CN117836583A

CN117836583A - Heat pipe for electronic component and electronic device including the same

Info

Publication number: CN117836583A
Application number: CN202180101565.7A
Authority: CN
Inventors: 安德里·拉萨马金; 付星
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-08-17
Filing date: 2021-08-17
Publication date: 2024-04-05
Also published as: WO2023020682A1

Abstract

A heat pipe for an electronic component is provided, the heat pipe comprising a hollow structure having an evaporator section, a condenser section, and a flexible transport section formed between the evaporator section and the condenser section, wherein a vapor passage is defined through the sections of the hollow structure. The heat pipe further includes a capillary structure disposed within the hollow structure, wherein the capillary structure is at least partially in direct contact with the inner surfaces of the evaporator section and the condenser section and freely suspended in the flexible transport section. The heat pipe includes a simple design, and improved heat transfer efficiency and improved thermal performance. The heat pipe further ensures the flatness requirements of the evaporation section and the condensation section.

Description

Heat pipe for electronic component and electronic device including the same

Technical Field

The present invention relates generally to the field of electronic devices, and more particularly, to heat pipes for electronic components and electronic devices including heat pipes.

Background

With the rapid development of electronic (or semiconductor) devices, there is an increasing demand for cooling systems capable of efficiently conducting heat from the electronic devices. Today, highly thermally conductive materials (e.g., copper and aluminum) are not capable of efficiently removing the high density heat flux generated by modern electronic devices (or integrated circuits or chips), thereby causing the modern electronic devices to overheat. Accordingly, heat is conducted from the electronic device (or semiconductor device) to the heat sink fins using a heat conduction device (e.g., a heat pipe) to provide adequate cooling to electronic components in the electronic device and to eliminate certain drawbacks associated with highly thermally conductive materials (i.e., copper and aluminum).

Traditionally, heat pipes are two-phase systems comprising an elongated body with heat transfer elements and a working fluid capable of being in a liquid phase and a gas phase. In such a system, when a heat source is provided to one end of the heat pipe, the working fluid evaporates into a gas phase, resulting in an increase in pressure. Furthermore, the gas phase tends to move from the high pressure zone to the low pressure zone and the low temperature zone. As a result, the gaseous phase of the working fluid condenses and the liquid phase of the working fluid returns through the heat transfer element under the capillary force generated by the heat transfer element. However, in this case, the total heat transfer rate (or effective thermal conductivity) is significantly higher by 2-3 orders of magnitude than the thermal conductivity in a solid body having the same dimensions made of copper (Cu) or aluminum (Al).

Rigid heat pipes may be used in some cases, which may transfer vibrations or thermal expansion back to the evaporation (or evaporator) area, which is unsafe for the electronic device (or chip). Such rigid heat pipes are not preferred for electronic devices because installing cooling systems based on conventional rigid heat pipes can damage the cooling assembly. Alternatively, there are conventional heat pipes having corrugated portions that exhibit partial flexibility. In conventional heat pipes, a rigid capillary wick is provided as a heat transfer element that is typically destroyed after several bends. There is another conventional heat pipe including a plurality of individual components, which results in an increase in structural complexity (i.e., design complexity).

In addition, the individual components and the connections between the individual components can affect the overall reliability of the heat pipe (e.g., cause leakage of working fluid) and increase overall manufacturing and maintenance costs. Furthermore, the multiple individual components in conventional heat pipes increase the risk of incompatibility with other heat pipe components, especially chemical reactivity with water, and therefore non-condensable gases are present that affect thermal performance. Thus, there are technical problems of mechanical stability, low thermal performance, high cost and complexity associated with conventional heat pipes.

Thus, in light of the foregoing discussion, there is a need to overcome the aforementioned drawbacks associated with conventional heat pipes.

Disclosure of Invention

The invention provides a heat pipe for an electronic component, and an electronic device including the heat pipe. The present invention provides a solution to the existing problems of low thermal performance, high cost and complexity associated with conventional heat pipes. It is an object of the present invention to provide a solution which at least partly overcomes the problems encountered in the prior art and to provide an improved heat pipe for an electronic assembly which is flexible and which exhibits improved thermal and mechanical properties, reduced costs and lower complexity.

One or more of the objects of the invention are achieved by the solution provided in the attached independent claims. Advantageous implementations of the invention are further defined in the dependent claims.

