Pulsating heatpipe heat sink

Abstract

The invention relates to a pulsating heatpipe heat sink (10; 10a) with a sandwich-like structure consisting of at least three layers (11, 12, 13), comprising a middle layer (17; 17a) which is covered on both sides by a cover layer (16, 18; 18a), wherein a first cover layer (16) is preferably designed as a flat cover layer (16), wherein in the middle layer (17; 17a) first channel sections (21) of a first channel (14) and second channel sections (22) of a second channel (15) for guiding a cooling medium are arranged alternately side by side, wherein the channel sections (21, 22) are separated from each other by webs (19) of the middle layer (17; 17a), and wherein the first and second channel sections (21, 22) are separated by the two cover layers (16, 18; 18a) to form closed cross-sections of the are covered by both channels (14, 15).

Description

Technical field

[0001] The invention relates to a pulsating heatpipe heat sink which is characterized by a particularly advantageous and cost-effective manufacturing process. State of the art

[0002] Pulsating heat pipe heat sinks for cooling components or assemblies (hereinafter also referred to simply as heat pipe heat sinks) are known in various forms from the prior art. In a heat pipe heat sink, a vaporizable cooling medium is evaporated in an evaporator section by the application of heat. Due to vapor bubble formation and pressure differences, the evaporated cooling medium then flows into a condenser section, where it condenses and flows back into the evaporator section. An (additional) heat sink or similar component can typically be arranged in the condenser section. The heat pipe heat sink has one or more channels in its housing, which, as closed channels, allow the cooling medium to flow between the aforementioned evaporator section and the condenser section. These channels typically run parallel to each other or in a meandering pattern.

[0003] From DE 10 2021 204 769 A1 of the applicant, a pulsating heatpipe heat sink with the features of the preamble of claim 1 is known. The known heatpipe heat sink is characterized by a sandwich-like and modular structure consisting of at least three layers: a middle layer in which several channels with a rectangular cross-section are formed side by side, and a lower and upper cover layer covering the middle layer, each of which is designed as a flat cover layer. Crucially, to guide the cooling medium, the aforementioned channels of the middle layer are formed in a quarter-circle shape in a partial area, so that by placing several heatpipe heat sink elements next to each other, deflection areas for guiding the cooling medium are formed between parallel channel sections.Due to the quarter-circle shape of the cooling channels in the bending areas, it is relatively complex to manufacture them from a sheet metal part using the deep-drawing process. Furthermore, the surface area of ​​the middle layer is not optimally utilized for the arrangement of cooling channels, as an area without a cooling channel is created in the space between two opposing quarter-circle bending areas of a heat pipe cooler element. Disclosure of the invention

[0004] The pulsating heatpipe heat sink according to the invention, with the features of claim 1, has the advantage that it is particularly easy to manufacture and, moreover, allows for a particularly high number of cooling channels relative to the base area of ​​the heatpipe heat sink. Thus, a relatively high efficiency can also be achieved.

[0005] The invention is based on the idea of ​​forming deflection zones between two secondary channels arranged on either side of a central channel by means of additional deformations or recesses on the side facing away from the central layer of one of the cover layers. This makes it possible, in particular, to form (exclusively) straight cooling channels within the central layer, which can thus have a particularly close spacing from each other, or the entire base area of ​​the central layer can be used for forming cooling channels.

[0006] In light of the above explanations, a pulsating heatpipe heat sink according to the invention, having the features of claim 1, therefore has a sandwich-like structure consisting of at least three layers, comprising a middle layer which is covered on both sides by a cover layer. A first cover layer is preferably designed as a flat cover layer, wherein first channel sections of a first channel and second channel sections of a second channel for guiding a cooling medium are arranged alternately side by side in the middle layer. The channel sections are separated from each other by webs of the middle layer, wherein the first and second channel sections are covered by the two cover layers to form closed cross-sections of the two channels.According to the invention, it is provided that in a second cover layer, recesses are formed in deflection areas of the second channel in the direction of the side facing away from the middle layer, which connect the cross-sections of two adjacent second channel sections, wherein the second cover layer is arranged outside the recesses in contact with a connecting section of the middle layer, which limits the cross-section of a first channel section, and which is arranged between two second channel sections.

