US20120006521A1

US20120006521A1 - Heat sink for an electronic component

Info

Publication number: US20120006521A1
Application number: US13/064,839
Authority: US
Inventors: Georg Moehlenkamp; Christian Keller
Original assignee: Converteam GmbH
Current assignee: GE Energy Power Conversion GmbH
Priority date: 2010-07-08
Filing date: 2011-04-20
Publication date: 2012-01-12
Also published as: DE102010026529A1; EP2405480A3; EP2405480A2

Abstract

Described is a heat sink for an electronic component. In at least one embodiment, the heat sink includes several cooling fins and carbon nanotubes, present between the top surface of the heat sink and the cooling fins. The carbon nanotubes extend from the top surface of the heat sink in the direction toward one of the cooling fins and are oriented at an angle to the orientation of the associated cooling fin.

Description

PRIORITY STATEMENT

The present application hereby claims priority under 35 U.S.C. §119 on German patent application number DE 10 2010 026 529.2 filed Jul. 8, 2010, the entire contents of which are hereby incorporated herein by reference.

FIELD

At least one embodiment of the invention generally relates to a heat sink with an electronic component, as well as to a heat sink for an electronic component.

BACKGROUND

The document DE 102 48 644 A1 discloses an arrangement in which an electronic semiconductor module is connected via carbon nanotubes to a heat sink. The carbon nanotubes in that case are oriented orthogonal to the surface of the heat sink. The carbon nanotubes can be formed on the desired surface, for example as disclosed in the DE 101 03 340 A1. With the aid of the carbon nanotubes, the heat generated by the semiconductor module can be dissipated to the heat sink.

SUMMARY

In at least one embodiment of the invention, an improvement in the heat dissipation for the known arrangement is disclosed.
At least one embodiment is directed to a heat sink with an electronic component, as well as by a heat sink for an electronic component.
According to at least one embodiment of the invention, the heat sink is provided with several cooling fins, wherein carbon nanotubes are disposed between the top surface of the heat sink and the cooling fins. These carbon nanotubes extend from the top surface of the heat sink in the direction toward one of the cooling fins and their orientation includes an angle of orientation to the orientation of the associated cooling fins.
At least one embodiment of the invention has the advantage that the heat released by the base of the electronic component is dissipated via the carbon nanotubes to the cooling fins. The excellent, heat-conducting properties of the carbon nanotubes can thus be utilized. With the aid of the invention, it is thus possible to dissipate more heat from the electronic component and consequently achieve an improved cooling of the electronic components. The distribution of the heat to the cooling fins is determined by the angle of orientation.
The orientation angle in this case can advantageously depend on the location in the heat sink.
For one embodiment of the invention, a base of the electronic component which rests against the heat sink and/or can be fitted against the heat sink is smaller than the area of the top surface for the heat sink. The carbon nanotubes furthermore extend from the top surface of the heat sink in the direction of several cooling fins, wherein the orientation angles for carbon nanotubes which are assigned to different cooling fins are different. The carbon nanotubes are thus oriented in different directions. The heat is consequently “spread out and/or fanned out” starting from the small base, wherein this has the advantage that the heat from the electronic component can be dissipated and distributed almost randomly to the cooling fins of the heat sink. The orientation angles can preferably be selected such that the thermal resistance is at a minimum for the heat to be dissipated.
According to a different embodiment of the invention, a plate-type region with therein disposed carbon nanotubes is respectively assigned to the cooling fins. Carbon nanotubes with the same orientation can thus be produced according to a known method and can then be formed into the desired plate-type region. For example, the identically oriented carbon nanotubes can be produced with the aid of a growth process or the like and the desired plate-type regions can then be created through cutting or the like.
It is particularly advantageous if the plate-type region has an approximately trapezoid shape, with a length along the top surface which approximately corresponds to the length of the electronic component and with a length along the underside which corresponds approximately to the length of the associated cooling fin. In this way, the heat can be dissipated over the total longitudinal side of the associated cooling fin.
It is furthermore advantageous if the cooling fins contain carbon nanotubes which are oriented toward the exposed end of the respective cooling fin and/or are oriented diagonally and/or transverse thereto. As a result, the heat can be dissipated with the aid of the carbon nanotubes within the cooling fins and can be transported therein to the cooling fin surface.
A particularly advantageous embodiment of the invention provides that the carbon nanotubes are embedded in a substrate. The regions of identically oriented carbon nanotubes, for example produced with a cutting method, can thus be arranged at optional locations within the heat sink and can be fixated at the desired location with the aid of the substrate. If applicable, the complete heat sink can thus be composed of the substrate with therein embedded carbon nanotubes. Not only does this result in advantages with respect to the production of the heat sink, but also with respect to its weight and the costs. The heat sink furthermore already has insulating characteristics because of the substrate, if applicable without requiring further measures.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features, options for use and advantages of the invention can be seen in the following description of the example embodiments for the invention, which are illustrated in the Figures. All described or illustrated features either by themselves or in any optional combination form the subject matter of the invention, regardless of how they are combined in the patent claims or the references back, as well as independent of their formulation and/or representation in the specification and/or the drawings.

