Electronic module, particularly for motor vehicles

Abstract

Electronic module, particularly for motor vehicles. The invention relates to an electronic module (10) comprising: an intermediate plate (20) extending along a first plane (P1) between an upper surface (21) and a lower surface (22) intended to come into contact with a cold source (30), a PCB (40) disposed on the upper surface (21) of the intermediate plate (20) and extending along a second plane (P2) parallel to the first plane (P1), a plurality of electronic components (50, 51, 52, 53, 54) connected to the PCB (40) and capable of emitting heat, a thermal element (60), the intermediate plate (20) having a through-hole (80) between its lower surface (22) and its upper surface (21), and the thermal element (60) extending through one of the through-holes (80), a lower surface (22) of said thermal element (60) being flush with the lower surface (22) of the intermediate plate (20). (Figure 1)

Description

Title of the invention: Electronic module, particularly for motor vehicles

[0001] The present invention relates to the field of electronic modules, particularly for motor vehicles, and more specifically to the field of cooling electronic boards equipping such modules.

[0002] The invention relates to an electronic module comprising an electronic board with optimized cooling for the components it carries. In such a module, the components are typically mounted on a printed circuit board (PCB), or electronic board, which allows them to be electrically connected. The electronic board acts as a mechanical support for these components. However, an electronic board alone is inefficient at transferring the heat produced by its components to the outside. It is necessary to provide a cooling device for the components. Indeed, the electronic board alone does not provide a solution for dissipating the heat generated by the components.

[0003] An electronic circuit board includes points with a higher temperature than the rest of the board. These hot spots correspond to the locations of certain components that emit heat. To ensure the dissipation of heat from these hot spots, heat pipes can be used. These are long metallic cylinders (for example, made of copper or aluminum) containing a fluid such as water. This water is in equilibrium between its gaseous and liquid phases, in the absence of any other gas. In the portion of the heat pipe located near the component to be cooled, the water heats up and vaporizes, absorbing energy from the heat emitted by this component. This gas then travels up the heat pipe to a cold source where it is cooled until it condenses back into a liquid.

[0004] In another existing solution, the electronic board bearing its components is placed on an intermediate plate. The assembly formed by the electronic board and the intermediate plate is hermetically sealed in a housing whose base is in contact with a cold surface, for example, the casing of a pre-cooled battery, for cooling by thermal conduction. This solution offers several advantages. Firstly, it ensures the cooling of the electronic board. Secondly, and importantly due to the fragility of electronic components, the hermetically sealed housing protects the board. protects electronics and its components from external aggressions such as humidity or dust, and can easily adapt to any cold plate.

[0005] In certain electronic modules, given that some electronic components deliver a lot of heat per unit of time, expressed in watts, it is necessary to be able to dissipate it efficiently in order to avoid exceeding their maximum permissible operating temperature.

[0006] We are then faced with the problem of rapid and efficient evacuation of the heat produced by the electronic components, in an environment with restricted dimensions and in a completely hermetically sealed manner to protect the components from dust or any other aggressive element from the environment.

[0007] The objective of the invention described in this document is therefore to provide a solution to the problems encountered in the prior art by proposing an electronic module capable of efficiently dissipating the heat emitted by its electronic components while meeting the requirements for a safe environment for the components. This innovative module thus exhibits excellent thermal performance.

[0008] To this end, the invention relates to an electronic module comprising: - an intermediate plate extending along a foreground between an upper surface and a lower surface designed to come into contact with a cold source, - a PCB positioned on the upper surface of the intermediate plate and extending along a second plane parallel to the first plane, - a plurality of electronic components connected to the PCB and capable of emitting heat, - at least one thermal element,

[0009] the intermediate plate having at least one through opening between its lower surface and its upper surface, and at least one thermal element extending through the at least one through opening, a lower surface of said thermal element being flush with the lower surface of the intermediate plate.

[0010] Thanks to these features, the electronic module has a passage through the intermediate plate dedicated to heat transfer between an electronic component and the lower surface of the intermediate plate, which is intended to be in direct contact with a cold source. The through-hole provides a direct path for dissipating the heat produced in the module. The thermal element is in direct contact with both the hot and cold sources, thus providing efficient cooling of the module. It is understood from the above that the thermal element acts as the physical and thermal link, directing the heat from a component to the cold source.

