Connection element between a heat-emitting electrical component and a heat sink, and electrical circuit board comprising such a connection element

Abstract

The invention relates to a connection element (100) between a heat-emitting electrical component (101) and a heat sink (102). The connection element is characterised in that the connection element (100) is constructed in layers from at least three material layers, wherein a first material layer (103) consists of a thermally conductive and electrically insulating first material and has a contact surface for the thermally conductive arrangement of the heat-emitting electrical component (101), a third material layer (105) which consists of a thermally conductive third material and has a contact surface for thermally conductive contact with the heat sink (102), and a second material layer (104) consisting of a thermally conductive and electrically conductive second material is arranged between the first material layer (103) and the third material layer (105).

Description

[0001] Connecting element between a heat-emitting electrical component and a heat sink, as well as an electrical circuit board with such a connecting element

[0002] The invention relates to a connecting element between a heat-emitting electrical component and a heat sink, an electrical circuit board with such a connecting element, a ground module GPM (English for “Ground Pad Module”) or a vehicle module CPM (English for “Car Pad Module”) of an inductive charging system with such a connecting element and an inductive vehicle charging system with such a ground module GPM or a vehicle module CPM.

[0003] Power electronic components, such as power semiconductors, or corresponding power electronic assemblies, sometimes generate large amounts of heat during operation, which must be dissipated to prevent overheating or even destruction of these components or assemblies. Typically, the heat-emitting components are thermally coupled to a heat sink, usually via a thermally conductive and electrically non-conductive interface material.

[0004] However, due to this thermal coupling of an electronic component of a power electronics assembly with a heat sink, a parasitic capacitance is created by the interface material, for example between a surface of a power semiconductor to be cooled and the heat sink thermally coupled via the interface material, which leads to undesired stray currents, particularly during electrical switching operations in the electrical component or in the power electronics assembly, and thus to undesired feedback effects on the power electronics circuit.

[0005] Power electronics components arranged directly on a printed circuit board (PCB), so-called surface-mounted device (SMD) components, therefore also require effective cooling to dissipate heat generated during operation, often through the PCB to a heat sink thermally coupled below the board. Heat conduction through the PCB can be achieved, for example, by heat conduction channels made of a highly thermally conductive material arranged in the PCB and thermally coupling this material to the heat sink. Here, too, the prior art typically thermally couples such heat conduction channels of PCBs to a heat sink using a thermally conductive and electrically non-conductive interface material, with the undesirable effects mentioned above.

[0006] The object of the invention is to provide a connecting element between a heat-emitting electrical component and a heat sink in which the parasitic capacitances mentioned above no longer occur or only occur in a greatly reduced form.

[0007] The invention is based on the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims. Further features, possible applications, and advantages of the invention will become apparent from the following description and the explanation of exemplary embodiments of the invention illustrated in the figures.

[0008] A first aspect of the invention relates to a connecting element between a heat-dissipating electrical component and a heat sink. The connecting element is characterized in that the connecting element is constructed layer by layer from at least three material layers, wherein a first material layer consists of a thermally conductive and electrically insulating first material and has a contact surface for the thermally conductive arrangement of the heat-dissipating electrical component, a third material layer consists of a thermally conductive third material and has a contact surface for thermally conductive contact with the heat sink, and a second material layer made of a thermally conductive and electrically conductive second material is arranged between the first material layer and the third material layer.

[0009] These three material layers are advantageously designed to be flat and arranged one above the other. Advantageously, the third material layer is arranged directly on the second material layer (contacting it) and / or the second material layer is arranged directly on the first material layer (contacting it). Advantageously, the heat-dissipating electrical component is arranged directly on the contact surface of the first material layer, and the heat sink is arranged directly on the third material layer.

[0010] The term "component" in this context can refer to a single electrical component (e.g., a power transistor) or a group of several electrical components that, taken together, form a heat-dissipating electrical component. An electrical component can therefore also be an electrical assembly. The term "heat sink" in this context refers to a passive and / or active heat sink.

[0011] The heat-dissipating electrical component can be enclosed by a housing. In this case, the housing, as the outer heat-dissipating contact surface of the electrical component, can contact the first material layer.

[0012] The first material layer acts as a non-conductive dielectric between the electrical component and the electrically conductive second material layer. This initially creates a parasitic capacitance between the electrical component and the electrically conductive second material layer.

