Electronic module including a modular heat dissipation device.

Abstract

The invention relates to an electronic device (1) comprising: An electronic module (2) comprising a first face (20) and a second face (21), the electronic module (2) comprising n openings (22) passing through the electronic module (2), n being a natural integer greater than or equal to 2, the electronic module (2) comprising at least one connector (23) extending from the second face (21), A thermally conductive plate (4) for extracting heat from the electronic module (2) through the first face (20), A printed circuit board (3) located away from the second face (21), connected to at least one connector (23), m inserts (5), m being a natural integer greater than or equal to 2 and less than or equal to n, each insert (5) being disposed in an opening (22), each insert (5) being a thermal conductor,the inserts (5) mechanically connecting the electronic module (2) to the thermally conductive plate (4) and being configured so as to thermally connect the electronic module (2) to the printed circuit board (3). Figure for the abbreviation: Fig. 1,

Description

Title of the invention: Electronic module comprising a modular heat dissipation device.

[0001] The invention relates to power electronics, in particular power electronics with heat sink.

[0002] Power electronics contains power components, including semiconductor elements but also so-called passive elements such as coils or diodes, which must be cooled during operation.

[0003] This task is generally accomplished by metallic heat sinks, which are placed directly against the components to be cooled, so as to ensure good heat transfer. Such a power electronics assembly also generally includes a printed circuit board that is also electrically connected to the power module. It is also envisaged to position the printed circuit board near the power module and to connect the printed circuit board to the heat sink so as to also dissipate heat from the power module to the heat sink via the printed circuit board.

[0004] However, today, with the increase in power levels on power equipment, printed circuits are not always able to meet thermal dissipation requirements.

[0005] Therefore, it becomes necessary for each power module to be equipped with a heatsink to dissipate the excess heat present at the power module. This heatsink is generally in direct contact with the heat sink, which acts as a thermal bridge between the electronic component and the heatsink that cools this electronic component.

[0006] However, adding a radiator to a power module has many disadvantages.

[0007] Indeed, positioning the radiator against the power module has the disadvantage of reducing the compactness of the power assembly and increasing its overall mass. However, for certain applications, such as in aeronautics or space, these dimensions represent a real challenge.

[0008] Furthermore, although the sizing is defined to compensate for all effective power levels, high power levels are in fact rarely reached and are most often of short duration. Operating the power module at full power may also not be required for the desired function. Therefore, oversizing the cooling device may prove inefficient compared to a relatively low power consumption of the power module.

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[0013] The invention aims to overcome all or part of the problems mentioned above by proposing an electronic device comprising a power module whose cooling means is adapted to meet the functional need of the power module, that is to say, to allow thermal efficiency if the power module generates a moderate amount of energy or increased cooling if the power module generates a greater amount of power. To this end, the invention relates to an electronic device comprising: - An electronic module comprising a first face and a second face opposite the first face, the electronic module comprising n openings passing through the electronic module so as to connect the first face to the second face, n being a natural integer greater than or equal to 2, the electronic module comprising at least one connector extending from the second face, - A thermally conductive plate comprising a first surface and a second surface, the first surface being in contact with the first face of the power electronic module, the thermally conductive plate allowing heat to be extracted from the electronic module through the first face, - A printed circuit board positioned opposite the second face of the electronic module, the printed circuit board being located away from the second face of the electronic module, the printed circuit board being electrically connected to at least one connector, - m insert, m being a natural integer greater than or equal to 2 and less than or equal to n, each insert of the m insert being arranged in an opening among the n openings, each insert of the m inserts being a thermal conductor, the m inserts mechanically connecting the electronic module to the thermally conductive plate, the m inserts being configured so as to thermally connect the electronic module to the printed circuit board to cool the electronic module in a first low dissipation configuration. According to one aspect of the invention, the electronic device comprises a heat sink, the heat sink being connected to the second surface of the thermally conductive plate, the inserts mechanically linking the electronic module, the thermally conductive plate and the heat sink, the inserts being distant from the printed circuit board, the heat sink being configured to cool the electronic module in a second high dissipation configuration. According to one aspect of the invention, n is equal to m. According to one aspect of the invention, n is equal to 2, the first face and the second face of the electronic module comprising lateral edges, each opening among the n or- vertures being positioned at an opposite lateral edge.