[0007] Advantageous further developments of the pulsating heatpipe heat sink according to the invention are listed in the dependent claims.

[0008] In order to minimize the increase in flow resistance for the cooling medium in the deflection areas formed by the depressions, it is provided that the cross-section of the depressions, viewed in a direction perpendicular to the longitudinal direction of the second channel sections, corresponds at least to the cross-section of a second channel section.

[0009] To maximize the length of the second channel sections or the second channel, the recesses are preferably arranged at the level of the end face regions of the middle layer.

[0010] Preferably, the cross-section of the channels and recesses is rectangular. This allows for the simple creation of media-tight connections between the channels, particularly through bonded joints such as soldered or welded connections. Furthermore, this maximizes the cross-section of the channels.

[0011] In a particularly simple way of increasing the cross-section of the second channel sections, the depressions are designed to extend beyond the deflection areas towards the second channel sections. In other words, this means that the depressions preferably run along the entire length of the second channel sections.

[0012] In a concrete, constructive further development of the last proposal, it is planned that the recesses in a plane running parallel to the second cover layer each form closed frame elements, in the central area of ​​which a further recess is sealedly connected to the middle layer in the area of ​​a connecting section.

[0013] In a further embodiment of the invention, the cross-sections of two adjacent first channel sections are connected at the end faces of the middle layer by means of additional deflection areas. These additional deflection areas thus serve to connect two adjacent first channels for the cooling medium, enabling it to flow in a meandering pattern within the heat pipe heat sink.

[0014] In a preferred embodiment of the aforementioned proposal, the additional deflection areas are formed on an insert located between the two cover layers. Such an insert can be formed by a stamping process, the thickness of which corresponds to the height of the middle layer between the two cover layers.

[0015] A preferred geometric design of the insert provides that the insert has semicircular recesses on the side facing the first channel sections to form the additional deflection areas and end faces between the recesses to close the cross-section of the second channel sections.

[0016] Furthermore, it is particularly advantageous that at least the cover layers are made of sheet metal, and that the recesses are formed by forming, especially deep drawing. This allows for a manufacturing process that is advantageous from a production standpoint and relatively inexpensive.

[0017] It is further preferred that the channel sections are straight and arranged parallel to each other. This allows for a particularly high density of channels for guiding the cooling medium.

[0018] Finally, the connection between the middle layer and the top layers is intended to be achieved through material-bonded connections. Depending on the material of the layers, soldering or welding processes, such as laser welding, are used.

[0019] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments of the invention and from the drawings. Brief description of the drawings Fig. Figure 1 shows a perspective view of a partial area of ​​a first embodiment of a pulsating heatpipe heat sink, Fig. 2 a section through a partial section of the heatpipe heat sink according to the Fig. 1, Fig. 3 A perspective, partially cutaway view of the heat pipe heat sink according to the Fig. 1, Fig. 4 a perspective view of an insert arranged between two cover layers, Fig. 5 a perspective view of recesses on a second cover layer of the heatpipe heat sink according to the Fig. 1, Fig. 6 a perspective view of a second heatpipe heat sink, Fig. 7 A partially cutaway perspective view of the heat pipe heat sink according to the Fig. 6 and Fig. 8 a section through the heat pipe heat sink according to the Fig. 6 in level VIII-VIII of the Fig. 6. Embodiments of the invention

[0020] Identical elements or elements with the same function are provided with the same reference numbers in the figures.

[0021] In the Fig. Figures 1 to 5 depict the essential components of a first embodiment of a pulsating heatpipe heat sink 10 for cooling at least one component or assembly not shown in the figures. The at least one component is, in particular, a heat-generating component during operation, for example, a power component, an integrated circuit (IC), or similar component. The heat-generating component is thermally connected to the heatpipe heat sink 10 in an evaporator section of the heatpipe heat sink 10 in a manner known per se, in particular by means of a thermally conductive adhesive. Furthermore, the heatpipe heat sink 10 has a condenser section at a distance from the evaporator section, on which, for example, a heat sink or similar component can be arranged. The pulsating heatpipe heat sink 10 can be part of a larger unit or assembly, such as a control unit, a component in the context of electromobility, or similar.