FIG. 1 shows a schematic side view of the lateral side of an example embodiment of a heat sink according to the invention, comprising an electronic component, as seen from the direction I in FIG. 2.

FIG. 2 shows a schematic side view of the longitudinal side of the heat sink with the electronic component, shown in FIG. 1, as seen from the direction II in FIG. 1.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

Various example embodiments will now be described more fully with reference to the accompanying drawings in which only some example embodiments are shown. Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. The present invention, however, may be embodied in many alternate forms and should not be construed as limited to only the example embodiments set forth herein.
Accordingly, while example embodiments of the invention are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments of the present invention to the particular forms disclosed. On the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the invention. Like numbers refer to like elements throughout the description of the figures.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments of the present invention. As used herein, the term “and/or,” includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element is referred to as being “connected,” or “coupled,” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” or “directly coupled,” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between,” versus “directly between,” “adjacent,” versus “directly adjacent,” etc.).
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments of the invention. As used herein, the singular forms “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms “and/or” and “at least one of” include any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature's relationship, to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are interpreted accordingly.
Although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, it should be understood that these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present invention.
FIGS. 1 and 2 illustrate a heat sink 10 with a preferably electronic component 11. The electronic component 11 can be any type of component which generates heat during its operation. For example, the electronic component can relate to a diode, a transistor, a thyristor, an IGBT (IGBT=insulated gate bipolar transistor) or several such components or a combination of such components.
The heat sink 10 of the present embodiment has an approximately quadrangular shape. The electronic component 11 is arranged on a top surface 12 of the heat sink 10. The electronic component 11 in this case has an approximately rectangular base which is smaller than the rectangular area of the top surface 12 of the heat sink 10. For the present example, the electronic component 11 is arranged approximately in the center of the heat sink 10. The electronic component 11 should rest with its complete surface on the top surface 12 of the heat sink 10. If applicable, a heat-conducting means or the like can be provided between the electronic component 11 and the heat sink 10.
The heat sink 10 furthermore comprises an end region 13 which is facing away from the top surface 12 and which contains a plurality of cooling fins 14. The cooling fins 14 are oriented approximately parallel, relative to each other, and extend parallel to one longitudinal side 15 of the heat sink 10. With respect to a lateral side 16 of the heat sink 10, the cooling fins 14 are arranged spaced apart. With respect to the top surface 12 of the heat sink 10, the cooling fins 14 project approximately at a right angle from the heat sink 10.
Between the top surface 12 and the end region 13, the heat sink 10 has a transition region 17. In FIG. 1, the transition region 17 is shown with view of the lateral side 16 of the heat sink 10 while in FIG. 2, the transition region is shown with view of the longitudinal side 15. The transition region 17 is embodied approximately rectangular.
The transition region 17 comprises several plate-shaped regions 18. For the present exemplary embodiment, the number of plate-shaped regions 18 corresponds to the number of cooling fins 14, wherein each cooling fin 14 is assigned to a plate-type region 18. The plate-type regions 18 extend from the top surface 12 of the heat sink 10 through the transition region 17 to the end region 13 and thus to the cooling fins 14 of the heat sink 10.
For the present embodiment, one of the plate-type regions 18 extends parallel to the associated cooling fin 14, wherein this plate-type region is given the reference number 18 a in FIG. 1. The plate-type region 18 a is furthermore also shown in FIG. 2.
According to FIG. 2, the plate-type region 18 a has an approximately trapezoid shape, wherein the length of the top approximately corresponds to the length of the electronic component 11. On its underside, this region has a length which approximately corresponds to the length of the associated cooling fin 14. The length of the top surface is shorter than the length of the underside. According to FIG. 1, the plate-type region 18 a has a width in crosswise direction which approximately corresponds to the width of the associated cooling fin 14. For the present example, this width is configured such that the widths of all plate-shaped regions 18 when taken together approximately correspond to the length of the electronic component 11 in transverse direction.
The plate-type region 18 a is substantially composed of a substrate with therein embedded carbon nanotubes, for example as known from the documents DE 102 48 644 A1 or DE 101 03 340 A1 (the entire contents of each of which are hereby incorporated herein by reference), wherein the substrate can be a synthetic material. The carbon nanotubes are oriented within the plate-type region 18 a in the direction as shown with an arrow 19 in FIGS. 1 and 2.