[0014] According to one aspect of the invention, n is equal to 2, the first face and the second face of the electronic module comprising corners, each opening among the n openings being positioned at an opposite corner.

[0015] According to one aspect of the invention, at least one connector comprises a mechanically filed end connected to the printed circuit board.

[0016] According to the aspect of the invention, the m inserts are made of a material whose thermal conductivity is equal to that of the thermally conductive plate.

[0017] According to one aspect of the invention, the thermally conductive plate is made of a material including copper, brass or an alloy of nickel, iron and cobalt.

[0018] The invention will be better understood and other advantages will become apparent upon reading the detailed description of an embodiment given by way of example, a description illustrated by the accompanying drawing in which:

[0019] [Fig-1] [Fig.1] represents a schematic front view of the electronic device according to the invention in a low power configuration;

[0020] [Fig.2] [Fig.2] represents a schematic front view of the electronic device according to the invention in a high power configuration;

[0021] [Fig.3] [Fig.3] represents a schematic plunge view of the power module of the electronic device according to the invention;

[0022] [Fig.4] [Fig.4] represents the thermal distribution of the electronic device according to the invention in low power configuration;

[0023] [Fig.5] [Fig.5] represents the thermal distribution of the electronic device according to the invention in high power configuration.

[0024] For the sake of clarity, the same elements will bear the same references in the different figures.

[0025] Figure 1 thus represents a schematic front view of an electronic device 1 comprising a power electronic module 2. The power electronic module 2 includes, in particular, a first face 20 and a second face 21 opposite the first face 20 along a vertical axis V. The power electronic module 2 also includes n openings 22 passing through the power electronic module 2 so as to connect the first face 20 to the second face 21. The number n is a natural number greater than or equal to 2. As shown in Figure 1, the number of openings n is equal to two. In other words, at least two openings 22 pass through the power module 2 and connect the first face 20 and the second face 21. However, it is possible for the power module 2 to include more than two openings 22. The power electronic module 2 also includes at least one connector 23 extending from the second face 21.

[0026] The electronic device 1 also includes a printed circuit board 3, also called a PCB, positioned opposite the second face 21 of the power electronic module 2. The printed circuit board 3 is located away from the second face 21 of the power electronic module 2. The printed circuit board 3 is also electrically connected to at least one connector 23 of the power module 2. In other words, the printed circuit board 3 is not connected to the second face 21 and provides an electrical connection to the power module 2 via at least one connector 23. Thus, a gap is identifiable between the second face 21 of the power electronic module 2 and the printed circuit board 3.

[0027] The first face 20 thus represents an upper face of the power module 2 while the second face 21 represents the lower face of the power module 2. Therefore, the printed circuit 3 is positioned below the power module 2 with respect to the vertical axis V.

[0028] The printed circuit board 3 also includes openings 32. The printed circuit board 3 includes n openings 32. Each opening 32 of the printed circuit board faces an opening 22 of the power module 2.

[0029] The electronic device 1 includes a thermally conductive plate 4 comprising a first surface 40 and a second surface 4L. The first surface 40 is in contact with the first face 20 of the power electronic module 2. The thermally conductive plate 4 extends over the first face 20 of the power module 2. The thermally conductive plate 4 thus allows heat to be extracted from the power electronic module 2 through the first face 20. In other words, the heat generated by the power electronic module 2 is transferred to the thermally conductive plate 4 by passing through the first face 20 and the first surface 40.According to a preferred variant, the thermal conductive plate 4 extends over the entire first face 20 of the power electronic module 2 so as to maximize the contact between the power module 2 and the thermal conductive plate 4 and thus improve the heat exchange by conduction between the power electronic module 2 and the thermal conductive plate 4.