[0011] In a variant of the electronic module according to the invention, at least one thermal element is one among the plurality of electronic components.

[0012] The local opening created in the intermediate plate allows an electronic component to be housed there, thus exposing it directly to the cold source. In other words, the lower surface of the component lies in the plane of the lower surface of the intermediate plate. It is therefore intended to be in contact with the cold source. The judicious positioning of the hot component in the through-hole allows for direct heat transfer from the hot source to the cold source. By proceeding in this way, there is no longer a thermal barrier between the component and the cold source, and the heat has less material to pass through. The thermal performance of the module is thereby improved.

[0013] In another variant of the electronic module according to the invention, the at least one thermal element is a heat transfer element having a first end, a second end, opposite to the first end, and a body between the first and second ends, the body being disposed through the at least one through opening, the first end being at least partially in contact with one among the plurality of electronic components and the second end being intended to be in contact with the cold source.

[0014] Thanks to this feature, heat transfer between the hot components and the cold source occurs directly. The heat from the components is absorbed at the first end of the heat transfer element and transferred to the other end. This reduces the overall thermal resistance.

[0015] Of course, the electronic module of the invention can include several through-openings, for example two, and a combination of thermal elements, one being a component housed in one of the two through-openings and the other being a heat transfer element whose body passes through the other of the two through-openings.

[0016] In one embodiment of the invention, the heat transfer element has a shape defined by a first branch and a second branch extending parallel between them and a base connecting the first and second branches, the first end being the first branch, the second end being the second branch and the body being the base.

[0017] The heat transfer element can be a heat pipe that transfers heat between the lower surface of an electronic component and the cold source by means of the principle of heat transfer by phase transition of a fluid. Within the heat pipe, the fluid in its liquid state vaporizes by absorbing thermal energy emitted by the hot component at its first end. The vapor flows through the heat pipe to its second end where it condenses upon contact with the cold source, allowing to transfer thermal energy to the cold source. The circulation that then occurs in the heat pipe results in the rapid and highly efficient transfer of heat. A heat pipe thus contributes to the rapid extraction of the heat generated in the module.

[0018] A heat pipe exhibits a high heat transfer capacity without requiring an external energy source. Furthermore, it contains no moving parts and offers a rapid response time.

[0019] In one variant, the first and second branches extend on the same side relative to the base. This is referred to as a U-shaped (or C-shaped) heat pipe.

[0020] In another variant, the first and second branches extend on either side of the base. This is referred to as an S-shaped heat pipe.

[0021] The orientation of the branches depends on the arrangement of the electronic module, and in particular on the positioning of the components, their shape and the space available to place the heat pipe through the intermediate plate.

[0022] According to the invention, the intermediate plate may further include a blind opening. This blind opening allows a component to be placed between the opening and the PCB. This configuration is advantageous in the case of a component of intermediate height, i.e., one shorter than the intermediate plate and / or producing less heat than other components. Such a component is placed between the PCB and the intermediate plate, and heat transfer occurs in the conventional manner through the intermediate plate. This results in a reduction in size.

[0023] Thus, advantageously, one among the plurality of electronic components extends between the PCB and an upper surface of the blind opening.

[0024] Advantageously, the electronic module further comprises a first layer of thermal interface material disposed on an upper surface of the blind opening.

[0025] The invention also relates to an electronic device comprising the electronic module described above and a second layer of thermal interface material disposed on the lower surface of the intermediate plate of the electronic module.

[0026] In both cases, the thermal interface material layer is designed to fill the microscopic spaces between the two non-uniform surfaces with a substance that has better thermal conductivity than air. This layer ensures efficient heat transfer from the component to the intermediate plate and / or from the intermediate plate to the cold source. In addition to its thermal function, the second layer contributes to the hermeticity of the electronic device by creating a continuous boundary for the electronic module.

[0027] Finally, the invention relates to an electronic assembly comprising a cold plate and such an electronic device, the second layer of thermal interface material being in contact with the cold plate.

[0028] During the assembly of the electronic device on the cold plate, the second layer of thermal interface material is brought into contact with the cold plate to connect the device to its destination cold source. In addition to establishing the thermal connection of the elements to be joined, the physical connection is simultaneously made. In other words, the second layer of thermal interface material completes the seal of the electronic device to the cold plate and ensures the required airtightness for such an assembly.

