system is advantageously metallic in order to maintain the electromagnetic protection of the device.

The protective housing is advantageously an inexpensive material that is easy to shape and withstands the temperatures of the application.

The electronics module advantageously comprises a dielectric liquid or a thermal interface material of the TIM (thermal interface material) type, which is arranged between the protective housing and the electronics module, configured to ensure heat transfer between the electronic device and the protective housing.

The positioning system is advantageously fastened to the electronics module, as a result of which the assembly process of the system is facilitated.

Advantageously, the positioning system comprises at least three tabs which are arranged to prevent contact of the electronic module with the enclosure.

Advantageously, the phase change material is a solid / liquid phase change material. The heat content of the phase change from solid / liquid is the greatest, which enables optimal management of the temperature of the electronic device and, more precisely, optimal thermal protection of the electronic module.

Advantageously, the enclosure comprises an expansion management system of the MCP upon phase change. Advantageously, the enclosure is configured to deform to absorb the change in volume of the MCP. It is therefore advantageous to select a metallic MCP that has a low expansion during the phase change.

The material with a phase change is advantageously selected in such a way as to have a fusion temperature which is between 50 ° C. and 200 ° C., preferably between 110 ° C. and 150 ° C.

The material with phase change is advantageously a binary eutectic which comprises tin and bismuth, preferably 42% tin and 58% bismuth, the fusion temperature of this binary eutectic being 138 ° C.

Advantageously, the electronics module comprises electrical connection means traversing the enclosure, the enclosure including a tight traversing passage to ensure the sealing of the enclosure with respect to the MCP. The enclosure is advantageously made from high-temperature plastic, for example from PPS or PBT. This type of plastic is good value for money. The enclosure forms an insulation, the thickness of which is a parameter that can make it possible to limit the heat flow to be stored in the MCP. The tight crossing passage can advantageously be ensured by a tight crossing, for example of the Spectite® brand.

Advantageously, the device comprises a system of retraction of the connecting means on itself, which system is arranged in the enclosure, around the connecting means between the traversing passage and to withdraw the electronics module. The retraction system of the connecting means is advantageously made of metal in order to ensure continuity of the electromagnetic shielding. Since the electrical connection wire is metallic, direct contact with the MCP is a priori undesirable and an insulating sheath may be necessary, thereby creating an inevitable opening in the electromagnetic shield. By forcing the pigtail to follow a diversion, the influence of this traversing passage is limited on the efficiency of the shielding and allows disturbances to traverse this opening with only numerous reflections, thereby reducing the disturbance.

The electronic device of the electronic module advantageously comprises an electronic card which is configured to control an EGR valve (exhaust gas recycling) for an internal combustion engine.

An electronic device is understood to mean any type of device that is produced by means of microelectronics. These devices further include purely electronic devices, micromechanical or electronic mechanical (MEMS, NEMS ...) devices, and optical or opto-electronic devices (MOEMS ...).

The device according to the invention comprises an electronic module 1 . The electronic module 1 comprises at least one electronic device, which can be an electronic card, in particular a printed circuit 10 and electronic components 5 includes. The electronic module 1 advantageously comprises a protective housing 11 It encases electronic device. The electronic device is, so to speak, from the protective housing 11 encapsulated. The protective housing defines the outer surface of the electronics module 1 which may be defined by the surface of the electronic device in their absence. According to this implementation mode, the electronics module comprises 1 a dielectric fluid or a thermal interface material of the type TIM (thermal interface material) to the thermal conduction of the heat generated by the self-heating of the electronic device to the outside of the electronic module 1 and in particular the MCP described below 3 to enable. For example, the dielectric fluid or a thermal interface material of the TIM type is selected from heat transfer oils, heat transfer greases, thermal interface materials silicone or solid space fillers.