[0030] Thus, according to the vertical ace V, it is possible to observe a superposition of the printed circuit 3, the power module 2 and the thermal conductive plate 4.

[0031] The thermally conductive plate 4 is made of a material including copper, brass or an alloy of nickel, iron and cobalt or any other material having good thermal conductivity.

[0032] The electronic device 1 also includes m inserts 5. The number m is a natural number greater than or equal to 2 and less than or equal to the number n. Each insert 5 of the m inserts is arranged in an opening 22 among the n openings 22. The m inserts 5 allow the power electronic module 2 to be mechanically connected to the thermal conductive plate 4, so that the thermal conductive plate 4 is fixed against the power electronic module 2. Each insert 5 is thus in contact with the thermal conductive plate 4. Each insert 5 of the inserts 5 is also a thermal conductor.

[0033] Each insert 5 of the m inserts 5 is also connected to the printed circuit board 3 without imposing any fixing between the power electronic module 2 and the printed circuit board 3. In other words, each insert 5 also passes through the printed circuit board 3 via an opening 32.

[0034] The inserts 5 are thus configured to thermally connect the power electronics module 2 to the printed circuit board 3 in order to cool the power electronics module 2 in a first configuration with low energy dissipation as shown in [Fig. 1]. The inserts 5 are made of a material whose thermal conductivity is equal to or greater than that of the thermally conductive plate 4 so as to promote heat conduction towards the inserts. By way of example, the thermal conductivity of the thermally conductive plate 4 and the inserts 5 is greater than 50 W / m*K.

[0035] Indeed, in a low-energy dissipation configuration, i.e., when the power module 2 generates a moderate amount of heat, the printed circuit board 3 is sufficient to dissipate the heat generated by the power module 2. Therefore, in the low-energy dissipation configuration of [Fig. 1], the heat generated by the power electronic module 2 is dissipated towards the thermally conductive plate 4 by passing through the first face 20 and the first surface 40. This heat is then transmitted to each insert 5 of the m inserts 5, which transmits it directly to the printed circuit board 3 for dissipation, as represented by the propagation direction 6.

[0036] Furthermore, the architecture of the printed circuit board 3 can be designed to promote heat dissipation. To this end, in the low heat dissipation configuration, the printed circuit board can include more thermally conductive elements, or the thickness of the printed circuit board 3 can be increased to increase the number of thermally conductive elements. As an illustrative example, adding copper to the printed circuit board 3 could be considered.

[0037] The electronic device 1 allows, in the low heat dissipation configuration, for dissipation through the printed circuit 3. This is possible when the power dissipated by the power module 2 is less than 4 watts.

[0038] Furthermore, each insert 5 of the inserts 5 comprises a head 51 and a tail 52. The head 51 of each insert 5 is thus placed in contact with the thermally conductive plate 4 such that the head exerts pressure on the thermally conductive plate 4 so as to hold the thermally conductive plate 4 against the module of power 2. And, the tail 52 of each insert 5 of the m inserts 5 is also in contact with the printed circuit 3 so as to allow the m inserts 5 to conduct the thermal energy to dissipate towards the printed circuit 3.

[0039] In a low heat dissipation configuration, the electronic device 1 thus has the advantage of being compact while allowing adequate cooling of the cooling module 2.

[0040] Figure 2 represents a second operating configuration of the electronic device 1, which can be described as a high heat dissipation configuration compared to the configuration of Figure 1. In this high heat dissipation configuration, i.e., when the power electronic module 2 supplies a significant amount of energy and heat, cooling via the printed circuit board is insufficient to dissipate the heat generated by the power module 2.

[0041] Therefore, in the high energy dissipation configuration, the electronic device 1 also includes a heat sink 7. The heat sink 7 is connected to the second surface 41 of the thermal conductive plate 4. It is thus possible to observe a superposition of the printed circuit board 3, the power module 2, the thermal conductive plate 4, and the heat sink 7 along the vertical axis V. It should be noted that only the power module 2, the thermal conductive plate 4, and the heat sink 7 are in direct contact. The printed circuit board 3, on the other hand, is separated from the power module 2.

