WO2011104361A1

WO2011104361A1 - Temperature-controlling system

Info

Publication number: WO2011104361A1
Application number: PCT/EP2011/052848
Authority: WO
Inventors: Oliver Zach; Martin Reinthaler
Original assignee: Sgl Carbon Se
Priority date: 2010-02-26
Filing date: 2011-02-25
Publication date: 2011-09-01
Also published as: EP2539932A1; DE102010002434A1; DE102010002434B4

Abstract

The invention relates to a temperature-controlling system (7), comprising a heat source (8) and a heat sink (4, 5) which is arranged thereon with a contact area (4a) and composed of a layer body (1) composed of a plurality of layers (3) of a film (2) containing expanded graphite, wherein the layers (3) are layered on top of one another with surfaces (3a, 3b) running in the planar directions (Z, U) of the film (2) and the thermal conductivity of the film (2) is greater in the planar directions (Z, U) thereof than in the thickness direction (R) thereof. According to the invention, the layer body (1) is compressed in at least one of the planar directions (Z, U) of the film (2) so as to form the heat sink (4, 5), wherein the contact area (4a) is perpendicular to the at least one planar direction (Z, U) of the film (2) in which the layer body (1) is compressed.

Description

Temperature System

The invention relates to a tempering system according to the preamble of claim 1 and of claim 2.

From US Pat. No. 6,482,520 B1, a tempering system with an electronic component as the heat source is known. On a heat dissipation side of the component, a flexible film made of graphite expander is attached, which serves as a so-called heat spreader, ie for rapid heat distribution of local overheating of the component in the surface direction of the film. For this purpose, the film has a high thermal conductivity in the surface direction, which is at least 20 times the thermal conductivity of its thickness direction. This strong aniosotropy of the thermal conductivity arises from the fact that, in the production of the film, the concertina or worm-shaped graphite expandate particles are aligned in the surface direction of the film. Heat energy can thus be dissipated very rapidly in the surface direction of the film with the film, but not in the thickness direction of the film. The heat is released to the environment thus on the front + sides of the film and moderately on the relatively large surface of the film, in this case, the relatively poor thermal conductivity in the thickness direction is a hindrance. The use of large surfaces for heat dissipation is not very effective there. Especially with a board with a variety of components from which the heat must be dissipated, there is quickly a problem with the available space above the board. In addition, such a film covers large parts of the board, so that it can come to heat accumulation elsewhere and also the parts in question are not accessible from above, e.g. for visual inspection or placements.

In order to overcome this disadvantage, there is proposed a layered body of a multiplicity of layers of graphite expanded material which are layered on top of each other and bonded to one another, said layer being produced by means of a flexible cutting section as described above. Place film of graphite expander is mounted on the component. In order to ensure the best possible heat dissipation through the laminated body, it is arranged with the end faces of the stacked and bonded together films on one side of the interface film, while the other side of the interface film is connected to the heat source. The heat energy emitted by the heat source thus initially spreads rapidly in the surface direction of the interface film and only then passes on to the layer body, which then conducts the heat energy from the one end faces of the layer foils to their further end faces and releases them from there to the environment.

It is therefore an object of the invention to provide a tempering, which overcomes the above-mentioned disadvantages and allows a fast and effective heat dissipation in a small footprint.

This object is achieved by a tempering with the features of claim 1 and claim 2. Advantageous developments and preferred embodiments of the tempering are given in the dependent claims.

An embodiment of the tempering system according to the invention is characterized in that the laminated body is compressed in at least one of the surface directions of the film to form the heat dissipator, wherein the contact surface is perpendicular to the at least one surface direction of the film, in which the laminated body is compressed. A further embodiment of the tempering system according to the invention is characterized in that the heat dissipator has a density of 1.3-2.2 g / cm ³ , preferably of 1.6-2.0 g / cm ³ and a ratio of the heat conductivity of the heat dissipator in a surface direction extending substantially parallel to the contact surface for thermal conductivity of the heat sink in a direction of thickness substantially perpendicular to the contact surface is greater than 1 and less than 15, preferably greater than 1 and less than 10, more preferably greater than 1 and less than 5 , In an advantageous embodiment of the tempering, the thermal conductivity of the Wärmeabieiters in a compression direction of the film in which the laminated body is compressed, be lower than the thermal conductivity of the film of the uncompressed composite in the compression direction or the same size as this. Advantageous values of this thermal conductivity of the heat dissipator in the compression direction can be 20-450 W / (m K), preferably 25-400 W / (m K) and particularly preferably 30-300 W / (m K). Particular preference is given to values of the heat conductivity of the heat dissipator in the compression direction of 40-200 W / (m K), in particular 50-150 W / (m K).