Apart from two edge regions 20, the carbon nanotubes in the in-between region 21 of the plate-type region 18 a are oriented in a direction pointing from the top 12 of the heat sink 10 to its end region 13, and thus to the cooling fins 14. In view of FIG. 1, an orientation angle for the carbon nanotubes is specified for the following explanations, which corresponds to the angle between the orientation for the carbon nanotubes and the orientation of the cooling fins 14. In the plate-type region 18 a, the orientation angle is thus between 0 degrees or 180 degrees, as the case may be.
In the two edge regions 20 of the plate-type region 18 a, the carbon nanotubes are oriented in a direction which respectively forms an angle to the orientation of the previously explained carbon nanotubes and is thus inclined to the respective lateral side 16 of the heat sink 10, as illustrated with the arrows 21 in FIG. 2.
A different plate-type region 18, taken as an example, is given the reference number 18 b in FIG. 1. The plate-type region 18 b essentially is embodied identical to the plate-type region 18 a. One difference, however, is that the plate-type region 18 b is not embodied parallel to the associated cooling fin 14, but is arranged at an angle thereto. The plate-type region 18 b is thus arranged within the transition region 17 at an angle or at a slight inclination. The orientation angle for the carbon nanotubes in the plate-type region 18 b for this example is therefore approximately 45 degrees.
Also different is the orientation angle at which different plate-type regions 18 are arranged, relative to the respectively associated cooling fin 14. The further the distance of the respective plate-type region 18 b from the center, the greater the inclination of the plate-type region 18 b will be, relative to the orientation of the associated cooling fin 14. As previously mentioned, only the plate-type region 18 a that is arranged approximately in the center has the same orientation as the associated cooling fin 14.
We want to point out that the introduction and explanation for the different regions is only designed to illustrate the configuration of the heat sink 10 for a better understanding. In the final analysis, it is only the carbon nanotubes in the substrate for the heat sink 10 which are correspondingly oriented. The illustrated regions are possibly not visible as such and/or their transitions do not exist. In that case, only the correspondingly oriented carbon nanotubes exist in the substrate.
As previously mentioned, the plate-type regions 18 extend from the electronic component 11 to the cooling fins 14 of the heat sink 10. It follows from FIGS. 1 and 2 that the top surfaces of all plate-type regions 18 form a surface area which approximately corresponds to the base of the electronic component 11. The heat generated by the electronic component 11 and dissipated to the heat sink 10 is thus conducted from the base of the electronic component 11, which is facing the heat sink 10, via the top surfaces of all plate-type regions 18 to the carbon nanotubes incorporated into the plate-type regions 18. With the aid of the correspondingly oriented carbon nanotubes, the heat is then conducted further to the cooling fins 14 of the heat sink 10.
The electronic component 11 in that case may have so-called hot regions, meaning individual regions in the base of the electronic component 11 which are hotter than other regions in the base. In that case, the plate-type regions 18 of the heat sink 10 need not be distributed evenly over the base of the electronic component 11, as previously explained, but can be embodied closer together in a hot region than outside of the hot region. A non-linear distribution of the plate-type regions 18 over the base of the electronic component 11 can thus be provided.
As a result of using the correspondingly oriented carbon nanotubes, the heat dissipated from the electronic component 11 to the heat sink 10 does not spread diffuse within the heat sink 10, but is purposely conducted via the plate-type regions 18 and therein contained carbon nanotubes to the cooling fins 14 of the heat sink 10.
This is achieved by orienting the carbon nanotubes within the plate-type region 18 in the direction toward one of the cooling fins 14 of the heat sink 10.
In particular, this is achieved by assigning each of the plate-type regions 18 to a specific cooling fin 14 and by orienting this region in the direction toward this fin. Each of the individual cooling fins 14 is thus assigned to a portion of the base of the electronic component 11, and the heat dissipated from this portion of the base of the electronic component 11 is then conducted via the carbon nanotubes of the associated plate-type region 18 to the also associated cooling fin 14.
The orientation at an angle of the carbon nanotubes in the two edge regions 20 of the plate-type regions 18 achieves that the heat within the respective cooling fin 14 is dissipated over the complete longitudinal side 15 of the heat sink 10.
As previously mentioned, the carbon nanotubes can be formed with the aid of a method as disclosed in the DE 101 03 340 A1. Carbon nanotubes formed in this way are all oriented in the same direction, wherein the regions needed to form the plate-type regions 18 or the edge regions 20 can subsequently be cut out of the carbon nanotubes formed in this way. For the plate-type regions 18 a, shown with the example in the FIG. 2, the two edge regions 20 and the region 21 in-between can thus be cut out separately from the produced carbon nanotubes and can then be combined in an optional manner, so as to form the complete plate-type region 18 a. Of course, the same applies for all plate-type regions 18. Alternatively, the carbon nanotubes can already be produced in such a way that the desired plate-type regions 18 are formed.