[0042] The inserts 5 then mechanically connect the power electronic module 2, the thermal conductive plate 4, and the heat sink 7. Thus, the inserts 5 secure the power electronic module 2, the thermal conductive plate 4, and the heat sink 7 together. Each insert 5 of the inserts 5 is spaced away from the printed circuit board 3.

[0043] The radiator 7 is then configured to cool the electronic module 2 in the second high dissipation configuration.

[0044] Thus, the heat generated by the power electronic module 2 is transferred towards the heat sink 7 and no longer towards the printed circuit board 3. In other words, the heat generated by the power module 2 is transferred to the thermal conductive plate 4 via the first face 20 and the first surface 40. The thermal conductive plate 4 then transfers this energy in the form of heat to the heat sink 7 via the second surface 4L. The heat sink 7 then dissipates this energy in the form of heat.

[0045] Thus, in the second energy dissipation configuration of [Fig.2], energy in the form of heat is not transmitted to the printed circuit 3 and is not transmitted to the inserts 5.

[0046] Furthermore, in the second high energy dissipation configuration, the direction of The attachment of each insert 5 is reversed. More precisely, the head 51 is in contact with the second face 21 of the power electronic module 2, and the tail 52 is in contact with the heat sink 7. Reversing the attachment direction of the inserts 5 improves the overall compactness, even with the addition of the heat sink 7. Since the head 51 has a certain thickness, each head 51 would protrude beyond the heat sink 7. Advantageously, reversing the attachment direction of the inserts 5 allows the heat sink 7 to be in direct contact with the thermal conductive plate 4, thus facilitating heat exchange.

[0047] As stated previously, in the second energy dissipation configuration of [Fig.2], there is no heat exchange between the power module 2 and the printed circuit board 3 via the inserts 5. Thus, it may be envisaged to add a thermal insulator between the head 51 of each insert 5 and the printed circuit board 3 so as to prevent any heat transfer in this direction.

[0048] According to a preferred configuration, the printed circuit board 3 is contoured around the heads 51 of the inserts 5 so as to avoid any direct contact between the inserts 5 and the printed circuit board 3. In other words, there is a space 53 between each head 51 and the printed circuit board 3 to ensure thermal insulation of the inserts 5. This simply involves increasing the cross-section of the opening 32 along a plane perpendicular to the vertical axis V. This spacing between the inserts 5 and the printed circuit board 3 also has the advantage of not over-stressing the mechanical connections between the printed circuit board 3 and the power module 2, which are already connected by means of at least one connector 23. Indeed, further stressing the mounting of the printed circuit board 3 could lead to deformation of the printed circuit board 3 or even damage to this component.

[0049] Thus, at least one connector 23 includes a filed end 230 or a "rat tail" mechanically connected to the printed circuit board 3 so as not to mechanically overstress the electronic device 1. This filed end 230 can thus be spiraled around a pin or a complementary connector in the printed circuit board 3 so that the printed circuit board 3 is held in a flexible manner against the power electronic module 2 along the vertical axis V. In other words, the printed circuit board 3 is connected to the power module 2 by means of this flexible connection which nevertheless allows relative freedom of movement along the vertical axis V.

[0050] Therefore, in the second high-energy-dissipation configuration, the inserts 5 serve only a mechanical fixing function for the power module 2, the thermal conductive plate 4, and the heat sink 7. The printed circuit board 7 serves only an electrical interconnection function. The thermal path is then modified so that the direction of heat propagation 6 is now directed towards radiator 7.

[0051] The second energy dissipation configuration reflects higher power module operation and energy dissipation greater than 30% of the power module's power.