[0029] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given by reference to the accompanying schematic drawings on the other hand, in which:

[0030] [Fig. 1] schematically represents a cross-sectional view of an electronic module according to the invention,

[0031] [Fig.2] schematically represents a cross-sectional view of a variant of the module electronic according to the invention,

[0032] [Fig.3] schematically represents the positioning of a heat pipe in a plate intermediate of the electronic module of the invention.

[0033] The features, variants, and different embodiments of the invention, as described or as they will be presented in the detailed description that follows, can be combined in various ways, provided that 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.

[0034] For the sake of clarity, the same elements are designated by the same references in the different figures.

[0035] Figure 1 schematically represents a cross-sectional view of an electronic module 10 according to the invention. The electronic module 10 comprises an intermediate plate 20 extending along a first plane PI between an upper surface 21 and a lower surface 22. The lower surface is advantageously flat, parallel to plane PI, and is intended to come into contact with a cold source 30. The intermediate plate 20 has a general shape extending along plane PL. As can be seen in Figure 1, the upper surface 21 that delimits the intermediate plate may not not be continuous. In other words, the intermediate plate may include recesses or blind openings as detailed below. The intermediate plate is made of a thermally conductive material, for example, aluminum.

[0036] In what follows, the invention is described with the example of a flat intermediate plate 20. However, the invention remains within the scope of the invention if the intermediate plate 20 is a wall or a bottom of an electronic housing, in which case it is this wall or bottom of the electronic housing that is intended to be brought into contact with a cold source.

[0037] The electronic module 10 comprises a PCB 40 (short for Printed Circuit Board, also called an electronic board) disposed on the upper surface 21 of the intermediate plate 20 and extending along a second plane P2 parallel to the first plane PL. At least a portion of the lower surface of the PCB 40 rests against the upper surface 21 of the intermediate plate 20. In a known manner, the PCB 40 is fixed to the intermediate plate 20 by fastening means 18, for example, a plurality of screws distributed at the four corners of the PCB. The PCB provides the mechanical support for the electronic components and allows their electrical connection according to the requirements of the electronic module.

[0038] The electronic module 10 comprises a plurality of electronic components 50, 51, 52, 53, 54 connected to the PCB 40 and capable of emitting heat. The plurality of electronic components generally extend perpendicularly to the first plane PI, with some of them extending at least partially between the PCB and the intermediate plate. During operation, the electronic components generate heat that must be dissipated to ensure proper functioning of the electronic module. Each electronic component is designed to operate within a specific temperature range. If the heat generated by the electronic components is not dissipated, the electronic components will overheat, and beyond a certain temperature threshold, their operation will be disrupted and they may be damaged.

[0039] The electronic module 10 comprises at least one thermal element 60. The thermal element has access to the heat emitted by at least one of the electronic components as will be described below. As will become clear from the description of the invention, the thermal element can be viewed as an internal element of the electronic module providing a thermal connection from a component to the cold source.

[0040] According to the invention, the intermediate plate 20 has at least one through-opening 80 between its lower surface 22 and its upper surface 21. And the thermal element 60 extends through the through-opening 80. In addition, a surface lower 22 of said thermal element 60 is flush with the lower surface 22 of the intermediate plate 20.

[0041] Thus, according to the principle of the invention, the electronic module is defined by the PCB 40 on which the electronic components are mounted. The PCB is placed on the intermediate plate, which includes a through-hole 80. This through-hole 80 forms a passage through the intermediate plate. The thermal element 60 passes through the through-hole. It is connected on one side to a component and on the other side is flush with the lower surface 22 of the intermediate plate 20. This means that one end of the thermal element 60 is in contact with the component, which represents a heat source. The fact that the second end of the thermal element 60 is flush with the lower surface 22 of the intermediate plate 20 means that the second end of the thermal element 60 terminates at the level of the lower surface 22.To be more precise, the second end of the thermal element 60 is either strictly contained in the plane of the lower surface 22, or almost contained in the plane of the lower surface 22 (i.e., slightly recessed from the surface 22).