The device according to the invention comprises an enclosure 2 , which is intended to have at least one electronic module 1 record. The description is made with reference to an electronic module 1 in an enclosure 2 , however, the invention can also include an enclosure 2 concern that several electronic modules 1 contains. The enclosure 2 defines a closed interior volume. The enclosure 2 includes a base 12 and a lid 9 to close the base 12 , like in the 2 shown. The base 12 includes a floor 13 and margins 14th . The enclosure 2 is advantageously fluid-tight (liquid and gas). The enclosure 2 is advantageously made of a material that can withstand the usage temperatures of the electronic module. Exemplary is the inclusion 2 made of a plastic material such as polyphenylene sulfide (PPS) a partially crystalline technical high-performance plastic with mechanical high temperature properties and extremely high chemical resistance, or poly (ethylene terephthalate), known under the abbreviation PBT, a partially crystalline thermoplastic from the polyester family.

Advantageously, the enclosure 2 To maintain the electromagnetic shielding, do not leave an opening that is larger than the value of the minimum wavelength from which it wants to protect itself.

The enclosure 2 has a thickness which influences the heat flow that is to be stored by the device according to the invention. By way of example, the thickness of the walls of the enclosure is comprised between 0.5 and 3 mm, more precisely on the order of 1 mm.

The device according to the invention comprises a material with a phase change 3 (MCP). The MCP 3 is in the enclosure 1 contain. The electronics module 2 is in the MCP 3 let in. Let in means that the MCP 3 the electronics module 2 advantageously covered on all sides, and preferably with the exception of the contact point or points with the positioning system. The electronics module 3 is advantageous in all directions with MCP 3 covered. The entire outer surface of the electronics module 1 and in particular the protective housing 11 is in contact with the MCP 3 . The device according to the invention is configured so that the electronics module 3 in the MCP 3 is enveloped.

According to the invention is the MCP 3 a metal or a metal alloy. Metal alloy means that the MCP 3 comprises several metallic MCPs. In the further course of the description, reference is made to an MCP 3 not limiting. The MCP formed from a metal alloy 3 is a Eutectic. The MCP is configured to allow for patency of a metal volume around the electronics module 1 worrying around. There are advantageously inclusions or possible openings in the volume of the MCP 3 made of metal.

The MCP according to the invention 3 is an MCP with transition from solid / liquid. Various metallic MCP can be used. To use an electronic device, more precisely, for example, an electronic card, the MCP used 3 a fusion temperature of the order of 50 to 200 ° C, more precisely from 110-150 ° C. Preferably, the MCP 3 a good heat capacity and the highest possible thermal conductivity.

By way of example, the MCP is a metal alloy that includes tin and bismuth. Preferably, bismuth is present for 58% by weight and tin for 42% by weight of the total weight of the alloy. This eutectic MCP has a fusion temperature of 138 ° C.

MCP 3 is a material with two phases, preferably solid and liquid, whose transition between these two phases stores or gives off energy. The transition from a first phase to a second phase preferably requires heat, which is thus stored in the MCP in its second phase. In contrast, the transition from the second phase to the first phase is exothermic and releases the stored heat. The heat content of the phase change from solid / liquid is relatively large compared to the sensitive energy variation of a material. This is why the systems with MCP are interesting, as the amount of stored energy per unit volume (and unit of mass) is greater than that obtained by a sensitive system (better storage density). Due to this fact, the storage and material volumes are also smaller, which reduces the price of the system.

The MCP 3 stores the calories in its environment. In the device according to the invention, the MCP stores the data from the electronics module 1 calories generated due to self-heating, as well as those of the external environment, for example an internal combustion engine in the case of application in the vehicle field. The MCP 3 stores the calories through sensible heat storage until the fusion temperature is reached. At this point the phase change of the MCP is 3 highly endothermic and absorbs calories through latent heat storage, which makes it possible to keep the electronic module at a temperature below its maximum operating temperature. Beyond its fusion temperature, the MCP 3 Save more calories through sensible heat storage.

