CN102748971A - Flexible heat conduction device based on low-melting-point metal joint - Google Patents

Abstract

A flexible heat conduction device based on low-melting-point metal joints, which is composed of N flexible pipe-type liquid metal joints and (N+1) heat pipes; the N is a positive integer of 1 to 9; the heat pipes are connected to the Both ends of the flexible pipe liquid metal joint; the flexible pipe liquid metal joint stores a low melting point metal with high thermal conductivity and liquid state at room temperature; Pipeline liquid metal joints realize heat transfer. Because the low-melting point metal has high thermal conductivity, the device can achieve efficient heat transfer performance; at the same time, the flexible liquid metal connection can ensure the flexible bending of the entire heat-conducting device; the invention has simple structure, excellent thermal conductivity, and bending flexibility High, can be used in notebook computers, mobile phones, servers and other IT and aerospace thermal management fields.

Description

A flexible heat conduction device based on low melting point metal joints

technical field

The invention relates to a heat conduction device, in particular to a flexible heat conduction device based on low melting point metal joints.

Background technique

Flexible heat conduction devices are generally used in occasions where there is relative movement at both ends of the heat transfer. For example, when a space satellite is in operation, there is mechanical vibration or movement between some heating elements and the radiation plate, so a flexible heat pipe is required to realize heat conduction (CN 200610063418.2). A flexible heat pipe generally consists of a flexible pipe connecting two rigid pipes. In order to ensure the free return of condensed liquid, capillary structures and support structures must be arranged in flexible pipes. However, the capillary structure greatly limits the bending flexibility of the pipe, and when the bending degree is greater than 90 degrees, it is easy to cause difficulty in liquid reflux and even failure of the heat pipe.

In addition, in the field of chip heat dissipation, IBM invented a heat conduction hinge device (US5796581) to realize the heat transfer from the CPU in the notebook computer to the liquid crystal backplane for heat dissipation. In this device, the two heat pipes are connected by a rotatable metal mechanical hinge. On the one hand, the hinge can meet the requirements of heat conduction between the two heat pipes, and at the same time, it can realize the relative rotation of the two heat pipes along the center line of the hinge, so the opening and closing of the LCD screen is not easy. Affected. However, the heat conduction through the hinge is solid-solid heat conduction, the contact thermal resistance is large, and the heat transfer efficiency is low. Moreover, the hinge can only realize one degree of freedom of rotation along the center line, and the flexibility is relatively poor.

Generally speaking, the above-mentioned flexible heat conduction device has the following disadvantages: (1) The flexible pipe part of the flexible heat pipe must be arranged with a capillary structure, which limits the bending flexibility of the flexible pipe section, and the heat pipe is prone to failure when the bending degree is greater than 90 degrees; ( 2) The metal mechanical hinge mechanism can only realize the solid-solid heat conduction between the two heat pipes, the contact thermal resistance is large, and the heat transfer efficiency is low. At the same time, the hinge can only realize one degree of freedom of rotation, and the flexibility is low. Therefore, finding more efficient flexible heat conduction methods and obtaining flexible heat conduction devices with strong thermal conductivity and high rotation flexibility are still problems that need to be solved urgently in the industry.

Contents of the invention

The object of the present invention is to provide a flexible heat conduction device based on low-melting-point metal joints, that is, the two ends of the flexible pipe-type liquid metal joints that are equipped with low-melting-point metals that are liquid at room temperature are respectively connected to heat pipes to realize heat passing through the flexible heat pipe from one end. The pipe-type liquid metal joint reaches the heat pipe at the other end for efficient heat conduction; at the same time, the flexible pipe-type liquid metal joint filled with liquid metal can ensure the flexible bending of the heat conduction device, is anti-vibration, and can realize the function of free movement at both ends of heat transfer.