[0042] Thanks to these characteristics, the through-hole constitutes a heat transfer channel between an electronic component and the lower surface of the intermediate plate intended to be in direct contact with a cold source. The through-hole forms an exit point for the heat produced in the module. This heat transfer occurs directly through the thermal element and provides efficient cooling of the module.

[0043] The through-hole has a cross-section with dimensions (width and length) slightly larger than those of the thermal element that passes through it. These dimensions allow for easy insertion of the thermal element into the through-hole.

[0044] As represented, the through opening extends preferentially perpendicularly to the plane PL. However, within the framework of the invention, it is entirely conceivable to consider a through opening extending through the intermediate plate along an axis secant to the plane PI (as could be applicable to the embodiment detailed on the basis of [Fig.2]).

[0045] According to one embodiment of the invention, the thermal element 60 is one of a plurality of electronic components 51, 52, 53. In other words, depending on the scenarios that will be explained below, the electronic component is wholly or partially disposed within the through-hole. The electronic components 51, 52, 53 each have an upper surface and a lower surface, the lower surface being disposed under the PCB (i.e., between the PCB and the intermediate plate). It is therefore understood from the above that the lower surface of the component, which is the thermal element 60, is flush with the lower surface 22 of the intermediate plate.

[0046] By proceeding in this way, the intermediate plate is locally opened by a through-hole to accommodate an electronic component in order to expose it directly to the cold source. This results in improved thermal performance of the module.

[0047] In the case of the electronic component 51, since it is short (i.e., having a dimension along an axis perpendicular to plane P2 less than the height of the intermediate plate), the component 51 is not tall enough to pass through the through-hole 80 on its own. It is offset so that its lower surface is substantially in the same plane as the lower surface of the intermediate plate. The component 51 is connected to the PCB by pins 55. Despite its short height, it is thus possible to provide direct contact between the component 51 and the cold source 30.

[0048] In the case of the electronic components 52, 53, the height of the component is equal to or greater than the distance between the lower surface of the PCB and the lower surface 22 of the intermediate plate. For a height equal to the distance between the lower surface of the PCB and the lower surface 22, the component occupies the through-hole 80 along its entire height. The upper surface of the component is in contact with the PCB, and its lower surface is flush with the lower surface 22 of the intermediate plate. For a height greater than the height of the through-hole, the component passes through the PCB and connects to the PCB via tabs (not shown) from the top of the component and the PCB. In the configurations of the components 52, 53, the component is tall enough to align with the lower surface 22, i.e., to come into contact with the cold source.

[0049] Finally, it can be noted that component 54 is located above the PCB. Heat transfer between component 54 and the cold source traditionally occurs through the intermediate plate.

[0050] Figure 2 schematically represents a cross-sectional view of a variant of the module electronic module 100 according to the invention. The elements of the electronic module 100 shown in [Fig. 2] are identical to those of the module 10 shown in [Fig. 1]. In this embodiment of the invention, the thermal element 70 is a heat transfer element. The electronic module 100 is shown here with two thermal elements 70, i.e., two heat transfer elements 110, 120. Each of the two heat transfer elements comprises a first end 111 (respectively 121), a second end 112 (respectively 122), opposite the first end 111 (respectively 121), and a body 113 (respectively 123) between the first and second ends. The body 113 (respectively 123) is disposed through a through opening 81. The first end 111 (respectively 121) is at least partially in contact with one of the electronic components 51 (respectively 52) and the second end 112 (respectively 122) is intended to be flush with the lower surface 22, to be in contact with the cold source 30.

[0051] Thanks to this feature, heat from the components is recovered at the first end of the heat transfer element and transferred to the other end. This heat transfer reduces the overall thermal resistance without adding bulk, since the heat transfer element passes through the intermediate plate. In other words, thanks to the invention, the heat transfer element travels in an innovative way through an area that is known in the prior art to have to be closed in order to convey heat out of the module to the cold source.

[0052] Fig. 3 schematically represents the positioning of a heat pipe in an intermediate plate of the electronic module of the invention.

[0053] The heat transfer element 110 (respectively 120) has a shape defined by a first branch 131 and a second branch 132 extending parallel to each other and a base 133 connecting the first and second branches 131, 132. It follows that the first end 111 (respectively 121) is the first branch 131, the second end 112 (respectively 122) is the second branch 132 and the body 113 (respectively 123) is the base 133. The heat transfer element 110, 120 can be a heat pipe.

