Device for the dissipation of heat from an electronics component of a motor vehicle and method for the production thereof

Abstract

The invention relates to a device and a method for the dissipation of heat from an electronics component (26) of a motor vehicle, comprising at least one heat-conducting element (12) having at least one connection face (16) which is designed such that heat can be dissipated, via the connection face (16), from the electronics component (26) arranged on a printed circuit board (24), wherein between the connection face (16) of the heat-conducting element (12) and the surface of the electronics component (26) a thermally conductive material (28) is arranged, comprising at least one housing (18) which at least partially encloses the printed circuit board (24), wherein the housing (18) has at least one housing opening (19), wherein at least part of the heat-conducting element (12) projects out of said housing opening (19), wherein the heat-conducting element (12) has at least one overhang (13) which at least partially covers the opening (19) of the housing (18), wherein at least one seal (30) and a curable fastening (32) are arranged between the overhang (13) and the housing (18).

Description

[0001] Description

[0002] title

[0003] Device for cooling an electronic component of a motor vehicle and method for its production

[0004] The invention relates to a device for cooling an electronic component of a motor vehicle and a method for producing the same according to the preamble of the independent claims.

[0005] State of the art

[0006] DE 10 2013 206 999 A1 discloses a control unit for a motor vehicle with a heat-conducting housing wall formed from a heat-conducting sheet metal and forming a heat sink. The heat-conducting housing wall is detachably connected to the housing and has an embossing in an area opposite the power semiconductor. The embossing brings the housing wall closer to the power semiconductor, so that a distance, in particular a gap, between the housing wall and the power semiconductor before embossing is greater than a distance, in particular a distance between the housing wall and the surface area, after embossing.

[0007] The invention is based on the object of ensuring reliable heat dissipation of the electronic component. This object is achieved by the features of the independent claims.

[0008] Disclosure of the invention

[0009] By arranging at least one seal and a curable fastener between the thermally conductive element and the housing, the gap between the electronic component and the thermally conductive element can be minimized, even when the electronic component has different geometries. The tolerances are compensated for by the preferably curable or relatively soft seal and the curable fastener after optimal positioning of the thermally conductive element in the sense of a minimal TIM gap. This minimizes the thermal resistance for cooling the electronic component via the thermally conductive element. Due to the priority setting of the gap, the applied amount of thermally conductive material between the connection surface and the electronic component can remain essentially the same. Furthermore, tolerances in the housing, in the circuit board, or other components can be made larger, which has a positive effect on manufacturing costs.

[0010] In a practical development, at least one receiving surface for the seal and / or the fastening is provided on the housing, and / or at least one counter-surface is provided on the heat-conducting element as a receptacle for the seal and / or as a receptacle for the fastening. Both the electromagnetic shielding or sealing, in particular, and the tolerance-compensating fastening can be provided at these locations.

[0011] In a useful development, a stepped arrangement comprising at least one receiving surface and / or at least one counter-surface is provided on the housing and / or on the projection as well as on the heat-conducting element. This allows particularly good sealing or fastening. The accessibility, in particular of the fastening for curing, can also be further improved. This is achieved particularly usefully by arranging the seal on one receiving surface of the stepped arrangement and the fastening on the other receiving surface of the stepped arrangement. For this purpose, the fastening is particularly usefully arranged at a greater distance from the opening than the seal.

[0012] In a practical development, the seal and / or the fastening are designed to be closed and circumferential around the opening. This allows the sealing and fastening to be further improved. In a practical development, it is provided that a maximum permissible height of the mating surface on the housing for receiving the seal relative to the circuit board is at least equal to the sum of a minimum permissible height between the connection surface and the receiving surface for the seal of the heat-conducting element, a minimum gap between the connection surface of the heat-conducting element and the surface of the electronic component to be cooled, and a minimum permissible component height of the electronic component to be cooled, less a minimum height of the seal.This allows a minimum gap to be set without the protrusion of the heat-conducting element resting on the housing and blocking further movement of the connection surface toward the surface of the electronic component before the minimum TIM gap is established. This improves the heat dissipation of the electronic component.

[0013] In a practical development, the seal is a liquid or pasty seal during assembly and / or an EMC seal and / or the fastening is a liquid or pasty fastening during assembly. Particularly preferably, the fastening is an adhesive, in particular an adhesive that is particularly preferably curable by UV light. This makes it particularly easy to compensate for corresponding component tolerances when setting a minimum TIM gap. Furthermore, the curing process can be controlled in a targeted manner.