In one aspect, the present invention provides a heat pipe for an electronic assembly, comprising: a hollow structure having an evaporation section, a condensation section, and a flexible transport section formed between the evaporation section and the condensation section, wherein a vapor passage is defined through the sections of the hollow structure; a capillary structure disposed within the hollow structure, wherein the capillary structure is at least partially in direct contact with the inner surfaces of the evaporator section and the condenser section and freely suspended in the flexible transport section.

The heat pipe of the present invention has a simple design and improved heat transfer efficiency. The hollow structure of the heat pipe provides flexibility properties to the heat pipe, and the capillary structure disposed within the hollow structure provides good thermal contact in the evaporator section and the condenser section. The capillary structure also supports free movement of the working fluid through the flexible transport section. The capillary structure advantageously provides improved thermal performance for the heat pipe and ensures flatness requirements for the evaporator and condenser sections.

In one implementation, the flexible transport section is in fluid communication with the evaporator section and the condenser section.

Advantageously, the flexible transport section is adapted to transport the working fluid from the condensing section to the evaporating section.

In another implementation, the capillary structure includes at least two layers of sintered discrete metal fibers.

By using at least two layers of sintered discrete metal fibers (or felt metal), the heat pipe achieves significantly improved thermal performance, flexibility properties, and good gravity (G) resistance. Sintering at least two layers of discrete metal fibers further provides the heat pipe with a wide range of structural parameters (e.g., height and width increase of the capillary structure).

In another implementation, the first layer of the capillary structure is disposed on a bottom surface and the second layer is disposed on upper surfaces of the evaporator section and the condenser section.

The first and second layers of capillary structure act as mechanical support elements to support the flatness requirements of the evaporator and condenser sections.

In another implementation, the second layer is disposed on top of the first layer by a sintering process.

By using a sintering process, the capillary structure of the heat pipe ensures an improved mechanical and thermal contact between the first layer and the second layer.

In another implementation, the capillary structure further includes a third layer disposed vertically between the first layer and the second layer.

In this implementation, the third layer provides mechanical strength to the heat pipe.

In another implementation, the thickness of the capillary structure is selected from a value in the range of 0.001mm to 10 mm.

The heat pipe serves as a thermal connection between the electronic component and the heat sink. Thus, a thickness of the capillary structure within a given range provides a good balance of high heat transfer and low thermal resistance between the electronic component and the heat sink.

In another implementation, the hollow structure is made of a single piece of thermally conductive material, wherein the evaporator section and the condenser section are configured to be flat, and the flexible transport section is corrugated to provide flexibility.

By using a single piece of thermally conductive material, the durability of the heat pipe is improved and the cost is reduced.

In another implementation, the thermally conductive material is one of copper, steel, silver, or alloys thereof.

In this implementation, the heat pipe exhibits improved thermal conductivity.

In another implementation, the working fluid is one of water, ethanol, methanol, refrigerant, or a combination thereof.

In this implementation, the heat pipe achieves reliability improvement under freezing conditions.

In another implementation, the capillary structure is connected to the inner surfaces of the evaporator section and the condenser section by a sintering process.

By using a sintering process, the capillary structure of the heat pipe ensures an improved mechanical and thermal contact between the inner surfaces of the evaporator and condenser sections.

In another implementation, the heat pipe is vacuum sealed at both ends.

In this implementation, the flexible transport section has improved flexibility properties during folding of the heat pipe, with less deformation of the flexible transport section near the vapor channel.

In another aspect, the present invention provides an electronic device including a heat pipe.

The electronic device achieves all the advantages and technical effects of the heat pipe of the invention.

It should be appreciated that all of the above implementations may be combined. It should be noted that all devices, elements, circuits, units and modules described in this application may be implemented in any suitable hardware element known to a skilled person. All steps performed by the various entities described in this application, as well as functions to be performed by the various entities described are intended to mean that the respective entities are adapted to perform the respective steps and functions. It will be appreciated that features of the invention are susceptible to being combined in various combinations without departing from the scope of the invention as defined by the accompanying claims.

Other aspects, advantages, features and objects of the invention will become apparent from the accompanying drawings and the detailed description of illustrative implementations explained in conjunction with the following appended claims.

Drawings

The foregoing summary, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings exemplary constructions of the invention. However, the invention is not limited to the specific methods and instrumentalities disclosed herein. Moreover, those skilled in the art will appreciate that the drawings are not drawn to scale. Identical elements are denoted by the same numerals, where possible.