[0054] A heat pipe is a device that transfers heat between two interfaces (here, the lower surface of an electronic component, referred to as the hot surface, and the cold source). Inside a heat pipe is a fluid that changes to a gaseous state when heated and condenses against the wall of the heat pipe when cooled. The circulation that then occurs within the heat pipe results in the rapid and highly efficient transfer of heat. A heat pipe thus contributes to the rapid extraction of the heat generated in the module.

[0055] A heat pipe exhibits a high heat transfer capacity without requiring an external energy source. Furthermore, it contains no moving parts and offers a rapid response time. For all these reasons, the use of a heat pipe within an electronic module is particularly suitable and advantageous. However, when used in the traditional manner between a component surface and a wall adjacent to the PCB, it remains bulky. In the invention, the through-hole in the intermediate plate makes the heat pipe's positioning particularly innovative since it provides access to both the hot and cold sources at its ends, without adding any extra bulk.

[0056] The principle of the invention using a heat pipe applies analogously to the use of a vapor chamber. A vapor chamber is based on the same technology as a heat pipe. Unlike linear heat transport While heat transfer occurs in one direction in a heat pipe, a vapor chamber allows heat to be transferred in two directions and more completely. Vapor chambers are typically around 3 mm thick and up to 300 x 300 mm in size.

[0057] It should be noted that the invention is based on the through-hole formed in the intermediate plate, which is used to create a heat transfer channel by inserting the hot component or by passing a heat pipe through the through-hole. The heat pipe thus constitutes a path for transferring heat between the hot component and the cold source.

[0058] As can be seen in [Fig. 3], the first branch 131 and the second branch 132 extend in the same direction relative to the base 133 (U). The heat transfer element is also said to be U-shaped.

[0059] Alternatively, the first branch 131 and the second branch 132 extend on either side of the base 133 (S). The heat transfer element is also said to be S-shaped.

[0060] The choice of one or the other of these variants is dictated by the arrangement of the components on the PCB and the space available to place the heat transfer element.

[0061] To install it, the heat pipe is inserted in a straight line and passed through the through-hole in the intermediate plate. The first arm 131 is bent towards the upper surface of the intermediate plate and the second arm is bent towards the lower surface of the intermediate plate, in one direction or the other (which will determine the U-shape or S-shape of the heat pipe in its final position in the module). Advantageously, the intermediate plate has recesses at the first and second arms to accommodate them. As a result, the heat pipe in its final position is flush with both the upper and lower surfaces of the intermediate plate, thus ensuring perfect contact between the hot component and the cold source.

[0062] As mentioned previously, the through-hole advantageously extends around an axis perpendicular to the PI plane to allow the insertion of a component, or alternatively, the straight insertion of a heat pipe. However, this axis can also intersect the PI plane, in which case the heat pipe is inserted along this axis and its two branches are positioned similarly to that described above. Such a configuration can be advantageous if blind openings accommodate other components near the heat pipe, thus leaving less space for the heat pipe body.

[0063] With reference to [Fig. 1] or [Fig. 2], it can be seen that the intermediate plate 20 can further include a blind opening 180, 181.

[0064] Such a blind opening allows an electronic component 50 with a height less than the height of the intermediate plate to extend between the PCB 40 and an upper surface of the blind opening 180. The transfer of heat between the component 50 and the cold source is done entirely via the intermediate plate.

[0065] As schematically represented at the blind opening 181, the electronic module according to the invention may further comprise a first layer 140 of thermal interface material disposed on an upper surface 182 of the blind opening 181. A thermal interface material (also known by its acronym TIM) fills the minute microscopic voids present between two non-uniform surfaces with a substance that has better thermal conductivity than air. TIMs can comprise various materials used to improve thermal conductivity, thus ensuring efficient heat transfer from the component to the intermediate plate. Here, the layer 140 of thermal interface material fills the micro-spaces between the upper surface 182 and the lower surface of the component 52, 53.