[0022] The heat pipe heat sink 10 has a housing with a sandwich-like structure consisting of three layers 11 to 13. The three layers 11 to 13 are preferably each formed from sheet metal parts, for example, from an aluminum sheet or a steel sheet. Layer 11 forms a first cover layer 16, which is designed as a flat cover layer 16 without deformations. The second layer 12 forms a middle layer 17 in the form of a channel sheet, which, by forming, in particular by deep drawing, has a plurality of adjacent, parallel first channel sections 21 of a first channel 14 and second channel sections 22 of a second channel 15. The first channel sections 21 and second channel sections 22 alternate in the lateral direction of the middle layer 17, wherein the channel sections 21, 22 are separated from each other by webs 19 extending perpendicular to the plane of the two layers 11, 13.The webs 19 are connected to each other by connecting sections 20 arranged parallel to each other and in sealing contact with the layers 11, 13. The connecting sections 20 limit the cross-section of the first channel sections 21 on one side. The cross-section of the middle layer 12 is therefore corrugated ( ). Fig. 3) The third layer 13 is formed as the second cover layer 18. The two cover layers 16 and 18 completely cover the middle layer 17.

[0023] According to the presentation of Fig. 2 and Fig. 3 The first channel sections 21 and the second channel sections 22 each have a rectangular cross-section, which is preferably at least approximately the same size. The heat pipe heat sink 10 is, overall, cuboid or plate-shaped with a rectangular base and has two opposite end faces 25 extending from the channel sections 21 and 22, as shown in the illustration. Fig. 1 and Fig. 3 only one of the two end faces 25 is visible. In the area of ​​the respective end face 25, at the height and in extension of the middle layer 17, i.e. between the two cover layers 16 and 18, an insert part 26, designed as a separate component, is arranged.

[0024] The insert 26, which is in the Fig. As shown in Figure 4 in detail, the channel is in particular strip-shaped and has semicircular recesses 28 on the side facing the channel sections 21, 22. The recesses 28 form first deflection areas 29 between two first channel sections 21 arranged directly next to each other. On the side facing the second channel sections 22, projections arranged between two recesses 28 form end faces 31, each of which serves to close or seal a second channel section 22 by either (butting up) against the end faces of the second channel sections 22 and covering them, or by (slightly) projecting into the cross-sections of the second channel sections 22.In both cases, the escape of cooling medium from the second channel sections 22 is preferably prevented by a material-bonded connection, for example in the form of laser welds or by a temperature-resistant adhesive.

[0025] It is essential that the second cover layer 18 has bulges or recesses 30 on the side facing away from the middle layer 17, which in the exemplary embodiment are designed as cuboid-shaped recesses 30. The recesses 30 each connect two adjacent second channel sections 22 at the level of an end region 32 of the middle layer 17 near the end faces 31 of the insert 26. The recesses 30 thus form second deflection areas 33 between two adjacent second channel sections 22. In order to minimize the increase in flow resistance for the cooling medium, the cross-section of the recesses 30, viewed in a direction perpendicular to the longitudinal direction of the second channel sections 22, is at least as large as the cross-section of a second channel section 22.The design and arrangement of the first and second channel sections 21, 22 described above, in conjunction with the insert 26 and the recesses 30, results in a meandering design of the two channels 14, 15.

[0026] Channels 14 and 15 serve to guide a vaporizable cooling medium that cools at least one component or part. As is known from the prior art, the cooling medium evaporates in the evaporator section of the heat pipe heat sink 10 and, due to pressure differences and vapor bubble formation, enters the condenser section, from where it flows back to the evaporator section after condensation.

[0027] In order to enable a media-tight guidance of the cooling medium in the channels 14, 15, the components described so far are sealed against each other at the relevant points by material-bonded connections, in particular by soldered or welded connections or adhesive connections.