[0014] Furthermore, a method for producing a device is proposed, characterized by the following steps: providing a housing with a printed circuit board on which an electronic component to be cooled is arranged, wherein the housing comprises at least one housing opening, providing a heat-conducting element with a connection surface which is designed such that the electronic component can be cooled via the connection surface, applying a seal, in particular a curable seal, and / or a curable fastening to the housing and / or to the heat-conducting element, applying a thermally conductive material to the connection surface of the heat-conducting element and / or to the electronic component, inserting the heat-conducting element into the housing opening, moving the connection surface of the heat-conducting element relative to the electronic component.The manufacturing process makes it particularly easy to set a minimum gap between the connection surface and the electronic component.

[0015] In a suitable further development, the connection surface is moved relative to the electronic component, particularly in a force-controlled and / or displacement-controlled and / or speed-controlled manner, so that a minimum gap is established between the connection surface and the electronic component. After setting a minimum gap, the seal and / or the fastening element hardens. By actively adjusting the TIM gap, the tolerance can be ignored and the gap can be adjusted via a corresponding measurement.

[0016] Further useful developments arise from further dependent claims and from the description.

[0017] Short description of the drawing

[0018] They show:

[0019] Figure 1 shows an overview of a control unit as a section from the side and in plan view (without heat-conducting element),

[0020] Figure 2 different control units in side view with different tolerance levels,

[0021] Figure 3 shows the different steps in assembling the control unit and

[0022] Figure 4 shows a section of the control unit with dimensions for a worst-case scenario.

[0023] Embodiment of the invention The invention is illustrated schematically using an embodiment and is described in detail below with reference to the drawing.

[0024] Figure 1 shows a control unit 10 in a side view as a section. An electronic component 26 to be cooled is arranged on a circuit board 24. For example, further electronic components that also need to be cooled can be arranged on the circuit board 24. The electronic component 26 can be, for example, a so-called SIP (System-In-Place) or a component thereof and / or a so-called System-On-Chip (SOC) or another semiconductor with high power dissipation.

[0025] The printed circuit board 24 can be at least partially enclosed by a housing 18. For this purpose, the printed circuit board 24 is connected to the housing 18 via fastening means 14, such as screws or the like. The housing 18 has at least one opening 19. A heat-conducting element 12 is at least partially accommodated in this opening 19. The heat-conducting element 12 protrudes slightly outward, beyond the surface of the housing 18, thus enabling particularly good heat dissipation. The housing 18 can be, for example, a die-cast housing, but also a sheet metal housing or a plastic housing, etc.

[0026] The heat-conducting element 12 serves to dissipate heat from at least the electronic component 26. In order to minimize the thermal contact resistance, the electronic component 26 is thermally coupled to the heat-conducting element 12 via a thermally conductive material 28. The thermally conductive material 28 is arranged between the electronic component 26 and a connection surface 16 on the heat-conducting element 12. The heat-conducting element 12 can be part of a cooler, for example with correspondingly provided cooling fins or with a connection to a water cooler. In any case, the heat-conducting element 12 serves as a heat sink for dissipating heat from the electronic component 26. The heat-conducting element 12 acts as a heat spreader, so that individual, particularly hot spots on the electronic component 26 are spread across the surface as quickly as possible in order to prevent thermal overload. Such heat-conducting elements 12 orHeat spreaders are particularly preferably made of aluminum or pure aluminum, copper (for example, in the form of a copper block), or are designed as a vapor chamber (effective heat dissipation by changing the state of the heat transfer medium provided in the vapor chamber) or similar. For particularly effective heat dissipation, it is advantageous to provide the housing opening 19 above the electronic component 26 to be cooled, for particularly effective heat dissipation without the need for an additional thermally conductive layer.

[0027] Thermally conductive material 28 (TIM: thermal interface materials) can include, for example, thermally conductive pastes, flexible materials in the form of a cushion or pad, etc. A gap x (so-called TIM gap) to be minimized is formed between the connection surface 16 and the surface of the electronic component 26 to be cooled. The smaller this gap x is, the better the power loss of the electronic component 26 can be dissipated. With an active adjustment of the TIM gap, as described in more detail below, the tolerance (for example, of the electronic component 26 and / or the thermally conductive element 12) is ignored and adjusted by measuring the gap. This leads to reproducibly small gaps x, which significantly improves the thermal contact resistance while maintaining the same quality of the thermally conductive material 28.Another advantage is that the applied amount of thermally conductive material 28 remains constant and does not have to be designed for a maximum gap. Furthermore, tolerances in the housing 18, the circuit board 24, or other components can be made larger, which has a positive impact on manufacturability and price.