[0066] The invention also relates to an electronic device 200 comprising the electronic module described above and a second layer 150 of thermal interface material disposed on the lower surface 22 of the intermediate plate 20 of the electronic module. As before, the layer 150 will fill the micro-gaps between the lower surface 22 and the upper surface of the cold plate on which the device 200 will be assembled. In addition, the layer 150 provides the required airtight seal for the electronic module. Once disposed on the surface 22, the layer 150 is advantageously covered with a removable film to protect it from dust. Although not shown, the device 200 can be housed in a casing that is open at its lower surface, i.e., encompassing the device from above, to protect the PCB and its components.

[0067] The invention also relates to an electronic assembly 300 comprising a cold plate 30, forming the cold source, and the electronic device 200 described above. The second layer 150 of interface material is in contact with the cold plate 30. Layer 150 has the same role as layer 140, namely filling the micro-gaps between the surface 22 and the upper surface of the cold plate 30. Thus, the electronic assembly 300 is completely hermetically sealed by assembling the housing of the device 200 onto the cold plate 30.

[0068] The invention thus makes it possible to obtain an electronic module that efficiently dissipates the heat generated by its electronic components. Although having one or more openings, the components of the electronic module of the invention are not subjected to the circulation of contaminants contained in the air that are harmful to the components (particularly the humidity of the surrounding air, but (also dust, ...)• Furthermore, the electronic module of the invention offers a weight reduction advantage over prior art solutions: the intermediate plate is perforated, and no additional device is required to dissipate heat. Last but not least, it offers excellent thermal performance.

[0069] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the features of different embodiments of the invention can be combined to carry out the invention, provided that these embodiments are not incompatible with each other.

Claims

Demands

1. An electronic module (10, 100) comprising: - an intermediate plate (20) extending along a first plane (P1) between an upper surface (21) and a lower surface (22) intended to contact a cold source (30), - a PCB (40) disposed on the upper surface (21) of the intermediate plate (20) and extending along a second plane (P2) parallel to the first plane (P1), - a plurality of electronic components (50, 51, 52, 53, 54) connected to the PCB (40) and capable of emitting heat, - at least one thermal element (60, 70), the electronic module being characterized in that the intermediate plate (20) has at least one through-hole (80, 81) between its lower surface (22) and its upper surface (21), and in that the at least one thermal element (60, 70) extends through the at least one opening through (80, 81), a lower surface (22) of said thermal element (60,70) flush with the lower surface (22) of the intermediate plate (20).

2. Electronic module (10) according to claim 1, wherein at least one thermal element (60) is one among the plurality of electronic components (51, 52, 53).

3. Electronic module (100) according to claim 1 or 2, wherein at least one thermal element (70) is a heat transfer element (110, 120) having a first end (111, 121), a second end (112, 122), opposite the first end (111, 121), and a body (113, 123) between the first and second ends, the body (113, 123) being disposed through at least one through opening (81), the first end (111, 121) being at least partially in contact with one among the plurality of electronic components (51, 52) and the second end (112, 122) being intended to be in contact with the cold source (30).

4. Electronic module (100) according to claim 3, wherein the heat transfer element (110, 120) has a shape defined by a first branch (131) and a second branch (132) extending parallel to each other and a base (133) connecting the first and second branches (131, 132), the first end (111, 121) being the first branch (131), the second end (112, 122) being the second branch (132) and the body (113, 123) being the base (133).

5. Electronic module (100) according to claim 4, wherein the first branch (131) and the second branch (132) extend on the same side with respect to the base (133).

6. Electronic module (100) according to claim 4, wherein the first branch (131) and the second branch (132) extend on either side of the base (133).

7. Electronic module (10, 100) according to any one of claims 1 to 6, wherein the intermediate plate (20) further comprises a blind opening (180, 181).

8. Electronic module (10, 100) according to claim 7, wherein one of the plurality of electronic components (50) extends between the PCB and an upper surface of the blind opening.

9. Electronic module (10, 100) according to claim 8, further comprising a first layer (140) of thermal interface material disposed on an upper surface (182) of the blind opening (181).

10. Electronic device (200) comprising the electronic module (10, 100) according to any one of the preceding claims and a second layer (150) of thermal interface material disposed on the lower surface (22) of the intermediate plate (20) of the electronic module.

11. Electronic assembly (300) comprising a cold plate (30) and the electronic device (200) according to the preceding claim, the second layer (150) of interface material being in contact with the cold plate (30).

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