WO2010012271A2

WO2010012271A2 - Apparatus, in particular for conducting current, and a method for producing an apparatus, in particular for conducting current

Info

Publication number: WO2010012271A2
Application number: PCT/DE2009/001051
Authority: WO
Inventors: Harald Redelberger
Original assignee: Brose Fahrzeugteile Gmbh & Co. Kg, Würzburg
Priority date: 2008-07-30
Filing date: 2009-07-29
Publication date: 2010-02-04
Also published as: WO2010012271A3; DE102008035485A1

Abstract

Apparatus, in particular for conducting current, having a heat-generating element (1), in particular a component through which current flows, in particular for high powers, having a current-conducting element (2), in particular a conductor grid to which the heat-generating element is applied, and having a heat-dissipating means (3), in particular a heat sink which, in order to dissipate heat, in particular as a result of power loss, is thermally coupled to the current-conducting element, wherein the heat-dissipating means should be thermally coupled using a layer (4) comprising a heat-conducting, in particular plastic, solid medium, in particular a metal layer, and at least one insulation layer (5) for at least partial electrical insulation between the current-conducting element and the solid medium layer is provided between the current-conducting element and the solid medium layer.

Description

Device, in particular for power line, and a method for producing a device, in particular for power line

The invention relates to a device, in particular for power line, according to the preamble of claim 1 and a method for producing a device, in particular for power line according to the preamble of claim 16.

It is known to make thermal contact between a conductive material and a heat dissipation device, in particular a copper or cast aluminum block with cooling fins, by means of a thermal barrier material.

A disadvantage of the known system of the prior art is that in the said copper or Aluminiumgussblöcken easily conductive contaminants can occur, which can break through this layer of the interface material and generate a short circuit that endangers the entire component.

Object of the present invention is to provide a device, in particular for power line, which avoids the disadvantages of the prior art and allows easy and safe heat dissipation.

The object is achieved by a device, in particular for power line, with a heat-generating element, in particular for high power, with a current-conducting element, in particular a conductor grid, on which the heat-generating element is applied, with a heat dissipation, in particular a heat sink, which is thermally coupled to the dissipation of heat, in particular as a result of power loss, to the current-conducting element, wherein the thermal coupling of the Wärmeabführmittels by means of a layer comprising a heat-conducting, in particular plastic solid medium, in particular a layer of a metal, run, and is provided between the current-conducting element and the layer of the solid medium at least one insulating layer for at least partial electrical insulation between the current-conducting element and the layer of the solid medium ,

The present invention provides a cost-effective construction technology, in particular in the case of a high heat input, that is, in particular in the case of components with high power, since in particular conductor grid and / or printed circuit board can be used, as well as simple cast heat sinks. In particular, the problem of conductive contamination, burrs, or sharp-edged unevenness on the heat dissipating agent, in particular a die-cast heat sink, but also on an extruded heat sink by punching burrs or chips of processing steps, is prevented in particular by potential differences by the present invention. In the prior art, an expensive surface processing of the heat sink is necessary so that no breakthroughs occur, expensive thermal adhesive would have to be applied in the prior art in large thickness, which also increases the thermal resistance. Although glass beads of sufficient thickness embedded in the thermal adhesive increase the distance, they do poorly conduct the heat and are distributed irregularly. The heat-generating components can be operated by the invention in a simple manner within acceptable limits and the life by the better cooling is extended. Complex heat-conducting foils with several layers or fracture-susceptible mica plates with possible air pockets can be dispensed with to improve the function. Surprisingly, the invention also proves to be very suitable for high-performance applications in which a high heat emission takes place.

A reliable heat dissipation even at high potential differences and large conductive impurities provides the device, when the thickness of the layer of the solid medium, in particular depending on the thermal, electrical and mechanical properties of the solid medium is selected so that electrical short circuits due to in and / or piercing electrically conductive compounds, in particular from the heat dissipating, be avoided. A further improvement of the electrical insulation is given if between the layer of the solid medium and the Wärmeabführmittel an insulating layer for at least partial electrical insulation is provided, in particular if at least one area with an unequal potential between the current-conducting element and heat dissipation means is present. Even with a thin insulating layer, a reliable prevention of damage by conductive impurities is given if the conductor grid and the heat sink is connected to the same or a similar electrical potential as the heat sink, in particular to ground.