In a further advantageous embodiment of the tempering, the thermal conductivity of the Wärmeabieiters perpendicular to the surface directions of the film of the uncompressed composite body may be greater than the thermal conductivity of the uncompressed composite in the same direction. Advantageous values of this heat conductivity of the heat dissipator may be 150-450 W / (m K), preferably 200-370 W / (m K) and particularly preferably 250-350 W / (m K).

Furthermore, it may be advantageous if the heat dissipator has a density of 1.3 to 2.2 g / cm ³ , preferably of 1.6 to 2.0 g / cm ³ and particularly preferably of 1 to 7 to 9 g / cm ³ . In an advantageous embodiment, the laminate may be compressed from a density of 0.5-1.1 g / cm ^{3 of} the starting film to the heat sink.

Advantageously, the heat sink may be compressed so much that it is stiff, making it easy to handle.

In an advantageous development of the temperature-control system, the heat-dissipator may have shaped cooling fins for the improved heat dissipation during the compression of the layered body. Advantageously, the cooling fins may extend into the at least one surface direction in which the layered body is compressed.

In terms of manufacturing technology, the film may consist of compressed graphite expandate. In an alternative embodiment, the film may consist of a Seal composed mixture of largely uniformly mixed with plastic particles and / or resin systems graphite expander exist to increase the stability of the film and the laminate formed therefrom and Wärmeabieiters. A plastic reinforcement can also be done by infiltration of a graphite foil with plastic. Thermoplastics, thermosets or elastomers can advantageously be used as plastics, in particular fluoropolymer, PE, PVC, PP, PVDF, PEEK, benzoaxins, phenolic resin, furan resin and / or epoxy resins.

Alternatively or additionally, it is furthermore advantageously possible to introduce metal particles into the film production as particles. This can additionally improve the thermal conductivity. As metal particles Cu, Al and their alloys can be used.

In one embodiment of the invention, the layered body may be formed from a film coiled in the form of a cylinder spiral, thereby providing a compact layered body which can not fall apart into different individual layers of the film. In an alternative embodiment of the invention, the laminated body may be formed from a plurality of superimposed individual graphite expander-containing films or sheets, which may preferably be glued or pressed together.

In a further embodiment of the invention, a metal foil may be introduced and compressed at least between individual individual layers of the film and / or partially. In particular, Cu, Al, Ag, Au and their alloys are suitable as metal foil.

The temperature control system may preferably contain an electronic or electrical component as the heat source.

In an advantageous embodiment, a heat dissipator described in detail above and below in the case of an electronic and / or electrical components can be used both for rapid distribution of local excess heat and for avoiding Hot spots as well as to dissipate heat energy of the component to the environment.

Other features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. Show it:

1 shows a laminated body for producing a Wärmeabieiters.

FIG. 2 shows a cross section through the central axis of the layered body from FIG. 1; FIG.

3 shows a cross section through a Wärmabieiter.

4 shows a cross section through an alternative Wärmeabieiter.

Fig. 5 is a schematic side view of a tempering system according to the invention.

A cylinder-shaped laminated body 1 shown in FIG. 1 is wound from a sheet 2 of expanded graphite. By way of example, some individual layers of the laminated body 1 are identified by the reference numeral 3.

The production of graphite expandate is well known, for example from US Pat. No. 3,404,061 A or DE 103 41 255 B4. The graphite expandate thus obtained consists of worm-shaped or accordion-shaped aggregates. The graphite expander is then compacted under the direction of a pressure, so that the layer planes of the graphite preferably arrange perpendicular to the direction of action of the pressure and the individual units interlock with each other. In this way, a flexible sheet of graphite expanded material can be obtained, which, for example, can be wound up. A film suitable for use herein is manufactured and sold by the Applicant or its affiliates under the trademark SIGRAFLEX. In the embodiment of FIG. 3, the graphite expander film 2 is wound with a density of 0.7 g / cm ³ , a thickness of 0.5 mm, a width of 7 mm and a length of 90 cm to the laminated body 1. For better understanding, only some of the spiral windings of the laminated body 1 have been indicated in FIGS. 1 and 2.

