Cooling device configured to cool an electronic module

Abstract

Title: Cooling Device Configured to Cool an Electronic Module The invention relates to a cooling device (3) configured to cool an electronic module (2) comprising, in particular, an electronic board (4) on which a plurality of electronic components (5) are mounted. The cooling device comprises: an enclosure (10) configured to receive the electronic module (2), an immersion fluid (100) in which the electronic module (2) is at least partially immersed, the immersion fluid containing a dielectric fluid and at least one electromagnetic barrier material mixed with the dielectric fluid. Figure for the abstract: Fig. 1

Description

Title of the invention: Cooling device configured to cool an electronic module

[0001] The present invention relates in particular to a cooling device configured to cool an electronic module.

[0002] It is known, in the context of cooling a power electronic board, such as that used in a DC-DC converter (this converter being designed to transform a direct current voltage from a first voltage value to a second voltage value) or a high-voltage inverter, to employ a coolant circulating in a plate that is in contact with the electronic board. Such a system involves a significant fluid flow rate and is energy-intensive. Moreover, the architecture of the electronic board can complicate access, in terms of cooling, to the hottest components.

[0003] The present invention aims in particular to further improve the thermal regulation, in particular the cooling, of an electronic module, while allowing good EMC protection (electromagnetic compatibility).

[0004] The invention thus relates to a cooling device configured to cool an electronic module comprising, in particular, an electronic board on which a plurality of electronic components are mounted, the cooling device comprising: - an enclosure configured to house the electronic module, - an immersion fluid in which the electronic module is at least partially immersed, the immersion fluid containing a dielectric fluid and at least one electromagnetic barrier material mixed with the dielectric fluid.

[0005] In the invention, the components can be completely immersed.

[0006] Thanks to the invention, the cooling of the electronic components is done by direct contact with the immersion fluid.

[0007] Furthermore, the invention makes it possible to attenuate / suppress electromagnetic wave emissions that could undesirably disrupt the operation of electronic components. The invention thus provides good protection in terms of electromagnetic compatibility (EMC) around the electronic module in a relatively simple manner, since this electromagnetic barrier is provided by the immersion fluid itself, and it is not necessary to provide additional EMC barrier components.

[0008] According to one aspect of the invention, the electromagnetic barrier material is chosen to absorb / attenuate electromagnetic radiation in a predetermined absorption spectral band.

[0009] According to one aspect of the invention, the predetermined absorption spectacle band contains at least the radio wave spectrum.

[0010] According to one aspect of the invention, the predetermined absorption spectral band contains, in addition to the radio wave spectrum, at least a part of the microwave spectrum and / or at least a part of the long wave spectrum.

[0011] According to one aspect of the invention, the predetermined absorption spectral band covers wavelengths from 102 to 108 m.

[0012] By absorbing / attenuating wavelengths in this predetermined spectacle band, the immersion fluid makes it possible to obtain good EMC protection.

[0013] According to one aspect of the invention, the dielectric fluid comprises oil.

[0014] According to one aspect of the invention, the material forming an electromagnetic barrier capable of absorbing / attenuating predetermined electromagnetic radiation contains molecules having a sufficiently high molar absorption coefficient in the predetermined spectral band, to absorb / attenuate electromagnetic radiation in this predetermined absorption spectral band.

[0015] According to one aspect of the invention, the molecules for absorbing / attenuating electromagnetic radiation are chosen from molecules with rotational transition for absorbing / attenuating electromagnetic radiation, particularly in the microwave spectrum.

[0016] According to one aspect of the invention, the molecules for absorbing / attenuating electromagnetic radiation are chosen from: - anthracene, which is a chemical compound with the formula Ci4HiO; - water (H2O); - nitrogen dioxide (N2O).

[0017] These three examples of molecules allow the absorption / attenuation of electromagnetic radiation in the microwave spectrum.

[0018] According to one aspect of the invention, the immersion fluid contains a single type of molecule to absorb / attenuate electromagnetic radiation.

[0019] Alternatively, the immersion fluid contains several types of molecules to absorb / attenuate electromagnetic radiation. For example, several types of molecules are chosen to absorb / attenuate electromagnetic radiation in spectra that are different (for example, that may overlap but remain distinct).

[0020] According to one aspect of the invention, the molecules are chosen so as to avoid the appearance of electric arcs when the immersion fluid is traversed by an electric current.

[0021] According to another aspect of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains atoms with nuclear spin chosen such that, when subjected to electromagnetic radiation, for example in the radio wave spectrum, the atomic nuclei of these atoms absorb the energy of the radiation.

[0022] According to one aspect of the invention, the atoms with nuclear spin are chosen from the following elements: *H, 13C, 17O, 19F, 31P, 129Xe.