[0028] In the Fig. Figures 6 to 8 show a modified heatpipe heat sink 10a. The heatpipe heat sink 10a is characterized by the fact that the recesses 30a formed in the area of ​​the second cover layer 18a are extended outside the second deflection areas 33 in the direction of the second channel sections 22, with the depth or height of the recesses 30a being constant in the exemplary embodiment. In particular, the recesses 30a extend over the entire length of the second channel sections 22, so that, viewed in the plane of the second cover layer 18a, the recesses 30a form closed frame elements 35. In the central areas of the frame elements 35, further recesses 34 are formed in the direction of the middle layer 17a. The further recesses 34 abut sealingly against connecting sections 20 between two second channel sections 22. As can be seen from the Fig. 6 and Fig.As can be further seen from Figure 8, the further recesses 34 end at a distance a from an end face 37 of the middle layer 17a. Because the recesses 30a are extended in the direction of the second channel sections 22, the cross-section of the second channel sections 22 is enlarged in the heat pipe cooling body 10a compared to the heat pipe cooling body 10.

[0029] The heat pipe cooling element 10, 10a described so far can be modified or adapted in a variety of ways without deviating from the inventive concept. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 204 769 A1

[0003]

Claims

[1] Pulsating heatpipe heat sink (10; 10a), comprising a sandwich-like structure consisting of at least three layers (11, 12, 13) comprising a middle layer (17; 17a) which is covered on both sides by a cover layer (16, 18; 18a), wherein a first cover layer (16) is preferably designed as a flat cover layer (16), wherein in the middle layer (17; 17a) first channel sections (21) of a first channel (14) and second channel sections (22) of a second channel (15) for guiding a cooling medium are arranged alternately side by side, wherein the channel sections (21, 22) are separated from each other by webs (19) of the middle layer (17; 17a), and wherein the first and second channel sections (21, 22) are separated by the two cover layers (16, 18; 18a) to form closed cross-sections of the two Channels (14, 15) are covered, characterized by, that in a second cover layer (18; 18a) in the direction of the side facing away from the middle layer (17; 17a) recesses (30; 30a) are formed in deflection areas (33) of the second channel (15) which connect the cross-sections of two adjacent second channel sections (22) to each other, wherein the second cover layer (18; 18a) is arranged outside the recesses (30; 30a) in contact with a connecting section (20) of the middle layer (17; 17a) which limits the cross-section of a first channel section (21) and is arranged between two second channel sections (22). [2] Heatpipe heat sink according to claim 1, characterized by , that the cross-section of the depressions (30; 30a) when viewed in a direction perpendicular to the longitudinal direction of the second channel sections (22) corresponds at least to the cross-section of a second channel section (22). [3] Heatpipe heat sink according to claim 1 or 2, characterized by, that the depressions (30) are arranged at the level of the end face regions (32) of the middle layer (17; 17a). [4] Heatpipe heat sink according to any one of claims 1 to 3, characterized by , that the cross-sections of the channels (14, 15) and the depressions (30; 30a) are rectangular. [5] Heatpipe heat sink according to one of claims 1, 3 or 4, characterized by , that the depressions (30a) outside the deflection areas (33) are extended in the direction of the second channel sections (22) to increase the cross-sections of the second channel sections (22). [6] Heatpipe heat sink according to claim 5, characterized by , that the recesses (30a) in a plane running parallel to the second cover layer (18a) each form closed frame elements (35), in the central area of ​​which a further recess (34) is sealedly connected to the middle layer (17a) in the area of ​​a connecting section (20). [7] Heatpipe heat sink according to any one of claims 1 to 6, characterized by , that the cross-sections of two adjacent first channel sections (21) are connected to each other at end face regions of the middle layer (17; 17a) by means of additional deflection areas (29). [8] Heatpipe heat sink according to claim 7, characterized by , that the additional deflection areas (29) are formed on an insert (26) which is arranged between the two cover layers (16, 18; 18a). [9] Heatpipe heat sink according to claim 8, characterized by , that the insert (26) has semicircular recesses (28) on the side facing the first channel sections (21) to form the additional deflection areas (29) and end faces (31) between the recesses (28) to close the cross-section of the second channel sections (22). [10] Heatpipe heat sink according to any one of claims 1 to 9, characterized by, that at least the cover layers (16, 18; 18a) are made of sheet metal, and that the recesses (30; 30a) are formed by forming, in particular deep drawing. [11] Heatpipe heat sink according to any one of claims 1 to 10, characterized by that the channel sections (21, 22) are straight and arranged parallel to each other. [12] Heatpipe heat sink according to any one of claims 1 to 11, characterized by , that the connection between the middle layer (17; 17a) and the top layers (16, 18; 18a) is made by material-bonded connections.

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