The MCP 3 releases the ingested calories when the temperature of the outside environment is lower than its own temperature. The MCP 3 its phase by exothermic transformation. The MCP 3 also sends the calories consumed to the electronic module 1 when its temperature is lower than that of the MCP, but advantageously also to the electronics module 1 . This makes it possible to have excessive and / or too rapid temperature variations in the area of the electronic module 1 and to carry out thermal management of the electronic module.

The MCP 3 thus enables thermal management of the electronic module 1 to care. Choosing a metallic MCP 3 it also enables electromagnetic protection for the electronic module 1 to care.

The phase change from solid / liquid of the MCP 3 is caused by a variation in the volume of the MCP 3 accompanied. This volume variation is advantageous with the metallic MCP 3 (especially with the alloy chosen, the variation of which is practically zero thanks to the presence of bismuth, the variation in volume of which is the reverse of most materials (such as water), thus compensating for the variation in tin).

According to one mode of implementation of the invention, the device comprises an expansion management system of the MCP 3 . According to a preferred first possibility, containment 2 configured to accept a deformation that corresponds to the volume expansion of the MCP 3 corresponds. According to a second possibility, containment includes 2 a gas vault that is configured to accommodate the volume expansion of the MCP 3 To be compressed is containment 2 configured to accept this pressure increase in their internal volume. The gas dome is advantageously configured around the MCP 3 not to damage. According to a third possibility, containment includes 2 a gas vault and in the area of its lid 9 an opening or a plurality of openings. According to one mode of implementation, the opening or the plurality of openings is small in size, advantageously smaller than the value of the wavelength to be blocked by the electromagnetic shield. The openings allow that Expose gas vaults without the pressure of the internal volume of the enclosure 2 to increase. This third possibility can only be considered if the device according to the invention is intended to always remain horizontal in order to avoid leaks from the MCP 3 to avoid.

According to the invention, the device comprises a system for positioning the electronic module 1 in the enclosure 2 . The positioning system allows for a constant position of the electronic module 1 in the enclosure 2 to ensure thermal and electromagnetic protection regardless of the state of the MCP 3 to guarantee. Because if the MCP 3 is in the liquid state, the system allows for positioning the electronics module 1 in the MCP 3 to keep in place without running the risk of damaging the electronic module 1 in contact with the enclosure 2 comes, whereby the thermal and electromagnetic protection would decrease or even extinguish.

The positioning system is advantageously metallic in order to enable electromagnetic protection. By way of example, the system for positioning is made of steel. According to a conversion module shown in the figures, the system for positioning comprises three metal tabs 4th that between the enclosure 2 and the electronics module 1 are arranged to a space between the electronics module 1 and the enclosure 2 to maintain. The positioning system can comprise at least one of lamellae, springs, pins, rigid wires, rods, or combinations of two or more of these elements. According to one possibility, the tabs are 4th only on the electronics module 1 attached. The tabs 4th are not at the enclosure 2 attached, which makes it possible to manage the expansion of the MCP 3 , especially by entrapment 2 to facilitate.

The device according to the invention, the electronic module 1 advantageously comprises an electrical connection means 6th by which it is connected to other organs, in particular an organ controlled by the electronics module. The electrical connection means 6th includes at least one wire or electrical cable. The twist or the electrical cable is advantageously flexible. As a preferred example, the connection means 6th a diameter of 0.1 to 3 mm. The enclosure 2 is advantageously configured around the passage of the connecting means 6th to allow between its internal volume and the external volume. The enclosure 2 preferably comprises a traversing passage 8th . The characteristics of the crossing passage 8th and the connection wire (s) are selected so as to keep the characteristic length of the insulation (plastic sleeve around the connection wire, which isolates the MCP from the connection wire) less than the wavelength. The crossing passage 8th is either through the lid 9 , or by the base 12 of the enclosure. The crossing passage 8th is preferably fluid-tight and in particular with respect to the MCP 3 , especially in the case of the crossing passage 8th on the base 12 of enclosure 2 is formed. The tightness can be ensured by a tight crossing, in particular by the Spectite® brand or by gluing.