[0023] According to one aspect of the invention, the cooling device includes a device for generating a magnetic field to act on the nuclear spin of the atoms so that they absorb the energy of the radiation.

[0024] According to one aspect of the invention, the device for generating a magnetic field is a self-inductance, in particular belonging to the module to be cooled.

[0025] Alternatively, the device for generating a magnetic field is a self-inductance belonging to a separate component of the module to be cooled.

[0026] According to yet another aspect of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains particles, in particular ferromagnetic particles, in particular of nanometric sizes.

[0027] According to one aspect of the invention, the particles are dispersed in the dielectric fluid, in particular with the presence of dispersing agents such as charged molecules, surfactants or polymers.

[0028] According to one aspect of the invention, the particles are of a metallic type, in particular of a ferrite type with iron oxide.

[0029] According to one aspect of the invention, the particles are dispersed in an iron-fluid.

[0030] Ferrofluids are, in particular, colloidal suspensions of ferromagnetic or ferrimagnetic nanoparticles with a size on the order of 10 nanometers in a solvent. These liquids become magnetic when an external magnetic field is applied while retaining their colloidal stability.

[0031] Ferrofluids also improve heat transfer within the cooling device. Indeed, particles (in the ferrofluid) heated above the Curie temperature lose their magnetization and their temperature drops. This provides a heat pump equivalent.

[0032] According to one aspect of the invention, the enclosure is formed on a plastic or, alternatively, metal casing, in particular aluminum.

[0033] The invention relates to a system comprising an electronic module and a device cooling as described above, configured to cool the electronic module placed in the enclosure.

[0034] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and several illustrative and non-limiting examples of embodiments given with reference to the attached schematic drawing on the other hand, in which:

[0035] [Fig-1] Fig. 1 is a schematic, cross-sectional representation of a system according to an example of an embodiment of the invention, with an electronic module in a housing of a cooling device.

[0036] The features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0037] Figure 1 shows a system 1 comprising an electronic module 2 and a cooling device 3 according to an embodiment of the invention, configured to cool the electronic module 2.

[0038] The electronic module 2 is part of a DCDC converter, or a high voltage inverter, particularly for motor vehicles.

[0039] The electronic module 2 includes, for example, an electronic board on which are mounted a plurality of electronic components, including MOSFET type transistors and / or inductors, these examples not being exhaustive.

[0040] The cooling device 3 includes a housing 10 configured to receive the electronic module 2, and to be filled with an immersion fluid 100.

[0041] This immersion fluid is used to cool the components of the electronic module 2 by contact of the immersion fluid 100 with these components.

[0042] The enclosure 10 is formed by a housing 12 made of plastic material.

[0043] The cooling device 3 further includes a cover 11, also made of plastic, configured to close the enclosure 10 in a hermetic manner.

[0044] The enclosure 10 is supplied with immersion fluid through a fluid inlet 14 and this fluid is discharged through the fluid outlet 15 after circulating in the enclosure 10. The fluid exits the enclosure 10 hotter than at the fluid inlet 14.

[0045] The fluid inlets 14 and fluid outlet 15 are for example part of a fluid circuit equipped with a compressor for the forced movement of the fluid.

[0046] The electronic module 2 is placed, for example, on pads 17 in such a way that the 100 immersion fluid can flow under electronic module 2.

[0047] The immersion fluid 100 in which the electronic module 2 is immersed contains a dielectric fluid such as a dielectric oil, and an electromagnetic barrier material mixed with the dielectric fluid.

[0048] The electromagnetic barrier material is chosen to absorb / attenuate electromagnetic radiation in a predetermined absorption spectral band, which contains the radio wave spectrum and at least part of the microwave spectrum and at least part of the long wave spectrum.

[0049] The predetermined absorption spectral band covers wavelengths from 102 to 108 m.

[0050] By absorbing / attenuating wavelengths in this predetermined spectacle band, the immersion fluid provides good EMC protection.

[0051] In a first example of implementation of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains molecules having a sufficiently high molar absorption coefficient in the predetermined spectral band, to absorb / attenuate electromagnetic radiation in this predetermined absorption spectral band.

[0052] Molecules for absorbing / attenuating electromagnetic radiation are chosen from molecules with rotational transition for absorbing / attenuating electromagnetic radiation, particularly in the microwave spectrum.

[0053] The molecules for absorbing / attenuating electromagnetic radiation are chosen from: - anthracene, which is a chemical compound with the formula Ci4HiO; - water (H2O); - nitrogen dioxide (N2O).

[0054] These three examples of molecules allow the absorption / attenuation of electromagnetic radiation in the microwave spectrum.