[0052] The electronic device 1 thus has the advantage of being able to adapt to different operating configurations: either a low-power configuration, resulting in low energy dissipation, in which the printed circuit board 3 is sufficient to dissipate the heat, or a high-power configuration, resulting in high energy dissipation, in which the heat sink 7 takes over from the printed circuit board 3 to ensure the dissipation of energy in the form of heat from the electronic module 2. Switching from one configuration to the other, i.e., from the configuration of [Fig. 1] to the configuration of [Fig. 2], only requires a change in the orientation of the inserts 5 relative to the vertical axis V. The electronic device 1 thus meets a large number of energy constraints by allowing a wider operating range and heat dissipation while being advantageously compact.Therefore, the heat dissipation function switches from the printed circuit board 3 to a heatsink 7 depending on the power developed by the power electronic module 2.

[0053] Fig. 3 represents a view perpendicular to the vertical axis V of the electronic device 1 and more specifically of the thermal conductive plate 4 positioned above the power module 2.

[0054] As previously stated, the thermally conductive plate 4 extends over the first face of the power module 2. The first surface 40 of the thermally conductive plate 4 is in direct contact with the first face 20 of the power module 2. And as observed in [Fig.3], the thermally conductive plate 4 extends over the entire first face 20 of the power module 2.

[0055] Similar to the power module 2 and the printed circuit board 3, the thermal conductive plate 4 comprises n openings 42, as shown in [Fig. 3], allowing each insert 5 to pass through the thermal conductive plate 4, the power module 2, and the printed circuit board 3. In the configuration of [Fig. 3], the thermal conductive plate 4 comprises two openings 42, just as the power electronic module 2 comprises two openings 22. The printed circuit board 3, although not shown in [Fig. 3], also comprises two openings 32.

[0056] Preferably, the electronic device 1 comprises the same number of openings as inserts 5. In other words, the number n of openings 22 is equal to the number m of inserts 5. Thus, an opening 22 of the power module 2, and therefore an opening 42 of the thermal conductive plate 4 (and an opening 32 of the printed circuit board) is occupied by an insert 5.

[0057] In an ideal architecture, the number n of openings 22 and the number m of inserts 5 is equal to two, as shown in [Fig. 3]. The first face 20 of the electronic module 2 includes corners 200, 201, 202 and 203. Similarly, the second face 21 also includes corners. And, each opening 22 among the two openings 22 is arranged so as to be at a distance from the other opening 22 among the two openings 22. The greater the distance between the two openings 22, the better the heat distribution in the thermal conductive plate 4. Indeed, the two openings 22 ensuring the thermal link between the thermal conductive plate 4 and the two inserts 5, in the low energy dissipation configuration, moving the two openings 22 further apart allows the energy transmission in the form of heat to the two inserts 5 to be distributed over the entire first face 20.

[0058] Preferably, the two openings 22 are positioned on opposite lateral edges. In other words, a first opening 22' can be located at a first corner 200 and a second opening 22" can be located at a third corner 202. This design allows for symmetry in the distribution of heat transfer towards the inserts 5.

[0059] Alternatively, the second 22” opening can be positioned at the level of the second corner 201 or the fourth corner 203.

[0060] Similarly, it may also be envisaged to distribute the two openings 22 along two lateral edges 205, 206, 207, 208. Preferably, the two lateral edges are opposite so as to promote good thermal distribution on the thermal conductive plate 4 between the two inserts 5.

[0061] In addition, if the number of openings 22 and inserts 5 is equal to 3, then it may be envisaged to position a first opening at the first corner 200, a second opening at the second corner 201 and a third opening at the third corner 202 or at the fourth corner 203 or to position the first opening at the first lateral edge 205, the second opening at the second lateral edge 206 and the third opening at the third lateral edge 207 or at the fourth lateral edge 208.

[0062] It may also be envisaged to position a first opening at the level of a corner of the first face 20 and a second opening at the level of a lateral edge of the first face 20.