The film 2 has in its surface directions, ie in the height direction marked Z in FIG. 1 and the circumferential direction of the layered body 1 marked U, a high thermal conductivity, typically around 180 W / (m K). In a radius direction designated R in FIG. 2, which in the cross section of FIG. 2 corresponds to the thickness direction of the film 2, it has a significantly lower thermal conductivity than in the surface directions, typically around 5 W / (m K). The layers 3 are wound on one another in the surface directions Z, U of the film 2 extending surfaces 3a, 3b.

In order to reduce the strong anisotropy of the thermal conductivity of the laminated body 1 of the film 2, the laminated body 1 is inserted into a mold or die and then pressed together by means of a punch in the Z direction, ie in one of the surface directions of the laminated body 1, whereby the layers 3 be compressed and partially fold, as indicated schematically in Fig. 3. The direction in which the laminated body 1 is compressed is also referred to as the compression direction K. This results in a heat dissipation 4 with a density of 1, 8 g / cm ³ , a thickness of 3 mm (in the thickness direction D) and a diameter of 22.5 mm. The Wärmeabieiter 4 can be compressed instead of the cylindrical shape shown here in other forms, for example, a cuboid or square with rounded corners.

As a result of the compression, the thermal conductivity of the laminated body 1 in the compression direction K decreases markedly from the abovementioned values of the foil 2 in this planar direction, the thermal diverter 4 then typically has a thermal conductivity in the compression direction K or thickness direction D of 60 W / (m K). Perpendicular to the compression direction K, ie in the R direction of the layer body or in Flächenhchtung F of the heat sink 4, however, the thermal conductivity of the heat sink 4 increases significantly. The heat dissipator 4 then typically has a thermal conductivity in its surface direction F, ie perpendicular to the compression direction K, of 260 W / (m K).

Even if the thermal conductivity in the compression direction K or thickness D of the heat sink 4 is significantly lower than the thermal conductivity of the film 2 of the uncompressed laminate 1 in this direction, the thermal conductivity in this direction is significantly higher, in this case by almost 10 times, than in the known use of a Graphitexpandatfolie, as in

US Pat. No. 6,482,520 B1. The anisotropy between the thermal conductivity of the heat dissipator 4 in its surface directions perpendicular to the compression direction K and its thermal conductivity in the compression direction K or thickness direction D can thus be significantly reduced. Compared to the quotient defined in US Pat. No. 6,482,520 B1 with a minimum value of 20 given there, the correspondingly defined quotient between the heat conductivity of the heat dissipator 4 in its surface directions perpendicular to the compression direction K and its thermal conductivity in the compression direction K is 4.3 (see FIG. 260 W / (m K) to 60 W / (m K)).

Therefore, the Wärmabieiter 4 due to its uniform thermal conductivity in its thickness direction D and its surface directions F for a local heat surpluses quickly distribute in its surface directions F, on the other hand also quickly derive heat energy from a heat source and quickly dissipate the heat energy dissipated to the environment.

In addition to the lower anisotropy of the thermal conductivity in the surface direction F and thickness direction D of the heat sink 4 is due to its compression as a further advantage a solid, dimensionally stable Wärmabieiter 4, which is easy to handle and much more extensive design options of shape and thickness than a conventional graphite foil. A heat dissipator 5 from FIG. 4 substantially corresponds to the heat dissipator 4 shown in FIG. 3, so that in the following, the same reference numerals are used for the same elements and, above all, the differences are discussed.

In contrast to the heat dissipator 4 shown in FIG. 3, the heat dissipator 5 has no upper, smooth surface in FIG. 4, but rather cooling fins 6 for enlarging the heat-effective surface. The cooling fins 6 can be easily produced by pressing the laminated body 1 in which e.g. the pressure stamp, with which the laminated body 1 is pressed into the die, has a negative shape corresponding to the cooling fins 6. Since the heat conductivity of the heat dissipater 5 in its surface directions F is greater than the thermal conductivity of the unpressed film 2 in its thickness direction (R direction in FIG. 2), fast heat energy can be dissipated on all sides of the cooling fins 6.