FIG. 1A is a perspective exterior view of a heat pipe for an electronic component provided by an embodiment of the present invention;

FIG. 1B is an enlarged cross-sectional view of a capillary structure of a heat pipe provided by an embodiment of the present invention;

FIG. 1C is a perspective exterior view of a heat pipe provided by an embodiment of the present invention, the heat pipe representing an interconnection between a first layer, a second layer, and a flexible transport section;

FIG. 1D is an enlarged cross-sectional view of a capillary structure of a heat pipe provided by another embodiment of the present invention;

FIG. 1E is an enlarged cross-sectional view of a capillary structure of a heat pipe provided by yet another embodiment of the present invention;

fig. 2 is a block diagram of an electronic device provided by an embodiment of the invention.

In the drawings, the underlined numbers are used to denote items where the underlined numbers are located or items adjacent to the underlined numbers. The non-underlined numbers are associated with items identified by lines associating the non-underlined numbers with the items. When a number is not underlined but with an associated arrow, the number without the underline is used to identify the general item to which the arrow refers.

Detailed Description

The following detailed description illustrates embodiments of the invention and the manner in which the embodiments may be practiced. While a few modes of carrying out the invention have been disclosed, those skilled in the art will appreciate that there may be other embodiments for carrying out or practicing the invention.

FIG. 1A is a perspective exterior view of a heat pipe for an electronic component provided by an embodiment of the present invention. Referring to fig. 1A, a heat pipe 100A for an electronic component is shown, the heat pipe 100A including a hollow structure 102, an evaporator section 104, a condenser section 106, a flexible transport section 108, a vapor channel 110, and a capillary structure 112.

The heat pipe 100A of the present invention is implemented as part of a cooling system for an electronic component. Here, the electronic component may be any electronic device that can be folded, including a notebook computer, a mobile phone, a computer, a tablet computer, a camera, and the like. In such electronic components, some heat generating components, such as arithmetic elements (or central processing units or processors) and integrated circuits, are constructed in a high-density manner, and thus hot spots, which locally increase in temperature, occur. Therefore, the rise in temperature becomes a limiting factor for the arithmetic operation speed, further resulting in a decrease in durability of the electronic component or the like. Heat pipe 100A, which is part of the cooling system of the electronic component, provides cooling of the electronic component.

The hollow structure 102 is an outer surface of the heat pipe 100A, and the hollow structure 102 is a closed container (both ends are sealed) and filled with a working fluid. The working fluid flows within the hollow structure 102, for example, between the evaporator section 104 and the condenser section 106, and in a circulating mode through the vapor channels 110 in a vapor state and through the capillary structures 112 in a liquid state, thereby ensuring heat transfer. In other words, a vapor passage 110 is provided for transporting the working fluid in its vapor state between the evaporator section 104 and the condenser section 106. The hollow structure 102 includes an evaporator section 104, a condenser section 106, and a flexible transport section 108. The hollow structure 102 is configured to transfer heat through the flexible transport section 108 due to a combination of different processes (e.g., evaporation and condensation). In one example, the hollow structure 102 (or simply a container) has a tubular shape or any other shape suitable for heat transfer in an electronic component.

The evaporator end 104 is a flat portion of the hollow structure 102. The evaporator end 104 is also referred to as an evaporation zone, a thermal load zone, an evaporator, and the like.

The condensing section 106 is also a flat portion of the hollow structure 102. The condensing section 106 is also referred to as a condensing zone, heat dissipation zone, condenser, etc.

The flexible conveying sections 108 are corrugated portions of the hollow structure 102 to provide flexible characteristics to the heat pipe 100A. The flexible conveying section 108 is formed from a corrugated tube, for example, based on a copper (Cu) corrugated tube made from a monolithic piece of copper tubing.

The steam channel 110 is also referred to as an empty space within the hollow structure 102 adapted to deliver steam. The capillary structure 112 is used to deliver the working fluid at high capillary pressure.

In one aspect, the present invention provides a heat pipe 100A for an electronic component, comprising: a hollow structure 102 having an evaporator section 104, a condenser section 106, and a flexible transport section 108 formed between the evaporator section 104 and the condenser section 106, wherein a vapor passage 110 is defined through the sections of the hollow structure 102; a capillary structure 112 disposed within the hollow structure 102. The capillary structure 112 is at least partially in direct contact with the inner surfaces of the evaporator section 104 and the condenser section 106 and is free to hang in the flexible transport section 108.