Technical scheme of the present invention is as follows:

The flexible pipe type liquid metal joint provided by the present invention, as shown in Figure 1, consists of N flexible pipe type liquid metal joints and (N+1) heat pipes; said N is a positive integer of 1 to 9, and said The heat pipes are connected to both ends of the flexible pipe-type liquid metal joint; the feature is that the pipe of the flexible pipe-type liquid metal joint stores a low-melting-point metal that is liquid at room temperature.

As shown in Figure 1, when N=1, the operation process of the device is: the first heat pipe 1 connected to one end of the flexible pipe type liquid metal joint 3 absorbs the heat of the heat source, and then through the heat conduction of the flexible pipe type liquid metal joint 3, the heat reaches the end of the flexible pipe type liquid metal joint 3. The other end of the flexible pipe-type liquid metal joint 3 is connected to the second heat pipe 2 and finally transferred out to realize the relay heat transfer function.

The capillary structure of the first heat pipe 1 and the second heat pipe 2 can be wire mesh type, groove type, powder sintered type or fiber type. Powder sintered heat pipes are preferred because of their highest heat transfer efficiency.

The pipe material of the first heat pipe 1 and the second heat pipe 2 can be aluminum, copper, stainless steel, nickel or Inconel. The selection of heat pipe tubes is related to the selection of low-melting-point metals, and the compatibility between low-melting-point metals and tubes must be ensured. If the low-melting-point metal is a gallium-based alloy, the heat pipe can be made of copper, stainless steel, nickel or nickel-plated aluminum tube, nickel-plated copper tube, etc.

The pipe material of the flexible pipe type liquid metal joint 3 can be polyethylene, polyvinyl chloride, polypropylene, polybutene, ABS engineering plastics, polyurethane, stainless steel bellows, stainless steel braid, etc.

The low melting point metal is sodium, potassium, lithium, rubidium, cesium, mercury, gallium, lead-bismuth alloy, gallium-based alloy, indium-based alloy, bismuth-based alloy, mercury-based alloy or sodium-potassium alloy with a melting point below 60°C . Among them, gallium-based alloy is the best choice because of its low melting point, non-toxicity, stable properties, and not easy to evaporate and leak.

Multiple flexible heat conduction devices can be cascaded in order to form a multi-stage flexible heat conduction device with multiple heat pipes and multiple flexible pipe-type liquid metal joints (see embodiment 2). The multi-level flexible heat conduction device can realize more flexible arrangement and bending.

The flexible heat conduction device based on low-melting-point metal joints of the present invention uses the first heat pipe 1 to absorb the heat from the heat source, and then releases the heat to the liquid metal joints. After heat conduction in the liquid metal joints, the heat finally reaches the second heat pipe 2 and is transferred. Go out to realize the heat transfer function of the relay type.

The flexible heat conduction device based on low melting point metal joints of the present invention has the following advantages:

(1) Strong thermal conductivity. Both the heat pipe and the liquid metal have extremely high thermal conductivity. At the same time, the contact between the heat pipe and the liquid metal is solid-liquid contact, and the contact thermal resistance is small, which can ensure high heat transfer efficiency; (2) High flexibility. The flexible hose filled with liquid metal can flexibly move, rotate, and bend to meet various movement needs at both ends of heat transfer. (3) The structure is simple and easy to implement. The invention can be widely used in IT, photoelectricity and aerospace heat management fields such as notebook computers, LEDs, mobile phones and servers.

Description of drawings

Accompanying drawing 1 is a schematic diagram of a flexible heat conduction device based on a low melting point metal joint;

Accompanying drawing 2 is a schematic diagram of a low-melting-point metal flexible heat conduction device applied to a notebook computer;

Accompanying drawing 3 is the structural diagram of the multi-stage flexible heat conduction device based on the low-melting point metal joint.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

The flexible heat conduction device based on the low-melting-point metal joint provided by the invention can be used for heat dissipation of electronic devices such as notebook computers and mobile phones. Figure 2 shows a schematic diagram of the structure of the low-melting-point metal flexible heat conduction device that conducts heat from the CPU of the laptop to the liquid crystal backplane for heat dissipation.