Alternatively, the cooling fins 6 may advantageously be formed of metal.

An example of an advantageous use of the heat dissipater 4 and a temperature control system 7 according to the invention is shown in FIG. 5. The temperature control system 7 has a heat source designed as an electronic IC component 8, which is soldered to a circuit board 10 in a known manner with connection pins 9. Instead of an IC component, other corresponding electronic or electrical components can also serve as a heat source. Such components have in common that they in operation, especially when used in computers, controls, microprocessor controls, light emitting diodes, etc., heat, and this heat energy must be dissipated. In particular, with the increasingly increasing clock frequencies in the field of processor technology cooling of such components or entire groups of components is becoming increasingly important.

To dissipate the heat generated by the component 8, an advantageous heat dissipator 4 according to the embodiment in Fig. 3 in a conventional manner with a perpendicular to the surface directions Z, U of the film 2 of the uncompressed composite body 1, in Fig. 5 lower surface 4a flush with the upper upper surface of the component 8 glued, preferably by means of a Wärmeleitklebers. For this purpose, the heat dissipater 4 may advantageously be provided on a contact surface 4a with an adhesive film in order to be easily adhered to the component 8. In an alternative embodiment, not shown, an adhesive film can also be mounted on a top in Fig. 5 upper heat transfer surface 4 b of the heat dissipater 4 to the heat dissipation 4 in addition to the component 8 and / or the board 10 surrounding housing or to an additional, on to be fixed to known heat sink. Alternatively, a clamp connection is used instead of the adhesive connection.

First, the heat generated during operation of the component 8 due to the good thermal conductivity of the Wärmeabieiters 4 in the thickness direction D is rapidly dissipated via the contact surface 4a of the Wärmeabieiters 4 in the Wärmeabieiter 4 and because of its good thermal conductivity in its surface direction F there quickly and evenly distributed. Because of its good thermal conductivity in the thickness direction D, the thermal energy introduced into the heat dissipator 4 is also quickly transported to the heat dissipation surface 4b of the heat dissipater 4 facing away from the component 8, where it is released over a large area to the environment. In addition, the front surfaces adjoining the surfaces 4a, 4b of the heat dissipator 4 can also be used for heat dissipation to the environment. Thus, the probability of local heat overheating or heat build-up in the component 8 as well as in the heat dissipator 4 is reduced, even completely prevented during normal operation.

Instead of the heat dissipator shown in FIG. 5 from FIG. 3, the heat dissipator 5 shown in FIG. 4 can also be used, whereby the speed of heat emission to the environment can be further increased.

The low aniosotropy of the thermal conductivity of the heat dissipator 4 or 5 allows an advantageous use of the above-described Wärmeabieiter 4 and 5 as a heat sink for electronic and / or electrical components for rapid distribution of local excess heat and avoid hot spots and for the dissipation of heat energy to the Surroundings. It is also possible, instead of a laminated body 1 wound from the graphite expandable film 2, to use a layered body of individual graphite expanded sheets or sheets which are laid on one another in a planar manner and which can advantageously be pressed or glued together. This layered body is then also advantageously compressed in one or both surface directions of the graph itexpandatfolien or plates to a Wärmeabieiter. Again, a variety of differently shaped, advantageously flat heat sinks can be provided.

It is also possible to insert a metal foil 1 1 between the graphite expander film when winding or laminating a laminated body, as shown in Fig. 3, whereby advantageously additional heat conduction in the compression direction can be achieved.

In order to increase the stability of the heat dissipator 4, 5, its end faces may advantageously be sealed with a lacquer or a film in order to avoid detachment of graphite particles.

Claims

claims

1 . A tempering system (7) having a heat source (8) and a heat dissipator (4, 5) mounted thereon with a contact surface (4a) formed from a laminated body (1) comprising a plurality of layers (3) of a graphite expander-containing film (2) , wherein the layers (3) with surfaces (3a, 3b) extending in surface directions (Z, U) of the film (2) are stacked on one another and the heat conductivity of the film (2) is greater in their surface directions (Z, U) than in its thickness direction (R), characterized in that the laminated body (1) for forming the Wärmeabieiters (4, 5) in at least one of the surface directions (Z, U) of the film (2) is compressed, wherein the contact surface (4a) perpendicular to the at least one surface direction (Z, U) of the film (2) extends, in which the laminated body (1) is compressed.