During operation of heat pipe 100A, heat from a heat source (e.g., an electronic component such as an integrated circuit (integrated circuit, IC) not shown in fig. 1A) is applied to evaporator end 104. As a result, the working fluid within the hollow structure 102 evaporates in the evaporation section 104. The vapor is then transferred from the evaporator section 104 to the condenser section 106 through the vapor passage 110 (or space), the flexible transfer section 108. Thereafter, the vapor state of the working fluid releases latent heat in the condensing section 106. As a result, the vapor is converted back to a liquid state of the working fluid, which is further transported from the condensing section 106 to the evaporating section 104 and through the capillary structure 112 by capillary action (or force).

Capillary structures 112 disposed within the hollow structure 102 are at least partially in direct contact with the inner surfaces of the evaporator section 104 and the condenser section 106. Thus, the capillary structure 112 (or sintered core structure) is configured to provide good thermal contact with the evaporator section 104, the condenser section 106, and the flexible transport section 108. In one example, the evaporator end 104 and the condenser end 106 of the heat pipe 100A include several layers of capillary structures 112, the capillary structures 112 being in good mechanical and thermal contact with the evaporator end 104 and the condenser end 106 in the hollow structure 102.

Furthermore, the capillary structure 112 is free-hanging (i.e., without mechanical contact) within the flexible conveying section 108 of the heat pipe 100A, as further shown and described with reference to fig. 1C. Thus, the capillary structure 112 supports free movement (i.e., unobstructed) of the working fluid through the flexible transport section 108. In one implementation, capillary structure 112 is based on a stair-shape, e.g., having two layers that facilitate providing improved thermal performance of heat pipe 100A and ensuring flatness requirements (e.g., mechanical tasks) of evaporator end 104 and condenser end 106. In addition, the heat pipe 100A has a simple design, and a simple production process and improved heat transfer efficiency. Advantageously, the heat pipe 100A of the present invention is flexible and less prone to deformation due to radial deformation than conventional heat pipes.

According to one embodiment, the flexible conveying section 108 is in fluid communication with the evaporator section 104 and the condenser section 106. In other words, the flexible conveying section 108 includes a portion that is in fluid communication with the evaporator section 104 and the condenser section 106. Thus, the flexible transport section 108 facilitates transport of the working fluid from the evaporator section 104 to the condenser section 106, or vice versa.

According to one embodiment, the thickness of the capillary structure 112 is selected from a value in the range of 0.001mm to 10 mm. The thickness of capillary structure 112 in the range of 0.001mm to 10mm provides a good balance of high heat transfer and low thermal resistance for heat pipe 100A. In one example, the above thickness ranges are fabricated using the production techniques of the present invention, thus reducing the production cost of heat pipe 100A.

According to one embodiment, the hollow structure 102 is made from a single piece of thermally conductive material, wherein the evaporator section 104 and the condenser section 106 are configured flat, and the flexible transport section 108 is corrugated to provide flexibility. Because the hollow structure 102 is formed from a single piece of thermally conductive material, the hollow structure 102 improves the reliability of the heat pipe 100A and avoids the need for additional weld locations between different segments, such as between flat and corrugated segments. For example, the hollow structure 102 avoids additional welding between the evaporator section 104 and the flexible transport section 108 and between the flexible transport section 108 and the condenser section 106. In addition, the single piece of metal reduces the overall cost of the heat pipe 100A.

According to one embodiment, the thermally conductive material is one of copper, steel, silver or an alloy thereof. Because the metal is one of copper, steel, silver, or alloys thereof, the hollow structure 102 ensures high thermal conductivity of the evaporator section 104, the condenser section 106, and the flexible transport section 108 and provides flexible properties to the heat pipe 100A. Furthermore, heat pipe 100A exhibits improved heat transfer performance and is reliable even at low temperatures. In one example, the thermal performance of heat pipe 100A is not significantly reduced.

According to one embodiment, the capillary structure 112 is connected to the inner surfaces of the evaporator section 104 and the condenser section 106 by a sintering process. During the sintering process, the capillary structure 112, the evaporator end 104, and the condenser end 106 are heated to a temperature, for example, without melting them. Advantageously, by using a sintering process (or method), the capillary structure 112 of the heat pipe 100A ensures improved mechanical and thermal contact between the inner surfaces of the evaporator end 104 and the condenser end 106.