[0013] The same applies to the third material layer. It acts as a non-conductive dielectric between the electrically conductive second material layer and the heat sink. This initially creates a parasitic capacitance between the conductive second material layer and the heat sink.

[0014] Particularly advantageously, the second material layer is kept constant at a predetermined electrical potential during operation of the electrical heat-dissipating component. This potential can advantageously be a static potential, such as electrical ground potential, or a positive or negative potential. The latter is advantageously a positive or negative potential of an associated DC link or a center point potential of an associated DC link.

[0015] The constant electrical potential of the second material layer ensures that the parasitic capacitance between the second material layer and the heat sink is not charged or discharged during operation of the heat-dissipating component, particularly during electrical switching processes (transient electrical states) in the component. During transient electrical states in the heat-dissipating component, only the parasitic capacitance between the electrical component and the second material layer is charged or discharged. Stray currents, as described above in the prior art, are thereby significantly reduced.

[0016] Depending on how the constant electrical potential is selected, the insulation requirements can be reduced (e.g., a center-point potential of the DC link represents an advantageous option here). In a further development of the proposed connecting element, the third material is electrically insulating. In a further development of the proposed connecting element, the third material is electrically conductive.

[0017] In an advantageous development of the connecting element, the second material layer or the second and first material layers or the third and second and first material layers are arranged within an electrical printed circuit board (PCB). This enables, in particular, effective cooling of SMD components on electrical printed circuit boards with significantly reduced stray currents generated by parasitic capacitances.

[0018] In an advantageous development of the connecting element, the third material layer is arranged directly on the second material layer and / or the second material layer is arranged directly on the first material layer. This means that the respective material layers are advantageously directly mechanically, electrically, and thermally coupled to one another.

[0019] Advantageously, the connecting element comprises exactly the first, second and third material layers.

[0020] Advantageously, the first material consists of

[0021] • FR4

[0022] • Ceramics,

[0023] • Alumina and / or alumina substrates

[0024] • Aluminum nitride and / or aluminum nitride substrates

[0025] • Silicon nitride and / or silicon nitride substrates

[0026] • Zirconium doped AI2O3 substrates

[0027] • Glass fiber reinforced plastic material

[0028] • Polyamide or a mixture thereof.

[0029] Advantageously, the second material consists of

[0030] • Copper

[0031] • Aluminum • Silver

[0032] • Gold

[0033] • Metal alloys with good electrical conductivity or a mixture thereof.

[0034] Advantageously, the third material consists of

[0035] • FR4

[0036] • Ceramics,

[0037] • Alumina and / or alumina substrates

[0038] • Aluminum nitride and / or

[0039] Aluminum nitride substrates

[0040] • Silicon nitride and / or silicon nitride substrates

[0041] • Zirconium doped AI2O3 substrates

[0042] • Glass fiber reinforced plastic material

[0043] • Polyamide

[0044] • a thermal paste

[0045] • Solder or a mixture thereof.

[0046] A further aspect of the invention relates to a floor module GPM or vehicle module CPM for an inductive vehicle charging system, wherein energy can be inductively transferred from a floor module GPM to a vehicle module CPM arranged in a vehicle and vice versa, and wherein the floor module GPM or the vehicle module CPM has at least one electrical component that dissipates heat during operation. The proposed floor module GPM or the proposed vehicle module CPM is characterized in that this heat-dissipating component is connected to a heat sink via a connecting element, as described above.

[0047] Advantageously, the heat-dissipating component is part of a power electronics circuit. Advantages and advantageous refinements of the proposed GPM floor module or the proposed CPM vehicle module result from an analogous and analogous application of the above statements.

[0048] A further aspect of the invention relates to a vehicle comprising a vehicle module CPM as described above.

[0049] A further aspect of the invention relates to an inductive vehicle charging system comprising a floor module GPM and / or vehicle module CPM, as described above.

[0050] A further aspect of the invention relates to an electrical circuit board PCB comprising at least one connecting element as described above.

[0051] The electrical circuit board PCB is advantageously designed to be flexible.

[0052] Further advantages, features, and details will become apparent from the following description, which – where appropriate with reference to the drawings – describes at least one embodiment in detail. Identical, similar, and / or functionally equivalent parts are provided with the same reference numerals.