2. tempering system (7) with a heat source (8) and a with a contact surface (4a) mounted thereon Wärmeabieiter (4, 5) formed from a multi-layers (3) of a Graphitexpandat containing film (2) laminated body (1) is, wherein the layers (3) in the surface directions (Z, U) of the film (2) extending surfaces (3a, 3b) are stacked and the thermal conductivity of the film (2) in their surface directions (Z, U) is greater than in its thickness direction (R), characterized in that the heat sink (4, 5) has a density of 1.3-2.2 g / cm ³ , preferably of 1.6-2.0 g / cm ³ , and a ratio the thermal conductivity of the heat dissipater (4, 5) in a surface direction (R, F) extending substantially parallel to the contact surface (4a) for thermal conductivity of the heat dissipater (4, 5) in a thickness direction (Z, Z) extending substantially perpendicular to the contact surface (4a) D) greater than 1 and less than 15, preferably gr SSER than 1 and less than 10, more preferably greater than 1 and less than 5 s.

3. temperature control system (7) according to claim 1 or 2, characterized in that the thermal conductivity of the Wärmeabieiters (4, 5) in a compression direction (K) of the film (2), in which the laminated body (1) is compressed, is less than the thermal conductivity of the film (2) of the uncompressed laminated body (1) in the compression direction (K) or the same size.

4. tempering system (7) according to claim 3, characterized in that the thermal conductivity of the Wärmeabieiters (4, 5) in the compression direction (K) 20- 450 W / (m K), preferably 30-300 W / (m K) and especially preferably 50-150 W / (m K).

5. tempering system (7) according to one or more of the preceding claims, characterized in that the thermal conductivity of the heat sink (4, 5) perpendicular to the surface directions (Z, U) of the film (2) of the uncompressed composite body (1) larger is in the same direction as the thermal conductivity of the uncompressed composite (1).

6. tempering system (7) according to claim 5, characterized in that the thermal conductivity of the Wärmeabieiters (4, 5) perpendicular to the surface directions (Z, U) of the film (2) of the uncompressed laminated body (1) 150-450 W / (m K), preferably 200-370 W / (m K) and particularly preferably 250-350 W / (m K).

7. tempering system (7) according to one or more of the preceding claims, characterized in that the Wärmeabieiter (4, 5) has a density of 1, 3-2.2 g / cm ³ , preferably from 1, 6-2,0 g / cm ³ and more preferably from 1, 7-1, 9 g / cm ³ .

8. tempering system (7) according to one or more of the preceding claims, characterized in that the laminated body (1) of a density of 0.5-1, 1 g / cm ³ to the Wärmeabieiter (4, 5) is compressed.

9. tempering system (7) according to one or more of the preceding claims, characterized in that the Wärmeabieiter (4, 5) is rigid.

10. Tempenersystenn (7) according to one or more of the preceding claims, characterized in that the Wärmeabieiter (4, 5) in the compression of the laminated body (1) formed cooling fins (6).

1 1. Temperature control system (7) according to claim 9, characterized in that the cooling ribs (6) in the at least one surface direction (Z), in which the laminated body (1) is compressed extend.

12. tempering system (7) according to one or more of claims 1 to 10, characterized in that the film (2) consists of compressed graphite expandate.

13. tempering system (7) according to one or more of claims 1 to 10, characterized in that the film (2) consists of a mixture formed before compaction of largely uniformly mixed with plastic particles and / or resin systems graphite expander or plastic infiltrated graphite foil.

14. tempering system (7) according to one or more of the preceding claims, characterized in that in the film production metal particles are introduced between Graphitexpandat.

15. tempering system (7) according to one or more of the preceding claims, characterized in that the laminated body (1) consists of a cylindrically spiral wound film (2) is formed.

16 tempering system (7) according to one or more of the preceding claims, characterized in that the laminated body (1) consists of a plurality of superimposed individual graphite expander containing films (2).

17. tempering system (7) according to one or more of the preceding claims, characterized in that at least between individual layers of the film and / or partially introduced a metal foil and compressed together with the film.

18. Tennpenersystenn (7) according to one or more of the preceding claims, characterized in that the heat source (8) is an electronic or electrical component.