According to one embodiment, heat pipe 100A is vacuum sealed at both ends. Thus, the flexible conveying section 108 provides improved flexibility performance during folding of the heat pipe 100A, and less deformation of the flexible conveying section 108 near the vapor channel 110, as compared to conventional heat pipes.

Accordingly, the heat pipe 100A has a simple design and an easy manufacturing process and improved heat transfer efficiency. Advantageously, hollow structure 102 is formed as a unitary structure from a single piece of copper tubing to avoid welding or any type of additional connection nodes, thereby improving the reliability of heat pipe 100A. In addition, flexible transport section 108 is also made of copper bellows that provide flexibility and resiliency to heat pipe 100A. Furthermore, the capillary structure 112 disposed within the hollow structure 102 provides good thermal contact with the evaporator end 104, the condenser end 106, and the conveyed working fluid. The capillary structure 112 also facilitates the transport of the working fluid through the different sections of the heat pipe 100A in its different phases. The capillary structure 112 also provides improved thermal performance for the heat pipe 100A and ensures flatness requirements for the evaporator end 104 and the condenser end 106.

Fig. 1B is an enlarged cross-sectional view of a capillary structure of a heat pipe provided by an embodiment of the present invention. FIG. 1B is described in conjunction with the elements of FIG. 1A. Referring to FIG. 1B, an enlarged cross-sectional view of a capillary structure of heat pipe 100B (e.g., capillary structure 112 of FIG. 1A) including first layer 114 and second layer 116 is shown. The heat pipe 100B also includes a hollow structure 102 and a vapor channel 110. The first layer 114 and the second layer 116 are two different layers of the capillary structure 112.

According to one embodiment, the capillary structure 112 comprises at least two layers of sintered discrete metal fibers. Thus, at least two layers of capillary structure 112 are used to form a stair-shaped wick design that ensures the thermal and mechanical properties of heat pipe 100B. By using at least two layers of sintered discrete metal fibers (felt metal), the heat pipe 100B achieves significantly improved thermal parameters, flexibility properties, and improved gravity (G) resistance. Alternatively, having two layers of sintered discrete metal fibers instead of one provides more options to select and adjust the appropriate structural parameters for the two layers (e.g., structural parameters such as height and width of capillary structure 112 may be increased) to improve the overall thermal performance of heat pipe 100B.

According to one embodiment, the first layer 114 of the capillary structure 112 is disposed on the bottom surface and the second layer 116 is disposed on the upper surfaces of the evaporator section 104 and the condenser section 106. In one implementation, each of the evaporator section 104 and the condenser section 106 includes a bottom surface and an upper surface, respectively. Further, the first layer 114 of the capillary structure 112 is disposed on the bottom surface of the evaporator end 104 and similarly disposed on the bottom surface of the condenser end 106. Further, the second layer 116 of capillary structure 112 is disposed on the upper surface of evaporator end 104 and similarly disposed on the upper surface of condenser end 106. Thus, the first layer 114 and the second layer 116 of the capillary structure 112 act as mechanical support elements to support the flatness requirements (e.g., avoid forming bends) of the evaporator end 104 and the condenser end 106.

According to one embodiment, the second layer 116 is disposed on top of the first layer 114 by a sintering process. In other words, the second layer 116 is disposed on top of the first layer 114 to provide a stair-step shape for the capillary structure (e.g., the capillary structure 112 of fig. 1A). In one example, one of the stair-shaped first layer 114 or the second layer 116 ensures thermal performance of the heat pipe 100B, and the other layer of the stair shape supports the flatness requirements of the evaporator section 104 and the condenser section 106 of the heat pipe 100B. Advantageously, the sintering process ensures improved mechanical and thermal contact between the first layer 114 and the second layer 116.

According to one embodiment, the working fluid is one of water, ethanol, methanol, refrigerant, or a combination thereof. In one implementation, the capillary structure 112 includes a layer of sintered discrete metal fibers. Therefore, by using water, ethanol, methanol, refrigerant, or a combination thereof for the working fluid, the reliability of the heat pipe 100B under freezing conditions is improved.