[0063] Positioning the thermal conductive plate 4 above the power module 2 along the vertical axis V thus has the advantage of allowing good energy transfer in the form of heat towards the inserts 5 in the low energy dissipation configuration and also allowing good energy transfer in the form of heat towards the radiator 7 in the high energy dissipation configuration. Furthermore, this position of the thermal conductive plate 4 It also offers the advantage of easy interfacing with the heatsink 7, which can be added without much effort if significant heat dissipation is required. The thermal conductive plate 4 can be machined to present a second surface 41 that is as smooth as possible to promote heat transfer towards the heatsink 7, and a first surface 40 that adapts to the height of the components of the power module 2 to minimize thermal resistance between the power module 2 and the thermal conductive plate 4.

[0064] Figure 4 shows a schematic view of the heat distribution in the electronic device 1 when the electronic device 1 is in the low power dissipation configuration. This view clearly shows a heat distribution centered mainly on the thermal conductive plate 4, the inserts 5, and the printed circuit board 3, which is then dissipated.

[0065] Conversely, [Fig. 5] shows a schematic view of the heat distribution in the electronic device 1 when the electronic device is in the heat dissipation configuration. Thus, [Fig. 5] shows a heat distribution more centered around the thermal conductive plate 4 and the heat sink 7 in order to dissipate it.

[0066] The temperature rise is on the order of one degree and allows a strong increase in the thermal performance of the power module 2 and much more efficient cooling.

Claims

Claims

1. Electronic device (1) comprising: - An electronic module (2) comprising a first face (20) and a second face (21) opposite the first face (20), the electronic module (2) comprising n openings (22) passing through the electronic module (2) so as to connect the first face (20) to the second face (21), n being a natural whole number greater than or equal to 2, the electronic module (2) comprising at least one connector (23) extending from the second face (21), - A thermal conductive plate (4) comprising a first surface (40) and a second surface (41), the first surface (40) being in contact with the first face (20) of the electronic power module (2), the thermal conductive plate (4) making it possible to extract heat from the electronic module (2) via the first face (20), - A printed circuit (3) arranged opposite the second face (21) of the electronic module (2), the printed circuit (3) being distant from the second face (21) of the electronic module (2), the printed circuit (3) being electrically connected to the at least one connector (23), - m inserts (5), m being a natural integer greater than or equal to 2 and less than or equal to n, each insert (5) of the m inserts (5) being arranged in an opening (22) among the n openings (22), each insert (5) of the m inserts (5) being a thermal conductor, the m inserts (5) mechanically connecting the electronic module (2) to the thermal conductive plate (4), the m inserts (5) being configured so as to thermally connect the electronic module (2) to the printed circuit (3) to cool the electronic module (2) in a first low dissipation configuration.

2. Electronic device (1) according to claim 1, comprising a radiator (7), the radiator (7) being connected to the second surface (21) of the thermal conductive plate (4), the m inserts (5) mechanically connecting the electronic module (2), the thermal conductive plate

3.

4.

5.

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7.

8. (4) and the radiator (7), the inserts (5) being distant from the printed circuit (3), the radiator (7) being configured to cool the electronic module (2) in a second high dissipation configuration. Electronic device (1) according to any one of claims 1 or 2, wherein n is equal to m. Electronic device (1) according to claim 3, wherein n is equal to 2, the first face (20) and the second face (21) of the electronic module (2) comprising lateral edges (205, 206, 207, 208), each opening (22) among the n openings (22) being positioned at an opposite lateral edge (205, 206, 207, 208). Electronic device (1) according to claim 3, wherein n is equal to 2, the first face (20) and the second face (21) of the electronic module (2) comprising corners (200, 201, 202, 203), each opening (22) among the n openings (22) being positioned at an opposite corner (200, 201, 202, 203). Electronic device (1) according to any one of the preceding claims, wherein the at least one connector (23) comprises a filed end (230) mechanically connected to the printed circuit (3). Electronic device (1) according to any one of the preceding claims, in which the m inserts (5) are made of a material whose thermal conduction is equal to a thermal conduction of the thermal conductive plate (4). Electronic device (1) according to any one of the preceding claims, wherein the thermal conductive plate (4) is made of a material among copper, brass or an alloy of nickel, iron and cobalt.

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