The device according to the invention advantageously comprises a retraction system of the connection means 6th on himself. The means of retreat is in the enclosure 2 between the crossing passage 8th and the electronics module 1 arranged and allows the connection means 6th in a curved shape between the crossing passage 8th and the electronics module 1 , for example, withdrawn to oneself, in particular in the form of a chicane, in order to maintain the electromagnetic shielding by limiting or even blocking the transmission of the waves. This is because the curved shapes limit the transmission of electromagnetic waves through the space between the MCP and the conductive connecting wire (s), i.e. the insulating sheath. The retraction system is advantageously of the same type as the positioning system. The retraction system is advantageously made of metal, such as steel, for example. A fastening or clamping strap 7th of the connection means 6th can be provided.

According to a preferred, in particular in 1 and 3 The implementation mode shown surrounds the MCP 3 the electronics module 1 at all dimensions in a constant thickness ep1 from MCP, for example Di 1 in the order of 1 to 10 mm, more precisely in the order of 3 mm. According to a preferred possibility, the thickness of the MCP 3 around the area of the retraction system of the connecting means 6th larger to ensure that the connection means 6th good in the MCP 3 is let in. As an example, this thickness is ep2 5 mm. To limit the additional costs, the retraction system is advantageously on one edge 14th of enclosure 2 arranged.

The invention also relates to a method for assembling a device according to the invention, as described below. The assembly process includes the following steps, which i the 2A to 2F are shown and described below.

The ones in the 2A depicted enclosure 2 is through a base 12 that formed a floor 13 and margins 14th includes. The enclosure includes walls that define an interior volume. The enclosure 2 is advantageously shaped or machined from a single block.

The preferably tight crossing passage 8th will be in the enclosure 2 , for example on an edge 14th , as in 2 B appropriate. The crossing passage 8th allows the connection means 6th by the enclosure 2 to run through. An opening is thus advantageously formed at the edges 14th of enclosure 2 and a tight crossing is advantageously made in the opening by making the connection means 6th runs through.

The positioning system is attached. Advantageously, the tabs 4th of the system for positioning on the electronic module 1 , in particular by welding attached. The retraction system of the connecting means 6th is also attached. The fastening tab 7th is preferred, as in the 2C shown on the electronics module 1 attached.

The connection means 6th is on the electronics module 1 connected. The electrical wire connectors are, as in 2C shown, advantageously to the electronic device, or, if available, to the protective housing 11 welded.

The electronics module 1 will be in the enclosure 2 , especially placed in the internal volume that passes through the base 12 of enclosure 2 is defined. The positioning tabs 4th are like in the 2D shown, advantageously in contact with the enclosure 2 .

The MCP 3 is preferably in the liquid phase, as in the 2E shown in the enclosure 2 brought in.

The lid 9 of enclosure 2 is attached to the enclosure 2 to make closed. The lid is advantageously thermally attached to the base 12 of enclosure 2 welded.

example

According to one example, the selected application is an actuator that is operated in a cyclical environment between 110 ° C and 150 ° C with a DC motor that generates 2 to 4 W and self-heating of 1 ° C to 5 ° C.

• - Die Außenumgebung des Aktors (unter der Motorhaube des Fahrzeugs, nahe dem Verbrennungsmotor) dessen Temperatur je nach Motordrehzahl zwischen 110°C und 150°C (die Temperatur von 150°C wird im Allgemeinen bei Bergauffahrten erreicht) schwankt. Ein typisches Bemessungsprofil nimmt Zyklen von 30 Min. bei 110°C, gefolgt von einer Anstiegsrampe von 15 Min. vor Erreichen von 150°C, gefolgt von einer Beibehaltung von 150°C für eine Dauer von 30 Min., und schließlich ein erneuter Abfall auf 110°C für die Dauer von 15 Min. an. Dieser Zyklustyp eignet sich besonders für die Verwendung eines MCP, da er einen Verfestigungsbereich (zum Freigeben der Wärme aus dem MCP) zwischen zwei Bedürfnissen einer thermischen Spitzenbegrenzung freilässt.
• - Der Gleichstrommotor, der eine Leistung in der Größenordnung von 0 bis 50 W erzeugt, von der ein Teil die Elektronikkarte erwärmt.
• - Die Selbsterwärmung der Elektronikkarte (Selbsterwärmungsleistung von 0 bis 10 W durch die Komponenten der Elektronikkarte).