The solution provides a good thermal connection and a reduced heat transfer resistance of the elements to be cooled to the heat transfer and at the same time reliably prevents short circuits even at high power. The components thus achieve a longer life and there is a safe operation option.

An improved thermal conductivity is given if a layer comprising a substantially thermally conductive, in particular elastic medium is provided between the current-conducting element and the layer of the solid medium and / or between the layer of the solid medium and the heat-dissipating. Intermediate see the current-conducting element and the layer of the solid medium and / or between the layer of the solid medium and the Wärmeabführmittel can thus be introduced a heat conducting layer, which may be preferably thin, in particular compared to conventional layers of heat conduction adhesives. In addition, a predetermined sufficient electrical insulation is given by the insulating layer. The invention has a low heat transfer resistance between the heat source and heat sink and at the same time a good electrical insulation of the individual power components with each other and with respect to the heat sink. The thermally conductive layer can also compensate for unevenness and improve the conductive contact for heat dissipation. Insulating air pockets in the layers are prevented in particular by the small thickness. The functions reduction of thermal resistance and insulation function to Prevention of short circuits between the current-conducting element and the heat-dissipating means are separated.

A safe and easy-to-manufacture insulation layer is present when the insulation layer comprises an electrical insulation by anodization, in particular in the case of a layer of aluminum, and / or that the insulation layer is composed of a substantially insulating lacquer and / or the insulation layer by surface refinement of the layer will be produced. Aluminum is also plastically deformable and good heat-conducting.

It is particularly advantageous that the anodization is very thin and also allows sufficient heat conduction instead. In particular, solder mask can be used to protect against corrosion and mechanical damage and it prevents the wetting of certain surfaces during soldering and improves electrical properties such as dielectric strength, in particular a solder mask. By such a device, the total thickness of the insulating layer and thermally conductive layer together may be less than a combination of the two layers in the prior art. In particular, the layer thickness of the heat-conducting adhesive is lower, in particular also possible as the sum of the two second layers than in the prior art for a layer of heat-conducting adhesive with glass beads.

It is advantageous if the layer of solid medium is a plastically deformable metal, in particular a layer of aluminum or copper sheet. The sheet metal can be easily produced with a sufficiently smooth surface, which contributes to a reduction in the risk of conductive contamination. In addition, the conductive impurities can penetrate into the sheet without leading to a short circuit when an insulating layer is introduced between the current-conducting element and the layer.

A simple production is given when the layer is formed substantially in one piece. It is advantageous if the insulating layer is applied to the layer of the solid medium and the thermally conductive layer is applied to the insulating layer.

It is advantageous if the insulating layer and thermally conductive layer are combined as a single layer.

It is advantageous if the thermally conductive layer substantially comprises a thermal adhesive and / or that the thermally conductive layer is formed by an adhesive film, which in particular does not have to have electrical insulation. This gives a very good thermal connection and at the same time a simple application possible, as well as a compensation of bumps easily possible.

It is advantageous if the thermally conductive layer is thin, in particular smaller than 150 micrometers. The thermal conduction function is sufficient even with very thin layers and there is a material savings and in particular cost savings, especially when using an expensive thermal adhesive before. The size specified is just an example. It is important that due to the implementation of the arrangement of the invention, the layer thickness of the thermally conductive layer need not be based on the size of the conductive impurities, as these are held up by the position substantially.

Advantageously, the present invention is used when the current-conducting element is a stamped conductor grid, which is in particular encapsulated, in particular with a plastic extrusion.

It is advantageous if the current-conducting element is a printed circuit board, in particular multi-layered, and provided with extending through the circuit board means for thermal conduction, which are thermally connected via the layer to the heat dissipation means, wherein the means for thermal conduction at least one thermal via is, in the form of relative to the circuit board substantially angularly arranged cable paths heat conduction from the current-carrying component ment allows the location of the solid medium to the heat dissipation. Another procedural document is saved if only the uppermost electrically conductive layer of the printed circuit board is coated with solder mask. At the same time a better thermal contact between the bottom layer of the circuit board and the position of the solid medium is given.

A simple production of the device according to the invention is possible if the heat dissipation means is a heat sink and / or serving as a heat sink component, in particular a diecast part, in particular an aluminum die-cast part, or a continuous casting and / or a bearing plate and / or a housing component.