[0028] The opening of the housing 18 is at least partially covered by a lateral projection 13 of the heat-conducting element 12. The projection 13 can be, for example, a flange, a thinner edge region, or the like. In the exemplary embodiment, the projection 13 is stepped, comprising at least one step 20 on the heat-conducting element 12 or projection 13. The stepped arrangement comprises, for example, at least two preferably flat surfaces formed essentially parallel to the surface of the housing 18 (or essentially parallel to the connection surface 16). These surfaces serve as receiving surfaces 15 (reference numerals, see Figure 3) for receiving at least one seal 30 and / or at least one fastening 32. The heat-conducting element 12 is sealingly connected to the housing 18 via the seal 30 and / or the fastening 32.The seal 30 and / or the fastening element 32 is / are arranged between the receiving surfaces 15 on the housing 18 and on counter surfaces 17 (reference numerals, see Figure 3) on the heat-conducting element 12. This connection (in the form of the seal 30 and / or the fastening element 32) allows a small gap x to be set between the connecting surface 16 and the surface of the electronic component 26 to be cooled. For this purpose, the seal 30 is flexible and / or liquid or pasty and is designed to harden during the manufacturing process. Thus, the seal could be designed in particular as an EMC seal for electromagnetic shielding of the interior of the housing 18. The seal 30 can, for example, be made of FIPG (FIGP: Form in Place Gasket (liquid during assembly)), CIPG (Cured in Place Gasket (hardened during assembly), FoF Fabric over Foam (fabric tube over foam core), tape, foam core, springs, etc.) and inserted or welded between the heat-conducting element 12 and the housing 18.be arranged to fully electrically shield or seal the housing 18. The receiving surfaces 15 on the housing 18, which accommodate the seal 30 and adhesive 32, can be suitably pretreated to improve the connection.

[0029] The fastening 32, for example in the form of an adhesive, primarily serves to fix the heat-conducting element 12 to the housing 18. However, this can also achieve media-tightness or dust-tightness. Furthermore, the fastening 32 can serve as protection against vibration, shock, etc. The fastening 32 is flexible and / or liquid and preferably hardens during the manufacturing process. Thus, the fastening 32 could be designed as an adhesive, in particular as an adhesive curable by UV radiation. Using these sealing / fastening options, the heat-conducting element 12 can be joined from above through the opening 19 of the housing 18 onto the surface of the electronic component 26 to be cooled. This simultaneously allows the thermally conductive material 28 to be pressed between the connection surface 16 and the surface of the electronic component 26 to be cooled, as can the seal 30 and the fastening 32.Subsequent curing allows the geometry, which is individually adjusted for the respective height b of the electronic component 26, to be applied and permanently fixed with a particularly small gap x. This improves the heat dissipation of the electronic component 26.

[0030] The plan view of Figure 1 shows that the seal 30 is designed as a seal 30 that completely surrounds the opening 19. In the exemplary embodiment, the seal 30 is applied to a recess in the housing 18. The fastening 32, which is in particular curable, in turn also surrounds the housing opening 19 in a closed form, completely enclosing the opening 19. The fastening 32 thus also has a sealing effect. Alternatively, however, the fastening 32 does not have to completely enclose the opening 19 in order to ensure the fixation of the heat-conducting element 12 in the housing 18. The fastening 32 is arranged, for example, on the surface of the housing 18 (on the receiving surface 15). Possibly, the fastening 32 could also be arranged in the recess in the housing 18 and the seal 30 on the surface of the housing 18.The stepped arrangement 20 and the further stepped arrangement 21 are advantageous for preventing the seal 30 and fastening element 32 from mixing during pressing. However, alternative designs can be provided that serve the same purpose.