It can be seen from Fig. 1 that the flexible heat conduction device based on low-melting-point metal joints of the present invention is composed of N flexible pipe-type liquid metal joints and (N+1) heat pipes; said N is a positive integer ranging from 1 to 10, so The above-mentioned heat pipes are connected to both ends of the flexible pipe-type liquid metal joint; the pipes of the flexible pipe-type liquid metal joint store liquid low melting point metal at room temperature.

In the embodiment shown in Figure 1, N=1, that is, the flexible heat conduction device based on the low melting point metal joint of this embodiment consists of a flexible pipe type liquid metal joint 3 and two ends connected to the flexible pipe type liquid metal joint 3 The first heat pipe 1 and the second heat pipe 2 are composed; the pipe of the flexible pipe type liquid metal joint 3 stores a low melting point metal with high thermal conductivity and liquid state at room temperature.

Fig. 2 is a schematic diagram of a low-melting-point metal flexible heat conduction device applied to a notebook computer. It can be seen from Fig. 2 that the first heat pipe 1 absorbs the heat of the CPU 4, and then releases the heat to the flexible pipe type liquid metal joint 3, passing through the liquid metal joint 3 therein. Heat conduction, the heat finally reaches the second heat pipe 2 and is transferred to the liquid crystal backplane 5 for heat dissipation. Because the flexible pipe-type liquid metal joint 3 filled with low-melting point metal has a high degree of bending freedom, the opening and closing of the liquid crystal back panel is not affected, and the switch is free.

The capillary structure of the first heat pipe 1 and the second heat pipe 2 can be wire mesh type, groove type, powder sintered type or fiber type. In this embodiment, a powder sintered heat pipe is used.

The pipe material of the first heat pipe 1 and the second heat pipe 2 can be aluminum, copper, stainless steel, nickel or Inconel. In this embodiment, copper pipes are used.

The pipe material of the flexible pipe type liquid metal joint 3 can be polyethylene, polyvinyl chloride, polypropylene, polybutene, ABS engineering plastics, polyurethane, stainless steel bellows, stainless steel braid, etc. In this embodiment, polyethylene is used as the flexible hose material.

The low melting point metal is sodium, potassium, lithium, rubidium, cesium, mercury, gallium, lead-bismuth alloy, gallium-based alloy, indium-based alloy, bismuth-based alloy, mercury-based alloy or sodium-potassium alloy with a melting point below 60°C . In this embodiment, the gallium-based alloy Ga ₆₁ In ₂₅ Sn ₁₃ Zn ₁ (61% Ga, 25% In, 13% Sn, 1% Zn by mass percentage) is selected.

Using the low-melting-point metal flexible heat conduction device in Figure 2 can achieve: (1) efficient transport of CPU heat to the LCD backplane; (2) free opening and closing of the LCD screen will not be affected.

Example 2:

As shown in Figure 3, the flexible heat conduction device based on low melting point metal joints provided by the present invention can be cascaded sequentially to form a multi-stage flexible heat conduction device with multiple heat pipes and multiple flexible pipeline liquid metal joints; multi-stage flexible heat conduction The device allows for more flexible placement and bending.

N=2 in this embodiment, that is: three heat pipes (the first heat pipe 1, the second heat pipe 2, the third heat pipe 4) and two flexible pipe type liquid metal joints (the first flexible pipe type liquid metal joint 3, the second Flexible pipe type liquid metal joint 5); the first heat pipe 1, the first flexible pipe type liquid metal joint 3, the second heat pipe 2, the second flexible pipe type liquid metal joint 5 and the third heat pipe 4 are sequentially connected to form a three-stage type Flexible heat transfer device.

Both the pipes of the first flexible pipe type liquid metal joint 3 and the pipes of the second flexible pipe type liquid metal joint 5 store low melting point metals that have high thermal conductivity and are liquid at room temperature.