[0053] It shows:

[0054] Fig. 1 shows a highly schematically illustrated connecting element 100

[0055] Fig. 1 shows a highly schematic connection element 100 arranged between a heat-dissipating electrical component 101, for example, a power semiconductor, and a heat sink 102. The connection element 100 is constructed layer by layer from three material layers, wherein a first material layer 103 consists of a thermally conductive and electrically insulating first material, for example, FR4, and has a contact surface for the thermally conductive arrangement of the heat-dissipating electrical component 101.

[0056] A third material layer 105 consists of a thermally conductive third material, for example a zirconium-doped Al2O3 substrate (DCB: English for "direct copper bond") and has a contact surface for thermally conductive contact with the heat sink 102. Between the first material layer 103 and the third material layer 105, a second material layer 104 is arranged, which consists of a thermally conductive and electrically conductive second material, for example copper.

[0057] The second material layer 104 is kept constant at a predetermined electrical potential during operation of the electrical component 101.

[0058] Although the invention has been illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned by way of example are truly only examples and should not be construed as limiting the scope, possible applications, or configuration of the invention in any way.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without departing from the scope of protection defined by the claims and their legal equivalents, such as a further explanation in the description.

[0059] List of reference symbols 100 connecting element

[0060] 101 heat-emitting electrical component / assembly

[0061] 102 heat sink

[0062] 103 first material layer

[0063] 104 second material layer 105 third material layer

Claims

Patent claims 1 . Connecting element (100) between a heat-emitting electrical component (101) and a heat sink (102), characterized in that the connecting element (100) is constructed in layers from at least three material layers, wherein a first material layer (103) consists of a thermally conductive and electrically insulating first material and has a contact surface for the thermally conductive arrangement of the heat-emitting electrical component (101), a third material layer (105) which consists of a thermally conductive third material and has a contact surface for thermally conductive contact with the heat sink (102), and a second material layer (104) made of a thermally conductive and electrically conductive second material is arranged between the first material layer (103) and the third material layer (105).

2. Connecting element (100) according to claim 1, characterized in that the second material layer (104) is kept constant at a predetermined electrical potential during operation.

3. Connecting element (100) according to claim 1 or 2, characterized in that the third material is electrically insulating.

4. Connecting element (100) according to claim 1 or 2, characterized in that the third material is electrically conductive.

5. Connecting element (100) according to one of claims 1 to 4, characterized in that the second material layer (104) or the second (104) and the first (103) material layer or the third (105) and the second (104) and the first (103) material layer is / are arranged within an electrical printed circuit board (PCB).

6. Connecting element (100) according to one of claims 1 to 5, characterized in that the third material layer (105) is arranged directly on the second material layer (104) and / or the second material layer (1049 is arranged directly on the first material layer (103).

7. Connecting element (100) according to one of claims 1 to 6, characterized in that the connecting element (100) comprises exactly the first (103), the second (104) and the third (105) material layer.

8. Connecting element (100) according to one of claims 1 to 7, characterized in that the first material consists of - FR4 - Ceramics, - Aluminium oxide and substrates - Aluminum nitride and substrates - Silicon nitride and substrates - Zirconium doped AI2O3 substrates - Glass fiber reinforced plastic material - Polyamide is selected.

9. Connecting element (100) according to one of claims 1 to 6, characterized in that the second material consists of - Copper - aluminum - Silver - Gold - Metal alloys with good electrical conductivity are selected.

10. Connecting element (100) according to one of claims 1 to 7, characterized in that the third material consists of - FR4 - Ceramics, - Aluminium oxide and substrates - Aluminum nitride and substrates - Silicon nitride and substrates - Zirconium doped AI2O3 substrates - Glass fiber reinforced plastic material - Polyamide - Thermal paste - Lot is selected.

11. Floor module (GPM) or vehicle module (CPM) for an inductive vehicle charging system, wherein energy can be transferred inductively from a floor module (GPM) to a vehicle module (CPM) arranged in a vehicle and vice versa, and wherein the floor module (GPM) or the vehicle module (CPM) has at least one electrical component (101) which emits heat during operation, characterized in that this heat-emitting component (101) is connected to a heat sink (102) via a connecting element (100) according to one of claims 1 to 10.

12. Floor module (GPM) and / or vehicle module (CPM) according to claim 11, characterized in that the heat-emitting component (101) is part of a power electronics circuit.

13. Inductive vehicle charging system comprising a ground module (GPM) and / or vehicle module (CPM) according to claim 11 or 12.

14. Electrical circuit board PCB comprising at least one connecting element (100) according to one of claims 1 to 10.

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