[0031] In the embodiment according to Figure 2, different geometries of the electronic component 26 are shown. The height b of the electronic component 26 in the upper embodiment corresponds to the desired nominal dimension (tolerance t = 0). In the middle embodiment, the height b of the electronic component 26 to be cooled is characterized by a certain excess (as an example dimension by tolerance t = +0.2). This excess or (up to a maximum) tolerance t is compensated for by a greater height of the seal 30 and / or fastening 32 while maintaining a constant gap dimension x (TIM gap of the thermally conductive material 28). In the lower embodiment, the height b of the electronic component 26 to be cooled is characterized by a certain undersize (exemplary tolerance t = -0.2). This undersize t is compensated for by a corresponding height of the seal 30 and / or fastening 32.It is essential that the TIM gap x, which the thermally conductive material 28 assumes between the surface 16 and the surface of the electronic component 26 to be cooled, is very small in the sense of a low thermal contact resistance.

[0032] In the embodiment according to Figure 3, the following seven manufacturing steps or assembly steps are shown schematically.

[0033] Step 1: In preparation for the subsequent steps, the printed circuit board 24 with base plate or a stiffener is installed in a control unit 10 and partially also connected to the housing 18 with a thermally conductive material (TIM). The printed circuit board 24 and housing 18 are joined together, for example, using the appropriate fastening means 14. These are screwed, for example, into corresponding receptacles in the housing 18 that protrude into the interior of the control unit 10. In this illustration, the receiving surfaces 15 on the housing 18 for receiving the seal 30 and / or the fastening 32 can be seen.

[0034] Step 2: For example, over two dispensing steps, the seal 30, in particular an EMC seal, is first applied (or dispensed) to the inner area surrounding the opening 19. Subsequently, or in parallel, the fastening 32 is applied around the seal 30. The fastening 32 is preferably an adhesive, in particular UV adhesive. The order in which the seal 30 and fastening 32 are applied is irrelevant.

[0035] Step 3: The thermally conductive material 28 is applied to the connection surface 16 of the thermally conductive element 12, for example, dispensed in liquid form. Alternatively, a flexible but rigid thermally conductive material 28 (for example, a cushion or pad) could also be applied to the connection surface 16. Preferably, the same amount of thermally conductive material 28 is always applied, regardless of the respective geometry of the electronic component 26. The thermally conductive element 12 is then rotated. In this view, the mating surfaces 17 on the thermally conductive element 12 are designated, which also serve to receive the seal 30 and / or the fastening 32. The seal 30 and the fastening 32 are arranged between the receiving surfaces 15 on the housing 18 and the mating surfaces 17 on the thermally conductive element 12. Step 4: The heat-conducting element 12 is inserted into the opening 19 of the housing 18 via a force-controlled movement.For this purpose, the heat-conducting element 12 is pressed onto the heat-conducting element 28 or against the circuit board 24 via a device in the housing 18. This device consists of a linear unit that can determine and control the travel and force.

[0036] Step 5: The heat-conducting element 12 is moved into the control unit 10 or the corresponding opening 19 until the force reaches a maximum. This force results from the maximum counterforce of the circuit board 24 and the pressed materials, namely the thermally conductive material 28, the seal 30, and the fastening 32. A certain force must not be exceeded in order to avoid causing damage to the circuit board 24 or its solder joints. By inferring from the material data of the heat-conducting element 28 and the flexural rigidity of the circuit board 24, coupled with the joining speed, a desired minimum gap x can be created. After the linear unit or the device has stopped the joining movement of the heat-conducting element 12 and thus remains in this position, the desired gap or the desired gap x has been created between the housing 18 and the heat-conducting element 12 or cooler.This gap x depends on the tolerance conditions of the thermally conductive element 12, the electronic component 26, and the deflection of the circuit board 24. The gap x between the surface of the electronic component 26 to be cooled and the connection surface 16 is filled with the thermally conductive material 28. This varying gap x must now be fixed so that this gap x is maintained even during the curing of the fastening 32, as described below. This could be achieved by the fixture for the joining position, by using a curable fastening 32, or by other measures.

[0037] Step 6: This is where the liquid or flexible fastening material 32 cures. For example, a UV adhesive is used as the fastening material 32. The adhesive or fastening material 32 is irradiated or flashed using UV light 34, thereby curing. This process step requires the fastening material 32 or UV adhesive to be positioned at the outer edge or outer projection 13 of the heat-conducting element 12 to make it accessible to the UV light 34.

[0038] Step 7: Once the mount 32 can absorb forces or has cured, the mounting fixture (not shown) can be removed. The entire control unit 10 can be further processed. For example, the seal 30 and / or mount 32 can be fully cured in an oven process.