When in use, the first heat pipe 1 absorbs the heat of the heat source, then releases the heat to the liquid metal in the first flexible pipe type liquid metal joint 3, and then transfers the heat to the second heat pipe 2 and the second flexible pipe type liquid metal joint 5, And finally transferred to the third heat pipe 4; because there are two sections of flexible pipes, the device has a higher degree of flexibility and can meet the needs of multiple bending.

The capillary structure of the first heat pipe 1 , the second heat pipe 2 and the third heat pipe 4 can be wire mesh type, groove type, powder sintered type or fiber type; groove type heat pipes are used in this embodiment.

The pipe material of the first heat pipe 1 , the second heat pipe 2 and the third heat pipe 4 can be aluminum, copper, stainless steel, nickel or Inconel alloy; in this embodiment, stainless steel pipe material is used.

The pipe material of the first flexible pipe type liquid metal joint 3 and the second flexible pipe type liquid metal joint 5 can be polyethylene, polyvinyl chloride, polypropylene, polybutene, ABS engineering plastics, polyurethane, stainless steel bellows , stainless steel braid, etc.; in this embodiment, polyurethane is used as the flexible hose material.

Low melting point metals are sodium, potassium, lithium, rubidium, cesium, mercury, gallium, lead-bismuth alloys, gallium-based alloys, indium-based alloys, bismuth-based alloys, mercury-based alloys or sodium-potassium alloys with melting points below 60°C; In this example, sodium potassium alloy Na ₂₂ K ₇₈ (22% Na, 78% K by mass percentage) is selected.

By analogy, N can be 1 to 9; multi-stage flexible heat conduction devices can be formed. Due to the existence of multi-segment flexible pipeline liquid metal joints, the flexible heat conduction device based on low melting point metal joints of the present invention is more flexible and can meet The need for multiple bends.

In the present invention, the selection of low-melting point metal materials is as follows: sodium, potassium, lithium, rubidium, cesium, mercury, gallium, lead-bismuth alloy, gallium-based alloy, indium-based alloy, bismuth-based alloy, mercury-based alloy or sodium-potassium alloy are applicable. Among them, gallium-based alloys, indium-based alloys, and bismuth-based alloys are the best choices because of their advantages of non-toxicity, stable properties, and difficulty in evaporation and leakage. Sodium, potassium, lithium, rubidium, cesium, and sodium-potassium alloys are chemically active and must be used in a well-packaged environment to isolate air and water. Mercury and its alloys are low in cost, but because of their toxicity, they must be well packaged before they can be used.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent replacements to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all of them should be included in the scope of the present invention. within the scope of the claims.

Claims (5)

1. flexible heat-transfer device based on the low-melting-point metal joint, it is made up of N root flexible duct formula liquid metals joint and (N+1) root heat pipe; Said N is 1～9 positive integer, and described heat pipe is communicated in the two ends in said flexible duct formula liquid metals joint; It is characterized in that, store the low-melting-point metal that is in a liquid state under the room temperature in the pipeline in described flexible duct formula liquid metals joint.

2. by the described flexible heat-transfer device of claim 1, it is characterized in that the capillary structure of said heat pipe is silk screen type, groove-shaped, powder sintered type or fibrous type based on the low-melting-point metal joint.

3. by claim 1 or 2 described flexible heat-transfer devices, it is characterized in that the material of said heat pipe is aluminium, copper, stainless steel, nickel or Inconel based on the low-melting-point metal joint.

4. by the described flexible heat-transfer device of claim 1, it is characterized in that the pipe material in said flexible duct formula liquid metals joint is polyethylene, polyvinyl chloride, polypropylene, polybutene, ABS engineering plastics or polyurethane based on the low-melting-point metal joint.

5. by the described flexible heat-transfer device of claim 1 based on the low-melting-point metal joint; It is characterized in that the low-melting-point metal that is in a liquid state under the described room temperature is that fusing point is at the sodium below 60 ℃, potassium, lithium, rubidium, caesium, mercury, gallium, lead bismuth alloy, gallium-base alloy, indium-base alloy, bismuth-base alloy, mercury-base alloy or Na-K alloy.

Images