The invention can be advantageously used when the heat-generating element is a current measuring resistor or a power component, for example a MOS FET.

The object is also achieved by a method for producing a device, in particular for power line, according to one of the preceding claims 1 to 15, wherein between a ström leitendes element, in particular a conductor grid and / or a printed circuit board, and a heat dissipation, in particular a heat sink, a layer of a thermally conductive, in particular plastic solid medium is introduced, in particular a layer of a metal, and between the current-conducting element and the layer of the solid medium at least one insulating layer for at least partially electrical insulation between the current-conducting element and the layer of the solid medium introduced, in particular at a layer of aluminum is anodized and in particular a thin, thermally conductive layer of a heat-conducting medium is introduced.

Further features and advantages of the invention will become apparent from the claims and the following description in which embodiments of the subject invention in conjunction with the drawings are explained in more detail. The references in the following embodiments are not intended to be limiting but merely exemplary. Show it:

1 shows a schematic cross section of a conductor grid with component and FIG. 2 shows a schematic cross section of a printed circuit board with component.

Fig. 1 shows a schematic cross section of an electrically conductive element 2 in the form of a conductor grid. On the conductor grid sits a heat-generating component 1, which is conductively contacted by means of an electrical contact 22 on the conductor grid. The conductor grid is provided with a plastic sheath 10 which serves as a spacer between the grid elements and for insulation. On the underside 21 of the conductor grid, a layer 4 comprising a heat-conducting, in particular plastic solid medium is attached. The layer 4 is provided at least between the layer 4 and the printed circuit board 2 with an insulating layer 5 and by way of example with a thermally conductive layer 8. The insulation layer 5 prevents an electrical short circuit and the thermally conductive layer 8 allows a dense and heat-conductive connection of the conductor grid to the heat dissipation means 3 adjoining the underside 25 of the layer 4.

Between the layer 4 and heat dissipating means 3, a second insulating layer 6 and / or a second thermally conductive layer 9 may be attached, which increases the electrical insulation and the thermal conductivity of the device. However, the function of the overall device in terms of insulation and heat conduction is also ensured if the second lower layers of conductive compounds are interrupted, which can occur in use with cast heat sinks. For this purpose, the layer preferably has a thickness which, even with the largest conductive connections, in particular burrs of cut-outs in the heat sink, is not completely broken through to the top side. The layer 4 is made of aluminum, for example, which is provided on both sides with an aluminum oxide skin, that is anodized. This layer allows insulation and is due to their small thickness sufficiently thermally conductive, wherein the heat conduction through the thermally conductive layer (s) on is improved. The device is sufficiently powerful even with greater heat input, especially because of the good heat dissipation.

Fig. 2 shows a schematic cross section through a current-conducting element 2 in the form of a printed circuit board. The printed circuit board 2 has, by way of example, four electrically conductive layers 12 and, between them, three insulating and bearing layers 13. On the uppermost electrically conductive layer 14, a solder resist 19 is applied, which prevents a flow of solder and limits corrosion. On the circuit board 2, the component 1 is mounted on a means for thermal conduction 24, in particular on a thermal Via 15, for example, which is integrated in the printed circuit board 2. The via 15 extends from the component 1 to the lower end of the printed circuit board 2. On the underside 21 of the printed circuit board 2 is a layer 4 comprising a heat-conducting, in particular plastic solid medium attached. The layer 4 is provided at least between the layer 4 and the printed circuit board 2 with an insulating layer 5 and a thermally conductive layer 8. Following the layer 4, a heat sink 3 is mounted, which is used for the removal of heat. By way of example, the heat sink 3 is connected to an electrical potential 20, which preferably corresponds essentially to an electrical potential 20 of a heat sink-closest electrical insulation layer 6 of the printed circuit board 2.

LIST OF REFERENCE NUMBERS

1 heat generating element

2 current-conducting element

3 heat laxative

4 location

5 insulation layer

6 insulation layer

7 thickness

8 layer

9 shift

10 sheathing

12 electrically conductive layer

13 location

14 uppermost electrically conductive layer

15 thermal via

19 solder mask

21 bottom

22 electrical contact

24 means for thermal conduction

25 bottom

Claims

1. Device, in particular for power line, with a heat-generating element (1), in particular a current-carrying component, in particular for high power, with a current-conducting element (2), in particular a conductor grid on which the heat-generating element is applied, with a Heat laxative (3), in particular a heat sink, which is thermally coupled to the removal of heat, in particular as a result of power loss, the current-conducting element, wherein the thermal coupling of the heat dissipation means by means of a layer (4) comprising a heat-conducting, in particular plastic solid medium , in particular a layer of a metal, is executed, and between the current-conducting element and the layer of the solid medium at least one insulating layer (5) for at least partially electrical insulation between the current-conducting element and the layer is provided from the solid medium.