Such an actuator is, for example, the actuator of an EGR valve for internal combustion engines. The actuator contains an electronic control card, the temperature of which may not locally exceed 150 ° C. This card is exposed to three thermal aggressions:

• - The external environment of the actuator (under the hood of the vehicle, close to the combustion engine), the temperature of which fluctuates between 110 ° C and 150 ° C depending on the engine speed (the temperature of 150 ° C is generally reached when driving uphill). A typical design profile takes 30 min cycles at 110 ° C, followed by a 15 min ramp up before reaching 150 ° C, followed by a hold at 150 ° C for 30 mins, and finally another decay to 110 ° C for a period of 15 minutes. This type of cycle is particularly well suited to the use of an MCP because it leaves a solidification area (to release the heat from the MCP) between two needs for thermal peak limitation.
• - The DC motor, which generates a power of the order of 0 to 50 W, part of which heats the electronic card.
• - The self-heating of the electronic card (self-heating power from 0 to 10 W by the components of the electronic card).

Selected MCP: In order not to exceed 150 ° C on the electronics card when the internal combustion engine is at 150 ° C and the DC machine is running, one must be able to absorb heat that is leaking from the device when the internal combustion engine is on 110 ° C. The selected MCP 3 must therefore have a fusion temperature that is between 110 ° C and 150 ° C.

• - Fusionstemperatur: 138°C.
• - Masseschmelzenthalpie: 44.8 J/g.
• - Volumenmasse: 8560 kg/m3
• - Speicherdichte: 106,5 kW.h/m3. Was angesichts dessen ein sehr guter MCP ist.
• - Volumenausdehnung bei der Phasenänderung < 1%
• - Wärmeleitfähigkeit: 30 W/m/K. Kann eine interessante Wärmeableitfunktion im Falle der Selbsterwärmung des Elektronikmoduls ermöglichen.
• - Spezifischer elektrischer Widerstand: σ = 1.25E-6 Siemens/m. (somit ein relativer elektrischer Widerstand von σr = 0.021)
• - Relative magnetische Permeabilität: µr = 1. Das Eutektikum 42%Sn 58% Bi ist sehr nahe den Eigenschaften des nicht rostenden Stahls, in Hinsicht auf den relativen spezifischen elektrischen Widerstand und die relative magnetische Permeabilität, was einen sehr zufriedenstellenden Werkstoff zur elektromagnetischen Abschirmung ergibt.

The MCP 3 is a eutectic comprising 42% Sn - 58% Bi, which has the following main properties:

• - Fusion temperature: 138 ° C.
• - Mass melting enthalpy: 44.8 J / g.
• - Volume mass: 8560 kg / m3
• - Storage density: 106.5 kW.h / m3. Which is a very good MCP, given that.
• - Volume expansion with phase change <1%
• - Thermal conductivity: 30 W / m / K. Can provide an interesting heat dissipation function in the event that the electronic module heats up itself.
• - Specific electrical resistance: σ = 1.25E-6 Siemens / m. (thus a relative electrical resistance of σr = 0.021)
• Relative magnetic permeability: µr = 1. The eutectic 42% Sn 58% Bi is very close to the properties of stainless steel in terms of the relative electrical resistivity and the relative magnetic permeability, which makes a very satisfactory material for electromagnetic shielding .