FIG. 1C is a perspective exterior view of a heat pipe provided by an embodiment of the present invention, the heat pipe representing an interconnection between a first layer, a second layer, and a flexible transport section. FIG. 1C is described in conjunction with the elements of FIGS. 1A and 1B. Referring to FIG. 1C, a perspective view of a heat pipe 100C is shown, the heat pipe 100C representing the interconnection between a first layer 114, a second layer 116, and a flexible transport section 108.

In one implementation, the capillary structure 112 (of fig. 1A) includes at least two layers disposed on top of the first layer 114, such as the first layer 114 and the second layer 116. Further, the capillary structure 112, including the first layer 114 and the second layer 116, is free-hanging (i.e., without mechanical contact) within the flexible conveying section 108 of the heat pipe 100C, as shown in fig. 1C. Thus, the capillary structure 112 facilitates the transport (i.e., does not clog) of the working fluid through the flexible transport section 108 in its different phases (liquid state of the working fluid).

FIG. 1D is an enlarged cross-sectional view of a capillary structure of a heat pipe according to another embodiment of the present invention. FIG. 1D is described in conjunction with the elements of FIGS. 1A, 1B and 1C. Referring to fig. 1D, an enlarged cross-sectional view of a capillary structure (e.g., capillary structure 112 of fig. 1A) of a heat pipe 100D is shown, the heat pipe 100D including a third layer 118, a hollow structure 102, a flexible conveying section 108, a first layer 114, and a second layer 116. The third layer 118 is similar to the first layer 114 and the second layer 116.

According to one embodiment, the capillary structure 112 further includes a third layer 118 vertically disposed between the first layer 114 and the second layer 116. In one implementation, the first layer 114 of the capillary structure 112 (of fig. 1A) is disposed on the bottom surface of the evaporator end 104 and similarly disposed on the bottom surface of the condenser end 106. Further, the second layer 116 of capillary structure 112 is disposed on the upper surface of evaporator end 104 and similarly disposed on the upper surface of condenser end 106. However, the second layer 116 is not disposed directly on the first layer 114, but rather the third layer 118 of the capillary structure 112 is disposed vertically between the first layer 114 and the second layer 116. In one example, the third layer 118 results in an increase in the height of the capillary structure 112, for example a resulting height of 3.0mm and a resulting width of 11.5mm. Thus, the third layer 118 provides a wide range of structural parameters (i.e., increased height and width of the capillary structure 112) for the heat pipe 100D, which is advantageous in providing thermal efficiency and mechanical support for the heat pipe 100D.

Fig. 1E is an enlarged cross-sectional view of a capillary structure of a heat pipe according to another embodiment of the present invention. FIG. 1E is described in conjunction with the elements of FIGS. 1A, 1B, 1C and 1D. Referring to fig. 1E, an enlarged cross-sectional view of a capillary structure of a heat pipe 100E (e.g., capillary structure 112 of fig. 1A) is shown, the heat pipe 100E including a fourth layer 120, a hollow structure 102, a flexible conveying section 108, a first layer 114, a second layer 116, and a third layer 118. The fourth layer 120 is similar to the third layer 118.

In one implementation, the capillary structure of heat pipe 100E (e.g., capillary structure 112 of fig. 1A) includes a fourth layer 120 and a third layer 118, such as fourth layer 120 and third layer 118 disposed vertically between first layer 114 and second layer 116. In one example, the fourth layer 120 is the same size as the third layer 118. Advantageously, each of the fourth layer 120 and the third layer 118 provides mechanical support for the heat pipe 100E as well as a wide range of structural parameters (i.e., increased height and width of the capillary structure 112), which is beneficial for further improving the thermal efficiency of the heat pipe 100E.

Fig. 2 is a block diagram of an electronic device provided by an embodiment of the invention. Fig. 2 is described in conjunction with the elements of fig. 1A. Referring to FIG. 2, a block diagram 200 of an electronic device 202 including one of heat pipes 100A, 100B, 100C, 100D, and 100E is shown.

The electronic device 202 referred to herein includes (i.e., incorporates) a heat pipe 100A. Electronic device 202 may also be referred to as an electronic device that includes various components (or electronic components) including passive or active components, semiconductors, interconnects, contact pads, transistors, diodes, light emitting diodes, etc., which are connected to form an integrated circuit to perform tasks. For example, electronic device 202 may include, but is not limited to, a notebook computer, a cell phone, a desktop computer, a smart phone, a mobile tablet, a camera, a printer, a radio, and the like. Further, the electronic device 202 may be a foldable device that may be folded during operation. The different components of the electronic device 202 may generate heat, and thus the electronic device 202 may require a cooling system to improve reliability and prevent premature failure of the electronic device 202.