[0055] The immersion fluid 100 contains a single type of molecule for absorbing / attenuating electromagnetic radiation, or several types of molecules for absorbing / attenuating electromagnetic radiation. For example, several types of molecules are chosen to absorb / attenuate electromagnetic radiation in spectra that are different (for example, that may overlap but remain distinct).

[0056] The molecules are chosen so as to avoid the appearance of electric arcs when the immersion fluid 100 is traversed by an electric current.

[0057] In another embodiment of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains atoms with nuclear spin chosen such that, when they are When subjected to electromagnetic radiation, for example in the scepter of radio waves, the atomic nuclei of these atoms absorb the energy of the radiation.

[0058] The atoms with nuclear spin are chosen from the following elements: *H, 13C, 17O, 19F, 31P, 129Xe.

[0059] The cooling device 3 includes a device for generating a magnetic field to act on the nuclear spin of the atoms so that they absorb the energy of the radiation.

[0060] The device for generating a magnetic field is a self-inductance (or "self-inductance" in English), in particular belonging to the module to be cooled, or is a self-inductance belonging to a component separate from the module to be cooled.

[0061] In yet another example of implementation of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains particles, in particular ferromagnetic particles, in particular of nanometric sizes.

[0062] The particles are dispersed in the dielectric fluid, in particular with the presence of dispersing agents such as charged molecules, surfactants or polymers.

[0063] The particles are of metallic type, in particular of ferrite type with iron oxide.

[0064] In one embodiment of the invention, the particles are dispersed in a ferrofluid. Ferrofluids are, in particular, colloidal suspensions of ferromagnetic or ferrimagnetic nanoparticles with a size on the order of 10 nanometers in a solvent. These liquids become magnetic when an external magnetic field is applied while retaining their colloidal stability. Ferrofluids also improve heat transfer within the cooling device. Indeed, particles (in the ferrofluid) heated above the Curie temperature lose their magnetization and their temperature decreases. This provides a heat pump equivalent.

Claims

Demands

1. Cooling device (3) configured to cool an electronic module (2) comprising in particular an electronic board (4) on which are mounted a plurality of electronic components (5), the cooling device comprising: - an enclosure (10) configured to receive the electronic module (2), - an immersion fluid (100) in which the electronic module (2) is at least partially immersed, the immersion fluid containing a dielectric fluid and at least one electromagnetic barrier material mixed with the dielectric fluid.

2. Cooling device (3) according to the preceding claim, wherein the electromagnetic barrier material is chosen to absorb / attenuate electromagnetic radiation in a predetermined absorption spectral band, the predetermined absorption spectral band including in particular at least the radio wave spectrum.

3. Cooling device (3) according to the preceding claim, wherein the predetermined absorption spectral band contains: - the radio wave spectrum, and - at least a part of the microwave spectrum and / or at least a part of the long wave spectrum.

4. Cooling device (3) according to the preceding claim, wherein the molecules for absorbing / attenuating electromagnetic radiation are selected from molecules with rotational transition for absorbing / attenuating electromagnetic radiation, particularly in the microwave spectrum.

5. Cooling device (3) according to the preceding claim, wherein the molecules for absorbing / attenuating electromagnetic radiation are chosen from: - anthracene which is a chemical compound of formula Ci4HiO; - water (H2O); - nitrogen dioxide (N2O).

6. Cooling device (3) according to claim 4 or 5, wherein the immersion fluid contains a single type of molecule for absorbing / attenuating electromagnetic radiation, or several types of molecule for absorbing / attenuating electromagnetic radiation.

7. Cooling device (3) according to any one of the preceding claims, wherein the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains atoms with nuclear spin selected such that, when subjected to electromagnetic radiation, for example in the radio wave spectrum, the atomic nuclei of these atoms absorb the energy of the radiation.

8. Cooling device (3) according to the preceding claim, wherein the atoms with nuclear spin are selected from the following elements: >H, 13C, 17O, 19F, 31P, 1MXe.

9. Cooling device (3) according to any one of the preceding claims, wherein the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains particles, in particular ferromagnetic particles, in particular particles of nanometric size, the particles being in particular metallic, in particular ferrite with iron oxide.

10. Cooling device (3) according to the preceding claim, wherein the particles are dispersed in a ferrofluid.

11. Cooling device (3) according to any one of the preceding claims, wherein the enclosure (10) is formed on a housing (12) made of plastic or, alternatively, of metal, in particular aluminum.

12. System (1) comprising an electronic module (2) and a cooling device (3) according to any one of the preceding claims, configured to cool the electronic module placed in the enclosure (10).

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