Detailed dimensioning of the device according to the invention

• - Höhe Hm 10 mm
• - Länge Lm 50 mm
• - Breite Im 50mm

The electronics module 1 our application has the following dimensions (with its components and the possibly existing protective housing 11 when making contact with the MCP 3 / the electronic component 5 want to avoid) on:

• - Height Hm 10 mm
• - length Lm 50 mm
• - width in the 50mm

From a geometrical point of view, the electronic card receives the thermal energy, it experiences thermal "aggression" from all directions: on top and on the sides it is very close to the local ambience under the hood and from below it receives the flow of the DC machine. The arrangement of the MCP 3 around the electronic card enables its protection in all directions.

The selected thickness is advantageously located ep1 of the MCP on all sides at 3 mm. Preferably, the side facing the connection means 6th contains, a greater thickness Di 2 of the MCP, advantageously by 5 mm. The electrical wire of the connection means 6th is flexible and has a wire passage cross section of 0.75mm ² , i.e. a wire diameter that contains the sheath close to 1 mm.

The positioning tabs 4th and fastening 7th the connection means 6th are iron cylinders with a diameter of 2 mm. The enclosure 2 is made of PPS.

The confinement is believed to be flexible enough to accommodate the 1% volume expansion with the phase change of the MCP 3 to absorb.

The MCP volume (42% Sn - 58% Bi) which surrounds the electronic module 1 is 27 cm ³ , or 336 g MCP 3 , or an energy absorption capacity with phase change of 10.5kJ (3 Wh).

Flow calculations and experimental measurements carried out with other MCPs have shown that this level of energy absorption is sufficient to cope with the thermal load on the electronics card, which is subject to the ambient temperature cycle, as well as the power output by the DC motor (but self-heating was not shown) to improve significantly.

In addition, the shielding obtained with this 3mm thickness of eutectic 42% Sn - 58% Bi is calculated as follows:

• - Unendliche flache Welle im entfernten Freifeld
• - Einfluss des Anschlussdrahtes vernachlässigt (dank der Schikane)
• - Mehrere Reflexionen vernachlässigt (wahr für eine Abschirmungsdicke größer als die Dicke der Haut)

Assumptions:

• - Infinite flat wave in the distant free field
• - Influence of the connecting wire neglected (thanks to the chicane)
• - Multiple reflections neglected (true for a shield thickness greater than the thickness of the skin)

• - Dicke der Haut:

$$\delta \left(mm\right)=\frac{66}{\sqrt{f\left(Hz\right)\ast {\mu }_r\ast {\sigma }_r}}$$

• - Abschwächung in Dezibel:

$$\text{Edb}=8.7\ast \frac{e}{\delta }$$

mit e als Dicke des MCP in mm.Absorption term:

• - thickness of the skin:

$$\delta \left(mm\right)=\frac{66}{\sqrt{f\left(Hz\right)\ast {\mu }_r\ast {\sigma }_r}}$$

• - Attenuation in decibels:

$$\text{Edb}=8.7\ast \frac{e}{\delta }$$

with e as the thickness of the MCP in mm.

• - Reflexionswirkung in Dezibel:

$$R_{dB}=20.{\text{log}}_{10}\left(\frac{1}{4}\cdot \sqrt{\frac{\sigma }{{\mu }_r\cdot {\epsilon }_0\cdot \omega }}\right)$$

Concept of reflection:

• - Reflection effect in decibels:

$${\mathrm{R.}}_{d\mathrm{B.}}=\mathrm{20th}{\text{log}}_{10}\left(\frac{1}{\mathrm{4th}}\cdot \sqrt{\frac{\sigma }{{\mu }_r\cdot {\epsilon }_0\cdot \omega }}\right)$$

Overall, the obtained attenuation of the frequencies is as follows: [Table 1] frequency Attenuation at 3mm on Sn42% Bi58% 0.1 kHz 132 db 1 KHz 124 Db 10 kHz 118 Db 50 kHz 118 Db 100 kHz 120 db 500 kHz 137 Db 1 MHz 151 Db 10 MHz 270 db 100MHz 665 Db 1GHz 1940 Db

The attenuation is very high at all frequencies, which confirms the electromagnetic shielding.