[0039] After the seal 30 and / or the fastening element 32 has cured, the heat-conducting element 12 is rigidly connected to the control unit 10 and can dissipate any forces that occur, such as vibration or handling, to the housing 18. This protects solder joints from stress. At the same time, the seal 30 creates an EM-tight connection between the housing 18 and the electrically conductive heat-conducting element 12, which may be necessary.

[0040] The height tolerances indicated in Figure 2, which arise due to the influences described above, are compensated for by the seal 30 and the fastening 32 as shown in Figure 2. If the distance between the heat-conducting element 12 and the housing 18 is greater, the seal 30 is squeezed less, and vice versa. This inaccuracy must be taken into account and compensated for by means of force control during pressing. For this purpose, the circuit board stiffness is simulated or measured, with the circuit board 24 being viewed as a spring. From this, the maximum force can be derived via the maximum stress of the circuit board 24. The time-dependent counterforce of the thermally conductive material 28 is known. The heat-conducting element 12 is moved down until the force has reached its maximum. This results in a minimal gap x. Since the seal 30 and / or the fastening 32 are still liquid orare pasty, the influence of force is limited.

[0041] In the exemplary embodiment, the heat-conducting element 12 has a lateral projection 13 which laterally covers the surface of the housing 18 and projects beyond the opening 19 of the housing 18 as a collar or edge. In particular, on the projection 13 of the heat-conducting element 12 and on the housing 18, the stepped arrangement 20, 22 can be designed, for example, in the form of several steps as counter surfaces 17 and discrete or continuous changes in distance relative to the connection surface 16. Other configurations are conceivable. Accordingly, the housing 18 can also be designed in a stepped manner with at least two receiving surfaces 15 for receiving the seal 30 and the fastening 32. The seal 30 and the fastening 32 harden between the receiving surfaces 15 on the housing 18 and the counter surfaces 17 on the heat-conducting element 12, so that a tight and secure connection is created between the heat-conducting element 12 and the housing 18.

[0042] In order to prevent the heat-conducting element 12 from resting on the housing 18, which could prevent the desired small gap x from forming, certain design relationships must be taken into account. As an example, in the worst-case scenario in Figure 4, a minimum permissible height Hmin of the heat-conducting element 12 is shown, which represents the distance between the connection surface 16 and the mating surface of the seal 30 on the heat-conducting element 12. The corresponding mating surface for the seal 30 on the housing 18 is spaced from the surface of the printed circuit board 24 by a maximum permissible distance Gmax. In a worst-case scenario, the minimum permissible component height Bmin of the electronic component 26 is as shown in Figure 4. In addition, a minimum TIM gap Xmin is shown in the worst-case scenario. Furthermore, a minimum permissible height Imin of the seal 30 is shown for the worst-case scenario.In order to prevent contact, the maximum permissible height Gmax of the counter surface for receiving the seal 30 on the housing 18 must be at least equal to the sum of the minimum permissible height Hmin of the heat-conducting element 12, the minimum Tim gap Xmin and the minimum permissible component height Bmin less the minimum height Imin of the seal 30 or the following equation:.

[0043] Gmax = Hmin + Xmin + Bmin - Imin.

[0044] The electronic components 26 comprise, in particular, high-performance computer cores that perform particularly computationally intensive functions in the motor vehicle. These can be, for example, autonomous or semi-autonomous driving functions, infotainment, communication interfaces between different bus systems (Ethernet, CAN, LIN, etc.) or gateway functionalities, certain security applications for granting authorization, for example to access the motor vehicle from outside, or other operations in the motor vehicle associated with particularly high computing power. The electronic components 26 are particularly preferably high-performance processors, multi-core processors, or highly integrated circuits (SoC, system-on-chip), which are characterized by high power losses. The electronic components 26 arranged on the circuit board 24 are particularly preferably designed to be functionally redundant.If one electronic component 26 fails, the other electronic component 26 can take over the functionality of the failing electronic component 26.

Claims

Claims 1. A device for cooling an electronic component (26) of a motor vehicle, comprising at least one heat-conducting element (12) with at least one connection surface (16) designed such that the electronic component (26) arranged on a printed circuit board (24) can be cooled via the connection surface (16), wherein a thermally conductive material (28) is arranged between the connection surface (16) of the heat-conducting element (12) and the surface of the electronic component (26), comprising at least one housing (18) which at least partially encloses the printed circuit board (24), wherein the housing (18) has at least one housing opening (19), wherein at least a part of the heat-conducting element (12) protrudes from this housing opening (19), wherein the heat-conducting element (12) has at least one projection (13) which at least partially covers the opening (19) of the housing (18),wherein at least one seal (30) and a curable fastening (32) are arranged between the projection (13) and the housing (18).