2. Apparatus according to claim 1, characterized in that the thickness (7) of the layer (4) of the solid medium, in particular depending on the thermal, electrical and mechanical properties of the solid medium, is selected so that electrical short circuits due to in and / or piercing electrically conductive connections, in particular from the heat dissipation means, are avoided.

3. Device according to claim 1 or 2, characterized in that between the layer of the solid medium and the heat dissipating an insulating layer (6) is provided for at least partial electrical insulation, in particular if at least one area with an unequal potential between current-conducting element and Heat removal is present.

4. Device according to one of claims 1 to 3, characterized in that between the current-conducting element and the layer of the solid medium and / or between the layer of the solid medium and the Wärmeabführmittel a layer (8, 9) comprising a substantially thermally conductive , in particular elastic medium is provided.

5. Device according to one of claims 1 to 4, characterized in that the insulating layer (5, 6) comprises an electrical insulation by anodization, in particular in the case of a layer (4) of aluminum, and / or that the insulating layer (5, 6 ) is constructed of a substantially insulating lacquer and / or the insulating layer (5, 6) by surface refinement of the layer (4) is produced.

6. Device according to one of claims 1 to 5, characterized in that the layer (4) of the solid medium is a plastically deformable metal, in particular a layer (4) made of aluminum or copper sheet.

7. Device according to one of claims 1 to 6, characterized in that the layer (4) is formed substantially in one piece.

8. Device according to one of claims 1 to 7, characterized in that the insulating layer (5, 6) on the layer (4) is applied from the solid medium and the thermally conductive layer (8, 9) on the insulating layer (5, 6 ) is applied.

9. Device according to one of claims 1 to 8, characterized in that the insulating layer (5, 6) and thermally conductive layer (8, 9) combined are formed as a single layer.

10. Device according to one of claims 1 to 9, characterized in that the thermally conductive layer (8, 9) is substantially a thermal adhesive comprises and / or that the thermally conductive layer (8, 9) is formed by an adhesive film, which in particular does not have to have electrical insulation.

11. Device according to one of claims 1 to 10, characterized in that the thermally conductive layer (8, 9) is thin, in particular smaller than 150 micrometers.

12. Device according to one of claims 1 to 11, characterized in that the current-conducting element (2) is a particular punched conductor grid, which is in particular encapsulated, in particular with a plastic extrusion (10).

13. Device according to one of claims 1 to 12, characterized in that the current-conducting element (2) is a printed circuit board, in particular multi-layered, and is provided with extending through the circuit board means for thermal conduction, which thermally over the position with the Wärmeabführmittel are connected, wherein the means for thermal conduction is at least one thermal via, which allows in the form of relative to the circuit board substantially angularly arranged conduit paths heat conduction from the current-carrying device on the layer (4) of the solid medium to the heat sink.

14. Device according to one of claims 1 to 13, characterized in that the heat dissipation means (3) is a heat sink and / or serving as a heat sink component, in particular a diecast part, in particular an aluminum die-cast part, or a continuous casting and / or a bearing plate and / or a housing component.

15. Device according to one of claims 1 to 14, characterized in that the heat generating element (1) is a current measuring resistor or a power device, such as a MOS FET.

16. A method for producing a device, in particular for power line, according to any one of the preceding claims 1 to 15, wherein between an electrically conductive of the element (2), in particular a conductor grid and / or a printed circuit board, and a heat dissipating means (3), in particular a heat sink, a layer (4) of a thermally conductive, in particular plastic solid medium is introduced, in particular a layer (4) of a metal , And between the current-conducting element (2) and the layer (4) from the solid medium at least one insulating layer (5, 6) for at least partially electrical insulation between the current-conducting element (2) and the layer (4) introduced from the solid medium, in particular in a Layer (4) of aluminum anodized, and in particular a particularly thin, thermally conductive layer (8, 9) of a heat-conducting medium is introduced.