The invention is not limited to the implementation modes described above and extends over all implementation modes covered by the claims.

List of reference symbols

1

Elektronikmodul

2

Einschließung

3

Werkstoff mit Phasenänderung

4

Positionierungslasche

5

Elektronische Komponente

6

Anschlussdraht

7

Befestigungslasche des Anschlussdrahtes

8

Dichter Durchgang

9

Deckel

10

Gedruckte Schaltung

11

Schutzgehäuse

12

Basis

13

Boden

14

Ränder

Hm

Höhe Elektronikmodul

Lm

Länge Elektronikmodul

Im

Breite Elektronikmodul

He

Höhe Einschließung

Le

Länge Einschließung

le

Breite Einschließung

ep1

Dicke MCP

ep2

Dicke MCP

[0096]

1

Electronics module

2

Containment

3

Phase change material

4th

Positioning tab

5

Electronic component

6th

Connecting wire

7th

Fastening strap of the connection wire

8th

Dense passage

9

cover

10

Printed circuit

11

Protective housing

12

Base

13

ground

14th

Margins

Hm

Electronics module height

Lm

Length of electronic module

in the

Width electronics module

Hey

Height enclosure

Le

Length of enclosure

le

Wide enclosure

ep1

Thick MCP

ep2

Thick MCP

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 7069979 B1 [0003]
• FR 2713327 A1 [0006]

Claims (12)

Device for thermal and electromagnetic management of an electronic module, comprising an electronic module (1), a phase change material (3) (MCP) and an enclosure (2) designed to contain the phase change material (3) and the electronic module (1), characterized in that: - the material with phase change (3) is a metal or a metal alloy into which the electronics module (1) is embedded, - the electronics module (1), an electronic device and a protective housing (11) which defines an outer surface of the electronic module and is intended to encapsulate the electronic device in order to avoid contact of the phase change material (3) with the electronic device, and - the device for thermal and electromagnetic management a system for positioning (4 ) of the electronics module in the enclosure configured to allow contact of the material with phases change (3) with the entire outer surface of the electronics module (1). Device according to the preceding claim, wherein the positioning system (4) is made of metal. Device according to one of the preceding claims, wherein the electronic module (1) comprises a dielectric liquid or a thermal interface material of the type TIM (thermal interface material), which is arranged between the protective housing (11) and the electronic module (1), configured for To ensure heat transfer between the electronic device and the protective housing (11). Device according to one of the preceding claims, wherein the system for positioning (4) is attached to the electronics module (1). Apparatus according to any preceding claim, wherein the positioning system comprises at least three tabs (4) arranged to prevent contact of the electronic module (1) with the enclosure (2). Apparatus according to any preceding claim, wherein the enclosure (2) comprises an expansion management system of the MCP (3) upon phase change. Device according to one of the preceding claims, wherein the phase change material (3) is selected so as to have a fusion temperature comprised between 50 and 200 ° C, more precisely between 110 ° C and 150 ° C. Device according to one of the preceding claims, wherein the selected material with phase change (3) is a binary eutectic comprising tin and bismuth, preferably 42% tin and 58% bismuth, the fusion temperature of this binary eutectic being 138 ° C. Device according to one of the preceding claims, wherein the electronic module comprises an electrical connection means (6) traversing the enclosure (2), the enclosure (2) comprising a tight transverse passage (8) in order for the enclosure to be sealed against the MCP (3 ) to care. Device according to the preceding claim, comprising a retraction system (7) of the connection means (6) on itself, which is arranged in the enclosure (2), in order to provide the connection means (6) between the traversing passage (8) and the electronics module (1 ) to withdraw. Device according to one of the preceding claims, wherein the electronic module (1) comprises an electronic card which is configured to control an EGR valve (exhaust gas recycling) for an internal combustion engine. Use of a device according to one of the Claims 1 to 10 , for the thermal and electromagnetic management of an electronic module (1) configured to control an actuator or a sensor of a road vehicle.

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