2. Device according to claim 1, characterized in that at least one receiving surface (15) for the seal (30) and / or the fastening (32) is provided on the housing (18), and / or that at least one counter-surface (17) is provided on the heat-conducting element (12) as a receptacle for the seal (30) and / or as a receptacle for the fastening (32).

3. Device according to one of the preceding claims, characterized in that a step-shaped arrangement (20, 22) is provided on the housing (18) and / or on the projection (13) as well as on the heat-conducting element (12), comprising at least one receiving surface (15) and / or at least one counter-surface (17) for the seal (30) and / or for the fastening (32).

4. Device according to one of the preceding claims, characterized in that on one receiving surface (15) of the step-shaped arrangement the seal (30) and the fastening (32) is arranged on the further receiving surface (15) of the step-shaped arrangement (20,22).

5. Device according to one of the preceding claims, characterized in that the seal (30) and / or the fastening (32) is / are designed to be closed and circumferential around the opening (19).

6. Device according to one of the preceding claims, characterized in that the fastening (32) is arranged at a greater distance from the opening (19) than the seal (30).

7. Device according to one of the preceding claims, characterized in that the seal (30) is or are designed as a hardenable seal and / or as a soft seal.

8. Device according to one of the preceding claims, characterized in that a maximum permissible height (Gmax) of the counter surface on the housing (18) for receiving the seal (30) relative to the circuit board (24) is at least equal to the sum of a minimum permissible height (Hmin) between the connection surface (16) and the receiving surface (17) for the seal (30) of the heat-conducting element (12), a minimum gap dimension (Xmin) between the connection surface (16) of the heat-conducting element (12) and the surface of the electronic component (26) to be cooled, and a minimum permissible component height (Bmin) of the electronic component (26) to be cooled, less a minimum height (Imin) of the seal (30), in particular according to the following equation: Gmax = Hmin + Xmin + Bmin - Imin.

9. Device according to one of the preceding claims, characterized in that the seal (30) is a seal (30) which is liquid or pasty during assembly and / or an EMC seal (30) and / or that the fastening (32) is a fastening (32) which is liquid or pasty during assembly, and / or that the seal (30) is a curable seal, in particular in the form of a mold in Place Gasket and / or the adhesive (32) is a curable adhesive, in particular an adhesive curable by UV light (34).

10. A method for producing a device according to one of the preceding claims, comprising the following steps: providing a housing (18) with a printed circuit board (24) on which at least one electronic component (26) to be cooled is arranged, wherein the housing (18) comprises at least one housing opening (19), providing a heat-conducting element (12) with a connection surface (16) designed such that the electronic component (26) can be cooled via the connection surface (16), applying a particularly curable seal (30) and / or a curable fastening (32) to the housing (18) and / or to the heat-conducting element (12), applying a thermally conductive material (28) to the connection surface (16) of the heat-conducting element (12) and / or to the electronic component (26), inserting the heat-conducting element (12) into the housing opening (19),Moving the connection surface (16) of the heat-conducting element (12) relative to the electronic component (26)., 11 . Method according to one of the preceding method claims, characterized in that the connection surface (16), in particular force-controlled and / or in particular path-controlled and / or in particular speed-controlled, is moved relative to the electronic component (26) so that a minimum gap (x) is established between the connection surface (16) and the electronic component (26), wherein after setting a minimum gap (x), the fastening (32) and / or the seal (30) hardens.

12. Method according to one of the preceding method claims, characterized in that the seal (30) and / or the fastening (32) is applied in a closed structure completely surrounding the housing opening (19).

13. Method according to one of the preceding method claims, characterized in that the seal (30) and / or the fastening (32) is applied to a receiving surface (15) on the housing (18) of a counter surface (17) on the heat-conducting element (12).

14. Method according to one of the preceding method claims, characterized in that the seal (30) is arranged on a receiving surface (15) of a step-shaped arrangement (20, 22) on the housing (18) and the fastening (32) is arranged on a further receiving surface (15) of the step-shaped arrangement (20, 22).

15. Method according to one of the preceding method claims, characterized in that a curable adhesive is used as the fastening (32), in particular an adhesive curable by UV light (34).

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