For example, it is possible for the carbon nanotubes of the plate-type regions 18 to be integrally cast into the substrate and to be arranged in this way inside the heat sink 10. Furthermore possible is that at least the transition region 17 of the heat sink 10 is composed of the substrate and that the plate-type regions 18 are incorporated into this substrate.
Alternatively, the plate-type regions 18 can also be held together with the aid of one or several frames. Respectively one frame can thus be provided for the top and the underside of the plate-type regions 18, wherein this frame is used to secure the plate-type regions 18 at the location. The plate-type regions 18 and thus also the carbon nanotubes can be connected via the frames to the electronic component 11 and the cooling fins 14 of the heat sink 10.
Another possibility is that the plate-type regions 18 as such do not even exit, as previously mentioned, but that the heat sink 10 as a whole is formed with the substrate and that the carbon nanotubes disposed in the substrate are oriented optionally inside the substrate, so as to point toward the desired direction. All method can be used for orienting the carbon nanotubes, for example any type of growth process or any type of electromagnetic process or the like.
It is furthermore possible that other areas of the heat sink 10 also contain additional regions with carbon nanotubes.
For example, it is possible that the cooling fins 14 are formed partially or completely with therein disposed carbon nanotubes. The carbon nanotubes in that case are oriented in particular in one or several of the directions illustrated with the arrow 22 for a cooling fin 14 in the example in FIG. 1. With these carbon nanotubes, the heat coming from the respectively associated plate-type region 18 is conducted further in the associated cooling fin 14, meaning in the direction toward the exposed end of the cooling fin 14, or at an angle thereto, or transverse to this direction. The heat is conducted in this way via the carbon nanotubes to the complete surface of the respective cooling fin 14.
Additional regions with carbon nanotubes can furthermore also exist between the plate-type regions 18 as well as outside of the plate-type regions 18, wherein this is illustrated in FIGS. 1 and 2, for example, with the arrows 23, 24, 25. With the aid of these carbon nanotubes, heat is conducted to the surfaces between the cooling fins 14 of the heat sink 10, as well as to the outside surfaces of the heat sink 10.
The regions between the plate-type regions 18, for which the orientation of the carbon nanotubes is shown with arrow 23 in FIG. 1, can in this case also be assigned to the plate-type regions 18 themselves. For example, the plate-type region 18 a can be expanded on the left and on the right, so as to include respectively one half of the adjoining region in-between region as part of the plate-type region 18 a.
On the whole, regions with carbon nanotubes which are respectively oriented in specific directions can thus exist within the complete heat sink 10. The carbon nanotubes can be embedded in the substrate and can in this way be fixated in the heat sink 10. The complete heat sink 10 can thus be formed with the substrate material with therein disposed carbon nanotubes. With the aid of the carbon nanotubes, the heat generated by the electronic component 11 is transported to the cooling fins 14 of the heat sink 10 and, if applicable, also to the surfaces of these cooling fins 14 and, if applicable, also to other top surfaces or outside surfaces of the heat sink 10.
The patent claims filed with the application are formulation proposals without prejudice for obtaining more extensive patent protection. The applicant reserves the right to claim even further combinations of features previously disclosed only in the description and/or drawings.
The example embodiment or each example embodiment should not be understood as a restriction of the invention. Rather, numerous variations and modifications are possible in the context of the present disclosure, in particular those variants and combinations which can be inferred by the person skilled in the art with regard to achieving the object for example by combination or modification of individual features or elements or method steps that are described in connection with the general or specific part of the description and are contained in the claims and/or the drawings, and, by way of combinable features, lead to a new subject matter or to new method steps or sequences of method steps, including insofar as they concern production, testing and operating methods.
References back that are used in dependent claims indicate the further embodiment of the subject matter of the main claim by way of the features of the respective dependent claim; they should not be understood as dispensing with obtaining independent protection of the subject matter for the combinations of features in the referred-back dependent claims. Furthermore, with regard to interpreting the claims, where a feature is concretized in more specific detail in a subordinate claim, it should be assumed that such a restriction is not present in the respective preceding claims.
Since the subject matter of the dependent claims in relation to the prior art on the priority date may form separate and independent inventions, the applicant reserves the right to make them the subject matter of independent claims or divisional declarations. They may furthermore also contain independent inventions which have a configuration that is independent of the subject matters of the preceding dependent claims.
Further, elements and/or features of different example embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims.
Example embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A heat sink with for an electronic component, comprising:

cooling fins; and

carbon nanotubes, disposed between a top surface of the heat sink and the cooling fins, the carbon nanotubes extending from the top surface of the heat sink toward at least one of the cooling fins and being oriented at an angle to an orientation of the at least one associated cooling fin.

2. The heat sink with for an electronic component according to claim 1, wherein a base area of the electronic component rests against the heat sink and is relatively smaller than the top surface of the heat sink, wherein the carbon nanotubes extend from the top surface of the heat sink toward several cooling fins, and wherein the angle of orientation for the carbon nanotubes associated with different cooling fins is different.

3. The heat sink with an electronic component according to claim 1, further comprising one plate-type region respectively assigned to each of the cooling fins, each including uniformly oriented carbon nanotubes disposed therein.

4. The heat sink with an electronic component according to claim 3, wherein the plate-type region includes an approximately trapezoid shape, a length of a top surface of the trapezoid shape corresponding approximately to a length of the electronic component and with a length of an underside of the trapezoid shape approximately corresponding to a length of the associated cooling fin.

5. The heat sink with an electronic component according to claim 3, wherein carbon nanotubes are present in an edge region of the plate-type region, each of the carbon nanotubes being orientable at an angle other than zero, relative to the other carbon nanotubes of the plate-type region.

6. The heat sink with an electronic component according to claim 1, wherein carbon nanotubes are present in the cooling fins, the carbon nanotubes being oriented in a direction toward an exposed end of a respective cooling fin, or at an angle thereto, or transverse thereto.

7. The heat sink with an electronic component according to claim 1, wherein the carbon nanotubes are embedded in a substrate.

8. A heat sink for an electronic component, comprising:

cooling fins; and

carbon nanotubes, disposed between a top surface of the heat sink and the cooling fins, the carbon nanotubes extending from the top surface of the heat sink in a direction toward at least one of the cooling fins and being oriented at an angle to an orientation of the at least one associated cooling fin.

9. The heat sink for an electronic component according to claim 8, wherein a base area of the electronic component which can rest against the heat sink is relatively smaller than the area of the top surface of the heat sink, wherein the carbon nanotubes extend from the top surface of the heat sink in a direction toward several of the cooling fins, and wherein the angles of orientation for the carbon nanotubes associated with different cooling fins are different.

10. The heat sink for an electronic component according to claim 4, wherein carbon nanotubes are present in an edge region of the plate-type region, each of the carbon nanotubes being orientable at an angle other than zero, relative to the other carbon nanotubes of the plate-type region.

11. The heat sink for an electronic component according to claim 2, further comprising one plate-type region respectively assigned to each of the cooling fins, each including uniformly oriented carbon nanotubes disposed therein.

12. The heat sink for an electronic component according to claim 11, wherein the plate-type region includes an approximately trapezoid shape, a length of a top surface of the trapezoid shape corresponding approximately to a length of the electronic component and with a length of an underside of the trapezoid shape approximately corresponding to a length of the associated cooling fin.

13. The heat sink for an electronic component according to claim 11, wherein carbon nanotubes are present in an edge region of the plate-type region, each of the carbon nanotubes being orientable at an angle other than zero, relative to the other carbon nanotubes of the plate-type region.

14. The heat sink for an electronic component according to claim 12, wherein carbon nanotubes are present in an edge region of the plate-type region, each of the carbon nanotubes being orientable at an angle other than zero, relative to the other carbon nanotubes of the plate-type region.