In another aspect, the present invention provides an electronic device 202 that includes a heat pipe 100A. Heat pipe 100A (of fig. 1A) is used as part of a cooling system for electronic device 202. The heat pipe 100A is placed near a heat generating component of the electronic device 202 to conduct heat from the electronic device 202, thereby keeping the electronic device 202 at a low temperature. In one example, the electronic device 202 is foldable, so the heat pipe 100A may bend with the electronic device 202 and not break when the electronic device 202 is folded. Furthermore, the heat pipe 100A provides efficient heat transfer even in the folded state of the electronic device 202. The heat pipe 100A with the hollow structure 102 also provides balanced flexibility, longevity, and vibration damping for the electronic device 202. Further, the electronic device 202 may include one of the heat pipes 100B, 100C, 100D, and 100E (fig. 1B-1E, respectively).

Modifications may be made to the embodiments of the invention described above without departing from the scope of the invention, as defined in the appended claims. Expressions such as "comprising," "combining," "having," "being/being" and the like, which are used to describe and claim the present invention, are intended to be interpreted in a non-exclusive manner, i.e. to allow for items, components or elements that are not explicitly described to exist as well. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments, or to exclude features from other embodiments. The word "optionally" as used herein means "provided in some embodiments and not provided in other embodiments. It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as in any other described embodiment of the invention.

Claims

1. A heat pipe (100A, 100B, 100C, 100D, 100E) for an electronic assembly, comprising:

-a hollow structure (102) having an evaporation section (104), a condensation section (106) and a flexible transport section (108) formed between the evaporation section (104) and the condensation section (106), wherein a steam channel (110) is defined by a section of the hollow structure (102);

-a capillary structure (112) arranged within the hollow structure (102), wherein the capillary structure (112) is at least partially in direct contact with the inner surfaces of the evaporation section (104) and the condensation section (106) and freely suspended in the flexible conveying section (108).

2. The heat pipe (100A, 100B, 100C, 100D, 100E) of claim 1, wherein the flexible conveying section (108) is in fluid communication with the evaporator section (104) and the condenser section (106).

3. The heat pipe (100A, 100B, 100C, 100D, 100E) of claim 1 or 2, wherein the capillary structure (112) comprises at least two layers of sintered discrete metal fibers.

4. A heat pipe (100A, 100B, 100C, 100D, 100E) according to claim 3, characterized in that a first layer (114) of the capillary structure (112) is provided on a bottom surface and a second layer (116) is provided on upper surfaces of the evaporation section (104) and the condensation section (106).

5. The heat pipe (100A, 100B, 100C, 100D, 100E) of claim 4, wherein the second layer (116) is disposed on top of the first layer (114) by a sintering process.

6. The heat pipe (100A, 100B, 100C, 100D, 100E) of claim 3 or 4, wherein the capillary structure (112) further comprises a third layer (118) disposed vertically between the first layer (114) and the second layer (116).

7. The heat pipe (100A, 100B, 100C, 100D, 100E) according to any of the preceding claims, wherein the thickness of the capillary structure (112) is selected from a value in the range of 0.001mm to 10 mm.

8. The heat pipe (100A, 100B, 100C, 100D, 100E) according to any one of the preceding claims, wherein the hollow structure (102) is made of a single piece of thermally conductive material, wherein the evaporation section (104) and the condensation section (106) are configured flat, the flexible conveying section (108) being corrugated to provide flexibility.

9. The heat pipe (100A, 100B, 100C, 100D, 100E) of claim 8, wherein the thermally conductive material is one of copper, steel, or silver.

10. The heat pipe (100A, 100B, 100C, 100D, 100E) according to any one of the preceding claims, wherein the capillary structure (112) is connected to the inner surfaces of the evaporator section (104) and the condenser section (106) by a sintering process.

11. The heat pipe (100A, 100B, 100C, 100D, 100E) according to any of the preceding claims, wherein both ends of the heat pipe (100A, 100B, 100C, 100D, 100E) are vacuum sealed.

12. An electronic device (202) characterized by comprising a heat pipe (100A, 100B, 100C, 100D, 100E) according to any of claims 1 to 11.